Alpha lipoic acid attenuated neuropathic pain induced by chronic constriction Injury of sciatic nerve in rats

Abstract

Abstract Background Chronic neuropathic pain syndrome is associated with impaired quality of life and is poorly manageable. Alpha lipoic acid (ALA) is a powerful antioxidant and showed its effectiveness on diabetic neuropathy and other acute peripheral nerve injuries but it was not evaluated in the chronic neuropathic pain, chronic constriction injury (CCI) in rat model by using duloxetine (DLX) as standard. Methodology The main objective of the study was to expedite ALA effect on chronic peripheral neuropathy induced by CCI of sciatic nerve in rats. In this study, male Wister rats were randomly divided into six groups (n = 8) including, normal saline, sham operated, surgery control, DLX 30mg/kg treated, ALA treated 25mg/kg, and ALA+DLX. The CCI of sciatic nerve was conducted on all animals except normal saline group and studied for 21 days (i.e. 14 days treatment period & 7 days treatment free period) by using different behavioral, biochemical and, histopathology studies. Results ALA showed minor but significant decrease of thermal hyperalgesia, cold allodynia, malondialdehyde (MDA), total protein, lipid peroxidation, and nitric oxide levels and significant increase of motor coordination, glutathione level and decreased axonal degeneration significantly. These effects sustained even during treatment free period. ALA enhanced the effect of DLX when given in combination by showing sustained effect. In conclusion, ALA acted as potent antioxidant may be this activity is responsible for the potent neuroprotective effect. Conclusion Hence, ALA attenuated the nueroinflammation mediated by chronic peripheral neuropathy. Further studies are warranted with ALA to develop as a clinically relevant therapeutic agent for the treatment of neuropathic pain.

Keywords

• Chronic neuropathic pain
• Alpha lipoic acid
• Duloxetine
• Thermal hyperalgesia
• Cold allodynia
• Axonal degeneration