大鼠心肌梗死后的原癌基因表达

Expression of c-myc,c-fos,c-jun and their limitation by captopril in myocytes after myocardial infarction in rats

目的本实验旨在探讨心肌梗死后左心室重构的分子生物学机制。方法用地高辛标记的原位杂交方法观察了大面积心肌梗死后存活心肌细胞的原癌基因c-myc,c-fos及c-jun的mR- NA水平的动态变化,并用巯甲丙脯酸进行干涉。大鼠随机分为三组:(1)单纯心肌梗死组;(2)梗塞给药组;(3)假手术组。梗塞给药组于手术前3d开始饲以巯甲丙脯酸(2g/L)。结果左室非梗塞区心肌的c-myc,c-fos及c-jun的mRNA水平手术后24h达峰值,c-myc于手术后10d,c-jun于手术后7d恢复到假手术组水平,但c-fos于术后持续高表达。在梗塞给药组,c-myc,c-fos于手术后7d、10d,c-jun于手术后各时间点其mRNA水平达假手术组程度。结论上述基因在非梗塞区心肌均有过量表达,持续时间较长,转换酶抑制剂对其有所抑制。

Objective Our study aimed at the changes of protooncogenes after myocardial infarc- tion. Methods We investigated the timed alterations on mRNA of the c-myc, c-fos and c-jan in surviving myocytes after large-sized infarction by using digoxin-labeled in situ hybridization in the rat as well as the effects of captopril on them. Rats were randomly divided into 3 groups ： （ 1 ） myocardial infarction （MI） ; （2） MI Captopril-treated （MI ＋ Cap） ; and （3） ：Sham-operated （SO）. The MI ＋ Cap group was administered with captopril（2g/L drinking water） 3 days before coronary artery ligation. Result It was showed that the maximum expression of these genes in non-infarction portions of left ventricle was at 24 hour time point after operation, with the expression returning to the level of sham-operated group on day 10 and day 7 for c-myc, c-jun respectively, and c-fos expression remained elevated on every time point. C-myc and c-fos expressions were attenuated and were comparable to that observed in sham-operated control hearts on day 7 and 10 after administered by captopri, and c-jun expression was decreased to the same level of sham-operated group by captopril on every time point after operation. Conclusion It is suggested that the overexpression of all of the three genes in non-infarcted region persist for longer time, and these are inhibited partly by captopril.