心肌周缺血频率对兔冠状动脉侧支循环生成的影响

Effects of the frequency of myocardial ischemia on the formation of coronary collateral circulation in rabbits

目的观察不同的心肌周缺血频率对新两兰兔冠状动脉侧支生成影响。方法健康成年新西兰兔32只，体重2．0～2．5kg。于兔冠状动脉左室吏安装气囊梗阻器，制作间断性心肌缺血模型，缺血负荷为2min／h，2次／d，每次缺血2min后恢复血供，隔58min后行第二次缺血刺激，共4周。根据不同周缺血天数将实验动物随机分为假手1术组和3d／周、5d／周及7d／周缺血组。采用微球技术检测各组缺血和非缺血区心肌冠状动脉侧支循环血流（CCBF）变化，采州苏木素一伊红染色观察各组缺血区侧支循环的形态学改变，于术前和缺血刺激前、后24h进行血清肌钙蛋白的检测。结果3d／周、5d／周及7d／周的缺血刺激均可引起缺血区CCBF和毛细血管密度显著增加，组间比较，差异无统计学意义。缺血刺激后24h，血清肌钙蛋白无明显升高。结论每周3d、5d或7d，共4周的心肌缺血刺激均可显著促进心肌缺血区侧支生成，且不损伤心肌；高于每周3d的缺血频率不一定能进-步促进侧支的生成。

Objective To investigate the effects of the frequency of myocardial ischemia （MI） on the formation of coronary collateral circulation（FCCC） in New Zealand rabbits. Methods Intermittent myocardial ischemia models were established by installing a balloon occluder （2 min /h, twice/d, for 4 w） on the left ventrieular branch （LVB） of coronary artery with 32 New Zealand rabbits, divided into a sham-operated group and three ischemic groups（3, 5 and 7 d/w ischemic stimulation）. The morphological changes of MI were observed by using of HE dyeing, while coronary collateral blood flow （CCBF） was measured with microsphere methods, as well as cardiac tro- ponin 1（eTnl） was detected pre-and 24 h post ischemic stimulation. Results Compared with those in the shamoperated group, CCBF and capillary density were significantly increased in three ischemic groups. There were no difference among ischemic subgroups, and cTnl was unchanged 24 h post ischemie stimulation in all subjects. Conclusion MI with the frequency of 3, 5 and 7 d a week （ for 4 w） could promote FCCC without obvious myocardial damage, lsehemie stimulation more than 3 d a week might have no extra effects on FCCC.