大鼠深低温停循环抑制Akt信号通路影响认知功能

Deep hypothermic circulatory arrest impairs cognitive function by inhibiting Akt signaling pathway in rats

目的:探究大鼠深低温停循环(DHCA)术后脑损伤情况及作用机制。方法:建立大鼠深低温停循环模型,16只SD大鼠随机分成假手术组和DHCA组。再灌注4 h后Western blot法检测海马组织丝氨酸/苏氨酸激酶(Akt)、磷酸化丝氨酸/苏氨酸激酶(p-Akt)、B淋巴细胞瘤/白血病-2(Bcl-2)、Bcl-2相关X蛋白(Bax)和活化胱天蛋白酸-3(cleaved caspase-3)表达水平。HE染色及尼氏染色评估术后第7天海马CA1区神经元损伤情况。Morris水迷宫评价大鼠学习记忆、空间感知及运动能力。结果:与假手术组相比,DHCA组海马CA1区p-Akt、Bcl-2的蛋白表达水平降低,Bax、cleaved caspase-3的蛋白表达水平升高(P均<0.05),两组Akt的蛋白表达水平无统计学差异。DHCA组病理评分明显高于假手术组,正常神经细胞数量均明显低于假手术组,大鼠逃避潜伏期、跨越原平台次数及运动速度均明显弱于假手术组(P均<0.05)。结论:DHCA通过抑制Akt信号通路介导神经细胞凋亡,对大鼠认知等功能造成损伤。

Objective:To observe the brain injury after deep hypothermic circulatory arrest(DHCA)in rats,and to investigate the mechanism of it.Methods:A rat model of DHCA was established.Sixteen Sprague-Dawley rats were randomly divided into sham operation group(Sham group)and DHCA group.The expression of serine/threonine protein kinase(Akt),phosphorylation Akt(p-Akt),B-cell lymphoma/leukemia-2(Bcl-2),Bcl-2 associated X protein(bax)and cleaved cysteine aspartyl protease-3(caspase-3)in hippocampus were detected by western blot analysis four hours after reperfusion.Hematoxylin-eosin(HE)staining and Nissl staining were used to evaluate the neuronal damage in hippocampal CA-1 sector on the 7th day after operation.Morris water maze was used to evaluate the learning,memorizing,space perception and exercise capacity in rats.Results:Compared with the Sham group,the expression of p-Akt and Bcl-2 in the hippocampus CA-1 sector of DHCA group was lower,while the expression of Bax and cleaved-caspase 3 was increased(all P<0.05).And there was no statistically difference between the two groups in terms of the expression of Akt.The pathological score in the DHCA group was higher than that in the Sham group,while the number of survival neurons in the DHCA group was fewer than that in the Sham group.Comparing with the Sham group,in the DHCA group the escape latency was longer,and the times of crossing platform were shorter with slower movement(all P<0.05).Conclusions:DHCA can mediate neuronal apoptosis by inhibiting Akt signaling pathway,and impair cognitive function in rats as result.