胰岛素对AD模型大鼠空间学习记忆能力的影响

THE EFFECT OF INSULIN ON THE SPATIAL LEARNING AND MEMORY ABILITIES OF THE ALZHEIMER'S DISEASE MODEL RATS

目的:探讨胰岛素对阿尔茨海默氏病(AD)模型大鼠学习记忆能力影响及其可能机制。方法:大鼠海马微量注射Okadaic acid(OA),胰岛素侧脑室注射。水迷宫实验检测大鼠学习记忆能力;Western blotting实验检测大鼠海马烟碱型胆碱能受体的表达;免疫组化观察大鼠脑内胶质纤维酸性蛋白(GFAP)的表达。结果:与对照组比较,模型组大鼠学习记忆能力明显下降(P<0.01),烟碱型胆碱能受体表达减少(P<0.05),GFAP免疫阳性星形胶质细胞增多(P<0.05)。与模型组相比,胰岛素组大鼠学习记忆能力明显提高(P<0.01),烟碱型胆碱能受体表达增多(P<0.05),GFAP免疫阳性星形胶质细胞减少(P<0.05)。结论:胰岛素提高AD模型大鼠的学习记忆能力可能与其改善模型鼠胆碱能系统功能及减少星形胶质细胞增生有关。

Aim： To investgate the mechnism through which insulin affect the learning and memory abilities of the Alzheimer＇ s disease-like rats. Methods： Okadaic acid（OA） was injected into the CA1 region of the rat hippocampus and the insulin was injected into the lateral cerebral ventricle of the rats. The learning and memory abilities of the rats were assessed through Morris water maze behavioral test, and the expressions of nicotinic acetylcholine receptors and GFAP were observed by Westem blotting and immunohistochemistry,respectively. Results： Compared with the control rats, the abilities of learning and memory were lowered significantly（ P 〈 0.01 ） and the expressions of the nicotinic acetylcholine receptors were decreased and the GFAP positive astrocytes were increased greatly in the model rats （ P 〈 0.05）. In the rats injected with insulin, it was found that their learning and memory abilities were improved significantly（P〈 0.01） and that the expression of the nicotinic acetylcholine receptors were increased and GFAP positive astrocytes were decreased obviously（ P 〈 0.05 ）, as compared with the model rats. Conclusion： Insulin is able to enhance the learning and memory abilities of the Alzheimer＇ s disease-like rats, possibly by improving the function of the acetylcholine system and decreasing the astrocytes proliferation in the brain.