The role of epithelial sodium channel in the neonatal rat bronchopulmonary dysplasia early pulmonary edema induced by hyperoxia / 中国综合临床

ABSTRACT

Objective To investigate the changes of epithelial sodium channel(ENaC) expression and sodium and water transport function in the neonatal rat pulmonary edema induced by hyperoxia.Methods The neonatal rats were randomly divided into the hyperoxia group and the control group.After 1,3,5 and 7 d hyperoxia exposure,the lung tissues were collected to measure the wet-to-dry weight ratio and the expression of α-,β-and γ-ENaC subunits were detected by western blot analysis.Alveolar fluid clearance (AFC) and amiloride-sensitive AFC were measured after 5 d to reveal the effect of hyperoxia on the activity of ENaC.Results The lung water contents significantly increased in the hyperoxia group indicating that pulmonary edemahappened(3 d(6.37 ±0.64) vs (5.56±0.15),t=3.46,P＜0.01;5 d(5.86 +0.52) vs (5.11±0.21),t=-3.82,P ＜0.01;7 d(5.56±0.45) vs (4.80±0.09),t =-4.72,P ＜0.01).AFC increased significantly,but no significant difference was found in amiloride-insensitive AFC between the two groups which indicate that amiloride-sensitive AFC increased significantly (AFC(20.32 ± 3.33) ％ vs (12.97 ± 2.46) ％,t =-6.16,P ＜ 0.01 ; amiloride-insensitive AFC(10.42 ± 3.44) ％ vs (8.67 ± 3.13) ％,t =-1.30 P =0.21).The expression of α-,β-and γ-ENaC did not reduced after hyperoxia exposure compared with the control group.Conclusion Although bronchopulmonary dysplasia of early pulmonary edema induced by hyperoxia,dysfunctional transport of Na + may not be a key factor involved in pulmonary edema at the early stage of bronchopulmonary dysplasia.