Effects of salvianolic-acid B on the p38MAPK signaling pathway and its transcriptional factor induced by transforming growth factor b1 in activated rat hepatic stellate cells

Abstract

To investigate the effects of Salvianolic-acid B on p38MAPK signaling pathway and its transcriptional factor activated by Transforming growth factor b1 in rat hepatic stellate cells. Hepatic stellate cells were isolated from normal rat by in situ perfusion and Nycodenz density-gradient centrifugation method.TGFb1 (10 ng/ml), PD98059(50 mumol/L), SB203580(10 mumol/L) and SA-B (10-6 mol/L) were directly added to the medium of the isolated HSCs. Groups: (1)The detection of total p38, MKK3/6, MEF2A and MEF2C induced by TGFb1 in HSC: include control group, SA-B group, SA-B+TGFb1 group and TGFb1 group. (2)The detection of the phosphorylation of p38, MKK3/6 and a-SMA induced by TGFb1 in HSC: include control group, SA-B group, SA-B+TGFb1 group, TGFb1 group, PD98059 group, PD98059+SA-B group, PD98059+TGFb1 group and SA-B+PD98059+TGFb1 group. (3)The effects of SA-B on activity of MEF2 reporter and collagen a 1(I) reporter induced by TGFb1 in HSC: include mt group, wt group, TGFb1 group, SA-B+TGFb1 group, SA-B group, SB203580+TGFb1 group and SB203580 group. Total and phosphorylated p38 and MKK3/6, MEF2A, MEF2C and a-SMA were assayed by Western blot. HSCs were transfected with either MEF2 or collagen a1(I) luciferase reporter gene by Lipofectamine 2000 transfection method, Cellular extracts were assayed for both MEF2 and collagen a1(I) luciferase activities. Comparisons between groups were performed with Student-Newman-Keuls test. The relative expression level of the phosphorylation of p38 of SA-B group is 0.33+/-0.05,obviously lower than control group(q=7.08, P less than 0.01); SA-B+TGFb1 group is 0.46+/-0.04, obviously lower than TGF b1 group(q=10.45, P less than 0.01); The relative expression level of the phosphorylation of MKK3/6 of SA-B group is 0.11+/-0.07, obviously lower than control group(q=3.944, P less than 0.05); SA-B+TGF b1 group is 0.28+/-0.07, obviously lower than TGFb1 group (q=7.91, P less than 0.01); The relative luciferase activity of MEF2 reporter of SA-B+TGFb1 group and SB203580+TGF b1 group is 2.93+/-0.09 and 2.50+/-0.05 respectively, both obviously lower than TGFb1 group(q=35.35 and 37.2, P less than 0.01); The relative expression level of MEF2C and MEF2A of SA-B group is 15.82+/-0.97 and 13.00+/-0.40 respectively, obviously lower than control group(q is 5.18 and 13.32, both P less than 0.01); SA-B+TGF b1 group is 13.40+/-0.72 and 20.47+/-0.83 respectively, obviously lower than TGFb1 group(q is 43.93 and 12.52,both P less than 0.01); The relative expression level of a-SMA of SA-B+TGFb1 group is 8.76+/-0.44, obviously lower than TGFb1 group(q=20.35, P less than 0.01); SA-B+SB203580+TGFb1 group is only 3.57+/-0.49, obviously lower than TGFb1 group(q=39.78, P less than 0.01); The relative luciferase activity of collagen a1(I) reporter of SA-B+TGF b1 group and SB203580+TGFb1 group is 1.61+/-0.05 and 1.42+/-0.07 respectively, obviously lower than TGFb1 group(q=26.4 and 27.62, both P less than 0.01). SA-B could inhibit activation of HSC induced by TGFb1 through inhibiting p38MAPK signaling pathway in hepatic stellate cells.