Ginsenoside Rg1 promotes peripheral nerve regeneration in rat model of nerve crush injury

Searching for effective drugs which are capable of promoting nerve regeneration after nerve injuries has gained extensive attention. Ginsenoside Rg1 (GRg1) is one of the bioactive compounds extracted from ginseng. GRg1 has been shown to be neuroprotective in many in vitro studies, which raises the possibility of using GRg1 as a neuroprotective agent after nerve injuries. However, such a possibility has never been tested in in vivo studies. The present study was designed to investigate the efficacy of GRg1 in promoting nerve regeneration after nerve crush injury in rats. All rats were randomly divided into four groups (n = 8 in each group) after crush injury and were intraperitoneally administrated daily for 4 weeks with 1 mg/kg, or 5 mg/kg GRg1 (low or high dose GRg1 groups), or 100 mu g/kg mecobalamin or normal saline, respectively. The axonal regeneration was investigated by retrograde labeling and morphometric analysis. The motor functional recovery was evaluated by electrophysiological studies, behavioral tests and histological appearance of the target muscles. Our data showed that high dose GRg1 achieved better axonal regeneration and functional recovery than those achieved by low dose GRg1 and mecobalamin. The final outcome of low dose GRg1 and mecobalamin was similar in both morphological and functional items, which was significantly better than that in saline group. These findings show that GRg1 is capable of promoting nerve regeneration after nerve injuries, suggesting the possibility of developing GRg1 a neuroprotective drug for peripheral nerve repair applications. (C) 2010 Elsevier Ireland Ltd. All rights reserved.