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>