短时低频电刺激体外培养许旺细胞髓鞘的形成

Effect of short-term low-frequency electrical stimulation on myelin formation of Schwann cells in vitro

背景:周围神经系统损伤后,短时低频电刺激已被证明可显著促进轴突再生和选择性功能修复,但目前对电刺激是否影响周围神经髓鞘的形成还知之甚少,而电刺激发挥作用究竟是通过神经元还是许旺细胞还有待证实。目的:建立体外背根神经元与许旺细胞联合培养模型,观察短时低频电刺激对许旺细胞髓鞘形成的影响。方法:体外培养背根神经元,纯化后预先施予电刺激(20Hz,100μs,3V),持续作用1h,24h后再加入许旺细胞悬液制成背根神经元/许旺细胞联合培养模型。在此基础上,用L-ascorbicacid诱导髓鞘形成,分别于诱导后第7,14天观察培养体系中髓鞘的形成。结果与结论:电刺激增强背根神经元分泌脑源性神经营养因子(P<0.05),经电刺激作用的背根神经元再与许旺细胞联合培养,最终表现为髓鞘形成增多以及髓鞘蛋白表达上调(P<0.05)。提示短时低频电刺激对体外许旺细胞髓鞘的形成具有促进作用,初步认为该作用至少通过刺激神经元分泌脑源性神经营养因子增多导致。

BACKGROUND：Short-time low-frequency electrical stimulation has the potential to promote axonal regeneration and target selection after peripheral nerve injury.However,studies concerning the effect of electrical stimulation on myelination are still elusive,and the possible target cell（neuron or Schwann cells） on which electrical stimulation impacts remains unknown.OBJECTIVE：To establish the co-culture model of dorsal root ganglion neurons and Schwann cells,and investigate the short-time low-frequency electrical stimulation effect on Schwann cell myelination in vitro.METHODS：Purified dorsal root ganglion neurons were subjected to continuous electrical stimulation（20 Hz,100 μs,3 V） for one hour.24 hours later,the purified Schwann cells suspension was added into pre-stimulated neurons/Schwann cell cultures.At 7 and 14 days after L-ascorbic acid induction,myelin formation was observed and determined.RESULTS AND CONCLUSION：Electrical stimulation enhanced brain-derived neurotrophic factor secretion from purified dorsal root neurons（P 〈0.05）.Dorsal root neurons treated with electrical stimulation cocultured with Schwann cells,which presented increased myelination and upregulated myelin protein expression（P 0.05）.These results have indicated that short-term low-frequency electrical stimulation promoted Schwann cell myelination in vitro,and the effect was at least initially mediated via the enhancement of neuronal brain-derived neurotrophic factor signals.