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目的:研究糖尿病高血糖大鼠海马星形胶质细胞形态和凋亡改变。方法:采用链脲佐菌素(STZ)诱导Ⅰ型糖尿病SD大鼠模型,并以正常SD大鼠作对照。分别于1、2、4周和8周用组织学、免疫组织化学、免疫荧光和Western Blot等方法对比研究糖尿病高血糖对大鼠海马区星形胶质细胞形态和凋亡的作用。结果:与正常对照比较,大鼠糖尿病高血糖1~2周,脑组织结构基本正常,海马区固缩神经元偶见,4~8周固缩神经元数明显(P<0.05),出现轻微脑水肿,星形胶质细胞胞体轻度肿胀;免疫荧光和免疫组织化学检测显示,糖尿病高血糖1~2周,星形胶质细胞胞体增大和突起增粗,4~8周时突起增粗变长,星形胶质细胞数量减少(P<0.05);Western Blot结果表明,大鼠糖尿病高血糖4~8周时,脑组织胶质原纤维酸性蛋白(GFAP)含量明显升高(P<0.05);免疫组化双标显示,糖尿病高血糖大鼠1~2周偶见cleavedcaspase-3阳性标记的星形胶质细胞(P<0.05),4~8周海马区双标阳性细胞数明显增多(P<0.01)。结论:大鼠糖尿病高血糖早期对星形胶质细胞可能有激活作用,而持续的糖尿病高血糖则可抑制海马区星形胶质细胞,并可能导致星形胶质细胞凋亡。
Objective: To study the changes of hippocampal astrocyte morphology and apoptosis in diabetic hyperglycemic rats. Methods: SD rats induced by streptozotocin (STZ) were used to induce type 1 diabetes mellitus, and normal SD rats were used as controls. Histological, immunohistochemical, immunofluorescence and Western Blot methods were used to compare the effects of hyperglycemia on the morphology and apoptosis of astrocytes in hippocampus of rats at 1, 2, 4 weeks and 8 weeks respectively. Results: Compared with the normal control group, the diabetic rats suffered from hyperglycemia for 1 to 2 weeks and their brain tissue structure was normal. The number of pyknosis neurons in hippocampus was occasionally increased (P <0.05) Brain edema and mild swelling of cell bodies of astrocytes. Immunofluorescence and immunohistochemistry showed that the astrocytes increased in size and protuberances increased in 1 ~ 2 weeks after hyperglycemia, (P <0.05). The result of Western Blot showed that the content of glial fibrillary acidic protein (GFAP) in brain tissue of diabetic rats increased significantly at 4 ~ 8 weeks (P < 0.05). Immunohistochemical double staining showed that the cleaved caspase-3 positive labeled astrocytes were occasionally seen in diabetic hyperglycemic rats for 1 to 2 weeks (P <0.05), and the number of double-labeled positive cells in hippocampus of 4 to 8 weeks was significantly Increased (P <0.01). CONCLUSION: The early stage of diabetic hyperglycemia may have an activation effect on astrocytes, while persistent hyperglycemia of diabetes may inhibit astrocytes in the hippocampus and may lead to apoptosis of astrocytes.