吸入麻醉药预处理对兔缺血再灌注心肌Bcl-2、Bax及p53基因表达的影响

Effects of inhalational anesthetic pretreatment on myocardial Bcl 2, Bax and p53 gene expression during ischemia / reperfusion in rabbits

目的探讨吸入异氟醚、七氟醚及地氟醚预处理对兔在体心脏局部缺血再灌注过程中心肌细胞Bcl-2、Bax及p53基因表达的影响。方法 40只新西兰白兔随机分成5组(n=8):假手术对照组(P组)、缺血再灌注对照组(IR组)、异氟醚预处理组(Ⅰ组)、七氟醚预处理组(S组)、地氟醚预处理组(D组)。除P组外,每组接受左冠脉前降支3 h阻断和3 h再灌注。吸入药预处理组在缺血前分别吸入1MAC的异氟醚、七氟醚或地氟醚,30 min后洗脱15 min。取心肌缺血区边缘组织用流式细胞仪测凋亡指数(AI)和Bcl-2、Bax及p53基因的蛋白表达量。结果 AI:P组为(0.93±0.27)％,IR组为(14±4)％,I、s、D组较IR组显著减少,分别为(6.7±1.8)％、(6.7±1.6)％、(7.4±2.0)％(P<0.01)。Bcl-2、p53、Bax基因的蛋白表达:Bcl-2基因的蛋白表达量I、S、D组高于IR组,Bax基因和p53基因的蛋白表达量I、S、D组低于IR组。结论 异氟醚、七氟醚及地氟醚预处理抑制缺血再灌注所致心肌细胞凋亡与上调BcI-2基因的蛋白表达、下调p53和Bax基因的蛋白表达有关。

Objective To investigate the effects of pretreatment with different inhalational anesthetic agents on myocardial Bcl-2, Bax and p53 gene expression during ischemia-reperfusion ( I/R) in rabbits. Methods Forty New Zealand white rabbits of both sexes were anesthetized with intramuscular ketamine 70 mg kg-1 tracheotomized and mechanically ventilated with 100% O2. PETCO2 was maintained at 4.0-4.5 kPa. Carotid artery and external jugular vein were cannulated for BP monitoring, fluid administration and medication. Anesthesia was maintained with midazolam 0.05-0.1 mg kg-1·h-1 , ketamine 2-5 mg· kg-1·h-1and vecuronium 0.05-0.1 mg· kg -1 · h-1 . Myocardial ischemia was induced by occlusion of anterior descending branch of left coronary artery. Ischemia was confirmed by cyanosis of local myocardium and elevation of S-T segment. The animals were randomly allocated to one of five groups with 8 animals in each group : group C sham operation; group I/R; group I isoflurane pretreatment; group S sevoflurane pretreatment and group D desflurane pretreatment. In guoup C animals underwent no I/R. In group I/R animals were subjected to 3h of ischemia followed by 3 h reperfusion. In group I, S and D animals inhaled 1.1% isoflurane or 2% sevoflurane or 6% desflurane for 30 min followed by 15 min of wash-out before I/R. Intravenous anesthetic infusion was suspended while inhalational anesthetic was being inhaled. Myocardium 100 mg was obtained from marginal zone of ischemic area and made into cell suspension for determination of apoptosis index ( AI) and expression of Bcl-2, Bax and p53 genes, using flow cytometry.Results AI was (14)% in group I/R and was significantly reduced to (6.7 ± 1.8)% ( group Ⅰ ), (6.7 ± 1.6)% ( group S) and (7.4±2.0)% ( group D) (P<0.05). The expression of Bcl-2 was downregulated and that of Bax and p53 were upregulated in group I/R. In group Ⅰ, S and D the expression of Bcl-2 was higher than that in group I/R while the expression of Bax and p53 were lower. Conclusion Inhalational anesthetic pretreatment inhibits myocyte apoptosis induced by I/R partly by modulation of expression of Bcl-2, Bax and p53 genes.