Effects of co-administration of chronic curcumin and forced exercise on behavioral pain responses in the neuropathic pain model of chronic constriction injury in rats

Introduction: Neuropathic pain is a chronic pain that results from damage to the central and peripheral nerves. According to the previous studies, curcumin and exercise can be effective treatments for alleviating sensory neuropathic pain individually. Now the combined effect of chronic curcumin (Cur) and forced exercise on behavioral pain responses in the neuropathic pain model of chronic constriction injury (CCI) in rats is considered. Materials and Methods: 80 Male Wistar rats were randomly allocated to eight groups (n=10). These groups include Sham+ Vehicle (Veh), Sham+Exercise, CCI+Veh, CCI+Exercise, CCI+Veh+Exercise, Cur+CCI, Exercise+Cur+CCI. First, neuropathic pain was induced by CCI in the respective groups. For the treatment of neuropathic pain in the Cur+CCI group, animals received curcumin (60 mg/kg) started 12 days after the surgery until day 26. The exercise started 12 days after surgery until day 33 in the CCI+Veh+Exercise and CCI+Exercise groups. Thermal hyperalgesia and mechanical allodynia were performed on days 12 and 34. Results: We found that CCI-induced neuropathy could produce thermal hyperalgesia and mechanical allodynia 12 days after CCI induction. In addition, co-administration of curcumin and moderate-intensity exercise in each of the treated groups individually could alleviate neuropathic pain compared with the nontreated CCI. Conclusion: Our findings showed that co-administration of curcumin and exercise individually, could alleviate neuropathic pain compared with nontreated CCI. In addition, there was not any additive or synergistic effect between the treatment of exercise and curcumin.