Acute effects of photobiomodulation applied on the dorsal root ganglion in gout model-induced rats

Gouty arthritis is an inflammatory disease that triggers symptoms such as pain, swelling, and joint stiffness. Since its main therapy is medication, research on other forms of treatment that do not generate side effects is necessary. Given this, the objective of this research was to evaluate the effects of combined photobiomodulation (LASER and LED) applied on the dorsal root ganglion (DRG) in an experimental model of gouty arthritis. For this, 40 Wistar rats were randomized into 4 groups: simulation of the model with saline injection, without treatment (CTL; n = 10); gout simulation with photobiomodulation treatment (CTL-PBM; n = 10); gout model with the injection of monosodium urate crystals (1.25 mg) in the femorotibial joint, without treatment (GOT; n = 10); or gout model with photobiomodulation treatment (GOT-PBM; n = 10). After 7 h of gout induction, photobiomodulation was performed with a cluster of 4 diodes applied to the GRD region in animals from the CTL-PBM and GOT-PBM groups. After analysing the results, it was concluded that the therapy favored the reduction of edema and joint incapacity, as well as the increase in the nociceptive threshold and plantar grip strength. Furthermore, PBM stimulated an increase in the inflammatory response (with increased levels of IL-1β and greater recruitment of leukocytes) and greater activation of the antioxidant system. Therefore, PBM can be considered an effective therapeutic alternative to improve the functional status in this model of joint disease.