缺氧诱导因子-1α及下游因子在缺氧性肺动脉高压新生大鼠肺内的表达研究

Expression of hypoxia-inducible factor-1α and downstream factors in lung tissue of newborn rats with hypoxic pulmonary hypertension

目的通过了解缺氧诱导因子-1α(HIF-1α)、内皮素-1(ET-1)及诱导型一氧化氮合酶(iNOS)的mRNA及蛋白质在缺氧性肺动脉高压(HPH)新生大鼠肺组织中的表达以及和肺动脉压力的关系,探讨三种因子在HPH发病机制中的作用。方法建立HPH新生大鼠模型;分别在缺氧3、5、7、10、14、21天检测平均肺动脉压力(mPAP);通过RT-PCR、免疫组织化学和Western blot方法分别对肺组织中上述三种因子的mRNA、蛋白质表达强度及蛋白质表达量进行分析;进行三因子和肺动脉压力的相关性分析。结果缺氧3、5、7、10天HIF-1αmRNA及蛋白质表达强度均明显高于对照组(P<0.05);缺氧5、7天其蛋白质表达量明显高于对照组(P<0.05)。缺氧3天ET-1mRNA表达明显高于对照组(P<0.05);缺氧3、5、7天ET-1蛋白质表达强度及蛋白质表达量均高于对照组(P<0.05),缺氧10天其蛋白质表达量仍高于对照组(P<0.05)。缺氧3、5、7天iNOS mRNA及蛋白质表达均高于对照组(P<0.05)。缺氧组在缺氧21天内HIF-1α表达总体与mPAP变化呈正相关(P<0.001);缺氧7天内ET-1、iNOS表达总体与mPAP变化呈正相关(P<0.05)。结论 HIF-1α、ET-1和iNOS在HPH新生大鼠肺组织中表达增加,与肺动脉压力呈正相关,三种因子在该病发病机制中可能具有重要作用。

Objective To study the mRNA and protein expression of hypoxia-inducible factor-1α （HIF-1α）,endothelin-1 （ET-1） and inducible nitric oxide synthase （iNOS） in lung tissue of neonatal rats with hypoxic pulmonary hypertension （HPH）,and to explore the roles of HIF-1α,ET-1 and iNOS in the pathogenesis of HPH.Methods HPH model of neonatal rats was established according to established method.Mean pulmonary arterial pressure（mPAP） was measured on day 3,5,7,10,14 and 21 after hypoxia.mRNA level,protein expression intensity and protein level of HIF-1α,ET-1 and iNOS in lung tissue of rats with HPH were analyzed by RT-PCR,immunohistochemistry and Western blot tests,respectively.Correlation analysis of the three factors and mPAP were performed.Results mRNA level and protein expression intensity of HIF-1α were significantly higher 3,5,7 and 10 days post hypoxia than those in the control group （P 〈 0.05）.HIF-1α protein level was significantly higher in hypoxia 5,7 days after hypoxia compare to the control group （P 〈0.05）.ET-1 mRNA expression 3 days post hypoxia was more prominent than the value in the control group （P 〈 0.05）.The expression intensity and the level of ET-1 protein were significantly higher 3,5,7 days post hypoxia than those in the control group （P 〈 0.05）.The level of ET-1 protein was also higherafter hypoxia for 10 days than the level in the control group （P 〈 0.05）.mRNA and protein expression of iNOS were significantly higher 3,5,7 days post hypoxia than those in the control group （P 〈0.05）.In general,HIF-1α protein expression was positively correlated with mPAP level on the 3-21 days after hypoxia （P 〈 0.001）,and ET-1 and iNOS protein expression were positively correlated with the level of mPAP 3-7 days after hypoxia （P〈0.05）.Conclusions The elevated expression of HIF-1α,ET-1 and iNOS in lung tissue of newborn rats with HPH were positively correlated with the level of pulmonary artery pressure,so these three factors may play important roles in the pathogenesis of hypoxic pulmonary hypertension.