亚低温对大鼠颅脑损伤后不同时段线粒体DNA缺失和酶活性变化的影响

摘要

Objective To investigate the effects of mild hypothermia on rat brain neuron mitochondria DNA deletion and the changes of enzymatic activity in different times after severe head injury and to determine the best treating time. Methods Severe head injury treated with mild hypothermia model was set up. Rats were divided into normal group, trauma groups (6 ,12 ,24 ,48 ,72, 96 ,120 h) and cooling groups (6,12,24,48,72, 96,120 h) randomly. mtDNA deletion was measured by PCR. The activity of mito-chondria Na -K -ATPase and cytochrome oxidase was measured. Results Deletion/total mtDNA in trauma and cooling groups were higher than that of normal group (P<0. 05). Deletion/total mtDNA presented uptrend in trauma groups (6 ,12 ,24 ,48 h) and cooling groups (6,12,24,48 h). The activity of cytochrome oxidase in trauma and cooling groups was lower than that of normal group (P<0. 05). The activity of cytochrome oxidase presented droptrend in trauma groups (6,12,24,48h) and cooling groups (6 , 12 ,24 ,48 h). The activity of Na+-K+-ATPase in trauma and cooling group was lower than that of normal group (P<0. 05). The activity of Na+-K +-ATPase presented droptrend in trauma groups (6,12,24,48 h) and cooling groups (6,12,24,48 h). Deletion/ total mtDNA,the activity of mitochondria Na+-K+-ATPase and cytochrome oxidase showed no differences in trauma groups(72, 96,120 h) and cooling groups (72,96,120 h). Conclusion Hypothermia treatment played a therapeutic role in rat brain mtDNA deletion and the failure of neuron energy within 72 h after injury.%目的 研究亚低温对颅脑损伤后不同时间神经细胞线粒体DNA(mtDNA)缺失及缺失DNA所编码的酶活性变化的影响,并探讨最佳治疗时程.方法 建立重型颅脑损伤及亚低温治疗重型颅脑损伤动物模型并进行区组随机化分组.分为正常组,损伤6、12、24、48、72、96、120 h组,降温6、12、24、48、72、96、120 h组,共15组,每组15只大鼠.检测mtDNA的缺失,线粒体Na+-K+-ATP酶及细胞色素氧化酶的活性.结果 损伤及降温各组的缺失/总mtDNA的比值较正常组均明显升高(P<0.05).损伤6、12、24、48 h组及降温6、12、24、48 h组的缺失/总mtDNA的比值均呈逐渐上升趋势.损伤及降温各组细胞色素氧化酶活性较正常组均明显下降(P<0.05).损伤6、12、24、48 h组及降温6、12、24、48 h组的细胞色素氧化酶活性均呈逐渐下降趋势.损伤及降温各组Na+-K+-ATP酶活性较正常组均明显下降(P<0.05).损伤6,12,24,48 h组及降温6,12,24,48 h组的Na+-K+-ATP酶活性均呈逐渐下降趋势.损伤72、96、120 h组及降温72、96、120 h组中缺失/总mtDNA的比值、细胞色素氧化酶活性和Na+-K+-ATP酶活性比较差异均无统计学意义(P>0.05).结论 亚低温治疗在一定的时间范围内对大鼠颅脑损伤后的脑线粒体能量代谢障碍和mtDNA缺失有保护作用.