腰神经根慢性损伤后背根神经节电生理与细胞内钙离子浓度变化的研究

目的　探讨受损背根神经节 (DRG)神经元异位自发放电与细胞内Ca2 浓度改变的关系。方法　纯种成年新西兰大白兔 3 2只 ,随机分为正常组、损伤 10d组、损伤 3 0d组、损伤 90d组 ,建立模拟腰椎间盘突出的兔腰神经根慢性损伤模型 ,于损伤后 10d、3 0d、90d应用在体电生理技术记录损伤DRG异位电活动的改变 ,应用激光共聚焦扫描显微镜技术结合荧光染色法检测受损DRG神经元细胞内Ca2 荧光强度变化。结果　①兔腰神经根慢性损伤后 ,受损DRG神经元异位自发放电频率和幅度随损伤时间延长而逐渐下降 ,损伤各组与正常组相比 ,DRG放电频率、放电幅度均显著增高 (P <0 .0 5 ) ;②兔腰神经根慢性损伤后受损DRG细胞内Ca2 浓度呈现不同程度的增高 ,随着损伤时间的延长 ,Ca2 浓度有下降趋势。结论　Ca2 与受损神经元的异位电活动的发生及变化相关 ,Ca2 浓度升高可导致受损神经元异位电活动的发生及传播。

Electrophysiological changes and intracellular Ca2+ concentration in DRG neurons in rabbits with chronic injury of lumbar nerve roots

Objective To investigate the relationship between ectopic firing and intracellular Ca 2 concentration of chronically injured neurons. Methods Thirty two purebred adult New Zealand rabbits was randomly divided into four groups: a control group, a 10d group, a 30d group and a 90d group. Chronically injury model of lumbar nerve root caused by disc herniation were made with rabbits. The in vivo electrophysiologic examination was conducted at the 10th,30th and the 90th days, respectively post injury to observe the spontaneous ectopic firing of the injured DRG neurons. Meanwhile, a laser confocal scanning microscope was used in conjunction with fluorescent staining to detect intracellular free Ca 2 concentration in injured DRG neurons. Results Ectopic firing was observed in DRG neurons post injury, whose firing frequency and amplitude were significantly higher than the those of the control group( P <0.05), and gradually decreased with time. After chronic injury, intracellular free Ca 2 concentration in DRG was increased to various extend, which was also gradually decreased with time. Conclusion It was shown that the intracellular free Ca 2 concentration was correlative to ectopic firing of the injured neurons; increased Ca 2 concentration can result in ectopic firingand its propagation in the injured neurons.