一氧化氮合酶在肝肺综合征大鼠肺组织中的表达

Expressions of NOS and NOS mRNA in the Lung of Rats with Hepatopulmonary Syndrome

目的研究一氧化氮合酶(NOS)蛋白及其mRNA在肝肺综合征(HPS)大鼠肺组织中的表达。方法雄性SD大鼠随机分4组:肝前型门静脉高压症组(PHPH组)、肝内型门静脉高压症组(IHPH组)、门腔端侧分流组(PCS组)和手术对照组(SO组)。各组均行动脉血气分析,测肺组织中NO2ˉ/NO3ˉ含量,免疫组化和原位杂交并结合图像分析检测肺泡毛细血管内皮细胞、肺泡小动脉内皮细胞中原生型NOS(ecNOS)和诱生型NOS(iNOS)蛋白和mRNA的表达强度。结果①动脉血气分析:动脉氧分压,IHPH组大鼠(73.85±6.51)mmHg,较PHPH组(97.39±1.33)mmHg、PCS组(95.23±2.22)mmHg和SO组(99.05±0.75)mmHg显著下降。②肺组织中NO2ˉ/NO3ˉ含量(μmol/g蛋白):IHPH组大鼠(19.78±5.33)显著高于PHPH组(13.21±3.99)、PCS组(13.89±3.16)和SO组大鼠(8.71±1.68)。③ecNOSmRNA表达:IHPH组大鼠(4.96±0.82),较PHPH组(1.81±0.39)、PCS组(1.88±0.53)和SO组大鼠(1.19±0.32)显著增高;④ecNOS蛋白表达:IHPH组大鼠(4.11±0.28),较PHPH组(1.63±0.18)、PCS组(1.83±0.16)和SO组大鼠(0.98±0.20)显著增高。结论HPS大鼠肺泡毛细血管内皮细胞ecNOSmRNA及蛋白表达显著增强、肺组织中NO含量显著增高,在HPS发病中可能起重要作用。

Objective To investigate the expressions of nitric oxide synthase （NOS） protein and mRNA in the lung of rats with hepatopulmonary syndrome. Methods Male Sprague-Dawley rats were divided into four groups： sham operation （SO）, intrahepatic portal hypertension （IHPH）, prehepatic portal hypertension （PHPH） and portasymstimic shunt （PCS）. Two weeks after preparation of rat models, the following measurements were performed： arterial blood gas analysis; the concentrations of NO in lungs; in situ hybridization of ecNOS and iNOS mRNA expressions in lung tissue sections with digoxin-labeled ecNOS and iNOS oligonucleotide probes; expressions of ecNOS and iNOS proteins by immunohistochemisty; image and semiquantitative analysis of the expressions of ecNOS, iNOS and their mRNA. Results PaO2 was （73.85 ±6.51） mmHg in IHPH rats, significantly lower than that in PHPH, PCS and SO rats [ 97.39 ± 1.33, 95.23 ± 2.22 and （99.05 ± 0.75 ） mmHg, respectively ]. The level of lung NO of IHPH was （ 19.78 ± 5.33 ） μmol per gram of protein,much higher than that of PHPH, PCS and SO [ 13.21 ± 3.99,13.89 ± 3.16 and （8.71±1. 68） μmol per gram of protein, respectively ]. In capillary endothelia, positive expressions of ecNOS mRNA and ecNOS protein in IHPH（4.96 ±0.82,4. 11 ±0.28） were significantly higher than those of PHPH （1.81± 0.39,1.63±0.18）, PCS （1. 88 ±0. 53,1. 83±0. 16）and SO（1. 19±0. 32,0.98±0. 20）. Conclusion The expressions of NOS protein and mRNA in the lung of rats with hepatopulmonary syndrome were increased, and the level of lung NO was elevated, which seems to play an important role in the pathogenesis of hepatopulmonary syndrome.