Pulmonary vascular microstructure in chronic hypoxic pulmonary hypertension
SHI Yun, DU Junbao, TANG Xiuying, et al. Department of Pediatrics,the First Hospital of Peking University ,Beijing 100034, P.R. China
Objective To explore the regularity of hypoxic pulmonary hypertension with microstructural changes in the diffe rent segments of intrapulmonary arteries.Methods Twenty three Wistar rats age and weight matched, were randomly divided into one week hypoxic group, two week hypoxic group and the control group. Pulmonary artery mean pressure mPAP) of each rat was evaluated using right cardiac catheterization . Lung tissues were dyed with Weigherts method. The percentage of each type of intra acinar pulmonary arteries was measured.Relative media thickness (RMT) and relative media area (RMA) of the intrapulmonary arteries accompanying with three segments of air way respectively were observed with a Computer Image Analysis System.Results mPAP significantly increased in two week hypoxic group as compared with that of one week hypoxic group and normal controls .And mPAP in one week hypoxic group markedly increased compared with that of normal controls (P0.05). The percentage of muscularized artery ,RMA and RMT of three segments of pulmonary arteries significantly increased in two week hypoxic group as compared with that of one week hypoxic group and normal controls,and the percentage of muscularized artery, RMT and RMT of pulmonary arteries at the level of alveoli in one week hypoxic group markedly increased compared with normal controls (P0.05). Compared with control group ,the thickness of internal elastic layer (IEL) in rats of two week hypoxic and two week hypoxic group reduced(P 0.05). mPAP was positively correalated with RMA and RMT of pulmonary arteries at the level of alveoli,and negatively correlated with the thickness of IEL of pulmonary arteries at the level of alveoli.Conclusion Segement dependent pulmonary vascular structural remodeling is of great importance in the pathological process of hypoxic pulmonary hypertension.