Effects of platelet-derived growth factor and interleukin-10 on Fas/Fas-ligand and Bcl-2/Bax mRNA expression in rat hepatic stellate cells in vitro

AIM: To investigate the effects of platelet-derived growth factor( PDGF) and interleukin-10 (IL-10) on Fas/Fas-ligand and Bcl-2/Bax mRNA expressions in rat hepatic stellate cells. METHODS: Rat hepatic stellate cells (HSCs) were isolated and purified from rat liver by in situ digestion of collagenase and pronase and single-step density Nycodenz gradient. After activated by culture in vitro, HSCs were divided into 4 groups and treated with nothing (group N), PDGF (group P), IL-10 (group I) and PDGF in combination with IL-10 (group C), respectively. Semi-quantitative reverse-transcriptase polymerase chain reaction (RT-PCR) analysis was employed to compare the mRNA expression levels of Fas/FasL and Bcl2/Bax in HSCs of each group. RESULTS: The expression levels of Fas between the 4 groups had no significant differences (P>0.05). FasL mRNA level in normal culture-activated HSCs (group N) was very low. It increased obviously after HSCs were treated with IL-10 (group I) (0.091 +/- 0.007 vs 0.385 +/- 0.051, P<0.01), but remained the low level after treated with PDGF alone (group P) or PDGF in combination with IL-10 (group C). Contrast to the control group, after treated with PDGF and IL-10, either alone or in combination, Bcl-2 mRNA expression was down-regulated and Bax mRNA expression was up-regulated, both following the turn from group P, group I to group C. Expression of Bcl-2 mRNA in group C was significantly lower than that in group P (0.126 +/- 0.008 vs 0.210 +/- 0.024, P<0.01). But no significant difference was found between group C and group I, as well as between group I and group P (P>0.05). Similarly, the expression of Bax in group C was higher than that in group P (0.513 +/- 0.016 vs 0.400 +/- 0.022, P<0.01). No significant difference was found between group I and group P (P>0.05). But compared with group C, Bax expressions in group I tended to decrease (0.449 +/- 0.028 vs 0.513 +/- 0.016, P<0.05). CONCLUSION: PDGF may promote proliferation of HSCs but is neutral with respect to HSC apoptosis. IL-10 may promote the apoptosis of HSCs by up-regulating the expressions of FasL and Bax and down-regulating the expression of Bcl-2, which may be involved in its antifibrosis mechanism.