间歇性低氧预处理对缺血心肌的促血管生成作用的实验研究

目的:采用冠状动脉左前降支部分结扎的方法复制慢性心肌缺血的动物模型,观察间歇性低压低氧预处理的促血管生成作用。方法: 成年雄性新西兰家兔29只,体重2.0-2.5 kg,随机分为3大组:正常组(N组,n=7),对照组(C组,n=11)和间歇性低氧预处理组(H组,n=11)。C组、H组行冠状动脉左前降支部分结扎,H组动物进行间歇性低氧预处理(5 000 m,6 h/d,连续7 d者为H1组,42 d者为H2组),按计划完成实验后测定血管内皮生长因子mRNA (VEGFmRNA)、低氧诱导因子-1 α mRNA (HIF-1 α mRNA)、内皮细胞一氧化氮合酶mRNA(eNOSmRNA)及血管内皮生长因子(VEGF)蛋白表达及毛细血管密度。结果: 间歇性低氧预处理VEGF mRNA、HIF-1 α mRNA、eNOS mRNA及VEGF蛋白持续增加,毛细血管密度增高。结论: 间歇性低氧预处理能促进慢性缺血心肌内的血管生成。

The angiogenesis effect of intermittent hypoxia precondition on ischemic myocardium in rabbits

AIM: To determine the effect of intermittent hypoxia (IH) precondition on ischemic myocardium by using a rabbit model of chronic myocardial ischemia with left anterior descending (LAD) banding. METHODS: Male, adult New Zealand white rabbits were assigned into three groups randomly. (1) normal group (N group), (2) control group (C group), (3) IH precondition group (H group). A LAD band was placed in C and H group first. The rabbits in H group were exposed to altitude of 5 000 m, for 6 h/day continuously. According to IH precondition duration, the animals were subdivided into 7-days group (H1) and 42-days group (H2). After these experiments, the mRNA concentrations of vascular endothelial growth factor (VEGF), hypoxia induced factor (HIF-1α), endothelial nitric oxide synthase (eNOS) and the expression of VEGF protein were detected. Tissue sections were stained for alkaline phosphatase with indoxyl-tetrazolium method to detect capillary density. RESULTS: The mRNA levels of VEGF, HIF-1α, eNOS and expression VEGF protein were increased in H group significantly. Compared with C and N group, the capillary density in H group was increased significantly. CONCLUSION: IH precondition increases angiogenesis in chronic ischemic myocardium in rabbits.