异氟烷预处理对缺血再灌注损伤鼠脑组织中Bcl-2和Bax的mRNA表达的影响

Effect of isoflurane preconditioning on Bcl-2 and Bax mRNA expression after ischemia/reperfusion in gerbil brain

目的:通过观察异氟烷(ISO)预处理对沙士鼠脑缺血再灌注(I/R)凋亡相关基因Bcl-2和Bax的mRNA在脑组织中的表达,探讨ISO预处理的作用机制。方法:50只沙士鼠随机分5组:SHAM组(假手术组),只分离双侧颈总动脉而未夹闭;I/R组,夹闭双侧颈总动5min后开放;ISO组,I/R前60min接受1.2%～1.5%的ISO预处理;5-HD+ISO组,线粒体ATP敏感性钾通道(mitoKATP)阻滞剂5-HD 10mg/kg腹腔内注射30min后同ISO组;5-HD组,5-HD腹腔内注射30min后行I/R损伤。24h后取鼠前脑,采用RT-PCR检测脑组织中Bcl-2、Bax基因的mRNA表达。结果:ISO组Bcl-2的mRNA表达增高,与SHAM组和5-HD+ISO组比较差异显著(P<0.05);I/R、5-HD+ISO和5-HD组Bax的mRNA表达明显增高,与SHAM组比较差异显著(P<0.05)。结论:ISO预处理对沙士鼠脑I/R的保护作用可能就是通过激活mitoKATP通道,使Bcl-2结合到线粒体膜上的量增加,同时阻止Bax转录到线粒体膜上,稳定了线粒体,发挥细胞保护作用。

Objective： To investigate the effect of isoflurane （ISO） preconditioning an Bcl-2 and Bax mRNA expression after isehemia/ reperfusion （I/R） in gerbil brain and the mechanism. Methods： Fifty gerbils were randomly divided into 5 groups： sham operation group, I/R group,ISO group,5-HD＋ISO group,and 5-HD group. The bilateral common carotid arteries were isolated but not occluded in the sham operation group and occluded for 5 minutes in I/R group. The animals received isoflurane （1.2%～1.5%） preconditioning 60 minutes before I/R in ISO group,received 5-HD （ 10 mg/kg）,the mitochondrial ATP-sensitive K^＋ channel （mitoK^＋） blocker,and ISO before I/R in 5-HD＋ ISO group,and received 5-HD 30 minutes before I/R in 5-HD group. After 24 hours,the forebrains were sampled,and the total RNA was isolated by trizol reagent. The expression of Bcl-2 and Bax mRNA was determined by reverse transeriptase polymerase chain reaction. Results： Bcl-2 rnRNA expression in ISO group was significantly higher than that in sham operation group and 5-HD＋ISO group （P 〈 0.05）. Bax mRNA expression in groups I/R,5-HD＋ISO,and 5-HD was significantly higher than that in sham operation group （P 〈 0.05）. Conclusion： The isoflurane preconditioning has a protective effect on gerbil brain after I/R by promoting the binding of Bcl-2 to mitochondria and simultaneously preventing Bax translocation to mitochondria, which is the result of the activation of mitoKATP.