Involvement of transient receptor potential melastatin-8 (TRPM8) in menthol-induced calcium entry, reactive oxygen species production and cell death in rheumatoid arthritis rat synovial fibroblasts

摘要: Abstract Rheumatoid arthritis is most prominently characterized by synoviocyte hyperplasia which therefore serves as an important target for clinical therapy. In the present study, it was observed that menthol, specific agonist of transient receptor potential melastatin subtype 8 (TRPM8), could induce sustained increases cytosolic calcium concentration ([Ca 2+ ] c ) in synoviocytes isolated from collagen-induced rats dose-dependent manner, evidently blocked applying extracellular Ca -free buffer. Menthol-induced [Ca increase also significantly inhibited potent TRPM8 antagonist capsazepine (CZP), indicating this elevation mostly attributed to TRPM8-mediated entry. Besides, RT-PCR indeed demonstrated presence synoviocytes. Meanwhile, found menthol evoked production intracellular reactive oxygen species, be abolished free solutions or CZP. Further experiments showed reduced cell numbers and survival This reduction associated with apoptosis suggested mitochondrial membrane depolarization, nuclear condensation a caspase 3/7 apoptotic assay. death both were obviously CZP, chelator BAPTA-AM, species inhibitor diphenylene iodonium, respectively. Taken together, our data indicated resulted via entry depending on activation.