457 - Alteration in Expression of Inflammatory and Epithelial to Mesenchymal Transition (EMT) Genes in Lung Alveolar Epithelial Cells (AEC) by Different Percentages of Oxygen

Poster Number: 457
Publication Number: 457.432

Wenxiang Luo, University of Illinois at Chicago, Chicago, IL, United States; HAMOOD U. MALIK, University of Illinois College of Medicine, CHICAGO, IL, United States; De-Ann Pillers, UIC Department of Pediatrics, CHICAGO, IL, United States

Background: Supplemental oxygen is an essential therapy used for neonatal resuscitation. Due to potential harmful effects, current recommendations for resuscitation of preterm newborns ( < 35 weeks of gestation) are to begin with 21% to 30% oxygen with subsequent titration. The effects of different levels of oxygen on preterm neonates are not fully understood. It is known that exposure of preterm neonates to excess oxygen may lead to chronic complications including bronchopulmonary dysplasia (BPD). Inflammation and fibrosis are known to be two important pathogenic features in BPD lungs, and EMT is involved in lung fibrotic pathogenesis.

Objective: To determine whether different levels of oxygen differentially alter the expression of inflammatory and EMT genes in AEC.

Design/Methods: Mouse C10 AEC (a non-tumorigenic line) were treated with 25%, 35%, 45%, 65%, and 85% oxygen mixed with 5% CO2 in room air for 36 hours whereas control cells were in room air with 5% CO2. Quantitative real-time PCR was used to measure mRNA levels of a panel of EMT and inflammation genes. Data were analyzed by ANOVA and t-test, A P value of < 0.05 was deemed significant.

Results: Interleukin-6 (IL6), an inflammatory marker, was induced slightly by 35% and markedly by 45%, 65%, and 85% oxygen, but it was not increased by 25%. Furthermore, IL6 mRNAs at 25% (P < 0.005) and 35% (P < 0.02) oxygen were lower than those at 65% and 85%. Serpin peptidase inhibitor clade E member 1(Serpine1), an EMT marker, was upregulated by all of tested doses of oxygen. Similar to IL6, Serpine1 mRNAs at 25% (P < 0.036) and 35% (P < 0.035) oxygen were lower compared with those at 65% and 85%. In contrast, expression of occludin (OCLN), an epithelial marker, was suppressed by all tested doses of oxygen. However, suppression of OCLN by 25% (P < 0.0036), 35%, (P < 0.004) and 45% (P < 0.01) oxygen was reduced in comparison with those by 65% and 85%. Alpha-smooth muscle actin, another EMT marker, was increased by all tested doses of oxygen.Conclusion(s): Although 25% and 35% oxygen altered expression of inflammatory and EMT genes, changed levels by the two low doses were lower than those by high doses (65% and 85%). Our findings suggest that resuscitation of preterm neonates with initial low level oxygen may reduce alteration in expression of inflammatory and EMT genes and mitigate potential negative effects on lung development in preterm neonates.