Protective effect of co-administration of curcumin and sildenafil in alcohol induced neuropathy in rats

Neuropathic pain associated with chronic alcohol consumption is a medico-socioeconomical problem that affects both central and peripheral nervous system and has no satisfactory treatment till date. The present study was designed to investigate the protective effect of co-administration of curcumin and sildenafil on alcohol induced neuropathic pain in rats. In order to carry out this, ethanol (35% v/v, 10g/kg, p.o.) was administered for 10 weeks to induce neuropathic pain. Curcumin (30 and 60mg/kg, i.p.) and sildenafil (5 and 10mg/kg, i.p.) were given alone and in combination at their lower doses (30mg/kg curcumin and 5mg/kg, sildenafil, i.p.) to investigate the changes in thermal and mechanical hyperalgesia, allodynia and histopathological parameters. Biochemical estimations of thiobarbituric acid reactive species, glutathione and protein was also carried out to evaluate oxidative stress. The results revealed that chronic alcohol consumption for 10 weeks caused significant thermal and mechanical hyperalgesia, allodynia and increased oxidative stress. Individual administration of both the drugs at their low as well as high doses were able to improve the symptoms of alcohol induced neuropathic pain. Whereas co-administration of curcumin and sildenafil at their lower doses itself were found to significantly improve nerve functions, biochemical and histopathological parameters as compared to their individual administration. It is therefore proposed that co-administration of curcumin and sildenafil may bring new dimension towards attenuation of alcohol induced neuropathic pain affecting central as well as peripheral nervous system.