不同强度跑台运动对脑缺血大鼠学习记忆及细胞周期蛋白表达的影响

关键词：脑缺血  跑台运动  学习记忆  细胞周期蛋白A  细胞周期蛋白E

Keywords:global cerebral ischemia  treadmill running  learning and memory  CyclinE  CyclinA

摘要：

      摘要 目的：探讨不同强度跑台运动预处理对脑缺血大鼠学习记忆及细胞周期蛋白表达的影响。 方法：将80只健康雄性SD大鼠随机分为正常组（n=20）、模型组（n=20）、强度Ⅰ组（n=20）和强度Ⅱ组（n=20）。造模前2周开始对强度Ⅰ和强度Ⅱ组大鼠进行跑台运动训练，其中强度Ⅰ组设置为20m/min*30min，强度Ⅱ组使大鼠运动强度递增，在3min内由10m/min的速度提高到预定的19.3m/min的速度，保持速度直到力竭。用四血管阻断法（Pulsinelli 4VO法）制备全脑缺血模型，分别在建模后3h、6h、24h、48h进行HE染色法观察各组大鼠脑组织神经元细胞形态的变化情况，免疫组织化学染色法检测各组大鼠脑组织海马区细胞周期蛋白A（CyclinA）和细胞周期蛋白E（CyclinE）的表达情况。建模后48h大鼠在处死前采用水迷宫检测各组大鼠学习记忆功能。 结果：与正常组比较，其他三组神经元存活数目显著减少，逃避潜伏期明显延长，穿台次数明显减少，差异均有显著性意义（P＜0.05）。其中，模型组神经元存活数目、穿台次数明显少于强度Ⅰ组（P＜0.05），显著高于强度Ⅱ组（P＜0.05），逃避潜伏期明显长于强度Ⅰ组（P＜0.05），显著短于强度Ⅱ组（P＜0.05）。与正常组比较，模型组各时间点CyclinA、CyclinE的表达水平明显增加（P＜0.05）。这两个因子的表达在模型组中多于强度Ⅰ组（P＜0.05），但明显少于强度Ⅱ组（P＜0.05）。 结论：中强度的跑台运动可保护脑组织，改善全脑缺血大鼠学习记忆功能，但高强度的运动会产生不良反应，可能与调控全脑缺血再灌注大鼠细胞周期蛋白的表达有关。

Abstract:

      Abstract Objective: To investigate the effect of different intensity of treadmill running precondition on learning and memory ability and the expression of cell cycle protein in rats after global cerebral ischemia reperfusion. Method: Eighty healthy male SD rats were randomly divided into: normal group (n=20), model group (n=20), intensity Ⅰ group (n=20) and intensity Ⅱ group (n=20). Two weeks before surgery, the rats of the intensity Ⅰ group and intensity Ⅱ group were trained on treadmill. The speed of intensity Ⅰ group was 20m/min*30 (30%VO2max).The speed of intensity Ⅱ group was 10m/min at first, then accelerated to 19.3m/min in 3minutes(70%VO2max) and hold the speed until the rats get exhausted. Global cerebral ischemia model was formed by improved four-vessel occlusion according to Pulsinelli's method. The morphological changes of neural cells in hippocampus at each time point were observed with HE staining; The expressions of CyclinA and CyclinE at each time point were detected with immunohistochemical staining; Visual-spatial memory of rats was measured with Morris water-maze test at 48h after modeling. Result: Comparing with normal group, the rates of survival neurons and, the times of crossing the area where the platform had been located on previous trials decreased, the escape latency of rats and , the expression of CyclinE and CyclinA significantly increased in all other groups (P＜0.05). Furthermore, the rates of survival neurons, the times of crossing the area where the platform had been located on previous trials were less in model group than in intensity Ⅰ group (P＜0.05), and more than in intensity Ⅱ group (P＜0.05). In model group, the escape latency of rats and the expression of CyclinE and CyclinA were more than in intensity Ⅰ group (P＜0.05), and less than in intensity Ⅱ group (P＜0.05). Conclusion: The moderate intensity exercise precondition could protect nerve tissue and improve the function of learning and memory after global cerebral ischemia. , while the High intensity exercise may be negative, which may be relate to the regulation of cell cycle protein.