胰岛素对痴呆鼠的保护作用及机制

目的探讨胰岛素对痴呆模型大鼠学习记忆能力的影响及其可能机制。方法设立正常组、拟阿尔茨海默病(AD)模型组、盐水治疗对照组及胰岛素治疗组共4组。采用凝聚态Aβ1～40进行海马CA1区微量注射建立拟AD大鼠模型,术后第2天治疗组分别皮下注射0.9%生理盐水(1 ml/kg)和速效胰岛素(1 U/kg)。造模2 w后进行水迷宫行为学试验检测大鼠学习记忆能力,用药3 w后行病理学检查和免疫组化方法观察海马CA1区Aβ1～40的表达。结果拟AD大鼠模型组与正常组相比,其学习记忆能力明显下降;胰岛素治疗组学习记忆成绩优于模型组(P<0.05),且海马CA1区Aβ1～40表达明显减少或消失,减轻凝聚态Aβ1～40对大鼠海马的病理损害。结论胰岛素能改善AD模型大鼠学习记忆能力,为临床合理应用胰岛素治疗AD提供一定的理论依据,海马CA1区Aβ1～40表达减少或消失是其可能机制。

Protective effect of insulin on rat with Alzheimer's disease and the mechanism

Objective To study the effects of insulin o n the learning and memory abilities of Alzheimer′s disease(AD) rats and reveal the mechanism. Methods 4 groups of experiment were set: the contrast,si mulated AD model,contrast of N acl and insulin treated groups.AD model rats were built by microinjection of a g gregated Aβ1~40 at hippocampal CA1 area,and were hypodermic injected wit h 0.9 % Nacl(1 ml/kg) or insulin(0.1 U/kg) separately in the next day.2 weeks afte r the modeling,the 4 groups were tested with water maze about the study and memor y function of rats.3 weeks after the injection,the expression of Aβ1~40 at h i ppocampal CA1 area was examined by pathological tests and immune histochemical m ethods. Results The study and memory abilities of rats were ameli orated signific antly in place navigation test and spatial probe test after the application of i nsulin indicating that insulin may amend the study and memory abilities of AD ra ts.Insulin can decrease the expression of Aβ1~40 at hippocampal CA1 are a to r educe the pathological damage of Aβ1~40 to the hippocampal area of rats. Conclusions The effect of insulin on improving the study and memory function is a theo retical proof of the clinical application of insulin against AD.The decreasin g of expression of Aβ1~40 at hippocampal CA1 area is the possible mechanis m of i nsulin on AD rats.