Effects of hyperoxia on expression of nuclear factor-erythroid 2-related factor 2 and Keap1 in premature newborn rats' lung

Objective To explore the expression of nuclear factor-erythroid 2-related factor 2(Nrf2) and the molecular chaperone of cytoplasmic Keap1 in premature newborn rats exposed to hyperoxia. Methods Completely randomized design method was performed, one-day old preterm SD rats were randomly divided into two groups: hyperoxia group and air group.The preterm SD rats in hyperoxia group were continuously exposed to oxygen(oxygen>0.85)and air group in room air.After 1, 4, 7, 10, 14 days of exposure, the preterm SD rats of two groups were sacrificed, whole lung of these rats were isolated, the lung histological changes were observed by HE staining.Total lung RNA was extracted, Nrf2 and Keap1 mRNA were detected by RT-PCR.Western-blot was used to detect the changes of Nrf2 protein expression. Results (1) Compaired with air group, the expression of Nrf2 in lung tissue of hyperoxia group significantly increased after 4, 7 days of exposure(4 d: 0.314±0.064 vs.0.521±0.086, 7 d: 0.440±0.121 vs.0.658±0.076)(P 0.05), but had a tendency of decreasing after 7 days.On day 10, 14, its expression in hyperoxia group became significantly weak compared with that of air group(10 d: 1.325±0.464 vs.0.755±0.348, 14 d: 1.662±0.474 vs.0.867±0.115)(P<0.05). Conclusion Oxidation outbreak results in the abnormal expression of Nrf2 and Keap1 in the lung of premature SD rats induced by hyperoxia exposure, which adjusts the levels of oxidative stress in the body, these changes participate in the development of hyperoxia induced lung injury, the activity of Nrf2 may be increased by hyperoxia exposure, and alleviate hyperoxia lung injury in premature rats through antioxidation of Nrf2. Key words: Hyperoxia; Lung injury; Nuclear factor-erythroid 2-related factor 2; Premature; Keap1,