高压氧对大鼠短暂全脑缺血半胱天冬酶-3的影响

为探讨高压氧 (HBO)对脑缺血半胱天冬酶 3 (简称caspase 3 )活性的影响 ,将 2 0 0～ 2 5 0 gSD大鼠分为缺血再灌注组 (I/R组 )、高压氧 (HBO)处理组及假手术组 ,以Pulsinelli等报道的四动脉阻断法建立脑缺血再灌注动物模型 ,缺血 2 0min,分别于再灌注 6、2 4、4 8及 96h取顶叶皮质匀浆 ,用显色法测定caspase 3活性。结果显示 :再灌注 6h ,HBO组及I/R组同假手术组相比 ,caspase 3活性无显著差异 (P >0 .0 5 ) ,但HBO显著高于I/R组 (P <0 .0 5 ) ;2 4h时间点HBO组及I/R组均高于假手术组 (P <0 .0 5 ) ,但前 2组之间无显著差异 ;4 8及 96h时间点HBO及I/R组虽高于假手术组 ,但差异无显著性意义 (P >0 .0 5 ) ,且此 2组间亦无显著差异 ,说明此时caspase 3已基本降至正常。提示全脑短暂性缺血再灌注后caspase 3被激活 ,缺血早期用HBO处理可促进其活化 ,而HBO处理多次后对凋亡的作用已不明显

Effect of Hyperbaric Oxygen on Cortical Caspase-3 Activity After Transient Global Cerebral Ischemia In Rats

To investigate the effect of hyperbaric oxygen(HBO)on caspase-3 activity, we devided 200～250 g Sprague-Dawlay rats into three groups: the ischemia/ reperfusion group(I/R), the group treated by HBO and the sham operated group(Sham-O)as the control. Global brain ischemia was induced by using a modified four vessel occlusion model originally described by Pulsinelli and Buchan. Cortex of parietal lobe was obtained and homogenized respectively at reperfusion time points of 6 h, 24 h, 48 h and 96 h after 20 minutes of ischemia. Then caspase-3 activity was measured by cleavage of the colorimetric substrate of DEVD-ρNA. Although both caspase-3 activity of the HBO group and I/R group were not statistically different from the Sham-O group at reperfusion time point of 6 h,the HBO group was higher than the I/R group(P<0.05). Both the HBO group and I/R group were higher than the Sham-O group(P<0.05)at 24 h of reperfusion, but there was no statistical difference between the former two groups. At reperfusion time points of 48 h and 96 h, the HBO and I/R group were higher than Sham-O group, but there was no statistical difference. And there was no statistical difference between the former two groups either, which indicated that caspase-3 activity had decreased to normal levels. The results of above indicated that caspase-3 was activated after global ischemia/reperfusion. HBO treatment at early time may aggravate this activation, but after several times of HBO treatment, this promotion effect becomes indistinct.