The Effect Of C-jun/AP-1 Inhibitor In Estrogen-regulated Expression Of BSEP And NTCP

Objective:To study the effect of different concentration level of 17(3 estradiol on the expression of Bile salt export pump (BSEP) and Na+-taurocholatecotransporting polypeptide (NTCP) in L-02 normal human liver cells, as well as the effect of c-jun/AP-1 inhibitor SP600125 on the expression of BSEP and NTCP role in estrogen-regulated liver cell.Methods:Culture human liver cell line L-O2, with 17β-estradiol of 500nM respectively for 6hours,12 hours,18 hours,24 hours,30 hours and 36 hours, as well as with different concentration levels of 17βestradiol (0.1,1.0,10,100,500,1000 nmol/L) for 24h, among which 0.1,1.0,10 nmol/L are the physiological concentration; using RT-PCR to analyze BSEP and NTCP mRNA expression respectively in hepatic cells,then adopt biochemical methods to detect bile acid secretion of liver cells.Results:As the action of 17β-estradiol prolonged,the expression of BSEP and NTCP mRNA was decreased, in each group had significant differences (P<0.05), while bile acid concentration in culture medium at 6 hours,12 hours,18 hours 24h, were no difference (P> 0.05),30 hours and 24 hours difference compared (P<0.05),36 hours and 30 hours showed no significant difference (P> 0.05); Physiological concentration levels of 17(3-estradiol (0.1,1.0,10 nmol/L) does not affect BSEP and NTCP expression and bile acid secretion in liver cells, with no significant difference compared to the control group (P> 0.05); high concentration levels of 17β-estradiol could down regulate the expression of BSEP and NTCP, and up regulate bile acid concentration (P<0.05, P <0.05, P<0.05), which proves to be dose-dependent; JNK inhibitor SP600125 could inhibit AP-1 activity, significantly affecting the down-regulation of estrogen on the expression of BSEP and NTCP. As a result, the level of BSEP and NTCP mRNA expression and bile acid are up-regulated, which are dose-dependent and significantly different compared with the control group.(P<0.05, P<0.05, P<0.05).Conclusions:Physiological concentration levels of 17β-estradiol does not affect BSEP and NTCP expression in liver cells, while concentration above the physiological level can down regulate the expression, which is dose-dependent;AP-1 inhibitor SP600125 can significantly down regulate BSEP and NTCP expression,which is also dose-dependent.