Effects of forced exercise on neuropathic pain induced by chronic constriction injury of sciatic nerve in male rat

Central and peripheral nerve injuries may lead to chronic neuropathic pain in addition to immobility in many injured persons. Exercise as a non-medical procedure has beneficial effects on the well being of individuals in normal and diseased state. Therefore, in the current study we aimed to measure the alleviating effect of physical exercise on neuropathic pain. Male wistar rats weighting 200±20 gram were divided into 5 groups: Intact, sham, neuropathic, exercise before neuropathy, and exercise after neuropathy. After anesthesia, rats underwent chronic constriction injury (CCI) procedure to induce neuropathic injury on the left sciatic nerve. After surgery animals were transferred to individual cages and covered with a towel to prevent hypothermia until regaining consciousness. Mechanical allodynia and thermal hyperalgesia were detected using von Frey Filament and Plantar test, respectively. Mechanical and thermal withdrawal response thresholds were reduced significantly (P<0.05) in the CCI group than sham and intact groups. On the other hand, there was a significant increase in the mechanical (P<0.01) and thermal (P<0.05) allodynia withdrawal response thresholds in post neuropathic exercise groups than the CCI group. Physical activity following certain models of neuropathic pain may lead to significant reduction in mechanical and thermal allonynia