一氧化氮对慢性缺氧高二氧化碳大鼠肺血管尾加压素Ⅱ的影响

目的： 探讨一氧化氮/L-精氨酸（NO/L-Arg）系统和尾加压素Ⅱ（UⅡ）在大鼠慢性缺氧（O2）高二氧化碳（CO2）肺动脉高压病理过程的作用及关系。 方法： 40只大鼠随机分成4组（每组各10只）：正常对照组（A组）、慢性缺O2高CO2 加生理盐水4周组（B组）、慢性缺O2高CO2 加L-Arg脂质体4周组（C组）、慢性缺O2高CO2 加N-硝基-L-精氨酸甲酯（L-NAME）4周组（D组）。免疫组化法和组织原位杂交法检测肺小动脉UⅡ和UⅡ mRNA、UⅡ受体（UT）mRNA的表达，并观察肺小动脉显微结构的变化。 结果： （1）肺动脉平均压(mPAP)、右心室(RV)和左心室+室间隔(LV+S)重量比值［RV/(LV+S)］:Ｂ组高于A组（均P<0.05）；C组低于B组（均P<0.01）；D组两指标不仅高于A组（P<0.01和<0.05），且mPAP也高于B组（P<0.01）。（2）肺小动脉管壁面积/管总面积（WA/TA）和中膜厚度（PAMT）：B组显著大于A组（P<0.05）；C组与B组的差异也有显著性（P<0.01）；而D组WA/TA也显著高于A组。（3）肺小动脉UⅡ、UⅡ mRNA、UT mRNA表达：同A组比较，Ｂ组、D组各指标都显著增高（均P<0.01）；C组UⅡ、UⅡ mRNA的表达较Ｂ组明显下调（P<0.01），同A组比较，其UⅡ表达下调但UT mRNA表达增加（均P<0.01）；D组UⅡ表达较Ｂ组低，而UT mRNA表达较Ｂ组高（均P<0.01）。 结论： 慢性缺O2高CO2肺动脉高压的发生发展可能与UⅡ的异常表达增加有关，而外源性NO可能有抑制UⅡ的作用。

Effect of nitric oxide on urotensin-Ⅱ expression in pulmonary arterioles of rats chronically exposed to hypoxia-hypercapnia

AIM: To investigate the roles of nitric oxide/L-arginine (NO/L-Arg) pathway and urotensin-Ⅱ (UⅡ) in the development of pulmonary hypertension induced by chronic hypoxia-hypercapnia in rats.METHODS: Forty male Sprague-Dawley rats were randomly divided into four groups (n=10): normal control group (A), hypoxia-hypercapnia+saline group (B), hypoxia-hypercapnia+L-Arg liposome group (C) and hypoxia-hypercapnia+N-nitro-L-arginine methyl ester (L-NAME) group (D).Contents of UⅡ, UⅡ mRNA and receptor of UⅡ (UT) mRNA in pulmonary arterioles were measured with immunohistochemistry analysis and in situ hybridization, respectively.Change of small pulmonary vascular microstructure was also investigated.RESULTS: (1) The mean pulmonary artery pressure (mPAP) and the weight ratio of right ventricle to left ventricle plus septum ［RV/(LV+S)］ in B and D groups were all higher than those in A group (respectively, P<0.05), with C group significantly lower than those in B group (respectively, P<0.01).(2) Light microscopy showed that the ratio of vessel wall area to total area (WA/TA) and the media thickness of pulmonary arterioles (PAMT) in B group were higher than those in A group (P<0.05), with C group significantly lower than those in B group.(3) The contents of UⅡ, UⅡ mRNA and UT mRNA in pulmonary arterioles in B and D groups were all higher than those in A group (respectively, P<0.01), while the expression of UⅡ and UⅡ mRNA in C group were lower than those in B group (P<0.01).CONCLUSION: The pathological process of pulmonary hypertension induced by chronic hypoxia-hypercapnia might be related to upregulation of UⅡ located in pulmonary arterioles, which might be partially inhibited by exogenous NO in rats.