血管紧张素Ⅱ对猪动脉内皮细胞内皮型一氧化氮合酶基因表达的异质性研究

Heterogeneity of angiotensin Ⅱ in endothelial nitric oxide synthase gene expression in porcine arterial endothelial cells

目的:通过观测血管紧张素Ⅱ(AngⅡ)对体循环和肺循环系统动脉内皮细胞内皮型一氧化氮合酶(eNOS)基因表达的影响,探讨体、肺循环系统病理生理学上的差异。方法:采用半定量逆转录聚合酶链式反应(RT-PCR)和免疫细胞化学方法(LSAB法)观察AngⅡ对培养的猪主动脉和肺动脉内皮细胞eNOSmRNA和蛋白质表达的影响。结果:AngⅡ分别作用6、12、24、36、48h后,主动脉内皮细胞eNOSmRNA及蛋白质的表达下调。在AngⅡ作用的早期(≤24h),肺动脉内皮细胞eNOSmRNA和蛋白质的表达也呈时间依赖性下调,但作用48h后,肺动脉内皮细胞eNOSmRNA恢复至正常水平,并且eNOS蛋白水平上调超过空白对照组,表现出先抑制后促进的特性。结论:AngⅡ对主动脉和肺动脉内皮细胞eNOS基因表达的影响不同,可能是由于不同的AT受体亚型或是不同的信使途径所调节,表明体循环和肺循环动脉之间存在着病理生理学的异质性。

Objective To investigate the difference of pathophysiology between systemic and pulmonary circulation by studying the effect of angiotensin Ⅱ （AT- Ⅱ ） on endothelial nitric oxide synthase （eNOS） gene expression in porcine aortic and pulmonary artery endothelial cells. Methods eNOS mRNA expression was measured by reverse transcription polymerase chain reaction （RT-PCR） and protein level by immunocytochemistry methods （LSAB）. Results 6, 12, 24, 36, and 48 hours after being treated by 10^-6 mol/L of AT-Ⅱ , the eNOS mRNA expression and protein level in aortic endothelial cells were decreased in a time-dependent manner and they reached to the lowest point at 24 h, being as （53.2 ± 8.1）% （P〈 0.01） and （45.5 ± 7.4）% （P〈 0.01） as those in the control group. The eNOS mRNA expression and protein level in pulmonary artery endothelial cells were downregulated in the early stage （≤ 24 h）, being （50.6 ±4.6）% （P 〈 0.01） and （63.7 ± 6.5）%（P 〈 0.01）, respectively. At 48 h the eNOS mRNA expression level became normal and was as （96.5 ± 5.3）% as that in the controls （P〉 0.05） while the protein level was （121.7 ± 9.6）% （P〈 0.05）. Conclusion The eNOS mRNA expression in aortic endothelial cells and that in pulmonary artery endothelial cells are affected differently by AT- Ⅱ , which may be involved in the regulation of different subtypes of AT receptors subtypes or different messenger pathways and may suggest that pathophysiological heterogeneity exists between the arteries of systemic circulation and those of pulmonary circulation.