RESUMEN
Objective:To study the role of miRNA-15b and vascular endothelial growth factor (VEGF) in the pathogenesis of novel bronchopulmonary dysplasia (nBPD) in rats.Methods:A total of 100 newborn SD rats were randomly assigned into BPD group and control group with 50 rats in each group. The BPD group was placed in oxygen chamber with 60% oxygen concentration and the control group received atmospheric air. The morphological changes of lung tissues were observed on 1 d, 7 d, 14 d and 21 d and the radial alveolar counts (RAC) and alveolar septal thickness (AST) were measured. The expression of miR-15b was measured using real-time quantitative PCR and the expression of VEGF in lung tissue was examined using ELISA method.Results:With prolonged oxygen exposure, the lung tissue of the BPD group showed a decrease in the number of alveoli, a gradual loss of the normal structure of alveoli and a significant widening of the alveolar septum. On 7 d, 14 d and 21 d, RAC values [(6.19±0.29) vs. (6.86±0.92), (5.35±0.67) vs.(9.75±0.34), (3.96±0.45) vs. (10.04±0.52)] were significantly lower in the BPD group than the control group ( P<0.05). On 7 d, 14 d and 21 d,the levels of AST in BPD group were significantly higher than the control group [(6.87±0.41) μm vs. (6.43±0.31) μm, (8.94±0.25) μm vs. (5.36±0.26) μm, (9.61±0.30) μm vs. (4.55±0.32) μm] ( P<0.05). On 7 d, 14 d and 21 d,the miR-15b expression in BPD group were significantly higher than the control group [(1.12±0.11) vs. (0.84±0.09), (1.33±0.09) vs. (0.73±0.07), (1.66±0.15) vs. (0.45±0.10)] ( P<0.05).On 7 d, 14 d and 21 d, VEGF in BPD group were significantly lower than the control group [(10.89±1.67) pg/ml vs. (23.86±4.38) pg/ml, (8.75±1.28) pg/ml vs. (53.94±3.49) pg/ml, (4.66±1.12) pg/ml vs. (70.37±3.10) pg/ml] ( P<0.05). Conclusions:MiR-15b and VEGF may play a role in the development of nBPD.