Effects of Photobiomodulation Associated with Platelet-Rich Plasma in Acute Rheumatoid Arthritis Induced in Female Wistar Rats' Knee.

Rheumatoid arthritis causes inflammation, pain, and joint degradation, necessitating treatment with anti-inflammatory drugs and corticosteroids, posing various challenges. We aimed to evaluate the effects of photobiomodulation (PBM) at two different doses associated to platelet-rich plasma (PRP) in an in vivo model of induced acute arthritis in Wistar rats' knee. Eighty-four Wistar rats were assigned into seven groups, including animals treated with PBM and/or PRP. On day 0, arthritis was induced in sham and treated groups through the intra-articular injection of zymosan (200 μg). Twenty-four hours after induction, the PBM groups were treated with an AsGaAl laser, whereas the PRP-treated groups received intra-articular injections with a concentration of 8 × 10 platelets obtained from another four animals. After 3 days, the animals were euthanized, and the interleukin (IL)-6 and complement C3 gene and protein expression levels were analyzed. Statistical analysis was performed using the mean ± SD with analysis of variance and Tukey's posttest, with a significance level set at 5% ( < 0.05). Synovial inflammation decreased in PBM-treated groups; however, PRP alone showed no significant difference. Gene expression analysis revealed a significant difference in IL-6 and C3 levels in the PBM and PBM+PRP-treated groups. Meanwhile, the PRP alone group exhibited significance for IL-6. Moreover, the PBM and PBM+PRP-treated groups showed a significant difference in C3 protein expression levels, whereas the PRP alone group showed no difference. The increase in cellular activity in the synovial membrane and the decrease protein expression levels are owing to the reduction in proinflammatory mediators following PBM therapy.