Ephrin-A5在脑梗死大鼠脑组织中的分布和动态表达

 目的： 研究发育期的轴突导向分子ephrin-A5在成年大鼠缺血性脑梗死皮层内的分布以及梗死灶周围不同时点的表达变化,探讨ephrin-A5基因在缺血性脑梗死后对神经再生的作用。方法: 建立大脑中动脉闭塞（MCAO）模型,采用免疫组化技术检测ephrin-A5的分布、细胞定位, 并于脑梗死后1、2、4周用荧光定量PCR法检测梗死灶周ephrin-A5表达量的变化。 结果: 免疫组化结果显示：大脑中动脉皮层支梗塞后ephrin-A5主要表达于梗死灶侧皮层的V2MM（第二视皮质内侧内区）、V2ML（第二视皮质内侧外区)、V2L（第二视皮质外侧区）、Au1（第一听皮质）、AuV（第二听皮质，腹侧区），分布在神经元胞体、树突中，轴突亦有少量分布。荧光定量PCR结果显示: ephrin-A5 ｍＲＮＡ在脑梗死后表达量上升，1周达到高峰,第2、4周保持第1周水平。 结论: 脑梗死后ephrin-A5在梗死灶周神经元胞体、树突中持续高水平表达，它可能是造成成年哺乳动物中枢神经系统损伤后神经轴突再投射障碍的重要原因之一。

Distribution and kinetic expression of ephrin-A5 after cerebral cortex infarction in rats

AIM: To study the distribution and kinetic expression of ephrin-A5 after cerebral cortex infarction in rats and to probe into the role of ephrin-A5 in regeneration of nerve after cerebral infarction. METHODS: The middle cerebral artery occlusion (MCAO) model was duplicated. The immunohistochemistry method was used to detect the distribution and location of ephrin-A5, and the change of expression was detected at 1 week, 2 weeks and 4 weeks after operation. RESULTS: The results of immunohistochemistry showed that ephrin-A5 distributed in the region of V2MM, V2ML, V2L, Au1, AuV in damaged cerebral cortex, and located in the body of neuron, cytodendrite, and somewhat in axon. The results of RT-PCR showed that ephrin-A5 mRNA increased after cerebral infarction, and peaked at 1 week, then maintained the same level till the 4th week. CONCLUSION: Ephrin-A5 is expressed in high level in the body of neuron and cytodendrite during 4 weeks after cerebral infarction, suggesting that ephrin-A5 may be one of the primary factors responsible for the failure of axon projection after cerebral infarction.