脑缺血大鼠海马CA1、CA3区及齿状回钙神经素的表达与学习记忆损伤的关系

The expression of CaN in CA1,CA3 and dentate gyrus of rat model of learning and memory disorder induced by cerebral ischemia

目的:建立脑缺血致大鼠学习记忆障碍模型,通过免疫组化检测海马CA1、CA3区和齿状回钙神经素(CaN)的分布与表达,探讨海马内CaN的表达与脑缺血后学习记忆损伤的关系。方法:SD雄性大鼠54只,随机分为对照组、假手术组、缺血组、缺血再灌注组,对后3组大鼠建立模型。大鼠造模后1周进行Morris水迷宫学习获得实验,3周后进行记忆保持实验。实验结束后取海马组织,HE染色观察海马CA1、CA3区及齿状回组织细胞形态,免疫组化法检测CaN的表达。结果:(1)与对照组及假手术组相比,缺血再灌注组海马病理学变化、学习记忆损伤程度最明显。(2)与对照组及假手术组相比,缺血组与缺血再灌注组CA1、CA3区及齿状回的CaN阳性细胞数明显增多(P<0.05);假手术组与对照组CA1、CA3区及齿状回的CaN阳性细胞数相比较差异无统计学意义;缺血组与缺血再灌注组CA1区和齿状回的CaN阳性细胞数相比较差异无统计学意义;缺血组CA3区CaN阳性细胞数与缺血再灌注组阳性细胞数差异有统计学意义(P<0.05)。结论:缺血组、缺血再灌注组大鼠学习记忆功能明显损伤,其海马CA1、CA3区及齿状回CaN表达明显增多,提示海马内CaN可能与大鼠脑缺血致学习记忆障碍有关。

Objective To establish the rat model of learning and memory disorder induced by cerebral ischemia. Immunohistoehemical method was employed to detect the CaN expression and localization in CA1, CA3 and dentate gyrus of hippocampal in order to explore the correlation between CaN expression of hippocampal and learning and memory disorder induced by cerebral ischemia. Methods Fifty-four SD male rats were randomly divided into 4 groups： control group, sham operated group, cerebral ischemia group and cerebral ischemia reperfusion group. Set rats models for the later three group. All rats were conducted by the Morris water maze test after one week. And three weeks later, all rats were conducted by the Morris maze memory maintenance trial. After all experiments finished, HE staining and immunohistochemistry method were used to observe cell morphologic change and CaN expression of CA1, CA3 and dentate gyrns, respectively. Results （1） Compared with control group and sham operated group, the most significant pathological changes in hippocampus and impairment of learning and memory disorder were observed in cerebral ischemia reperfusion group. （2） Compared with control and sham operated groups, the numbers of CaN positive cells in cerebral ischemia group and cerebral ischemia reperfusion group were significantly increased （P 〈 0.05）. There was no obvious difference of the numbers of CaN positive cells in CA1, CA3 and dentate gyrus between sham operated groups and control group. There was no obvious difference of the numbers of CaN positive cells in CA1 and dentate gyrns between cerebral ischemia group and cerebral ischemia reperfusion group. But the numbers of CaN positive cells in CA3 in cerebral ischemia group was less than that in cerebral ischemia reperfusion group （P 〈 0.05）. Conclusions The learning and memory function in cerebral ischemia group and cerebral ischemia reperfusion group were dominantly impaired, and CaN expression in CA1, CA3 and dentate gyrus of hippocampal tissue were increased significantly. The expression of CaN in hippocampal tissue might be correlation with learning and memory disorder of rats, which induced by cerebral ischemia.