臂丛损伤再生中GAP-43 mRNA及其蛋白的表达

Expression of GAP-43 mRNA and protein following brachial plexus avulsion injury

目的:分析臂丛损伤后脊髓前角运动神经元表达GAP-43 mRNA及其蛋白的变化规律,探讨神经损伤再生的机制。方法:建立3种臂丛损伤模型:右C7前根撕脱(A组);右C7前根撕脱+同侧C5-T1后根断离(B组);右C7前根撕脱+右C5与C6之间脊髓半横断(C组)。用荧光定量RT-PCR方法检测术后14 d时C7前角GAP-43 mRNA的表达量。用免疫组化方法检测术后1、3、7、14 d脊髓前角GAP-43免疫阳性运动神经元的表达。结果:对照组C7前角GAP-43 mRNA呈低表达,损伤组GAP-43 mRNA表达显著上调。损伤组术后1 d、3 d时均未见C7前角GAP-43免疫阳性神经元,术后7 d各损伤组GAP-43免疫阳性神经元开始出现,14 d时免疫阳性神经元数目达到高峰。3组间比较,C组表达量最高,B组最低,A组居中。结论:臂丛损伤诱导运动神经元GAP-43mRNA及其蛋白表达上调,GAP-43合成增加是神经元蛋白重组所致,与轴索再生和神经功能重建有关。

AIM： To investigate the expression of GAP -43 mRNA and protein of the motor neurons in spinal cord following the brachial plexus avulsion injury. METHODS： In the present study, three kinds of models of brachial plexus avulsion injury were made： right C7 anterior root avulsion （group A）, C7 anterior root avulsion with right C5 -T1 posterior roots breaking （ group B）, right C7 anterior root avulsion with hemi - transect between C5 and C6 segment of spinal cord （group C）. The expression of GAP -43 mRNA in anterior horn of spinal cord was detected at 14 days after operation by SYBR green quantification RT - PCR technique. The amounts of GAP - 43 positive neurons in spinal cord were detected at 1, 3, 7 and 14 days after operation by immunohistochemistry technique. RESULTS： In control group, the expression of GAP -43 mRNA was very low in anterior horn. By 14 days after operation, the expression of GAP -43 mRNA was evidently up -regulated compared with control group. GAP-43 positive neuron was observed in control group at 1st day and 3rd day after operation. GAP -43 positive neurons appeared at 7th day and peaked at 14th day after operation. The expression of GAP - 43 mRNA and protein were maximum in group C, group B was the lowest. CONCLUSION： The expression of GAP -43 mRNA and GAP- 43 protein were up- regulated following brachial plexus injury. The expression of GAP- 43 protein results from the recombination of proteins. GAP - 43 is closely related to the axon regeneration and functional reconstruction.