模拟失重对鼠大脑和小脑皮层超微结构的影响

目的 研究模拟失重条件下鼠脑皮层超微结构的变化及其可能的机制。方法 采用大鼠尾吊模型模拟失重，并于悬吊第7、14、21、28天心脏灌流取材，进行大脑皮层和小脑皮层超微结构的观察。结果模拟失重作用下，大脑皮层神经元内质网池扩张，高尔基器扁平囊扩张，线粒体肿胀、破裂；大脑皮层第Ⅳ层中的突触小泡数量减少；毛细血管管腔褶皱增多、基底膜变厚。小脑蚓部皮层浦肯野细胞的粗面内质网出现明显的脱粒和边集现象。上述变化于悬吊第14、21天表现最为明显，28d时趋于恢复正常。结论 模拟失重可引起鼠脑皮层超微结构的改变。超微结构随着模拟失重的进程而改变，有恢复的趋势，表现出适应性的变化。

Ultrastructural Changes in Cerebral Cortex and Cerebellar Cortex of Rats under Simulated Weightlessness

Objective: To study the ultrastructural changes in the cerebral cortex and cerebellar cortex of rats under simulated weightlessness and the possible mechanism. Method: The tail-suspended rats model (-30 degrees head down tilt) was adopted to simulate weightlessness in the experiment. The rats were suspended for 7 d, 14 d, 21 d, and 28 d, and then were perfused through the hearts. The specimens were drawn from the rats' cerebral cortex and cerebellar cortex for electron microscopy. Result: The results showed that under simulated weightlessness, the main changes in the neuron can be described as follows: swelling of mitochondria, endoplasmic reticulum and Golgi complex, even formation of big empty vesicles; reduction of number of synaptic vesicles in IV layer; increase corrugation of capillary lumen and thickening of basement membrane. Degranulation of rough endoplasmic reticulum in Purkinje's cells of the cerebellar cortex occurred obviously. On the 14th and the 21st day of suspension, the changes were most significant and tended to return to normal on the 28th day. Conclusion: The experimental results demonstrated that simulated weightlessness led to ultrastructural changes in the cerebral cortex and cerebella cortex of rats. The ultrastructure changed with the course of simulated weightlessness and tended to return to normal. It showed an adaption to the simulated weightlessness.