不同缺血再灌注时间对脑梗死大鼠运动及认知功能的影响

关键词：短暂性大脑中动脉闭塞  缺血再灌注  运动  认知

Keywords:transient middle cerebral artery occlusion  ischemia reperfusion  motor  cognition

摘要：

      摘要 目的：比较不同缺血再灌注时间对短暂性大脑中动脉闭塞（transient middle cerebral artery occlusion, tMCAO）大鼠的运动及认知功能的影响。 方法：取穿梭箱主动回避率超过70%的大鼠60只随机分为4组：根据Bederson评分及存活率缺血再灌注60min组（n=8）、90min组（n=11）、120min组（n=7）及假手术组（n=7）纳入最终行为学研究。术后28天行TTC染色计算梗死体积。于术后第1、3、7、14、21、28天进行改良神经功能缺损程度（mNSS）评分，第3、7、14、21、28天进行前肢抓握力测试；于术后第14、21、28天进行穿梭箱测试。 结果：缺血再灌注时间越长，大鼠的生存率越低（χ2=12.694，P=0.005）；梗死体积随缺血再灌注时间增加而增大（F=14.056，P=0.01）。缺血时间越长，mNSS评分越高（F=9.100，P=0.001）；梗死组较假手术组抓握力量减小（F=11.630，P＜0.05）；穿梭箱实验显示各时间点90min组主动回避率较假手术组降低（P＜0.05），120min组第14、21天时较假手术组主动回避率降低（P＜0.05）。 结论：tMCAO大鼠随缺血再灌注时间延长，运动功能障碍严重程度增加，缺血60min再灌注不出现认知功能障碍，且因运动功能自发性恢复速度快，不适用于认知功能及长期运动功能行为学测试。缺血90min、120min出现认知功能障碍。

Abstract:

      Abstract Objective: To compare effects of different duration of ischemia reperfusion on transient middle cerebral artery occlusion (tMCAO) rats’ motor and cognitive function. Method: Sixty Sprague-Dawley rats with 70% active avoidance response rate (AARR) were randomly divided into four groups: 60min group（n=8）, 90min group（n=11）, 120min group（n=7） and sham group（n=7） were included in the final behavioral study according to Bederson score and the survival rate. Infarcted volume ratio was calculated by TTC staining. Each group was assessed with modified neurological severity scores(mNSS) on days 1, 3, 7, 14, 21 and 28 after operation; Forelimb grip strength test was carried out on days 3, 7, 14, 21 and 28 after operation; Shuttle box test was assessed on days 14, 21 and 28 after operation. Result: With the duration of ischemia reperfusion became longer, the survival rate decreased (χ2=12.694, P=0.005). The infarct volume was larger with the extended reperfusion time (F=14.056, P=0.01). The mNSS was higher in longer ischemic duration groups (F=9.100, P=0.001). There was a significant difference in the forelimb grip strength between ischemia groups and the sham group (F=11.630, P＜0.05). 90min group had a lower AARR at every time point compared to the sham group (P＜0.05). AARR was lower in 120min group than that in the sham group on days 14 and 21 (P＜0.05). Conclusion: The severity of motor dysfunction was associated with the duration of ischemia in tMCAO rats. 60min ischemia reperfusion do not induce cognitive dysfunction with rapid motor function recovery, which may not be suitable for cognitive and long-term motor behavior tests. 90min and 120min ischemia reperfusion can induce cognitive dysfunction.