Hotspots and comparative analysis of international acupuncture research over the past decade via Web of Science

1.   Introduction

Acupuncture is an ancient Chinese treatment that has been systematically used for over 3 000 years ^[1]. In the past decade, acupuncture has received wide attention in Asia, North America, Europe, Oceania, and other countries and regions. Acupuncture research has also developed rapidly during this period, and the relevant articles published reflect its evolution process ^{[2, 3]}.

In order to comprehensively understand the application of acupuncture in China and abroad, the relevant research on acupuncture in China and abroad was sorted out and compared to summarize and predict the application status and development trend of acupuncture. This study mainly adopts the CiteSpace 6.1.R3 visualization tool to systematically study the published information of acupuncture literature retrieved from the Web of Science database in recent 10 years, in order to reveal the current status and trends of international acupuncture research.

2.   Data and methods

2.1   Data sources

This study used the Web of Science database as the data source, with specific search formulas as shown below set for the time span from January 1, 2012 to December 31, 2021. The “CU” is a specific field tag in the Web of Science advanced search. Papers with Chinese and non-Chinese authors collaborating were included in China's scope due to searching formula restrictions.

The search strategy for experimental research on acupuncture in China is as follows: TS = [“acupuncture” AND (“rat” OR “rats” OR “dog” OR “dogs” OR “mice” OR “horse” OR “veterinarian” OR “veterinary” OR “animal” OR “mouse model” OR “rabbit” OR “cat”) NOT (“human” OR “clinical trial” OR “meta-analysis”)] AND CU = (“China”).

The search strategy for clinical research on acupuncture in China is as follows: TS = [“acupuncture” AND(“clinical trial” OR “clinical-trial” OR “case reports” OR “randomized clinical-trial” OR “randomized controlled trial” OR “randomized clinical trial” OR “randomized study” OR “in patient” OR “women” OR “randomized, parallel” OR “randomized trial” OR “a comparative clinical pilot study” OR “a prospective observational study” OR “meta-analysis” OR “meta analysis” OR “children” OR “a randomized crossover” OR “investigation” OR “double-blind” OR “double blind” OR “single-blind” OR “a pilot study” OR “elderly person” OR “systematic review” OR “prospective survey” OR “a feasibility study” OR “volunteers” OR “treat” OR “efficacy” OR “controlled trial” OR “trial” or “clinical trials” OR “Cochrane review” OR “cohort of” OR “healthy human” OR “healthy subjects” OR “people”)] AND CU = (“China”).

The search strategy for experimental research on acupuncture abroad is as follows: TS = [“acupuncture” AND (“rat” OR “rats” OR “dog” OR “dogs” OR “mice” OR “horse” OR “veterinarian” OR “veterinary” OR “animal” OR “mouse model” OR “rabbit” OR “cat”) NOT (“human” OR “clinical trial” OR “meta-analysis”)] NOT CU= (“China”).

The search strategy for clinical research on acupuncture abroad is as follows. TS = [“acupuncture” AND (“clinical trial” OR “clinical-trial” OR “case reports” OR “randomized clinical-trial” OR “randomized controlled trial” OR “randomized clinical trial” OR “randomized study” OR “in patient” OR “women” OR “randomized, parallel” OR “randomized trial” OR “a comparative clinical pilot study” OR “a prospective observational study” OR “meta-analysis” OR “meta analysis” OR “children” OR “a randomized crossover” OR “investigation” OR “double-blind” OR “double blind” OR “single-blind” OR “a pilot study” OR “elderly person” OR “systematic review” OR “prospective survey” OR “a feasibility study” OR “volunteers” OR “treat” OR “efficacy” OR “controlled trial” OR “trial” or “clinical trials” OR “Cochrane review” OR “cohort of” OR “healthy human” OR “healthy subjects” OR “people”)] AND CU = (“China”).

2.2   Inclusion criteria

(i) Articles on acupuncture research obtained through retrieval on the Web of Science.

(ii) Types of articles: original research articles, reviews, conference proceedings, and online articles.

(iii) Time of publication: January 1, 2012 to December 31, 2021.

(iv) Language: English.

2.3   Exclusion criteria

(i) Articles that required manual searching.

(ii) Corrected papers and book chapters.

(iii) Duplicate articles.

(iv) Articles unrelated to acupuncture research.

2.4   Data specification and collection

First, the name of each institution was unified as the first-level name of the institution. For example, “School of Acupuncture-Moxibustion and Tuina, Beijing University of Chinese Medicine” was standardized as “Beijing University of Chinese Medicine”. Second, the name of the country was unified into the official name. For example, “PEOPLES R CHINA” was standardized as “China”. Finally, the included literature in the RefWorks format in the Web of Science was exported and imported into CiteSpace 6.1.R3 software for format conversion after being renamed “download_.txt”.

2.5   Data analysis

CiteSpace 6.1.R3 is a multivariate, time-sharing, and dynamic knowledge-mapping tool ^[4]. For the software parameter settings, the time span was set from January 1, 2012 to December 31, 2021, and the time partition was one year as a unit under the “Time Slicing” module. In the formed knowledge map, different nodes represent different authors or countries, and the size of nodes or fonts reflects their productivity. The connection strength between nodes indicates the cooperation strength between countries and authors. Additionally, the CiteSpace algorithm is used to cluster keywords into different groups. Each cluster is identified with a different color. The label size of the term indicates the number of acupuncture articles of the term. The articles were stratified and systematically analyzed according to the year of articles, authors, countries, and journals. Furthermore, the references and keywords of articles in China and abroad were assessed and analyzed from clinical and experimental medicine aspects. The research process of this paper is shown in Figure 1.

Figure  1.  Flow chart for the research

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3.   Results

Through searching and screening, there are a total of 1 215 articles in the field of acupuncture experimental medicine, and 3 805 articles in the field of acupuncture clinical medicine in China; 551 articles in the field of acupuncture experimental medicine, and 4 538 articles in the field of in acupuncture clinical medicine abroad. These four parts of the literature have duplicate records, and a total of 9 155 articles were obtained after duplication by CiteSpace software. The data process is shown in Figure 2.

Figure  2.  Flow chart of data procession

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3.1   Analysis of annual articles

The annual changes in the number of articles issued in the field of acupuncture in China and abroad in recent 10 years are shown in Figure 3. It can be seen that the trend of the number of foreign annual articles is stable and flat, with a small fluctuation and an average of 475 articles per year. The number of annual articles in China has shown a trend of gradual growth, with the largest increase in 2020 (an increase of 205 articles compared with the previous year) and an average annual release of 440 articles. By comparison, the cumulative amount of foreign acupuncture research articles has been greater than that of domestic research in the past decade. From 2012 to 2018, the number of foreign acupuncture research articles was higher than that of domestic research articles, and the number gap generally decreased annually. After 2018, the number of domestic acupuncture articles was higher than that of foreign research articles, and the number gap had been increasing annually.

Figure  3.  Annual articles of acupuncture research in China and abroad

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3.2   Analysis of co-authors

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Table  1.  The top 10 high-output authors of acupuncture research during 2012 - 2021

No.	Author	Institution	Country	n (%)
1	LIU Cunzhi	Beijing Hospital of Traditional Chinese Medicine	China	90 (0.98%)
2	Lee Myeong Soo	Korea Institute of Oriental Medicine	South Korea	89 (0.97%)
3	LIU Zhishun	China Academy of Chinese Medical Sciences	China	80 (0.87%)
4	LAO Lixing	University of Hong Kong	China	75 (0.82%)
5	LIANG Fanrong	Chengdu University of Traditional Chinese Medicine	China	68 (0.74%)
6	Park Hi Joon	Kyung Hee University	South Korea	61 (0.67%)
7	LI Ying	Chengdu University of Traditional Chinese Medicine	China	59 (0.64%)
8	YANG Jingwen	Hefei University of Technology	China	57 (0.62%)
9	SHI Guangxia	Beijing University of Chinese Medicine	China	50 (0.55%)
10	ZHAO Ling	Chengdu University of Traditional Chinese Medicine	China	49 (0.54%)

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The cooperation of authors in the field of acupuncture research is shown in Figure 4. We imported the research literature into CiteSpace 6.1.R3 software, then selected “author” for the node and the top n was set to 20, selected “pruning the merged network” for the pruning algorithm, and finally drew the knowledge map. It can be seen that in the knowledge map, network structure of four author collaboration group are mainly formed, namely, the network structure centered on Kim Tae-hun from Kyung Hee University, with the research focusing on the acupuncture treatment scheme of chronic kidney disease and the systematic review of acupuncture clinical research ^{[5, 6]}; the network structure centered on Lee Myeong Soo from Korea Institute of Oriental Medicine and Park Hi Joon from Kyung Hee University, with the research focusing on systematic summary of acupuncture treatment of gynecological diseases and low back pain ^{[7, 8]}; the network structure centered on LIANG Fanrong and LI Ying from Chengdu University of Traditional Chinese Medicine, with research focusing on the experimental study of acupuncture and treatment of primary dysmenorrhea and migraine ^{[9, 10]}; the network structure centered on LIU Cunzhi from Beijing Hospital of Traditional Chinese Medicine affiliated to Capital Medical University and WANG Liqiong from Beijing University of Chinese Medicine, with the research focusing on the effect of acupuncture and related symptoms after stroke ^[11].

Figure  4.  Co-occurrence network of authors in the acupuncture research field

The nodes in the figure indicate the authors. The lines between the nodes’ indicate collaborative relationships; the thicker the line the more collaboration, and the darker the line the older it is.

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3.3   Analysis of countries

From 2012 to 2021, 95 countries and regions participated in acupuncture research, with the high contributing countries and regions shown in Table 2 and Figure 5. China had the highest number of articles (4 844, 52.91%), followed by the USA (1 710, 18.68%) and South Korea (964, 10.53%). England contributed 472 articles, accounting for 5.16%, while other countries accounted for less than 5%. However, countries with a high volume of articles do not have many collaborative links, and those with fewer articles have closer collaborative links.

Table  2.  The top 10 high-output countries in acupuncture research during 2012 - 2021

No.	Country	n (%)
1	China	4 844 (52.91%)
2	USA	1 710 (18.68%)
3	South Korea	964 (10.53%)
4	England	472 (5.16%)
5	Australia	417 (4.55%)
6	Germany	313 (3.42%)
7	Brazil	269 (2.94%)
8	Canada	256 (2.80%)
9	Japan	178 (1.94%)
10	Italy	161 (1.76%)

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Figure  5.  National co-occurrence network in the acupuncture research field during 2012 -2021

The nodes in the figure indicate countries, the larger the node the greater the number of articles. The lines between the nodes indicate collaborative relationships. The more connected the lines the closer the collaboration, and the darker the lines the longer the collaboration.

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3.4   Analysis of journals

The top 10 journals following the number of published acupuncture papers are shown in Table 3. The Journal Evidence-based Complementary and Alternative Medicine published the highest number of papers (958, 10.46%), followed by Medical (674, 7.36%) and Acupuncture in Medicine (498, 5.44%), with the other journals publishing under 300 papers. The journal with the largest impact factor was BMC Complementary and Alternative Medicine with an impact factor of 4.782, in the JCR Q1 region, followed by PLoS One (3.752, JCR Q2) and Complementary Therapies in Medicine (3.335, JCR Q2). Among the top 10 journals publishing articles in acupuncture research, four are English journals, four American journals, one German journal, and one Chinese journal.

Table  3.  The top 10 journals publishing articles on acupuncture research during 2012 - 2021

No.	Journal	IF-2021/JCR	Country	n
1	Evidence-based Complementary and Alternative Medicine	2.650/Q3	England	958
2	Medicine	1.817/Q3	US	674
3	Acupuncture in Medicine	1.976/Q3	UK	498
4	Trials	2.728/Q4	US	284
5	Journal of Alternative and Complementary Medicine	2.381/Q3	US	256
6	BMC Complementary and Alternative Medicine	4.782/Q1	UK	224
7	European Journal of Integrative Medicine	1.813/Q4	Germany	169
8	Complementary Therapies in Medicine	3.335/Q2	UK	166
9	Journal of Traditional Chinese Medicine	2.547/Q3	China	166
10	PLoS One	3.752/Q2	US	160

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3.5   Analysis of co-cited references

Highly cited papers provide important information about the current state of research in a field, and help to analyze hotspots and trends in the research field ^[12]. This research produced tables of the top 10 most frequently cited references in literature.

3.5.1   Analysis of co-cited references on experimental acupuncture research in China

The top 10 highly cited papers on experimental acupuncture research in China are shown in Table 4. The most frequently cited paper is a comparative study in the journal Trends in Neurosciences, which investigated the effects of acupuncture and specific frequencies of electrical stimulation on specific neuropeptides in the central nervous system ^[13]. The paper with the highest impact factor (51.598, Q1) is a historical article on acupuncture in Annals of Internal Medicine, which provided a general discussion of the historical origins, theoretical doctrines, and therapeutic effects of acupuncture ^[14]. Other studies focused on model experiments, and mechanistic research of acupuncture analgesia, and electroacupuncture stimulation of nerve receptors.

Table  4.  The top 10 highly co-cited papers in the field of experimental acupuncture research in China

No.	Title	Journal	IF-2021/JCR	Total cites	Year
1	Acupuncture: neuropeptide release produced by electrical stimulation of different frequencies	Trends in Neurosciences	16.978/Q1	79	2003
2	Adenosine A1 receptors mediate local anti-nociceptive effects of acupuncture	Nature Neuroscience	28.771/Q1	70	2010
3	Acupuncture and endorphins	Neuroscience Letters	3.197/Q3	34	2004
4	Quantitative assessment of tactile allodynia in the rat paw	Journal of Neuroscience Methods	2.987/Q3	32	1994
5	Acupuncture: theory, efficacy, and practice	Annals of Internal Medicine	51.598/Q1	28	2002
6	A new model of chronic visceral hypersensitivity in adult rats induced by colon irritation during postnatal development	Gastroenterology	33.883/Q1	26	2000
7	A peripheral mononeuropathy in rat that produces disorders of pain sensation like those seen in man	Pain	7.926/Q1	25	1988
8	Acupuncture analgesia: areas of consensus and controversy	Pain	7.926/Q1	24	2011
9	Acupuncture: a novel hypothesis for the involvement of purinergic signalling	Medical Hypotheses	4.411/Q2	22	2009
10	Electroacupuncture exerts anti-inflammatory effects in cerebral ischemia-reperfusion injured rats via suppression of the TLR4/NF-κB pathway	International Journal of Molecular Medicine	5.314/Q2	21	2013

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3.5.2   Analysis of co-cited references on clinical acupuncture research in China

The top 10 highly cited papers on clinical acupuncture research in China in the last decade are shown in Table 5. The most frequently cited paper with the highest journal impact factor was the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) statement published in the journal BMJ ^[15]. Papers published in the BMJ were the study of the development of Grading of Recommendations Assessment, Development and Evaluation (GRADE) ratings for guideline development ^[16] and of the measurement of inconsistency in meta-analysis ^[17]. All the 10 papers were published in the JCR Q1 journals, and are seminal papers in the field of evidence-based and mechanistic research in acupuncture.

Table  5.  The top 10 highly co-cited papers in the field of clinical acupuncture research in China

No.	Title	Journal	IF-2021/JCR	Total cites	Year
1	Preferred reporting items for systematic review and meta-analysis protocols (PRISMA-P) 2015 statement	BMJ	93.333/Q1	145	2009
2	Cognitive-behavioural interventions for children who have been sexually abused (Review)	Cochrane Database of Systematic Reviews	12.008/Q1	116	2012
3	Acupuncture: neuropeptide release produced by electrical stimulation of different frequencies	Trends in Neurosciences	16.978/Q1	115	2003
4	Acupuncture: theory, efficacy, and practice	Annals of Internal Medicine	51.598/Q1	110	2002
5	Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement	BMJ	93.333/Q1	109	2009
6	Neural mechanism underlying acupuncture analgesia	Progress in Neurobiology	10.885/Q1	109	2008
7	GRADE: an emerging consensus on rating quality of evidence and strength of recommendations	BMJ	93.333/Q1	106	2008
8	Measuring inconsistency in meta-analyses	BMJ	93.333/Q1	104	2003
9	Acupuncture for chronic pain individual patient data meta-analysis	JAMA Internal Medicine	44.409/Q1	104	2012
10	Revised standards for reporting interventions in clinical trials of acupuncture (STRICTA): extending the CONSORT statement	PLoS Medicine	11.613/Q1	103	2010

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3.5.3   Analysis of co-cited references on experimental acupuncture research abroad

The top 10 highly cited papers on experimental acupuncture research abroad in the last decade are shown in Table 6. The most frequently cited and highest journal impact factor was the research on the mechanism of action of adenosine release during acupuncture stimulation published in the journal Nature Neuroscience ^[18]. Nine of the papers in the table were published in the JCR Q1 journals, and one in the JCR Q3 journal (Neuroscience Letters), which provided a systematic review of the mechanisms of endogenous opioid peptides such as endorphins in mediating electroacupuncture analgesia ^[19].

Table  6.  The top 10 highly co-cited papers in the field of experimental acupuncture research abroad

No.	Title	Journal	IF-2021/JCR	Total cites	Year
1	Adenosine A1 receptors mediate local anti-nociceptive effects of acupuncture	Nature Neuroscience	28.771/Q1	63	2010
2	Neural mechanism underlying acupuncture analgesia	Progress in Neurobiology	10.885/Q1	56	2008
3	Acupuncture: neuropeptide release produced by electrical stimulation of different frequencies	Trends in Neurosciences	16.978/Q1	48	2003
4	A proposed transpositional acupoint system in a mouse and rat model	Research in Veterinary Science	2.554/Q1	48	2008
5	Ethical Guidelines for investigations of Experimental Pain in Conscious Animals	Pain	7.926/Q1	30	1983
6	Acupuncture and endorphins	Neuroscience Letters	3.197/Q3	28	2004
7	Mechanisms of acupuncture-electroacupuncture on persistent pain	Anesthesiology	8.986/Q1	27	2014
8	Mechanical signaling through connective tissue: a mechanism for the therapeutic effect of acupuncture	Federation of American Societies for Experimental Biology Journal	5.834/Q1	23	2001
9	Therapeutic application of anti-arthritis, pain-releasing, and anti-cancer effects of bee venom and its constituent compounds	Pharmacol Therapeut	13.400/Q1	23	2007
10	The central serotonergic system mediates the analgesic effect of electroacupuncture on Zusanli (ST36) acupoints	Journal of Biomedical Science	12.771/Q1	22	2004

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3.5.4   Analysis of co-cited references on clinical acupuncture research abroad

The top 10 highly cited papers on clinical acupuncture research abroad in the last decade are shown in Table 7. The most frequently cited was a meta-analysis of studies of acupuncture for chronic pain published in the Archives of Internal Medicine ^[20], and the journal with the highest impact factor was a survey study of trends in the use of alternative medicine in the USA published in 1998 ^[21]. Other acupuncture studies have focused on survey analyses and retrospective studies of patients’ data.

Table  7.  The top 10 highly co-cited papers in the field of clinical acupuncture research abroad

No.	Title	Journal	IF-2021/JCR	Total cites	Year
1	Acupuncture for chronic pain individual patient data meta-analysis	Archives of Internal Medicine	44.409/Q1	254	2012
2	Neural mechanism underlying acupuncture analgesia	Progress in Neurobiology	10.885/Q1	157	2008
3	Acupuncture and endorphins	Neuroscience Letters	3.197/Q3	112	2004
4	German acupuncture trials (GERAC) for chronic low back pain	Archives of Internal Medicine	44.409/Q1	106	2007
5	Introducing a placebo needle into acupuncture research	The Lancet	202.731/Q1	104	1998
6	Safety of acupuncture: results of a prospective observational study with 229 230 patients and introduction of a medical information and consent form	Forschende Komplementarmedizin	1.306/Q4	98	2009
7	Acupuncture: theory, efficacy, and practice	Annals of Internal Medicine	51.598/Q1	94	2002
8	Trends in alternative medicine use in the United States, 1990 -1997 results of a follow-up national survey	JAMA	157.335/Q1	93	1998
9	The impact of patient expectations on outcomes in four randomized controlled trials of acupuncture in patients with chronic pain	Pain	7.926/Q1	93	2007
10	Adenosine A1 receptors mediate local anti-nociceptive effects of acupuncture	Nature Neuroscience	28.771/Q1	91	2010

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3.6   Analysis of co-occurring keywords clusters

Keywords act as high generalization of the content of the literature, which reveals the research focus and contributes to the understanding and analysis of the theme and research content of the whole literature ^[22].

3.6.1   Analysis of keywords clusters on experimental acupuncture research in China

A total of 1 215 articles in the field of experimental acupuncture research in China were retrieved in Web of Science. CiteSpace was introduced to select the keyword latent semantic indexing (LSI) cluster. Further, the results were extracted from the literature keywords, and each cluster was automatically identified. There are 12 clusters, as shown in Table 8 and Figure 6, namely, impairment, neural regeneration, expression, acupuncture analgesia, spinal cord, Alzheimer's disease, stroke, myocardial ischaemia, oxidative stress, rat, gastric motility, and spinal cord injury. The mechanism of acupuncture on nerve regeneration or nerve recovery is an important topic in the research field, and many scholars have established mouse models of spinal cord injury, and conducted randomized controlled trials to explore the mechanism of acupuncture on nerve function recovery at the molecular level from different perspectives ^{[23, 24]}. The mechanism by which acupuncture improves Alzheimer's disease has been another key topic in recent years, and studies have found that acupuncture can improve cognitive status in Alzheimer's disease ^[25], but the mechanism remains unclear. Therefore, this topic has also been the focus of scholars' attention.

Figure  6.  Keywords co-occurrence network in the field of experimental acupuncture research in China

The nodes in the graph indicate keywords, and different colors of the blocks and nodes’ indicate different clusters. The lines between the nodes’ indicate co-occurrence relationships; the thicker the line, the stronger the correlation.

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Table  8.  Clustering table of keyword co-occurrence network in the field of experimental acupuncture research in China

Cluster ID	Size	Year	Terms (LSI)
0	27	2013	Acupuncture; analgesia; stimulation; involvement; mechanical allodynia; mechanism; impairment; electrical stimulation; myoelectrical activity; improves dyspeptic symptom
1	23	2013	Neural regeneration; nerve regeneration; traditional Chinese medicine; dorsal cord; upper cervical cord; grants-supported paper; irritable bowel syndrome; peripheral nerve injury; visceral hypersensitivity; photographs-containing paper
2	22	2013	Activation; acupuncture; mechanism; neuropathic pain; contribute; expression; pathway; protein degradation; atrophy; proteolysis
3	22	2014	Stimulation; electroacupuncture; pain; efficacy; preventing nausea; acupuncture; cerebral ischemia; moxibustion; acupoint; hippocampal
4	21	2015	Spinal cord; neuropathic pain; P2X4 receptor; chronic visceral hyperalgesia; Sanhuangshuai Decoction; mechanism; expression; activation; guideline; hyperalgesia
5	20	2015	Alzheimer’s disease; adenosine monophosphate-activated kinase; vascular dementia; Crohn’s disease; thioredoxin-interacting protein; brain; acupuncture; seizure; intractable epilepsy; rat model
6	20	2013	Acupuncture; receptor; electroacupuncture; in vivo; nerve stimulation; stroke; differentiation; expression; focal cerebral ischemia; proliferation
7	19	2013	Neuropathic pain; involvement; acupuncture; inflammatory pain; analgesia; cumulative effect; acupuncture analgesia; chronic neuropathic pain; memory impairment; cholinergic activities
8	18	2012	Oxidative stress; nucleus pulposus cell; intervertebral disc degeneration; cannabinoid type; exercise intensity; nerve regeneration; neural regeneration; ludmila belayev test; acupuncture treatment; tunel assay
9	17	2014	Electroacupuncture; pain; efficacy; sevoflurane; droperidol; acupuncture; stimulation; expression; inhibition; distension
10	16	2014	Acupuncture; inhibition; gastric motility; heterotopic acupoint; efficacy; electroacupuncture; protect; activation; ferroptosis; mediated autophagy
11	12	2015	Spinal cord injury; inflammatory response; erythroid 2-related factor; oxidative stress; nuclear factor; pathway; rat model; mouse; cyclase; hippocampus

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3.6.2   Analysis of keywords clusters on clinical acupuncture research in China

There are 3 805 articles of clinical acupuncture research in China in the recent decade. The keyword clustering yielded Figure 7 and Table 9, with the 15 clusters in the chart as follows: stroke, acupuncture therapy, frmi, clinical trial, in vitro fertilization, heart rate variability, neuropathic pain, systematic review, validation, Alzheimer's disease, electrical stimulation, relief, cortex, cell, and neural regeneration. Acupuncture for neuropathic pain, a common symptom, is a research topic. Several retrospective studies have shown that acupuncture plays a role in relieving pain associated with such lesions of the somatosensory system ^[26–28], but the quantity and quality of evidence are insufficient and further research is warranted. Acupuncture for dysfunctional disorders is a hot topic in this area of research, with studies demonstrating its efficacy in improving functional dyspepsia ^[29], cognitive disorders ^[30], and infertility ^[31].

Figure  7.  Keywords co-occurrence network of clinical acupuncture research in China

The nodes in the graph indicate keywords, and different colors of the blocks and nodes’ indicate different clusters. The lines between the nodes’ indicate co-occurrence relationships; the thicker the line, the stronger the correlation.

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Table  9.  Cluster of keyword co-occurrence network of clinical acupuncture research in China

Cluster ID	Size	Year	Terms (LSI)
0	43	2016	Systematic review; transcutaneous electrical acupoint stimulation; cognitive function; postoperative cognitive dysfunction; maintenance disorders; controlled trial; recovery; pain; clinical trial; surgery
1	36	2016	Systematic review; auricular acupuncture; cancer-related depression; electrical acupuncture; general anesthesia; acupuncture therapy; controlled trials; maintenance disorders; sleep initiation; electrical acupuncture
2	36	2015	Stimulation; electroacupuncture; pain; efficacy; preventing nausea; functional magnetic resonance imaging; systems biology; Chinese herbal medicine; gastrointestinal disorder; Huiyang Shengji Formula
3	30	2015	Clinical trial; sensorineural tinnitus; pre-frontal cortex; Chinese herbal medicine; brain function; controlled trial; pre-frontal cortex; Chinese herbal medicine; Brain function; spinal column
4	30	2015	Systematic review; female infertility; risk assessment; subacute pain; sex hormone level; vitro fertilization; embryo transfer; clinical pregnancy rate; physiological rats; pituitary-ovary axis
5	28	2016	Functional dyspepsia; irritable bowel syndrome; functional constipation; functional gastrointestinal disorders; point; Parkinson's disease; iron accumulation; chronic visceral hyperalgesia; sham acupuncture; coronary artery disease
6	28	2015	Acupuncture; fatigue; quality; acupressure; insomnia; neuropathic pain; spinal cord; airway inflammation; risk assessment; interacting protein kinase
7	27	2016	Systematic review; risk assessment; posterior circulation ischemia; of-flight mass spectrometry; Chinese herbal medicine; polycystic ovary syndrome; insulin resistance; insulin sensitivity; sham acupuncture; homeostasis model assessment
8	27	2014	Controlled trial; acupuncture; involvement; adjunctive therapy; model; efficacy; electroacupuncture; stimulation; pain; preventing nausea
9	26	2015	Alzheimer’s disease; adenosine monophosphate-activated kinase; memory; network meta-analysis; multiple interventions; vascular dementia; cognitive impairment; expert consensus; breast cancer; pituitary gland
10	26	2015	Acupuncture; stroke; treatment; meta-analysis; insomnia; acupoint; nausea; relaxation; risk; acupressure
11	25	2015	Systematic review; phantom limb syndrome; phantom limb sensation; transcutaneous electric nerve stimulation; phantom limb pain; acupuncture; exercise; metaanalysis; pain; mobility
12	23	2016	Cortex; modulation; network; stimulation; therapy; complementary medicine; alternative medicine; functional connectivity; resting-state functional magnetic resonance; functional network
13	23	2016	Acupuncture; cell; histamine; transduction; lipid peroxidation; expression; pain; interleukin 1 production; st36; cyclooxygenase 2
14	23	2015	Neural regeneration; nerve injury; cerebral palsy; botulinum toxin; constraint-induced movement therapy; nerve regeneration; selective serotonin reuptake inhibitor; primary unipolar depression; symptom checklist-90; signaling pathway

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3.6.3   Analysis of keywords clusters on experimental acupuncture research abroad

A total of 551 pieces of literature abroad in the field of experimental acupuncture research were retrieved in Web of Science. There are 14 clusters, as shown in Figure 8 and Table 10, namely, neuron, bee venom, dexmedetomidine, visualization, traditional Chinese medicine, spinal cord, stimulation, antioxidant, long term potentiation, expression, apipuncture, Parkinson's disease, median nerve stimulation, and opioid receptors. Research on the mediators, receptors and signaling pathways involved in the anti-inflammatory and anti-nociceptive effects of acupuncture has been a central focus of experimental acupuncture research abroad. Goldman has reported that adenosine triphosphate (ATP) is released locally at acupuncture points in response to acupuncture stimulation to metabolize adenosine, activate adenosine A1 receptors, and produce analgesia in inflammatory pain ^[18]. A study by Torres Rosa demonstrated that there is in fact an anti-inflammatory pathway activated by electroacupuncture that involves the vagus and sciatic nerves, and is mediated by dopamine ^[32]. Meanwhile, global scholars have focused on the effects of electroacupuncture stimulation on the protective mechanisms of the cardiovascular system. YANG et al. ^[33] highlighted the neuroprotective effects of electroacupuncture on memory dysfunction, neuroinflammation, and glucose metabolism caused by bilateral common carotid artery occlusion, suggesting that electroacupuncture may be a treatment that can improve memory and reduce dementia-related neuroinflammation.

Figure  8.  Keywords co-occurrence network in the field of experimental acupuncture research abroad

The nodes in the graph indicate keywords, and different colors of the blocks and nodes’ indicate different clusters. The lines between the nodes’ indicate co-occurrence relationships; the thicker the line, the stronger the correlation.

DownLoad: Full-Size Img PowerPoint

Table  10.  Clustering table of keyword co-occurrence network in the field of experimental acupuncture research abroad

Cluster ID	Size	Year	Terms (LSI)
0	36	2015	Trpa1 channel; blockade; ear acupuncture; cutaneous allodynia; gene related peptide; gaba; morphine; extinction; reinstatement; drug seeking
1	32	2014	Oxidative stress; propionic acid; neural cell death; comet assay; animal venom; Parkinson’s disease; motor dysfunction; amyotrophic lateral sclerosis; bee venom acupuncture; central nervous system
2	26	2017	Dexmedetomidine; acupuncture; analgesia; sedation; feline; impregnated polyethylene; benign esophageal; intestinal transit; acral lick dermatitis; fos protein
3	22	2014	Acupuncture; mammalian organ; surface; thread like structure; tissue; pain; release; microneedle; mechanism
4	22	2014	Electroacupuncture; expression; Parkinson’s disease; mechanism; neurogenesis; activation; acupuncture; inflammation; ganglion neuron; dorsal horn
5	21	2014	Spinal cord; seasonal allergic rhinitis; low frequency; involvement; inflammatory pain; dopamine d1; paraventricular nucleus; phospholipase c; ascending nociceptive control
6	20	2015	Acupuncture; stimulation; brain; thread like structure; surface; analgesia; neuropathic pain; morphine; questionnaire; pharmacokinetics
7	20	2016	Acupuncture; model; cell; classification; sclerosis; bee venom; dopamine; haloperidol; natural compounds; release
8	20	2015	Vascular dementia; dysfunction; Alzheimer’s disease; artery occlusion; brain-derived neurotrophic factor; camp-response element-binding protein; cholinergic neurons; chronic pain; cortical acetylcholine release
9	19	2015	Expression; edema; complementary; oncology; animal model;suppression; electroacupuncture; spinal glial activation; involvement; pain
10	19	2014	Acupuncture; acupoint stimulation; acupuncture point; nerve injury; model; water soluble fraction; neuropathic pain; modulation; activation; expression
11	18	2014	Parkinson's disease; motor dysfunction; resiniferatoxin; release; bone resorption; activation; macrophage infiltration; accumulation; insulin resistance; increase
12	18	2014	Parkinson's disease; motor function recovery; chemotherapy-induced peripheral neuropathy; analgesia; atopic dermatitis; neuropathic pain; bee venom; motor function recovery; chemotherapy-induced peripheral neuropathy; analgesia
13	16	2014	Blockade; acupuncture analgesia; dynorphin; endorphin; delta eeg; beta endorphin; chronic pain; mechanism; peptide; cord

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3.6.4   Analysis of keywords clusters on clinical acupuncture research abroad

There are 4 538 articles of clinical acupuncture research abroad in recent 10 years, keywords were clustered, as shown in Figure 9 and Table 11. The 10 clusters were dry needling, chronic pain, prevalence, integrative medicine, alternative medicine, hot flashes, Korean medicine, mechanism, therapy, and management. The role of acupuncture in pain management has been an important topic, while foreign studies have focused more on the treatment of cancer ^[34], osteoarthritis of the knee ^[35], chronic pain ^[36], etc. In recent years, acupuncture for mood disorders such as depression and anxiety is also a key topic of acupuncture research abroad. A study by Peggy Bosch demonstrated that acupuncture is an effective and safe treatment for major depression, and that sleep and quality of life (involving mood) in patients with depression and schizophrenia can be improved with acupuncture treatment ^[37].

Figure  9.  Keywords co-occurrence network in the field of clinical acupuncture research abroad

The nodes in the graph indicate keywords, and different colors of the blocks and nodes’ indicate different clusters. The lines between the nodes’ indicate co-occurrence relationships; the thicker the line, the stronger the correlation.

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Table  11.  Clustering table of keyword co-occurrence network in the field of clinical acupuncture research abroad

Cluster ID	Size	Year	Terms (LSI)
0	41	2014	Dry needling; needle tenotomy; tendon fenestration; patient anxiety; chronic fatigue disorders; controlled trial; traffic accident; clinical trial protocol; pain; low-level laser
1	38	2014	Chronic pain; complementary therapies; health knowledge; health personnel; negative findings; stimulation; manual acupuncture; trigger point; blood flow; moxibustion
2	37	2014	Breast cancer; neck cancer; symptom burden; randomized controlled trial; chronic migraine; alternative medicine; traditional medicine; mind-body medicine; irritable bowel syndrome; education
3	35	2015	Alternative medicine; complementary therapies; longitudinal analyses; hysterectomy oophorectomy; systems biology; integrative medicine; mood disorders; systems biology; general practitioner; endocrine system
4	35	2013	Alternative medicine; herbal medicine; massage therapy; parent; disability index; complementary medicine; parent; disability index; knee osteoarthritis ; dysmenorrhea
5	35	2015	Hot flashes; androgen deprivation therapy; chemotherapy-induced nausea; home care device; high-intensity exercise; breast cancer; systematic review; chemotherapy-induced nausea; home care device; high-intensity exercise
6	32	2014	Alternative medicine; herbal medicine; massage therapy; knee osteoarthritis; home care device; systematic review; knee osteoarthritis; home care device; underserved area; chinese herbal medicine
7	32	2014	Acupuncture; mechanism; analgesia; zusanli acupoint; rat model; system; expression; activation; trpv1 channel; pathway
8	31	2014	Therapy; medicine; children; acupressure; auricular acupuncture; acupuncture; depression; qualitative; research; antenatal
9	31	2014	Acupuncture; therapy; placebo; symptom; multicenter; management; care; relief; preterm; familiar odor

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4.   Discussion

From the number of articles, it can be drawn that global acupuncture research has reached a stable period, and domestic acupuncture research is developing rapidly. In recent years, the annual publication volume in China has exceeded that abroad.

From the analysis of the authors, LIU Cunzhi from China and Lee Myeong Soo from South Korea made important contributions, and they also led the formation of their respective research cooperation networks. There are collaborative relationships among authors in different collaborative networks, but the intensity of collaboration is relatively low. The construction of the international cooperation network of authors in the field of acupuncture needs to be further strengthened. The same holds true for cooperation between countries.

In journal analyses, most of the journals with high publication volume are in the JCR Q3 and Q4, and most of them are English journals located in the USA. The construction of journals in the field of acupuncture needs to be reinforced urgently.

Through the analysis of keywords and references, we found that acupuncture analgesia is an important topic of common concern in China and abroad. In China, more emphasis is placed on the therapeutic effect of acupuncture on visceral pain, stroke, neuropathic pain, and other non-traumatic pain, while more emphasis is put on the role of acupuncture or electroacupuncture at the molecular or cellular level in anti-inflammatory and analgesic mechanisms abroad. As a traditional therapy, acupuncture has marked effects in treating various difficult and miscellaneous diseases. The application of acupuncture in China mainly centered on the treatment of internal medicine diseases, such as functional dyspepsia, endocrine disorders, and other diseases, while global studies are more focused on the treatment of cancer and mental diseases. It can be predicted that in the future, domestic acupuncture research may pay more attention to the treatment of internal diseases, such as visceral pain, spinal pain, visceral dysfunction, etc. Acupuncture treatment of inflammatory pain and psychological disorders is expected to become the future trend of acupuncture research abroad.

In summary, this study used the bibliometric method to sort out and analyze the current situation and hotspots of acupuncture research in China and abroad in the past decade, and predicted the future research directions in China and abroad. However, the present study also has objective limitations. On one hand, the data were only obtained from the acupuncture-related literature from the Web of Science database, so some articles published in other databases were not included in the analysis. On the other hand, due to the limitation of specific retrieval methods, some acupuncture articles may not be collected, and the overall study may have deviation.

5.   Conclusion

In this study, bibliometrics was employed to conduct a comprehensive analysis of acupuncture research in China and abroad in the past decade. The results show that acupuncture research has established several stable cooperation teams, but the cooperation between the author's cooperation network and countries is not close. It is necessary to promote the standardization construction and international exchange of acupuncture, and strengthen the cooperation between institutions and countries. Acupuncture analgesia research is an eternal research focus in this field, but in clinical application, there are differences between Chinese and global research focus. In China, more attention is paid to the treatment of internal medicine diseases and pain, while in foreign countries, attention is attached to the alleviation and improvement of acupuncture on cancer and psychosocial diseases.

Fundings

Scientific and Technological Innovation Project of China Academy of Chinese Medical Sciences (CI2021B002 and CI2021A00501).