[The change and distribution of endothelin-1 in lung of hypoxic pulmonary hypertension rat].
摘要
This study was aimed to determine the distribution and change of ET-1 in the lung of rat with chronic hypoxic pulmonary hypertension. Immunohistochemical analysis (Avidin-Biotion Complex) was used to localize the ET-1 immunoreactivity in the rat lung. The ET-1 concentration in plasma and in lung homogenate was measured by radioimmunoassay. In normal rats, the mean ET-1 concentration in venous plasma was 2.25 +/- 0.68 ng/L, in arterial plasma 1.52 +/- 0.63 ng/L and in lung 1.75 +/- 0.46 ng/L. There was no significant increase of ET-1 level in rats exposed to hypoxia for 2 hours, but there was significant increase of ET-1 after 24 hours hypoxia, and the high levels of ET-1 were maintained in the sustained hypoxia. There was significant correlation between the ET-1 level in arterial plasma(or in lung homogenate) and the maen pulmonary artery pressure. Similaryly, there was significant negative correlation between ET-1 in arterial plasma(or in lung homogenate) and PaO2. Immunohistochemical analysis revealed that the ET-1 immunoreactivity was seen in the endothelium of pulmonary arteries, particularly more positive staining was seen in the band between the endothelium and the smooth muscle cells. Chronic hypoxia elevated the mean pulmonary arterial pressure, caused vessel remodelling and the right ventricular hypertrophy. These changes were accompained by an increase of ET-1 in plasma and lung homogenate. The expression and production of ET-1 were localized to endothelium and airway epithelium in the lungs.