Expression and significance of markers from lung epithelium cells in neonatal rats with bronchopulmonary dysplasia / 中华实用儿科临床杂志

ABSTRACT

Objective To investigate the dynamic expression of mRNA and protein of surfactant protein C (SPC),E-cadherin (E-cad),N-cadherin (N-cad) and α-smooth muscle actin (α-SMA) and elucidate the significance of epithelial-mesenchymal transition (EMT) in a newborn rat model of Bronchopulmonary dysplasia (BPD).Methods A newborn rat model of BPD in hyperoxia was established,and a control group exposed to air was established.Lung tissue was collected on days 3,7,14,and 21,respectively.Alveolar development was evaluated by radical alveolar counts(RAC),including thickness of alveolar septum,ratio of alveolar and septa.Real-time PCR and Western-blot were used to detect levels of markers of epithelial cells (SPC,E-cad) and interstitial cells (N-cad,α-SMA) in AT2 and protein expression.Results On day 7,14,and 21,compared with the control group,RAC (7.38 ± 0.92,9.25 ± 0.70,9.88 ± 0.99) and alveolar area/pulmonary septal area ratios (A/S) (2.53 ± 0.02,3.34 ± 0.09,3.96 ± 0.13) were all higher in BPD group [RAC (5.88 ± 0.83,5.14 ± 0.83,4.38 ± 0.52) and A/S (1.88 ± 0.03,1.95 ± 0.03,1.89 ± 0.02)] (all P ＜ 0.05) ; the alveolar septum (8.53 ± 0.04,10.75 ± 0.46,13.55 ± 0.84) in BPD group were thicker than those (5.77 ± 0.09,4.40 ± 0.12,3.67 ± 0.18) in the control group (all P ＜ 0.01).The expressions of SPC and α-SMA in BPD group were significantly higher than those in the control group on day 14 and 21 (all P ＜ 0.05).The level of E-cad mRNA (2.43 ± 0.60,2.59 ± 0.48,3.37 ± 0.53) and protein (18.39 ± 1.77,18.29 ± 1.52,11.48 ± 1.72) for E-cad were higher in the control group than those (mRNA:1.48 ± 0.55,1.57 ± 0.48,1.12 ± 0.45 ;protein:9.50 ± 1.38,8.57 ± 1.06,8.22 ± 1.31) in BPD group was lower(P ＜ 0.05),while the level of N-cad was significantly higher(P ＜ 0.05) on day 7,14,and 21.Conclusions In the development of BPD,the markers of lung epithelial cells were down regulation,while the markers of interstitial cells were up-regulation,and these findings suggest that EMT from lung epithelial cells contributes to the occurrence of BPD.