Comparative effects of α lipoic acid and melatonin on cisplatin-induced neurotoxicity.

Cisplatin is a carcinogenic agent having important cytotoxic effects. Cisplatin treatment increases the levels of free oxygen radicals in neurologic tissues. We investigated the effects of alpha lipoic acid (ALA) and melatonin (MEL) on the electrophysiological parameters and on activities of nerve fibers having different conduction properties on cisplatin neurotoxicity. Neurotoxicity was induced by a single injection of 10 mg/kg intraperitoneal (ip) cisplatin. Supplementation was started 1 day before cisplatin injection with either 100 mg/kg/day ip ALA or 4 mg/kg/day ip MEL for 7 days. Compound action potentials were recorded from isolated sciatic nerves in vitro, and numerical analyses were conducted. Cisplatin-induced neurotoxicity resulted in a significant decrease (p <.05) in maximum depolarization (mV), areas (mV·ms), and maximum and minimum upstroke velocity values (mV/ms). Although these decrements were restored by ALA and MEL, ALA was found to be more effective. Conventional conduction velocity measurements and conduction velocity distribution histograms have shown that ALA supplementation can recover the effects of cisplatin while MEL cannot. The conduction velocity distribution histograms have shown that antioxidant supplementation results in a restoration on contribution of fast-conducting fibers (51.8-77.7 m/s), which is deteriorated by cisplatin. Consequently, ALA has more potential to make up for the deleterious effects of cisplatin-induced neurotoxicity.