Abstract: Rheumatoid arthritis (RA) is a chronic systemic autoimmune inflammatory disease characterized by synovial hyperplasia, synovial joint damage and dysfunction. At present, the treatment of RA mainly includes drug therapy, surgical treatment and physical therapy. In physical therapy, light therapy is used extensively as an adjuvant therapy because of its non-invasive and painless advantages. Therefore, in this study, 630 nm LED red light was used to explore the mechanism of photobiomodulation in the treatment of rheumatoid arthritis by promoting the apoptosis of synovial fibroblasts. The result of JC-1 assay demonstrated that the depolarization of mitochondrial membrane potential increased and the membrane potential decreased after 630 nm LED illumination. Using CASP3 and CASP9 activity detection kit, it is demonstrated that 630 nm LED promoted the activity of the pro-apoptotic CASP3 and CASP9 in synovial fibroblasts. RT-qPCR and Western blot showed that the expression of TRPV1 was promoted by 630 nm LED in MH7A cells. CCK-8 assay showed that the viability of MH7A cells was significantly inhibited by 630 nm LED, whereas the activity of MH7A cells treated with TRPV1 antagonist and TNF-α was not inhibited by 630 nm LED. TUNEL assay showed that apoptosis of MH7A cells was promoted by 630 nm LED, whereas apoptosis of MH7A cells treated with TRPV1 antagonist and TNF-α was not promoted by 630 nm LED. In conclusion, 630 nm LED red light promoted apoptosis by regulating TRPV1 in the TNF-α induced MH7A cells.
Key words: LED; rheumatoid arthritis; apoptosis; fibroblast-like synovial cells; transient receptor potential vanilloid 1
（Acta Laser Biology Sinica, 2022, 31(3): 224-233）