The expression and effect of nuclear transporter KPNA2 in bronchopulmonary dysplasia neonatal rats / 中国小儿急救医学

ABSTRACT

Objective:To study the dynamic changes of the localization and expression of nuclear transporter KPNA2 in the occurrence and development of bronchopulmonary dysplasia(BPD) in neonatal rats, and explore its role in the pathogenesis of BPD in premature infants.Methods:The BPD model of newborn SD rats was induced with 85% oxygen concentration( n=50), and the control group was inhaled with air( n=50). The lung tissue samples were collected on 1 d, 3 d, 7 d, 10 d, and 14 d, respectively, in the two groups and separated.Purification and culture of alveolar type Ⅱ epithelial cells.The distribution and expression of KPNA2 were detected by immunohistochemistry, immunofluorescence, western blot and RT-PCR. Results:Immunohistochemistry showed that KPNA2 mainly located in alveolar epithelial cells′ cytoplasm and nucleus, and BPD group was more expressive than control group.Cell immunofluorescence showed that KPNA2 in control group was mainly localized in the nucleus, and in BPD group, KPNA2 was mainly localized in the cytoplasm from 3 d to 14 d. The nuclear expression of KPNA2 was weaker than that in the control group, and the cytoplasmic expression was stronger than that in the control group.The expression trends of KPNA2 total protein, plasma protein and mRNA were basically the same.The BPD group began to increase on the 1st day ( P<0.05), and was still higher than the control group on the 14th day( P<0.05); in BPD group, KPNA2 nucleoprotein expression began to decrease on the 3rd day( P<0.01), continued to decrease to 14 days( P<0.05). Conclusion:The dysfunction of KPNA2 nuclear transport in neonatal rats exposed to hyperoxia may be an important mechanism that affects the early initiation of the DNA damage response of BPD alveolar epithelial cells.