丰富环境干预强度对脑缺血大鼠肢体功能及神经生长相关蛋白的影响

摘要

Objective:To observe the effects of enriched environment(EE) intervention of different intensities on sensorimotor functional and neuropathological recovery after cerebral ischemia in rats, and further to explore the mechanism of neural plasticity.rnMethod: Permanent middle cerebral artery occlusion(MCAO) model was replicated by string ligation,and Sprague-Dawley rats were divided into 5 groups: a sham-operation group, and a model group were reared in standard cage and other 3 groups were reared in an EE cages lasted lh, 12h and 24h daily respectively for 20d (n= 17 rats/group). The limb sensorimotor function was evaluated with beam-walking, bar-grasping and tactile stimulation test at 20d post ischemia; the pathological changes of neurons and Nissl bodies of sensorimotor region of cortex were observed by Nissl staining and image analysis technology. Western blot method was used to evaluate the expression of nerve growth associated protein-43(GAP-43) of ischemia cortex 20d post ischemia. Result:EE intervention for 12h and 24h daily could promote the limb sensorimotor functional recovery of ischemia rats,and increase the number of neurons, relieve the Nissl bodies depigmentation and upregulate the expression of GAP-43 in sensorimotor region of cortex. But EE intervention for lh could promote the recovery of tactile sensitivity or fine motor function only, compared with 12h and 24h groups there was no significant difference of beam-walking ability, bar-grasping evaluating and pathological changes in sensorimotor region of cortex(P<0.01 or 0.05).rnConclusion: EE intervention of a certain intensties could promote the limb sensorimotor functional recovery, the possible mechanisms were protecting the neurons, increasing the expression of GAP-43 and promoting axonal re-genaration.%目的:探讨丰富环境(EE)的不同干预强度对脑缺血大鼠肢体运动感觉功能及神经病理学的影响,并从神经可塑性角度探讨其机制.方法:线栓法建立永久性大脑中动脉缺血(MCAO)模型,随机分为5组:假手术组、模型组,以及丰富环境干预1h组、12h组、24h组.横木行走、抓握力量、触觉刺激实验评价肢体运动感觉功能的变化;尼氏染色结合图像分析技术观察皮质运动感觉区神经元及尼氏体的病理变化;Western blot检测神经生长相关蛋白GAP-43的表达.结果:每天1h丰富环境干预可增加缺血大鼠触觉敏感度(P＜0.05),但对横木行走能力、前肢抓握力量及神经病理学没有明显影响;12或24h丰富环境干预,可增强肢体运动感觉功能,增加皮质运动感觉区神经元数量,减轻尼氏体脱失程度,上调GAP-43蛋白表达,较模型组有显著性差异(P＜0.01或P＜0.05).结论:适宜强度丰富环境干预可促进脑缺血大鼠肢体感觉功能康复,其机制可能与上调GAP-43蛋白表达和促进神经元轴突再生有关.