低氧对人脐静脉内皮细胞一氧化氮和内皮素-1的生成及诱导型一氧化氮合酶mRNA表达的影响

目的：通过观察低氧对人脐静脉内皮细胞(HUVECs)分泌一氧化氮(NO）、内皮素-1(ET-1)以及诱导型一氧化氮合酶(iNOS)mRNA 表达的影响，探讨低氧性肺动脉高压(HPH)形成的机制。 方法： 在离体培养人脐静脉内皮细胞基础上，采用硝酸还原酶和放射免疫分析方法检测了低氧（3％O2）培养6 h、12 h和24 h人脐静脉内皮细胞分泌NO和ET-1的变化，同时运用半定量RT-PCR对iNOS mRNA表达情况进行分析。 结果： 低氧组各时点培养液中NO2-/NO3-和ET-1水平显著高于常氧组(P<0.01)，同时观察到iNOS基因mRNA的表达也相应增高(P<0.01)。 结论： 低氧能刺激人脐静脉内皮细胞生成释放NO和ET-1, NO生成增多与低氧正调iNOS基因mRNA的表达有关。

Effects of hypoxia on levels of nitric oxide, endothelin-1 and inducible nitric oxide synthase mRNA expression in cultured human umbilical vein endothelial cells

AIM: To observe the effects of hypoxia on the levels of nitric oxide (NO), endothelin (ET-1) and the expression of inducible nitric oxide synthase (iNOS) mRNA in human umbilical vein endothelial cells (HUVECs), and further investigate the mechanism of hypoxic pulmonary hypertension. METHODS: On the basis of the HUVECs culture model, the methods of nitrate reductase and radioimmunoassay were used to determine the changes of NO and ET-1 in the medium secreted by HUVECs, and the expression of iNOS mRNA was analyzed by semi quantitative RT-PCR after exposure to hypoxia (3% O_2) for 6, 12 or 24 h. RESULTS: The contents of NO_2-/NO_3-and ET-1 in hypoxia group in the medium was significantly higher than that in control group at different time points (P<0.05). Also, iNOS mRNA expression increased significantly (P<0.05). CONCLUSION: Hypoxia stimulates the release of NO and ET-1 from HUVECs, also induces iNOS-mRNA expression. The change of NO may be the result of iNOS mRNA upregulation induced by hypoxia.