颈7神经根切断后靶肌肉内乙酰胆碱受体γ／ε亚基的表达变化

An experimental study of γ- and ε-AchR subunits mRNA expression in target muscles after transection of Cr nerve root

目的 采用SYBR Green Ⅰ荧光定量聚合酶链反应方法，研究颈，神经根切断后靶肌肉内乙酰胆碱受体γ-和ε-亚基的mRNA表达水平的变化，来探索颈，神经根切断后的代偿机制。方法36只雄性SD大鼠，随机分成6组，每组6只。右侧建成颈，神经根切断模型，左侧为健康对照组。用SYBR GreenⅠ荧光定量RT-PCR方法，检测术后第1、2,4、6、8、12周肱三头肌内乙酰胆碱受体γ-、ε-和α-亚基的mRNA表达水平的变化曲线。收集所有数据后，用SPSS12．0软件进行均值、标准差计算和方差统计学分析。结果s-AchR的mRNA在颈，神经根切断术后第1—6周下调表达（P〈0．05），第6周下降到谷底，在第12周基本恢复到健康对照组水平。γ-AchR的mRNA表达在颈，神经根切断术后第1周就开始上升，到第6周达顶峰（P〈0．05），在第12周下降至正常水平。结论运用SYBRGreenⅠ荧光RT-PCR技术，证实在SD大鼠颈，神经根切断后第1—6周内，其靶肌肉内γ-AchR／ε-AchR会出现失神经的转换，但在第12周左右恢复正常表达。

Objective To explore the compensatory mechanisms after transection of Ca nerve root by quantifying ε-AchR/T-AchR subunit mRNA expression using RT-PCR with SYBR Green Ⅰ. Methods Thirtysix male SD rats were randomly divided into 6 groups, with 6 each. The right C7 nerve root was transected while the left C7 was left intact to serve as control, mRNA expressions of ε-AckR/γ-AchR subunits in the triceps brachii muscles of experimental sides and normal sides were tested at week 1, 2, 4, 6, 8, and 12 after Ca nerve root transection using real-time fluorescence quantitative reverse transcriptase-polymerase chain reaction with SYBR Green I. SPSS12.0 software was used to calculate the mean and standard deviation of the values, and statistical analysis of the variance. Results In the 1st, 2nd, 4th, and 6th week, mRNA expression level of ε-AchR subunit of the experimental group was down-regulated comparing to that of the control.（ P 〈 0.05）. The level of s-AclR, subunit mRNA expression was lowest during the 6th week, but then returned to normal level 12 weeks after the transection. γ-AchR subunit mRNA expression increased in the first postoperative week and peaked during the 6th week （ P 〈 0.05）. γ-AchR subunit mRNA expression returned to normal level 12 weeks after the transection. Conclusion The change of ε-AchR/γ-AchR subunit mRNA expression indicated that Ca nerve root transection caused denervation changes in subtype structures of the target muscle within the first 6 weeks. Compensatory recovery occurred in the 12th week.