Protective effect of Acorus calamus L. in rat model of vincristine induced painful neuropathy: an evidence of anti-inflammatory and anti-oxidative activity.

The study investigates the protective effect of Acorus calamus L. (AC) in vincristine-induced painful neuropathy. Vincristine (75μg/kg, i.p. for 10 consecutive days) was administered to induce painful neuropathy in rats. Various tests were performed to assess the degree of painful neuropathy at different days i.e., 0, 1, 7, 14, and 21st day. Sciatic nerve TNF-α, superoxide anion generation, total calcium, and myeloperoxidase activity level were also estimated after 21st day of study. Hydro-alcoholic extract of AC (HAE-AC, 100 and 200mg/kg, p.o.) and pregabalin (10mg/kg, p.o.) were administered for 14 consecutive days. Vincristine significantly induced neuropathic pain manifested in the terms of thermal hyperalgesia and allodynia (increase in hind paw licking, lifting or jumping from hot plate); mechanical hyperalgesia (increase in left hind paw lifting duration in pin-prick test) and allodynia (left hind paw withdrawal reflexes to non-noxious stimuli in Von Frey test); and sciatic functional index (analysis of footprints of the feet) along with rise in the levels of various biochemicals. HAE-AC attenuated vincristine induced behavioral, and biochemical changes comparable to that of pregabalin (positive control). HAE-AC attenuated vincristine induced painful neuropathy, which may be attributed to its multiple effects including anti-oxidative, anti-inflammatory, and calcium inhibitory actions.