[Collagen expression of intra-acinar pulmonary arteries and right ventricle and intervention of Radix Astragali in rats with hypoxic pulmonary hypertension].

OBJECTIVE: To investigate the collagen expression effect of intra-acinar pulmonary arteries and the right ventricle and to observe the intervention effect of Radix Astragali in rats with hypoxic pulmonary hypertension. METHODS: Wistar male rats were divided into three groups: hypoxia group, which was fed in hypoxic environment (oxygen concentration was 9%-12%) under normal atmospheric pressure for three weeks (12 hours every day); intervention group, which was abdomenly injected with Radix Astragali and fed in the same environment as hypoxia group; and control group, which was fed in normal environment. Pulmonary artery pressure and cardiac output of the right ventricle were measured with catheterization and Fick's method. Protein expression of collagen in intra-acinar pulmonary arteries was assessed with histopathologic method. mRNA expressions of collagen in the right ventricle, and endothelin-1 and nitric oxide synthase in lung tissue were evaluated by RT-PCR technique. RESULTS: Compared with those in control group, pulmonary artery pressure and protein expression of collagen in intra-acinar pulmonary arteries and mRNA expression of type I collagen in the right ventricle and endothelin-1 in lung tissue were obviously increased in hypoxia group (mean pulmonary artery pressure: (24.8 +/- 3.6) mm Hg vs (18.8 +/- 1.7) mm Hg, P < 0.01; protein expression of collagen: (20.4 +/- 4.5) AU vs (3.4 +/- 1.1) AU (P < 0.01), but mRNA expression of nitric oxide synthase in lung tissue was declined. Compared with the data obtained in hypoxia group, cardiac output and mRNA expression of nitric oxide synthase in lung tissue were raised in intervention group (cardiac output: [(141 +/- 20) ml/min vs (118 +/- 40) ml/min, P < 0.01], but protein expression of collagen in intra-acinar pulmonary arteries and mRNA expression of type I collagen in the right ventricle and endothelin-1 in lung tissue were markedly decreased (protein expression of collagen: [(5.6 +/- 1.2) AU vs (20.4 +/- 4.5) AU, P < 0.001]. CONCLUSION: Changes of collagen expression in intra-acinar pulmonary arteries and right ventricle are one of the most important features in remodeling of pulmonary arteries and right ventricle in hypoxic pulmonary hypertension. Radix Astragali can partly inhibit the remodeling of pulmonary arteries and right ventricle, and regulate mRNA expression of endothelin-1, nitric oxide synthase, and collagen, thus contributing to the treatment of hypoxic pulmonary hypertension.