Expression And Significance Of Aquaporin 5 In Human Fetal Lung Development

Objective:1. To detect the expression and localization of aquaporin 5 (AQP5) in human fetal lungs of different gestational weeks (from 27 week to 37 week).2. To compare the differential gene expression of normal and abnormal human fetal lungs.3. To discuss the role of AQP5 in fetal lung development and pulmonary fluid metabolism.Methods:1. The AQP5 mRNA expression was evaluated by reverse transcriptase- polymerase chain reaction (RT-PCR).2. The expression difference of AQP5 mRNA was detected by semi-quantitative real-time PCR.3. The AQP5 protein expression was assessed by immunohistochemistry.Results:1. AQP5 mRNA was detected by RT-PCR in fetal lungs from 27 weeks to 37 weeks, including normal and abnormal lungs.2. Expression level of AQP5 mRNA was significantly reduced in abnormal fetal lung group compared to normal fetal lung group (0.627±0.145 VS 1.019±0.069, P < 0.05).3. AQP5 mRNA expression showed upward trend with increasing gestational age (from 28+2 week to 37+4 week) in normal fetal lung group. In abnormal fetal lung group the partial pulmonary atelectasis tissue (31+4 week) had the highest AQP5 mRNA expression and the dysplasia lung (28+6 week) had the lowest AQP5 mRNA expression. The AQP5 mRNA expression in pulmonary edema tissue was higher in 31 week fetal lung than in 27+2 week one.4. Immunohistochemistry showed that AQP5 protein was primarily localized in the apical membrane of type I alveolar epithelial cells (AECs-I) in normal human fetal lungs, but little was stained at neither pulmonary edema tissue nor dysplasia lung.Conclusion:1. AQP5 mRNA expression occurs as early as 27 week in human fetal lung. AQP5 protein is primarily localized in the apical membrane of type I alveolar epithelial cells (AECs-I) in normal human fetal lungs.2. AQP5 mRNA and protein show decreased expression in abnormal fetal lungs than normal lungs.3. AQP5 may have a significant impact on normal lung development and pulmonary fluid metabolism.