Curcumin attenuates the expression of NMDAR-NR1 in Chronic Constructive Injury model of neuropathic pain

Abstract

Objective : Neuropathic pain is a prevalent desease that greatly impairs the patients quality of life. A lack of the understanding of its aetiology, inadequate relief, and development of tolerance and potential toxicity of classical antinociceptives warrant the investigation of the newer agents to relieve this pain. The aim of the present study was to explore the antinociceptic effect of curcumin and its effect on expression of N-methyl-D-aspartate (NMDA) receptor in spinal dorsal horn and dorsal root ganglion in chronic constriction injury (CCI) mode of neuropathic pain of rats. Methods : Paw withdrawal mechanical threshold (PWMT) and paw withdrawal thermal latency (PWTL) of rats were measured on 2^th pre-operative and 1, 3, 5, 7, 10, 14 post-operative days, and the expression of NMDAR NR-1 in spinal dorsal horn and DRG was measured by Immunohistochemical staining and western-blot. Results : CCI rats exhibited significant hyperalgesia after operation as compared with control rats. Chronic treatment with curcumin 100mg/kg/day for 14days starting from the 1 ^th day after CCI operation significantly attenuated PWMT and PWTL. Curcumin also inhibited the expression of NMDAR NR-1 in spinal dorsal horn and DRG. Conclusion : These results indicate an antinociceptive activity of curcumin possibly through its inhibitory action on expression of NMDAR NR-1 in spinal dorsal horn and DRG and point towards its potential to attenuate neuropathic pain.