OBJECTIVETo observe the effects of Nrf2 gene expression induced by RU486 at different doses on A549 cell damage induced by paraquat (PQ).

METHODSAfter A549 cells transfected with Ad-RUNrf2 were treated by RU486 at the doses of 10(-10), 10(-9), 10(-8) and 10(-7) mol/L for 6 h, A549 cell cultures were exposed to 10(-3) mol/L of PQ for 48 h. Then qRT-PCR and EMSA assays were used to detect the expression of Nrf2 gene, and qRT-PCR and ELISA assays were utilized to measure the effects of Nrf2 gene on the expression of the inflammatory cytokines IL-6, IL-10 and TNF-α, apoptotic factors Caspase-3, Caspase-9 and Cytochrome C. The oxidation factors (CAT and MDA protein contents) were observed by Chemical Colorimetric Analysis.

RESULTSNrf2 gene relative expression and protein contents increased with RU486 concentrations, and the above expression was the highest when the concentration of RU486 was 10(-7) mol/L, which was significantly higher than those in control and PQ exposure groups (P < 0.01 or P < 0.05). The relative gene expression and protein expression of IL-6 and TNF-α enhanced with the reduced concentrations of RU486, which were the lowest when RU486 concentration was 10(-7) mol/L, as compared with control and PQ exposure groups (P < 0.01 or P < 0.05), while the change of IL-10 content was the opposite. The relative expression of Caspase3, Caspase9 and Cytochrome C genes also increased with the reduced concentrations of RU486, which were the lowest when RU486 concentration was 10(-7) mol/L, as compared with control and PQ exposure groups (P < 0.01 or P < 0.05). The content of CAT enhanced with RU486 concentration, which was the highest when RU486 concentration was 10(-7) mol/L, as compared with control and PQ exposure groups (P < 0.05). But the change of MDA content was the contrary.

CONCLUSIONNrf2 expression induced by RU486 can promote the balance of oxidation-antioxidation system in A549 cells and inhibit the inflammation and apoptosis factors, which has a protective effect on A549 cell injury induced by PQ.