Mitigation of inflammation and oxidative stress by sarsasapogenin in complete Freund’s adjuvant-induced arthritis: evidence from in silico and in vivo studies

Objective To evaluate the anti-arthritic efficacy of sarsasapogenin (SG) alone and in combination with the corticosteroid fluticasone (FC) in a rat model of rheumatoid arthritis (RA), which was induced by complete Freund’s adjuvant (CFA).

Methods Network pharmacology analysis was conducted to identify the potential molecular targets and signaling pathways of SG in RA. Targets were identified with multiple databases, including SwissTargetPrediction, GeneCards, DisGeNET, and Search Tool for the Retrieval of Interacting Genes/Proteins (STRING), and pathway enrichment analysis was performed using Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) databases. Molecular docking was performed to validate the binding affinity of key SG constituents with the predicted hub targets. Male Wistar rats were randomly divided into normal control (NC), CFA, SG, FC, and SG + FC groups (n = 6 per group). RA was induced in all groups except NC group by a single intradermal injection of CFA (0.1 mL) into the left hind paw on day 1. After successfully induction of RA (day 12), treatments were administered intradermally from day 12 to 28 as follows: SG (50 µg/rat, 40 µL per paw), FC (50 µg/rat, 40 µL per paw), or a combination of SG and FC (25 µg/rat each, total 40 µL per paw). Therapeutic outcomes were evaluated via the paw volume, joint diameter, arthritis scores, hematological and biochemical indicators, oxidative stress markers, inflammatory cytokines, and histopathological assessments of rats’ ankle joint. The gene expression analysis was performed by quantitative reverse transcription polymerase chain reaction (qRT-PCR). Acute toxicity, body weight, and immune organ indices (spleen and thymus) were also monitored to assess the potential mitigation of SG of corticosteroid-induced adverse effects.

Results Network pharmacology analysis revealed 138 potential SG-associated targets, involving 10 key hub genes. KEGG enrichment indicated the participation of pathways involving phosphoinositide-3-kinase regulatory subunit 1 (PIK3R1), estrogen receptor 1 (ESR1), E1A binding protein P300 (EP300), mammalian target of rapamycin (mTOR), C-X-C chemokine receptor type 4 (CXCR4), signal transducer and activator of transcription 3 (STAT3), and toll-like receptor 4 (TLR4). GO enrichment analysis also revealed significant involvement of inflammatory and immune-related biological processes. Molecular docking confirmed strong binding interactions between major SG constituents and the identified hub targets. SG and SG + FC groups preserved body weight, and normalized spleen and thymus indices compared with FC group (P < 0.05 or P < 0.01), suggesting the mitigation of corticosteroid-induced adverse effects. SG and SG + FC groups significantly reduced paw volume, ankle diameter, and arthritis scores compared with CFA group (P < 0.05, P < 0.01, or P < 0.001). These treatments also significantly normalized hematological indicators red blood cells (RBC), white blood cells (WBC), hemoglobin (Hb), and platelets (PLT) and biochemical indicators aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alkaline phosphatase (ALP) (P < 0.05, P < 0.01, or P < 0.001). Serum proinflammatory cytokine levels tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-12, and thromboxane B2 (TXB₂) were markedly decreased, accompanied by restored antioxidant defenses superoxide dismutase (SOD) and glutathione (GSH) and reduced oxidative stress markers malondialdehyde (MDA) and myeloperoxidase (MPO) (P < 0.05, P < 0.01, or P < 0.001). The qRT-PCR analysis demonstrated favorable downregulation of STAT3, mTOR, and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) expression levels in joint tissues in all treatment groups compared with CFA group (P < 0.05, P < 0.01, or P < 0.001). Histopathological findings corroborated these effects, indicating reduced inflammatory infiltration and preservation of joint architecture.

Conclusion SG exerts protective effects against RA by modulating key inflammatory and immune pathways. The combined application of SG with FC enhances the therapeutic outcomes, while potentially reducing the corticosteroid-related adverse effects. These findings support SG as a promising adjunctive therapy in RA management, offering favorable efficacy and safety alongside conventional corticosteroid treatment.