心肺复苏后大鼠脑线粒体通透性转换孔变化在细胞能量代谢障碍中的作用及机制

The Role of MPTP in Energy Dysmetabolism of Neural Cells post Cardiopulmonary Resuscitation in Rats

目的研究大鼠心跳骤停/心肺复苏后神经细胞线粒体通透性转换孔的变化在能量代谢障碍中的作用及可能机制。方法首先建立窒息联合冰氯化钾致大鼠心跳骤停、心肺复苏的动物模型,断头后提纯大脑皮质组织内线粒体,采用分光光度法测定线粒体MPTP在不同时相的开放程度,应用高效液相法测定脑细胞ATP、ADP和AMP含量。结果心跳骤停/心肺复苏后大鼠神经细胞线粒体功能明显受损,ROSC后神经细胞MPTP持续处于开放状态,开放程度并不是瞬间增至最大,而是具有时间依赖性。ROSC后6h内神经细胞MPTP开放程度保持低水平,6h以后开始迅速大量开放,12h开放程度达到最大,24h开放程度略有缩小,表明线粒体开始收缩,至48h开放程度再次加大,72h又明显缩小,但未达到正常水平(P<0.05或P<0.01)。ROSC后各组ATP含量较对照组均下降(P<0.05或P<0.01),72h较对照组略有升高,但无统计学意义,各组比较线粒体合成ATP能力在CA/CPR并ROSC后呈双相变化即在ROSC后3h和24h分别出现两个合成低谷。结论 CPR后MPTP开放是加重神经细胞能量代谢障碍的主要原因,线粒体能量代谢和氧化磷酸化功能严重受损,导致ATP产生短时内骤降;促使了MPTP的进一步开放。

Objective To investigate the opening degree and rules of neurocyte mPTP post Cardiopulmonary resuscitation,and study the relationship between the mitochondria energy dysmetabolism and the MPTP. Methods Sprague Dawley rats＇ cardiac arrest was induced by asphyxiation and ice -cold for 5 minutes of no circulation. 56 male Sprague Dawley rats were randomly divided into 7 groups with each group of 8 rats. After cardiopuhnonary resuscitation, the rats were allowed to reperfuse spontaneously for 3h ,6h, 12h,24h,48h and 72h. The rats were killed by decapitation and the brains were removed,weighed and processed for isolation of mitochondria. Determinations of the mitochondrial permeability transition were based on the absorbance changes of the mitochondrial suspension at 540nm. The levels of ATP（ adenosine triphosphate） ,ADP（ adenosine diphosphate）and AMP（ adenosine monophosphate） in brain tissue were determinated by high performance liquid chromatography with uhraviolet detection. Results Mitochondrial respiratory function was severly injured after CA/CPR. MPTP of T Neural cells always remained opening post ROSC. The openiag degree of MPTP did not reach the peak instantly, while its change depended on time. It remained low level within 6h post ROSC ,then rapidly opened,till 12h reached the peak ,and at 24h post ROSC slightly shrunken. All these suggested that mitochondria started to shink. While at 48h the opening degree largen again, shrunken once more at 72h,but did not reach the normal level（P 〈 0.05 or P 〈 0.01 ）. While there existed two low point at 3hour and 24hour post cardiopulmonary resuscitation respectively. Conclusion The opening of mPTP is the main cause of neuroeyte energy dysmetabolism. it is critical to take measure to inhibit the opening of mPTP within 12h post ROSC.