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

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

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6h、12h和24h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。

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% O2） for 6, 12 or 24 h. RESULTS： The contents of NO2 ^-/NO3^ - 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.