Effect of Pulsed Radiofrequency with Various Time-Course on Rheumatoid Arthritis Joint Pain in Rats

This study aimed to evaluate the effect of pulsed radiofrequency (PRF) treatment with various time courses on rheumatoid arthritis (RA)-caused joint pain and pathological damage in rats.

SD rats were randomly assigned to five groups: a sham group, an RA group, a PRF/1min group, a PRF/2min group, and a PRF/3min group. RA model rats were established by injecting a mixture of type II collagen and Freund's adjuvant. Four times after 8 weeks, the dorsal root ganglia (DRG) of L4-6 segments were stimulated with PRF for 1, 2, and 3 minutes, respectively. Joint diameters were measured weekly before and after modelling. After 14 days of PRF treatment, morphological changes in cartilage were scored using pathological staining. ELISA determined TNF-α, IL-6, and IL-1β in peripheral blood. Ki67 expression in synovial tissues was detected using immunohistochemistry. Finally, the expression of transient receptor potential ankyrin 1 (TRPA1) and transient receptor potential vanilloid 1 (TRPV1) in synovial tissues were examined by Western blotting, qRT-PCR, and immunofluorescence.

Among the RA rats, PRF treatments of 2 minutes and 3 minutes ameliorated joint damage, and both were superior to the 1-minute treatment. Compared to the RA group, the PRF-treated groups showed significantly lower Mankin and OARSI scores, and reduced levels of TNF-α, IL-1β, and IL-6 in peripheral blood. Additionally, there was a decrease in Ki67 expression and levels of TRPA1 and TRPV1 in synovial tissues.

RA rats treated with PRF experienced reduced cartilage damage, which appears to be associated with inhibition of joint inflammation.