Comparing Effects of Aerobic Versus Resistance Exercise on Expression of MicroRNA-155, Serum- and Glucocorticoid-Regulated Kinase 3, and Pain Threshold in Mice with Experimental Autoimmune Encephalomyelitis.

Objectives: Multiple sclerosis is a complex neurological disorder in which the immune system attacks the myelin sheath, leading to a range of symptoms. microRNA-155 plays a significant role in the pathogenesis of multiple sclerosis and neuropathic pain. Serum- and glucocorticoid-regulated kinase 3 (SGK3) protein is the target of microRNA-155. Exercise can induce long-term changes in the expression of microRNAs and their target proteins. This study aims to compare the effects of resistance and aerobic exercises on the expression of microRNA-155, SGK3, and pain threshold in experimental autoimmune encephalomyelitis mice.

Methods: For this purpose, 24 female C57BL6 mice were divided into four groups using a simple random sampling method: healthy, experimental autoimmune encephalomyelitis, resistance exercise + experimental autoimmune encephalomyelitis, and aerobic exercise + experimental autoimmune encephalomyelitis. The exercise groups underwent four weeks of training, consisting of 5 sessions of 30 minutes per week. The expression of microRNA-155, SGK3 protein, and pain threshold were assessed using the real-time polymerase chain reaction method, Western blot analysis, and the tail flick test, respectively.

Results: The results indicated significant changes in the expression of microRNA-155 (F = 22.05, P = .0003), SGK3 (F = 26.70, P = .0002), and pain threshold (F = 5.05, P = .009). Both resistance and aerobic exercises significantly down-regulated microRNA-155 and increased the expression of SGK3 compared to the experimental autoimmune encephalomyelitis control group (P < .05). The pain threshold in the mice also increased in both exercise groups (P < .05). No significant differences were observed between the resistance and aerobic exercise groups in any outcomes (P > .05).

Conclusion: Exercise training, through its impact on epigenetic factors, may serve as an effective therapeutic intervention to alleviate pain in individuals with multiple sclerosis and could significantly manage disease symptoms.