Expression of ET-1 mRNA in the lung of hepatopulmonary syndrome rats / 中华外科杂志

ABSTRACT

<p><b>OBJECTIVE</b>To investigate the expression of ET-1 mRNA in the lung of rats with hepatopulmonary syndrome.</p><p><b>METHODS</b>Male Sprague-Dawley rats were divided into four groups SO, IHPH, PHPH and PCS. Two weeks after production of rat models, all measurements were performed. Arterial blood gas was analyzed. The concentrations of NO and ET-1 in lungs were measured by using radioimmunoassay. In situ hybridization, ET-1 mRNA expressions were detected in lung tissue sections with digoxin-labeled ET-1 oligonucleotide probes. Liver and lung tissues and all the results of in situ hybridization were analyzed by one pathologist. At a magnification of 10 x 40, percent areas of positive stains were detected to indicate the expressions of ET-1 mRNA in the arteries, capillaries and branches.</p><p><b>RESULTS</b>Arterial blood gas analysis showed that PaO(2) (mmHg) decreased more significantly in IHPH (73.85 +/- 6.51) rats than in PHPH (97.39 +/- 1.33), PCS (95.23 +/- 2.22) and SO rats (99.05 +/- 0.75). Alveolar-arterial oxygen gradient (A-aG) (mmHg) increased more significantly in IHPH rats (32.99 +/- 6.57) than in PHPH (4.98 +/- 1.69), PCS (6.51 +/- 2.04) and SO rats (3.23 +/- 0.81). Changes of vascular active substance in plasma and lung indicated that the level of lung NO of IHPH (19.78 +/- 5.33) was increased significantly more than that of PHPH (13.21 +/- 3.99) and PCS (13.89 +/- 3.16). These levels in lung homogenate increased more significantly than those SO (8.71 +/- 1.68). The levels of ET-1 in IHPH rats (195.1 +/- 36.2) was significantly lower than in PHPH (234.8 +/- 71.0), PCS (240.4 +/- 66.5) and SO rats (271.8 +/- 40.6). ET-1 mRNA in situ hybridization showed that there was no significant difference in positive expression of ET-1 mRNA in alveolar arteries and small bronchi. The expression of ET-1 mRNA was significantly lower in alveolar capillary endothelia (5.12 +/- 1.27) than in PHPH (7.43 +/- 0.83), PCS (7.07 +/- 0.86) and SO (7.81 +/- 1.98) rats.</p><p><b>CONCLUSION</b>The low expressions of ET-1 mRNA in HPS rat alveolar capillary endothelia accompanied by decreased ET-1 levels in lung may play an important role in the mechanism of HPS.</p>