小鼠脑缺血再灌注早期核因子-κB活性的变化

目的 :研究脑缺血再灌注 (brainischemia reperfusion ,I/R)早期核转录因子 κB(NF κB)活性变化及作用。方法 :采用小鼠脑缺血再灌注损伤模型 ,记录异常神经症状 (abnormalnervoussymptoms,ANS) ,用RT PCR技术和免疫组织化学法分别检测脑缺血再灌注后不同时期NF κB亚单位P6 5及其抑制因子κBα(I κBα)的mRNA和蛋白表达。结果 :小鼠脑缺血再灌注后 30minP6 5蛋白活性增加 ,2h达高峰 ,2 4h仍维持较高水平 (均P <0 .0 5 ) ,而NF κBP6 5mRNA的表达无明显改变 (均P <0 .0 5 ) ;I κBα蛋白量于再灌注后 30min下降 ,2h达最低 (均P <0 .0 5 ) ,以后逐渐恢复正常 ,I κBαmRNA的表达与其蛋白表达相一致 (r =0 .75 1;P <0 .0 5 ) ;P6 5蛋白活性与异常神经症状呈正相关 (r =0 .795 ;P <0 .0 5 ) ,I κBα的蛋白及其mRNA的表达与异常神经症状均呈负相关 (r蛋白= 0 .75 2 ;rmRNA= 0 .70 9,均P <0 .0 5 )。结论 :小鼠脑缺血再灌注损伤早期脑组织神经细胞中存在NF κBP6 5的激活及其I κBα的减少 ;NF κB的激活可能参与了脑缺血再灌注早期的损伤过程。

Nuclear factor-κB activity at the early stage of brain ischemia and reperfusion in mice

Objective To observe the activity of nuclear factor-κB(NF-κB) during reperfusion after temporary brain ischemia and to evaluate its effect. Methods The brain ischemia-reperfusion(I/R) model of mice was established with ligating bilateral common carotid arteries and bleeding for 0.3 ml in the tail. Abnormal nervous symptoms (ANS) were recorded. Immunohistochemical technique was used to detect the activity of NF-κB subunit P65 and the inhibitory factor-κB α(I-κBα) in cerebral cortex during different periods of ischemia and reperfusion. Their mRNA expressions were also measured by RT-PCR. Results NF-κB P65 activity significantly increased 30 minutes after the reperfusion,peaking at the 2nd hour, and remaining high within 24 hours (all P<0.05).But the mRNA expression didn’t change much;I-κBα and its mRNA expression began to decrease at 30 minutes after the reperfusion, peaking at the 2nd hour after the reperfusion (P<0.05) and then gradually restored. Positive correlation was found between NF-κB P65 activity and ANS (P<0.05), while negative correlation was shown among I-κBα,its mRNA,and ANS (P<0.05,respectively). Conclusion Both activated NF-κB and decreased I-κBα exist in the neural tissues of mice at the early stage of brain ischemia-reperfusion. The activated NF-κB may be involved in the ischemia-reperfusion injury.