Effect of hydroalcoholic extract of Acorus calamus on tibial and sural nerve transection-induced painful neuropathy in rats.

This study was designed to investigate the therapeutic potential of hydroalcoholic extracts of Acorus calamus (AC) in tibial and sural nerve transection (TST)-induced neuropathic pain in rats. The hot plate, paw heat allodynia, acetone drop, and pinprick tests were performed to assess the degree of heat hyperalgesia, heat and cold allodynia, and mechanical hyperalgesia, respectively, at different time intervals, i.e., day 0, 1, 3, 6, 9, 12, 15, 18, and 21. The tissue superoxide anion and total calcium were measured as markers of oxidative stress. Tissue myeloperoxidase activity was measured as a specific marker of inflammation. Histopathological evaluation was also performed in the nervous tissue to assess the axonal degeneration. Pregabalin served as positive control in this study. TST in rats significantly induced thermal hyperalgesia and allodynia, mechanical hyperalgesia, and increased the levels of superoxide anion, total calcium, and myeloperoxidase (MPO) activity. Moreover significant histological changes were also observed. Oral administration of AC hydroalcoholic extract (100 and 200 mg/kg for 14 days) attenuated TST-induced behavioral, biochemical, and histological changes. Acorus calamus has ameliorative potential in TST-induced painful neuropathy, and this effect may be attributed to its multiple actions including anti-inflammatory, antioxidant, and neuroprotective actions.