Effect of valproic acid on Ca2+ and cell apoptosis in spinal cord motor neurons after brachial plexus injury in rats / 中华显微外科杂志

ABSTRACT

Objective To examine the effect of valproic acid (VPA) on concentration of Intracellular Ca2+ and on cell apoptosis in spinal cord motor neurons after brachial plexus injury in rats. Methods Totally 210 adult male Wistar rats were randomly divided into Sham operation group (disposed the brachial plexus nerve root, but not cutted it off), control group (rats with brachial plexus nerve root amputating wound)and VPA group(rats with brachial plexus nerve root amputating wound and fed by VPA water),with 70 rats in each group.The specimens were taken at 12,24,48,72 h,1,2 and 4 weeks after operation.Whole-cell patch-clamp recording techniques were used to assayed the L-type calcium channel of motoneuron and monitored the changes in intracellular concentration of Ca2+ with spectrofluorometer. The motoneruron apoptosis was detected by TUNEL. Results The set of indicators did not change in the sham group.From 12h to 1 weeks after the operation, the electrical current of L-type calcium channel and the intra-cellular Ca2+ concentration of the neuron were obviously more in control group than in sham operation group (P ＜0.05). From 12 h to 4 weeks after the injury, there were more apoptosis neurons in control group than in sham operation group (P ＜ 0.05). There was no obviously difference in electrical current of L-type calcium channel between the VPA group and the control group at each time point(P ＞ 0.05).Compared to the control group,the intra-cellular Ca2+ concentration was lower in VPA group from 48 h to 1 week after nerve injury (P ＜ 0.05) ; the number of apoptosis neurons were less in VPA group from 24 h to 2 weeks after the injury (P ＜ 0.05). Conclusions Brachial plexus nerve root amputating wound in rats can increase the intra-cellular Ca2+ concentration and apoptosis of the motor neuron.VPA can reduce the intra-cellular Ca2+ concentration and apoptosis,but has no effect on the L-type calcium channel of the motor neuron.