糖尿病加重大鼠脑缺血再灌注损伤的研究

Study on exacerbation of cerebral ischemical reperfusion injury caused by diabetes in rats

目的:建立稳定的慢性实验性糖尿病大鼠脑缺血再灌注损伤模型,明确糖尿病与正常大鼠脑缺血损伤的异同之处。方法:以链脲佐菌素诱导产生实验性糖尿病大鼠,饲养40d左右,经测定血糖(大于13.5mmol/L)确定糖尿病模型的建立。以线栓法制作大鼠脑缺血再灌注模型,测定脑血流和梗死体积、进行神经功能评分,行苏木精-伊红染色和Luxol坚牢蓝-甲苯紫染色,观察超微结构的变化,用胶质纤维酸性蛋白标记来观察星形胶质细胞的激活情况。结果:糖尿病大鼠比正常大鼠再灌注时,脑血流恢复差犤再灌注23h时,缺血中心区血流分别为(40.3±7.5)%和(48.2±5.5)%,半暗区血流分别为(55.0±5.5)%和(64.5±5.8)%,t分别为2.40,3.25,P<0.05犦,神经功能评分高(分别为2.85±1.23和1.23±0.44,t=4.51,P<0.01),梗死体积大犤分别占各自对侧体积的(28.3±8.10)%和(14.8±7.8)%,t=3.39,P<0.01犦,光镜和电镜观察显示脑组织缺血损害和髓鞘脱失时程提早且更为严重,早期胶质细胞激活差。结论:从组织形态学等方面证实本模型的可靠性和可重复性,揭示实验性糖尿病大鼠脑缺血再灌注损伤重于正常大鼠。

AIM: To establish model of cerebral ischemia/reperfusion (CI/R ) injury in chronic experimental diabetic rats, and to compare the differences between diabetic and normal rats after CI/R. METHODS: The diabetic rats induced by streptozotocin were bred for 40 days, the diabetic model was confirmed by measuring the blood glucose (>13.5 mmol/L). The focal CI/R model was operated with the thread occlusion method, the blood flow in brain, area of infarction and score of neurological function were measured. Hematoxylin eosin(H E) staining and Klüver Barrera (KB) staining were made to the model, the changes of ultrastructure were observed, the activation of astrocyte was observed by the marking of glial fibriliary acidic protein (GFAP). RESULTS: The blood flow in the ischemic core [(40.3±7.5)%, (48.2±5.5)%] and penumbra [(55.0±5.5)%, (64.5±5.8)%] reduced more significantly in diabetic rats than those in normal rats during reperfusion 23 h (t=2.40,3.25, P< 0.05). The score of neurological function (2.85±1.23, 1.23±0.44,t=4.51, P< 0.01) was higher and the infarction area [(28.3±8.10)%, (14.8±7.8)%of contralateral volume, t=3.39, P< 0.01] increased more significantly in diabetic rats than those in normal rats., The brain tissue injury appeared earlier and more seriously showed by light microscope and electron microscope, the loss of myelin showed by KB staining was more serious and astrocyte activation was lower showed by GFAP staining in diabetic rats. CONCLUSION: The reliability and reproducibility of the model is confirmed by histomorphology, CI/R in experimental diabetic rats is more serious than that in normal rats.