目的 观察丰富环境对脑缺血再灌注(cerebral ischemia reperfusion,CIR)大鼠学习记忆能力和神经功能评分及脑源性神经营养因子(brain-derived neurotrophic factor,BDNF)表达的影响,探讨丰富环境的脑保护机制.方法 选取50只成年雄性SD大鼠,采用Longa法建立大鼠大脑中动脉缺血再灌注模型.将大鼠随机分为假手术组(n=10)、脑缺血组(n=20)和丰富环境组(n=20).分别于丰富环境干预的第1天及第30天对各组大鼠行神经功能评分;采用免疫荧光染色检测大鼠海马CA1区BDNF蛋白的表达情况.于丰富环境干预30天后进行连续5天的Morris水迷宫实验评定大鼠的学习记忆能力.结果 丰富环境干预的第1天,脑缺血组和丰富环境组大鼠的神经功能评分和BDNF蛋白表达均高于假手术组(均P<0.05),而脑缺血组和丰富环境组间比较无统计学差异(均P>0.05);丰富环境干预的第30天,丰富环境组大鼠神经功能评分低于脑缺血组,但BDNF蛋白表达高于脑缺血组(均P<0.05).与假手术组比较,脑缺血组及丰富环境组大鼠的逃避潜伏期延长,跨越平台次数减少(均P<0.05),而与脑缺血组比较,丰富环境组逃避潜伏期缩短,跨越平台次数增加(均P<0.05).结论 丰富环境能明显改善脑缺血再灌注大鼠的学习记忆能力,提高神经功能评分,其机制可能与上调海马CA1区的BDNF蛋白表达有关.%Objective To observe the effects of enriched environment on the abilities of learning and memory and neurological function score of rats after cerebral ischemia reperfusion (CIR) and the expression of brain-derived neurotrophic factor (BDNF) and explore the possible mechanism of brain protection with enriched environment. Methods Fifty adult male SD rats were selected to establish the model of middle cerebra artery occlusion. The rats were randomly divided into the sham operation group (n=10) ,cerebral ischemia group (n=20) and enriched environment (EE) group (n= 20) . The expression of BDNF protein in the hippocampus CA1 region was assessed by immunofluorescent staining of rats in each group on the first day and the thirty day of the enriched environment intervention. After 30 days of enriched environment intervention ,Morris water maze test was conducted to assess the learning and memory abilities of rats for consecutive 5 d. Results On the first day of enriched environment intervention ,the neurological function scores and the expression of BDNF protein of rats in the cerebral ischemia group and the EE group were higher than that in the sham operation group (all P<0.05) ,but there was no significant difference between the two groups (all P>0.05) . However ,on the thirty day of enriched environment intervention ,the neurological function score in the EE group was lower than that in the cerebral ischemia group (P<0.05) ,and the expression of BDNF protein was higher in the EE group than that in the cerebral ischemia group (P<0.05) .Compared with the sham operation group ,the evasive incubation period of rats in the cerebral ischemia group and the EE group were prolonged and the number of crossing platforms decreased (all P< 0.05);the evasive incubation period of rats were shortened and the number of crossing platforms increased in the EE group compared with the cerebral ischemia group (all P < 0.05) .Conclusions EE plays a positive role in reinforcing the learning and memory ability and improving the neurological function score ,which may be related to the up-regulation of BDNF protein in CA1 of hippocampus.
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