Abstract Objective: Rheumatoid arthritis (RA) is a chronic inflammatory disease that severely affects patients’ quality of life and requires lifelong treatment. Luofushan rheumatism plaster (LFS), a clinically approved transdermal formulation, shows therapeutic potential for RA but lacks mechanistic evidence. This study investigated the efficacy and underlying mechanism of LFS in a collagen-induced arthritis (CIA) rat model. Methods: CIA rats were treated transdermally with LFS (1.6–6.4 cm2/ankle) for 14 d. Arthritis severity, paw swelling, plasma IL-6/TNF-α levels, histopathology, and immune organ indices were evaluated. Network pharmacology and molecular docking were applied to identify potential targets and pathways, which were validated by real-time polymerase chain reaction analysis (RT-qPCR) and immunohistochemistry. Cardiac, hepatic, and renal biomarkers were analyzed for safety. Results: LFS ameliorated arthritis in a dose-dependent manner, attenuated paw swelling, suppressed plasma IL-6 and TNF-α levels, and normalized immune organs’ hyperplasia. Histopathological analysis further revealed that LFS diminished synovial inflammation and attenuated cartilage destruction. Network pharmacology analysis indicated that LFS exerts anti-RA effects via the toll-like receptor 4 (TLR4) and interleukin-17 (IL-17) signaling pathways, with molecular docking confirming high-affinity binding of key constituents, quercetin, ursolic acid, and luteolin to both targets. Subsequent experimental validation by RT-qPCR and immunohistochemistry demonstrated LFS significantly suppressed synovial TLR4 and IL-17 mRNA and protein expression, mechanistically linking its therapeutic efficacy to pathway inhibition. Crucially, safety assessment showed no abnormalities in cardiac, hepatic, or renal functional biomarkers. Conclusions: LFS exerts anti-RA effects primarily through targeted inhibition of the TLR4/IL-17 pathway while maintaining an exemplary safety profile, supporting its potential as a promising therapeutic alternative.
Tan et al. (Wed,) studied this question.