大鼠脊髓半损伤后前角运动神经元5-羟色胺2A受体的持续高表达

Expression of 5-HT2A receptor in anterior horn motor neuron followed after hemi-contusion of the spinal cord in rats

目的：研究胸段脊髓半损伤后5-羟色胺2A受体免疫反应（5-HT2A）的变化，为脊髓损伤后痉挛发生的病理生理学机制提供神经生物学依据。方法：大鼠随机分成8组，即8h、1d、3d、7d、14d、21d、28d、60d组。每组再分为手术组和假手术组，手术组用改良Allens装置建立第12胸段脊髓右半侧损伤模型，假手术组只去除椎板。免疫荧光染色检测损伤节段以下5-HT2A受体免疫反应的变化。结果：脊髓前角运动神经元区5-HT2A受体免疫反应阳性神经元的密度在手术组8h时与假手术组相比无明显变化；手术组损伤侧与假手术组相比，损伤侧5-HT2A受体免疫反应阳性神经元的密度在1、3、7、14、28、60d随时间的增加而逐渐增高，与假手术组相比差异有统计学意义；损伤对侧1、3、7d随时间的增加而逐渐增高，到14、21、28、60d时与假手术组相比差异有统计学意义。结论：脊髓损伤后同侧及对侧前角运动神经元5-HT2A受体免疫反应均逐渐增高，但对侧免疫反应升高迟于同侧。

Objective： To study the changes of 5-HT2A-IR within spinal thoracic segment after hemLcontusion of spinal cord injury, for the pathophysiology of spinal cord injury to provide a the oretical basis. Methods： Wistar rats were randomly separated into eight groups： 8 h, 1 d, 3 d, 7 d, 14 d, 21 d, 28 d and 60 d groups. Each group of 8 rats randomly subdivided into a spinal transection group and a sham-operation group. In the operated groups, the SCI models were prepared according to the modified Allen＇s method, while the sham-operation group performed only by cutting open the lumbar vertebral region, but the spinal dura mater was kept intact. When the survival time was up, the rats were killed, and the slices were prepared with freezing microtorne from the spinal cord which was below the injury for 5-HT2AR was up, immunoreaetivity staining and fluorescence immunolabeling. Results： There was no significant difference between the spinal semi-injury group and the sham operation group in 5-HT2AR-IR density in the anterior horn motor neuron region in 8 hours, while the density of 5-HT2AR- IR in the semi-contusion group was increased significantly in the groups of 1, 3, 7, 14, 21, 28 and 60 days compared with the sham-operation group. There was significant difference in 5-HT2AR-IR density in 14, 21, 28 and 60 days survival between the semi-injury non-contusion side group and the sham operation group. Conelusion： 5-HT2AR-IR density of 5-HT2AR immunoreactivity was increased both in the contusion side and the opposite non-contusion side significantly in motor neuron pool with a remarkable difference, but the elevation of the 5-HT2AR immunoreactivity in contralateral side was late on the same side.