局灶性脑缺血再灌注时神经元、胶质细胞形态变化与TNF-α、c-Myc表达相关的实验研究

目的:探讨局灶性脑缺血再灌注时神经元、神经胶质细胞形态变化特点和TNF-α、c-Myc表达的相关性。方法: 采用线栓法大鼠大脑中动脉阻塞复制局部脑缺血再灌注模型,缺血2 h分别再灌注1 d、3 d、7 d,应用光镜和免疫组化法,观察缺血侧额顶叶皮质神经元,神经胶质细胞形态变化及TNF-α、c-Myc蛋白表达。结果: 局灶性脑缺血再灌注后,同侧额顶叶皮质梗死区神经元、小胶质细胞、星形胶质细胞出现变性、坏死,梗死灶周围小胶质细胞和星形胶质细胞增生,呈现时间相关性,变性、死亡以再灌注3 d最为显著,星形胶质细胞和小胶质细胞增生以再灌注7 d最为显著且位于梗死周围区。再灌注后,TNF-α、c-Myc阳性细胞表达也显著增加,以再灌注3 d最为显著,且主要表达于星形胶质细胞、小胶质细胞,少量表达于神经元。结论: 脑缺血再灌注后神经元、神经胶质细胞之间在损伤、抗损伤及修复中相互影响,而TNF-α、c-Myc蛋白表达的增加可能是联系不同细胞间相互作用的主要调节物质之一。

Relationship between morphologic changes in neuron or neuroglial cells and expression of TNF - α and c - Myc in cortex after focal cerebral ischemia/reperfusion in MCAO rats

AIM: To investigate the relationship between morphologic changes in neuron or neuroglial cells and expression of tumor necrosis factor α (TNF-α) and c-Myc in cortex after focal cerebral ischemia/reperfusion in MCAO rats. METHODS: The focal cerebral ischemia/reperfusion model was established by intraluminal thread occlusion of the middle cerebral artery (MCAO). The middle cerebral arteries of rats were occluded for 2 hours and reperfused for 1, 3 and 7 days. Using the techniques of immunohistochemical staining and optical microscopy, the morphologic changes in neuron or neuroglial cells were observed in the cortex of frontal or parietal lobe; the cell types which dynamicaly expressed TNF-α, c-Myc in the different period were also observed. RESULTS: The degeneration or necrosis of neuron or neuroglial cells were observed at the center of infarction, it was very serious at 3 d after reperfussion. Astrocyte and microglial cell proliferation were observed at the broder of infarction. TNF-α and c-Myc positive cells, most of which were astrocytes and microglial cells, increased significantly at 3 d after reperfusion. CONCLUSION: TNF-αand c-Myc may play an important role in the regulation of neuron or neuroglial cells after focal cerebral ischemia with reperfusion.