帕金森病大鼠模型额叶皮质的代谢及形态改变

目的：探讨帕金森病中大脑额叶皮质的形态及代谢改变。方法：大鼠实验组于6-OHDA毁损后用BIOSPEC47／30磁共振波谱仪(4．7T)，采用点分辨波谱法对双侧额叶皮质行H-MRS检测，分析该区N-乙酰天门冬氨酸／肌酸(NAA／Cr)和胆碱／肌酸(Cho／Cr)比值的变化，并用电镜观察该区神经元及突触的形态变化。结果：实验组大鼠损毁侧额叶皮质．NA．A／Cr比值显著低于对侧，对照组两侧无显著差别；Cho／Cr比值在两组的两侧相比均无显著差别。电镜观察显示：损毁侧额叶皮质的突触数量较对侧减少，突触前、后膜和突触小泡结构异常，典型突触结构消失，树突棘出现大片低电子密度区，细胞器消失。结论：帕金森病大鼠模型损毁侧额叶皮质内存在神经元缺失或突触数量的减少，突触结构异常及功能异常。

Morphological and metabolic changes of frontal cortex in rat Parkinson's disease model

Objective: To investigate the morphological and metabolic changes of frontal cortex of Parkinson's disease rats. Methods:Three to five weeks after lesion, 4 rats of model group and 2 rats of pseudosurgery group were examined using 4.7T BIOSPEC47/30 MRS for analyzing the changes of NAA/Cr and Cho/ Cr of bilateral frontal cortex. The ultrastructural changes of the neurons and synapses were observed by electronic microscope. Results: The ratio of NAA/Cr in frontal cortex was obviously lower in lesion side than that of the control group, while the contralateral side showed no changes. In PD rats the ratio of NAA/Cr was also decreased compared with the other side. These phenomena did not present in control group. The PD rat groups showed the ratio of Cho/Cr had no distinct change on 2 sides. The same result appeared in the lesioned rats with the control group. Compared with the unlesioned side, the density of synapse in frontal cortex on the lesion side was decreased. There were abnormal changes of the structure of presynaptic membrane, postsynaptic membrane and synaptic vesicles. The typical synaptic structure disappeared and large areas of low electronic density could be seen in dendric spines with the matrix utensils disappeared. Conclusion: There are losses of neuron or the synapse decrease and the abnormal synaptic structure in frontal cortex in lesion side of PD rats.