亚低温对颅脑创伤大鼠脑线粒体活性氧和ATP酶合成能力的影响

The Influence of Moderate Hypothermia on ROS and ATP Synthesis of Mitochondria in Traumatic Brain Injury

目的:研究亚低温治疗对颅脑创伤(TBI)大鼠线粒体活性氧(ROS)生成和ATP酶合成能力的影响。方法:72只动物随机分为假手术组、常温TBI组(肛温36℃～37℃)、亚低温TBI组(肛温31℃～33℃,亚低温持续2h),后2组利用液压打击(FPI)制作中度TBI模型。各组于脑外伤后2h,24h,3d和7d断头取伤侧大脑组织,差速离心法提取伤侧脑线粒体,酶荧光法检测线粒体ATP合成能力,荧光法测定线粒体ROS的生成。结果:常温TBI组脑创伤后线粒体ATP合成能力显著下降,24h降至最低,至7d时仍显著低于假手术组,ROS在各时间点均显著升高,3d时为最高。亚低温TBI组线粒体ATP合成能力在各时间点均高于常温TBI组,除2h外,其他时间点ROS低于常温TBI组。结论:颅脑创伤后线粒体ATP合成能力显著下降,ROS显著升高,亚低温可以改善线粒体ATP酶合成能力,抑制活性氧大量生成,从而保护脑组织。

Objective： To study the effect of moderate hypothermia on cerebral mitochondrial reactive oxygen species （ROS） and ATP synthesis in with traumatic brain injury （TBI）. Methods： Seventy-two rats were randomly divided into 3 groups which included sham（uninjured ） control group, normothermic TBI group（37 ℃ ） and moderate hypothermic TBI group （31 ℃-32 ℃, 2 h ）. The moderate TBI model was founded with FPI. The ipsilateral brain was dissected and homogenized brain tissue was extracted to obtain mitochondria by density-centrifugation and speed-centrifugation 2 h,24 h,3 d,and 7 d after TBI. ROS and capacity of ATP synthesis were tested by fluorescent method. Results： The capacity of ATP synthesis in TBI group decreased,reached the lowest at 24 hours,and still lower than that in sham group 7 days after injury. ROS increased remarkably after TBI,and got highest level at 3 days. The capacity of ATP synthesis increased in hypothermia group than that in normothermic TBI group （P 〈 0.01 ）, and ROS decreased than that in normothermie TBI group except 24 hours （P 〈 0.01）. Conclusion： Hypothermia can take the protection of brain tissue after TBI by improving the capacity of ATP and inhibiting ROS production of the cerebral mitochondria.