Expression of cyclin A2 and its inhibitory factor in BPD neonatal rats and its effect on alveolar development / 国际儿科学杂志

ABSTRACT

Objective To investigate the effects of cyclinA2 and its inhibitor p21 on alveolar development in bronchopulmonary dysplasia (BPD) neonatal rats.Methods Eighty newborn rats were randomly divided into a model group (FiO2 =80％-85％) and a control group (FiO2 =21％).The degree of alveolar development was evaluated by radial alveolar count (RAC) and alveolar septal thickness.The distribution and expression of cyclinA2 and p21 were detected by immunohistochemistry and Western blot.Results The RAC value of the model group was lower than that of the control group from 3 days.The thickness of the alveolar seprum was higher than that of the control group from 7 days (P ＜0.05).The expression of p21 protein in the model group began to increase from 3d,peaked on 14d,and lasted for 21d.The expression of cyclinA2 protein in model group was higher than that in control group at 14d and 21d (P ＜0.05).There was a negative correlation between RAC and p21 protein expression in model group (r =-0.5966,P ＜0.01),and no correlation with cyclinA2 (r=0.7276,P＞0.05);there was no correlation between RAC and p21 in the control group (r =-0.2929,P ＞ 0.05),and positively correlated with cyclinA2 (r =0.8476,P ＜ 0.01).The alveolar septal thickness of the model group and the control group were both positively correlated with p 21 (r =0.4291,P＜0.05;r=0.4447,P ＜0.05),and negatively correlated with cyclinA2 (r=-0.6814,P ＜0.01;r=-0.7636,P ＜0.01).Conclusion The imbalance of cell cycle regulatory protein cyclinA2 and its inhibitor p21 expression in neonatal rats exposed to hyperoxia may be one of the related factors that interfere with the development of BPD alveoli.