糖尿病大鼠认知功能障碍与脑形态学改变关系的研究

A study on the association of cognition with cerebralmorpltological change in streptozotocin-diabetic rat

目的通过观察糖尿病早期1～3个月时大鼠学习记忆功能及脑组织形态学改变，探讨糖尿病中枢神经系统病变的发病机制。方法雄性Wistar大白鼠35只，分为STZ糖尿病组和正常对照组。于糖尿病成模后1个月行水迷宫实验，于1个月、3个月行脑组织海马区免疫组化及海马、颇叶皮层、隔区电镜超微结构检查。结果两组于1个月时血糖、体重有显著性差异（P＜0．001）。水迷宫试验游泳时间STZ－DM组显著长于对照组（P＜O．01）。高血糖3个月时，糖尿病组海马NT－3阳性染色较正常对照组明显减少，NF染色阳性神经元突起排列紊乱、不连续。透射电镜检查糖尿病1个月时已经出现预叶皮层、海马等神经元的退行性改变，但无明显毛细血管基底膜增厚等改变。3个月时神经元的退行性改变较前更加明显。结论糖尿病早期出现的脑组织形态及学习记忆功能的损害，可能主要是由高血糖直接引起的。

Objective To study the impact of hyperglycemia on the central nervous system. Methods 35 maleWistar rats (BW 150--2009) were divided into STZ-diabetic group (n ~ 20), and normal control group (n ~ 15). Atthe first, second and third month of DM, water maze test, brain ultrastructure and immunohistochemistry of NF, NT3 were studied separately. Results After one month of diabetes, significant differences of blood glucose and bodyweights were found between the two groups (P ado. 001). The swimming time of water maze test also had significantdifference as early as at 1 month of diabetes (P <0. 01). There were less NT--3 immu no histochemicall y pos it ive s tamedneurons, the a-cons of NF positive neurons became disordered and discontinued in STZ-DM group. Under transmissionelectron microscopy scattered degenerative changes of neurons in the rat hippocampal CAI region, temporal cortex, andseptal area were found after one month of diabetes I but no thickening of capillary basement membrane was detected atthe same time. Conclusion Hyperglycemia may directly cause the cerebral morphological damage and abnormalcognition in the early stage of diabetes.