早期糖尿病大鼠Morris水迷宫及神经血管单元超微结构观察

A study of Morris water maze and ultrastructure alteration of neural-vascular unit in early stage diabetic rat

目的观察早期糖尿病大鼠学习记忆行为学及脑组织超微病理学改变。方法45只雄性SD大鼠分为对照组、糖尿病1组与糖尿病2组,腹腔注射链脲佐菌素(Streptozocin,STZ)制备糖尿病大鼠模型,糖尿病2组饲以高脂饮食;成模5周检测各组大鼠体重、血糖,行Morris水迷宫实验检测学习与记忆功能,用透射电镜观察大鼠海马及额、颞叶皮层超微结构改变。结果成模5周后,糖尿病组与对照组大鼠体重及血糖有显著性差异(P<0.01)。Morris水迷宫定向航行实验:游泳速度糖尿病2组与对照组间有显著差异(P<0.01);与糖尿病1组间有显著差异(P<0.05)。超微组织病理学观察:成模5周时糖尿病1组、2组海马及额叶、颞叶皮层神经元出现退行性改变,毛细血管管周足突水肿明显,血管管腔狭窄;固缩神经元旁见小胶质细胞附着。结论早期糖尿病大鼠Morris水迷宫实验游泳速度增快,潜伏期无缩短,系搜索策略评分低、游泳距离增多所致,其游泳速度表现为无效速度。早期糖尿病大鼠海马及额、颞叶皮层神经血管单元受损,糖尿病高脂饮食组损害最为显著。

Objective To investigate the alteration of learning and memory function and brain ultrastructure in early stage diabetic rats. Methods 45 male SD rats were divided into 3 groups ： control group, diabetes group 1 and diabetes group 2. Diabetic rat models were made by injection of Streptozocin, diabetes group 2 was fed with high fat diet. After 5 weeks of diabetes, following detections were carried out ： body weight and blood glucose measurment, Morris water maze experiment to test learning and memory function, and transmission electron microscope to observe uhrastructure alteration of hippocampus,frontal lobe and temporal lobe in rats. Results 5 weeks after diabetes, there was significant difference in body weight and blood glucose between diabetes groups and control group（ P 〈 0.01 ）. In Morris place navigation test, there were significant difference in swimming speed between diabetes group 2 and control group（ P 〈0.01 ） ,and there was also statistical difference in every diabetes group（P 〈 0.05 ）. Under transmission electron microscope, degenerative changes of neurons of both diabetes groups in hippocampus and cerebral cortex were detected, with obvious swelling in end foot of astrocytes were noted ; the cavities of capillaries became narrow;microglial cell attached to the abnormal neurons. Conclusions In Morris place navigation test, diabetic rats swam further distances due to their poor searching strategy. Their fast swimming speed was considered ineffective because of their unshortened latency. Neural-vascular unit in hippocampus and cortex of early stage diabetic rats was injured. Damage in the diabetes group with high fat diet was the most serious.