Electrophysiological and theoretical analysis of melatonin in peripheral nerve crush injury

Electrophysiological and theoretical studies have been performed to investigate peripheral nerve injuries and nerve regeneration. The aim of this work is to evaluate the effect of melatonin functionally and electrophysiologically on peripheral nerve crush injury. Adult male Wistar rats (n=32, 200+/-50 g) were randomly allocated into four groups. Sciatic crush was constituted on left sciatic nerves. Treatment groups received intraperitoneal melatonin at doses of 5 and 20mg/kg for 21 days. Functional nerve recovery was evaluated using sciatic functional index (SFI) every week during the experiment. In vivo electrophysiological measurements were performed at the end of the treatment. The electrophysiological data were also analyzed by wavelet analysis. Melatonin treatments increased the SFI values in the injured sciatic nerves. In vivo electrophysiological measurements showed that melatonin increased the conduction velocities and also decreased the latency values. The wavelet analysis showed that melatonin treatment reduced the densities of high frequency components of compound muscle action potential (CMAP). These results suggest that melatonin application is a promising strategy for the treatment of peripheral nerve crush injuries. Furthermore, analysis of EMG data with wavelet methods seems to give more reliable results to evaluate the nerve recovery.