The Effect Of Different Oxygen Concentrations On The Fetal Lung Development Of Rats In Vitro

Background:Oxygen is essential for fetal lung development. Preterm children for a long time to receive oxygen therapy, can suffer bronchopulmonary dysplasia (BPD). Intrauterine hypoxia can also cause fetal lung growth restriction. Studies in vitro have found that normal embryonic development required3%～5%O2.The issue of whether the oxygen which is higher than5%O2or less than3%O2should inhibit fetal lung development and what are the molecular mechanisms need to be discussed.Objective:The purpose of this study was to investigate the effects of oxygen on fetal lung morphology and cell proliferation by fetal lung explants culture, further observe the mRNA changes of some genes associated with fetal lung development, and explore whether the effects of oxygen on lung development should be associated with these genes.Methods:1. Fetal lung explants culture and grouping:dissected fetal rat lungs at E13, then respectively cultured48hours at3%O2,1%O2and19%O2, to observe the number of terminal lung buds, growth area and cell proliferation by immuno-labeled for EdU in red.2. Real-time PCR technique was used to detect mRNA expression of HIF-la, HIF-2a, VEGF and TN-C which genes are associated with fetal lung development.Results:1. Explants cultured at1%O2and19%O2compared with3%O2had less number of terminal lung buds, smaller growth area and weaker fluorescence intensity of EdU (P<0.05).2. Real-time PCR showed that the mRNA expression of VEGF and TN-C is down regulated in explants cultured at1%O2and19%O2compared with3%O2(P <0.05),and the mRNA expression of HIF-1α and HTF-2α is a no significant change (P>0.05).Conclusion:1. successfully established a fetal rat lung explants model at E13.2. For the first time observed the effect of3%O2,1%O2and19%O2on fetal rat lung development in vitro, discovered that too low oxygen (1%O2) and too high oxygen (19%O2) both can inhibit fetal lung development.3. For the first time found that too low oxygen (1%O2) and too high oxygen (19%O2) both can inhibit the expression of VEGF and TN-C, suggesting that hypoxia (1%O2) and hyperoxia (19%O2) inhibition of the fetal lung development may be associated with the decrease of the expression of VEGF and TN-C.