Neuroprotective Effect of Coenzyme Q10 in Chronic Constriction Injury-Induced Neuropathic Pain in Rat

Background: Oxidative stress contributes to neuropathic pain. Coenzyme Q10 (CoQ10) is used for the treatment of neurodegenerative diseases. However, there is no report regarding the therapeutic effect of CoQ10 on neuropathic pain. Objectives: The present study investigated the effects of CoQ10 on pain alleviation in animals with chronic constriction injury (CCI) of the sciatic nerve. Materials and Methods: Wistar male rats were randomly allocated to four groups. Nerve injury was induced by four loose ligatures around the sciatic nerve. CoQ10 (200 mg/kg) or vehicle were daily injected intraperitoneally for 10 days. Behavioral tests were performed before nerve injury and on fifth and tenth days after injury. Radiant heat, Randall Selitto test, and Von Frey filaments were used to assess the pain threshold. At the end of the experiment, the animals were perfused transcardially. Lumbar spinal cord was removed and prepared for Nissl staining. Analysis of variance (ANOVA) and Mann-Whitney were used for statistical analysis. P-value below 0.05 was considered statistically significant. Results: Reduction in pain threshold and the number of neurons in dorsal horn of the spinal cord after nerve injury (P ≤ 0.001) were resulted. Injection of CoQ10 and vehicles increased the pain threshold (P ≤ 0.001 and P ≤ 0.01) and prevented cell loss in neuropathic rats compared with injured animals with no treatment (P 0.05). Significant differences observed between animals that had received coQ10 compared with vehicle treated ones (P 0.05). Conclusions: CoQ10 abolished neuropathic pain in CCI rats. Prevention of cell loss might be attributed to the analgesic effect of CoQ10. Hence, it might be used as a therapeutic intervention for neuropathic pain.