缺氧诱导因子-1α在缺氧预处理预防心肌细胞损伤中的作用  

Role of hypoxia-inducible factor-1α in the prevention of cardiomyocyte injury induced by hypoxic preconditioning

作　　者：徐菲菲[1] 刘秀华[1] 蔡莉蓉[1] 

机构地区：[1]中国人民解放军总医院基础医学研究所病理生理研究室,北京100853

出　　处：《生理学报》2004年第5期609-614,共6页Acta Physiologica Sinica

基　　金：This work was supported by the National Natural Science Foundation of China (No. 30270550) and the Natural Science Foundationof Beijing(No. 7032044).

摘　　要：本工作旨在研究缺氧预处理(hypoxic preconditioning, HPC)对于心肌细胞外信号调节激酶(extracellular signal-regulatedprotein kinases, ERK)活性、缺氧诱导因子 -1α(hypoxia-inducible factor-1α, HIF-1α)表达的影响,及其在缺氧复氧诱导心肌细胞损伤中的作用。通过在培养的SD 乳鼠心肌细胞缺氧/ 复氧(H/R)模型上, 观察HPC 对于24 h 后H/R 诱导心肌细胞损伤的影响, 以台盼蓝排斥实验检测心肌细胞存活率、以 TUNEL 法检测细胞凋亡、并用荧光素染料 Hoechst33258 测定心肌细胞凋亡率; 制备心肌细胞蛋白提取物,以磷酸化的 ERK1/2 抗体测定 ERK1/2 活性, 以抗HIF-1α 抗体检测 HIF-1α 的表达,并观察ERKs 的上游激酶(MEK1/2)抑制剂PD98059 对于HPC 诱导的ERKs 磷酸化、HIF-1α 表达以及心肌细胞保护作用的影响,并分析细胞损伤与 ERK1/2 活性、HIF-1α 表达量之间的相互关系。结果显示缺氧复氧造成心肌细胞损伤, HPC 可以增加心肌细胞 H/R 后存活率,降低凋亡率,并激活 ERK1/2,诱导 HIF-1α 表达;细胞凋亡与 ERKs 活性、HIF-1α 表达量之间存在负相关,即 ERKs 活化、HIF-1α 表达与预防细胞损伤有关;而 ERKs 活性与 HIF-1α 表达量之间存在正相关,ERKs 的上游激酶MEK抑制剂PD98059 可以消除HPCIn order to understand the intracellular mechanism of preconditioning, we investigated the relationship among activities of extracellular signal-regulated protein kinases (ERKs), the expression of hypoxia-inducible factor -1α (HIF-1α) and the effect of hypoxic preconditioning (HPC) on cell injury induced by hypoxia-reoxygenation in cultured neonatal rat cardiomyocytes 24 h after brief hypoxia. Cultured cardiomyocytes of neonatal Sprague-Dawley rats were divided into four groups: hypoxia/reoxygenation (H/R), hypoxia preconditioning (HPC), hypoxia preconditioning + mitogen-activted protein kinase (MAPK) inhibitor PD98059 (HPC+PD98059), and control (C). We measured the survival rate and apoptosis rate of cardiomyocytes at 6 or 12 h after hypoxia/reoxygenation, activities of extracellular signal-regulated protein kinases (ERKs), and expression of hypoxia-inducible factor -1α (HIF-1α). We found that the survival rate of cardiomyocytes in hypoxic preconditioning group increased by 6.08% and 7.91% at 6 and 12 h after hypoxia/reoxygenation (n=6, P<0.05), respectively, and the apoptotic rate decreased by 10.92% and 14.34% (n=6, P<0.05) respectively. Hypoxic preconditioning increased the abundance of phospho-ERK1/2 by 3-folds and expression of HIF-1α by 1-fold in whole cell extracts from hypoxic preconditioned cardiomyocytes. PD98059, an inhibitor of the upstream kinase of ERKs, abolished the anti-injury effect, ERKs activation, and expression of HIF-1α induced by hypoxic preconditioning. Statistical analysis indicated that there was negative correlation between apoptotic rate and activities of ERKs or expression of HIF-1α, and positive correlation between activities of ERKs and expression of HIF- 1α. It is concluded that hypoxic preconditioning protects cardiomyocytes from hypoxia/reoxygenation-induced injury and that upregulation of HIF-1α through ERKs pathway mediates the cardioprotection of hypoxic preconditioning.

关 键 词：缺氧诱导因子-1Α 缺血预处理 细胞凋亡 心肌细胞 

分 类 号：R541[医药卫生—心血管疾病]