LAUSR

In former research, cyp7a1 expression was decreased but Nrf2 transcription and hepatic arachidonic acid (AA) concentration were increased in high-fat diet fed mice. This study aims to investigate the influence of AA in CYP7A1 expression and the role of Nrf2 in regulating CYP7A1 in the process. HepG2 cells were administered with different concentrations of AA. Nrf2 and CYP7A1 expressions were analyzed by real-time PCR and western blot. Nrf2 silenced and over-expressed cell models were constructed by Nrf2 siRNA and eukaryotic expression vector transient transfections and were used to investigate the role of Nrf2 in regulating CYP7A1 following AA administration. The results showed that Nrf2 was increased dose-dependently but CYP7A1 was decreased dose-dependently in cells treated with increasing concentrations of AA. The expression of CYP7A1 was increased by Nrf2 silence and was decreased by Nrf2 over-expression in HepG2 cells treated with different concentrations of AA. In conclusion, Nrf2 plays a significant role in the down-regulation of CYP7A1 induced by AA in HepG2 cells.