Extracellular signal-regulated kinase in liver fibrogenesis of rat

Chinese herbs Kangxian ruangan keli inhibits expression of MEK-1 and c-fos in hepatic stellate cell indused by PDGF

AIM: To investigate the effect of Kangxian ruangan keli (KXR) on the expression of MEK-1 and c-fos in hepatic stellate cell (HSC) indused by PDGF.

METHODS: In a serum-free culture system, HSC was treated with a KXR preparation for 24 hours, followed by stimulation with PDGF-BB for 24 hours. Then the cells were incubated again in the medium containing KXR for 3 hours stimulated with PDGF-BB for 5 minutes, and collected. The proliferation of HSC was examined using an MTT assay. MEK-1 was detected with Western blotting and visualized by the enhenced chemiluminescent (ECL) method. The expression of c-fos mRNA was analyzed with in situ hybridization.

RESULTS: The A values for the HSC growing in the media without and with addition of PDGF were 0.170±0.060 and 0.820±0.050, respectively. The PDGF-induced increase was hindered remarkably by KXR preparation in a dose-dependent manner. Reaction values for the systems with 5 g/L and 1.25 g/L of KXR were 0.280±0.030 and 0.430±0.040 respectively, lower significantly than that in the culture free of KXR (0.820±0.050, P < 0.01). In addition, values for MEK-1 in HSC treated with 5 mg/mL and 1.25 mg/mL of KXR were 0.143±0.013, and 0.170±0.007, respectively, being lower than that in the cells treated only with PDGF-BB (0.186±0.010, P < 0.01). The expression level of c-fos mRNA was 0.152±0.010 and 0.163±0.005, respectively, also lower than that of the PDGF group (0.183±0.014, P < 0.01).

CONCLUSION: Within the dose range used in the present study, KXR preparation shows an inhibitory effect on HSC proliferation induced by PDGF. The mechanism of this process may involve interference with Ras-MEK-MAPK singal transduction mediated by PDGF.