环境刺激对缺氧缺血性脑损伤新生大鼠海马微管相关蛋白-2表达的影响

Effects of environmental stimulation on the expression of microtube associated protein-2 in hippocampus after hypoxic-ischemic brain damage in neonatal rats

目的探讨早期丰富环境刺激对缺氧缺血性脑损伤(HIBD)新生大鼠学习记忆能力和海马微管相关蛋白(MAP-2)表达的影响。方法7日龄SD大鼠结扎左侧颈总动脉,吸入氧体积浓度为8%氧氮混合气体,制作HIBD新生动物模型,制模后随机分为干预组和非干预组,同时设假手术对照组。采用早期丰富环境刺激进行干预,Morris水迷宫检测学习记忆能力、免疫组化和图像分析技术检测各组海马CA1区MAP-2的表达。结果干预组大鼠空间学习记忆能力和海马MAP-2免疫反应光密度值明显高于非干预组(F=30.862,P<0.01),而与对照组之间比较,差异无统计学意义(P>0.05)。结论早期丰富环境刺激有利于HIBD大鼠学习记忆能力的改善,海马MAP-2蛋白表达的变化可能参与了丰富环境对HIBD神经可塑性的影响机制。

Objective To study the effects of early and enriched environmental stimulation on learning and memory abilities, and on expression of microtube associated protein-2 （MAP-2） of hippocampal CA1 district after hypoxia-ischemic brain damage （HIBD） in neonatal rats. Methods Seven days old Sprague-Dawley rats were selected for this study. The HIBD models were established by ligation of left common carotid artery and then were exposed to 8% oxygen and 92% nitrogen mixture for 2 hours. The HIBD rats were randomly divided into two groups, intervention group and non-intervention group; the sham-operation rats were selected as control group. The rats in intervention group were kept in enriched environment in stimuli for 20 days; the rats in non-intervention group and control group were kept in a standard environment for the same period of time. Learning and memory abilities were measured by Morris water maze. The expression of MAP-2 was measured immuno-histochemically in paraffin sections of hippocampus. Results The leaming ability of rats in non-intervention group was much lower than those of intervention group and control group （P 〈0. 01 ）. The corrected optical densities （COD） of immunoreactive products of the MAP-2 of hippocampal CA1 district were significantly decreased in rats of non-intervention group compared with those of intervention group and control group （P 〈0. 01 ）. There was no significant differences in learning ability and amount of reactive COD of MAP-2 between rats in intervention group and those in control group （P 〉 0. 05 ）. Conclusions Early, enriched environmental stimulation can improve the leaming and memory abilities of neonatal rats after HIBD. The changes of MAP-2 in hippocampus are possibly associated with the influence of environment.