ABSTRACT
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 PaO_ 2 was (73.85?6.51) mmHg in IHPH rats, significantly lower than that in PHPH, PCS and SO rats97.39? 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)?mol 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)?mol 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.