低氧条件下大鼠肺动脉平滑肌细胞中活性氧与低氧诱导因子-1α和细胞增殖的关系(英文)

The relationships among reactive oxygen species, hypoxia-inducible factor 1α and cell proliferation in rat pulmonary arterial smooth muscle cells under hypoxia

在低氧条件下,观察大鼠肺动脉平滑肌细胞(pulmonary arterial smooth muscle cells, PASMCs)中活性氧(reactive oxygenspecies, ROS)的变化,探讨 ROS 的变化是否通过调控低氧诱导因子 -1α (hypoxia-inducible factor 1α, HIF-1α)的表达影响 PASMCs的增殖。采用组织块法原代培养大鼠PASMCs,分成3 组:常氧组(21% O2, 24 h),低氧组(5% O2, 24 h),低氧+ Mn-TBAP组(5% O2,24 h,Mn-TBAP 是一种ROS 清除剂)。用激光共聚焦显微镜荧光染色法检测细胞内ROS 的变化;用RT-PCR 和免疫组织化学方法分别测定HIF-1α mRNA 和蛋白的表达;用MTT 法检测细胞增殖程度。结果显示:(1) 低氧组 PASMCs内ROS水平明显高于常氧组(P<0.05),低氧+ Mn-TBAP 组ROS 水平明显低于低氧组(P<0.05),但仍高于常氧组(P<0.05) ;(2)低氧组及低氧+ Mn-TBAP 组的HIF-1α mRNA 和蛋白表达均高于常氧组(P<0.05),且低氧组表达高于低氧+ Mn-TBAP 组(P<0.05) ;(3) 低氧组细胞增殖明显高于常氧组和低氧+ Mn-TBAP 组(P<0.05),低氧+ Mn-TBAP 组细胞增殖高于常氧组(P<0.05)。结果表明:在低氧条件下大鼠PASMCs 中 ROS 水平明显升高,且ROS 的变化能够调节HIF-1α的表达,进而影响平滑肌细胞的增殖,提示ROS 可能在肺动脉高压的发病机制和低氧信号转导中具有重要作用。

The objectives of this paper were to observe the changes of reactive oxygen species （ROS） in rat pulmonary arterial smooth muscle cells （PASMCs） under hypoxic condition and to test if hypoxia-induced proliferation of PASMCs was mediated by ROS. PASMCs were divided into three groups： normal group, hypoxia group and hypoxia ＋ Mn-TBAP （a ROS scavenger） group. The level of ROS was determined by a laser scanning confocal microscope. The expression of hypoxia-inducible factor 1α（HIF-1α） mRNA was detected by semi-quantitative reverse transcription PCR （RT-PCR）. HIF-1α protein was detected using immunohistochemical staining, and the proliferation of PASMCs was examined by MTT colorimetric assay. The results were as follows： （1） The level of ROS in hypoxia group was significantly increased as compared with that in the normal group （P〈0.05）. The level of ROS in hypoxia ＋ Mn- TBAP group was significantly decreased as compared with that in hypoxia group （P〈0.05）, but was increased as compared with that in the normal group （P〈0.05）. （2） The expressions of HIF-1α mRNA and protein in hypoxia group and hypoxia ＋ Mn-TBAP group were increased as compared with those in the normal group （P〈0.05）, and these changes were more significant in hypoxia group than those in hypoxia ＋ Mn-TBAP group. （3） The proliferation of PASMCs in hypoxia group was more obvious than that in the normal group and hypoxia ＋ Mn-TBAP group （P〈0.05）, and the proliferation of PASMCs in hypoxia ＋ Mn-TBAP group was increased more significantly than that in the normal group （P〈0.05）. The results indicate that ROS is significantly increased in rat PASMCs under hypoxia, and that ROS affects the expression of HIF-1α and the proliferation of PASMCs under hypoxia. Therefore, ROS may play an important role in the pathogenesis of pulmonary hypertension and hypoxic signal transductions.