慢性神经痛大鼠脊髓运动神经元缝隙连接蛋白43对运动神经元凋亡及其运动功能恢复的影响

Effect of expression of connexin 43 in motor neurons of spinal cord in rats with chronic neuropathic pain on the apoptosis of motor neurons and motor functional recovery

目的:研究慢性神经痛大鼠脊髓缝隙连接蛋白43(connexin43,Cx43)在运动功能调节中的作用。方法:实验于2003-01/2004-06在广州市临床医学研究中心完成。10只SD大鼠接受右坐骨神经结扎手术,模拟慢性神经痛模型。手术前以及手术后1,3,5,7,14d,观察大鼠疼痛行为学并测定右后肢热刺激回缩潜伏期(pawwithdrawthermallatency,PWTL)、电刺激回缩潜伏期(pawwithdrawelectricthreshold,PWET的变化,然后于第14天切取大鼠L4～5)脊髓采用免疫组化分析两侧脊髓运动神经元Cx43表达差异。结果:手术前,右后肢PWTL,PWET分别为(13.0±1.9)s和(12.5±0.3)mA,第14天右后肢PWTL,PWET比术前明显降低(t=9.17和27.41,P<0.01)。右侧脊髓大量运动神经元Cx43表达阳性,200倍单个视野内阳性数量为28.9±6.7)个,而左侧仅为((9.6±4.2)个,明显少于右侧(t=7.72,P<0.01)。结论:慢性神经痛大鼠脊髓运动神经元缝隙连接蛋白43表达增加,提示缝隙连接可能对慢性神经痛后运动协调和康复起着重要作用。

AIM:To investigate the role of connexin 43(Cx43) in motor neurons of spinal co rd in rats with chronic neuropathic pain in the regulation of motor function. METHODS:The experiment was completed in Guangzhou Research Center for Clinical Medical Sciences from January 2003 to June 2004.Ligation was performed in right sciatic nerves of 10 SD rats to replicate a model of chronic neuropathic pain.T he pain related behavior were observed,and paw withdraw thermal latency(PWTL) a nd paw withdraw electric threshold(PWET) changes of posterior right paws were as sessed before operation and at postoperative 1,3,5,7,14 days.On the 14th day aft er operation,the spinal L4-5 segment was removed,then the immunohistochemistry of Cx43 in motor neurons of spinal cord was studied and their expressions of two sides were analyzed and compared. RESULTS:Before operation,the PWTL and PWET of the posterior right paws were(13 .0±1.9) seconds and(12.5±0.3) mA respectively,while on the 14th day after oper ation,the PWTL and PWET of posterior right paws were shorter or lower than that of preoperation(t=9.17 and 27.41 respectively,P< 0.01).In a single sight under a 200 microscope,plenty of Cx43 in motor neurons of right spinal cord was positiv e(28.9±6.7),significantly less in left spinal cord(only 9.6±4.2)(t=7.72,P< 0.0 1). CONCLUSION:The expression of Cx43 is increased significantly in motor neurons of spinal cord in rats with chronic neuropathic pain,implicating that gap juncti on may play an important role in maintaining and coordinating of locomotion afte r chronic neuropathic pain.