The Expression And Effect Of Nuclear Transporter KPNA2 In BPD Neonatal Rats

Objective:To study the dynamic changes of the localization and expression of nuclear transporter KPNA2 during the occurrence and development of bronchopulmonary dysplasia(BPD)in neonatal rats,and to explore its role in the pathogenesis of BPD in premature infants.Methods:100 newborn rats were randomly divided into a BPD group(n=50)and a control group(n=50)within 12 hours after birth.The model was prepared using the previous method of the research group,the BPD group inhaled oxygen concentration(Fi O2)was80%～85%.The control group inhaled air.The two groups collected lung tissue samples on1,3,7,10,and 14 days respectively,and separated,purified and cultured alveolar type Ⅱepithelial cells(AEC Ⅱ).The localization and expression of KPNA2 in lung tissue were observed by immunohistochemical technique,the localization and expression of KPNA2 in AECⅡ were observed by immunofluorescence technique,KPNA2 protein expression in the nucleus and cytoplasm of lung tissue was detected by nucleoplasm separation technique and Western blot,and the KPNA2 mRNA expression was detected by fluorescence realtime PCR.Results:Immunohistochemistry showed that KPNA2 was mainly located in alveolar epithelial cells and bronchial epithelial cells,and expressed in cytoplasmic nuclei.The expression of KPNA2 in the BPD group was stronger than that in the control group.Further cellular immunofluorescence showed that KPNA2 was expressed in the cytoplasm and nucleus.The control group was mainly located in the nucleus at each time point.The BPD group was mainly located in the nucleus at 1d,and there was no significant difference in expression.3d to 14 d,it was mainly located in the cytoplasm,compared with the control group.In contrast,the nuclear expression of KPNA2 was significantly weakened,and the cytoplasmic expression was significantly enhanced.The expression trends of KPNA2 total protein and plasma protein were basically the same.Compared with the control group,the BPD group began to increase at 1d(P<0.05),reached a peak at 3d(P<0.05),began to decrease gradually at 7d(P<0.05),and remained high at 14 d Compared with the control group(P<0.05);compared with the control group,the expression of KPNA2 nucleoprotein in the BPD group had no significant difference at 1d(P>0.05),and it began to decrease significantly at 3d(P<0.01),and continued to decrease to 14d(P<0.05).Compared with the control group,the expression of KPNA2 mRNA in the BPD group began to increase at1d(P<0.05),reached a peak at 3d(P<0.05),began to decrease gradually at 7d(P<0.01),and was still higher than that of the control group at 14d(P<0.05)Conclusion:Although the expression levels of KPNA2 protein and genes are up-regulated in newborn rats exposed to hyperoxia,their distribution is abnormal and a large amount is retained in the cytoplasm,suggesting that KPNA2 nuclear transport dysfunction may affect the early initiation of the DNA damage and repair response of BPD lung epithelial cells Important mechanism.