Transient receptor potential channels TRPA1 and TRPV1 are involved in chronic pain relief via Pulsed Radiofrequency in Rheumatoid Arthritis rat

The relevance of transient receptor potential (TRP) channels ankyrin 1 (TRPA1, a sensor of noxious cold and mechanical stimuli) and vanilloid 1 (TRPV1, a nociceptor and heat sensor) in the pathogenesis of chronic pain associated with rheumatoid arthritis (RA) is profound. Multiple clinical studies have shown that pulsed radiofrequency (PRF) is effective in alleviating pain. However, the precise mechanism through which PRF alleviates pain remains unclear. In this study, we employed a collagen-induced arthritis (CIA) rat model to investigate the effects of intra-articular PRF or dorsal root ganglion (DRG) PRF on TRPA1 and TRPV1 in RA pain. Behavioral assessments indicated that PRF inhibited hyperalgesia in RA rats. Western blotting, real-time qPCR, and immunofluorescence staining demonstrated increased expression and activity of TRPA1 and TRPV1 in both the peripheral tissues and the peripheral nervous system of rats with RA. These changes were reversed by PRF treatment, indicating that TRPA1 and TRPV1 are crucial for RA pain. Notably, PRF treatment on DRGs resulted in a more pronounced downregulation of TRPA1 and TRPV1 than intra-articular PRF treatment. In conclusion, PRF may effectively treat chronic pain in RA rats by inhibiting TRPA1 and TRPV1 expression in the peripheral tissues and the peripheral nervous system.