Ameliorative potential of angiotensin-converting enzyme inhibitor (ramipril) on chronic constriction injury of sciatic nerve induced neuropathic pain in mice.

Introduction: The present study was designed to investigate the effect of ramipril (angiotensin-converting enzyme inhibitor) on the chronic constriction injury of sciatic nerve induced neuropathic pain in mice.

Methods: The neuropathic pain was induced by four loose ligations of the right sciatic nerve in mice. The battery of behavioral tests, i.e. plantar, pin prick, tail flick, tail pinch, rota rod tests, were performed to assess the degree of thermal and mechanical hyperalgesia in ipsilateral paw and tail, and motor in-coordination activity respectively. In addition, the biochemical tests, i.e. total protein, thiobarbituric acid reactive substances and reduced glutathione, were also performed in sciatic nerve tissue samples.

Results: The administration of ramipril (2 and 4 mg/kg, p.o.) significantly attenuated chronic constriction injury-induced rise in peripheral as well as central pain sensitivity (thermal and mechanical) along with impairment of motor in-coordination activity. Further, it also produces ameliorative effects on chronic constriction injury-induced rise in thiobarbituric acid reactive substances and decrease in glutathione levels when compared with a normal control group.

Conclusion: It may be concluded that angiotensin-converting enzyme inhibitor may be a potential new target for the management of neuropathic pain.