PECAM1 and bronchopulmonary dysplasia: Importantly, the current study showed that downregulation of miR-29a could repress cell apoptosis and promote cell proliferation, thus preventing the BPD through the upregulation of GAB1, evidenced by increased expression of Bax and Caspase-3 as well as stimulated positive expression rate of Ki67 and CD31 proteins, yet diminished Bcl-2 expression.