AIM:Hepatic stellate cell(HSC)plays a pivotal role inliver fibrosis and is considered as the therapeutic targetfor the treatment of hepatic fibrosis.Tyrosine proteinkinase plays an important role in the proliferation,activation of HSC.The purpose of the study is toinvestigate the effects of the tyrosine protein kinaseinhibitor genistein on the proliferation and activationof cultured rat HSC.METHODS:Rat HSC were isolated from Wistar rats by insitu perfusion of collagenase and pronase and single-stepdensity Nycodenz gradient.Culture-activated HSC wereserum-starved and incubated with 10~(-9)to 10~(-5)mol/Lconcentration of genistein for 24,48 or 72 h.In PDGF-induced HSC proliferation,HSC were stimulated with 10μg·L~(-1)PDGF-BB for 15 rain,and then treated with genisteinfor the same time.Cell proliferation was measured byMTT assay and based on flow cytometric analysis of cellcycle.The a-smooth muscle actin(α-SMA)expression inHSC was studied with confocal laser microscopy and flowcytometry,c-fos,c-jun and cyclin D_1 expression in HSCwas also detected by flow cytometry.RESULTS:Genistein inhibited basal and PDGF-inducedproliferation of HSC at the concentration of 10~(-8)to 10~(-5)mol/L,and treatment with 10~(-7)mol/L concentration ofgenistein for 48 h inhibited the HSC proliferationsignificantly(the inhibition rate was 70.3 %,P<0.05).Immunofluorescence detected by confocal lasermicroscopy and flow cytometry showed that treatmentwith 10~(-7)mol/L genistein for 48 h suppressed theexpression of α-SMA significantly in HSC(the specificfluorescence intensity were 60.2±21.5 vs 35.3±11.6and 12.8±10.4 vs9.54±6.39,respectively,both P<0.05).The intensity of c-fos,c-jun and cyclin D_1 expression ofHSCs treated with 10~(-7)mol/L genistein for 48 h wasalso significantly decreased compared with the controls.CONCLUSION:Genistein influences proliferation of HSC,suppresses the expression of α-SMA in HSC and t inhibits the intensity of c-fos,c-jun and cyclin D_1expression of HSCs.Genistein has therapeutic potentialagainst liver fibrosis. AIM: Hepatic stellate cell (HSC) plays a pivotal role inliver fibrosis and is considered as the therapeutic target for the treatment of hepatic fibrosis. Syrosine proteinkase plays an important role in the proliferation, activation of HSC. The purpose of the study is to investigate the effects of the tyrosine protein kinase inhibitor genistein on the proliferation and activation of cultured rat HSC. METHODS: Rat HSC were isolated from Wistar rats by insitu perfusion of collagenase and pronase and single-step intensity Nycodenz gradient. Culture-activated HSC were purified-starved and incubated with 10 ~ (-9) to 10 ~ (-5) mol / L of concentration of genistein for 24, 48 or 72 h.In PDGF-induced HSC proliferation, HSC were stimulated with 10 μg · L -1 PDGF- and then treated with genistein for the same time. Cell proliferation was measured by MTT assay and based on flow cytometric analysis of cell cycle. a-smooth muscle actin (α-SMA) expression in HSC was studied with confocal laser microscopy and flowcytometr HSC was also detected by flow cytometry. RESULTS: Genistein inhibited basal and PDGF-inducedproliferation of HSC at the concentration of 10 ~ (-8) to 10 ~ (-5) mol / L, and treatment with 10 ~ (-7) mol / L concentration of genistein for 48 h inhibited the HSC proliferationsignificantly (the inhibition rate was 70.3%, P <0.05) .Immunofluorescence detected by confocal lasermicroscopy and flow cytometry showed that treatment with 10 ~ (-7) mol / L genistein for 48 h suppressed the expression of a-SMA significantly in HSCs (the specific fluorescence intensity were 60.2 ± 21.5 vs 35.3 ± 11.6 and 12.8 ± 10.4 vs 9.54 ± 6.39, respectively, both P <0.05). The intensity of c-fos, c-jun and cyclin D_1 expression of HSCs treated with 10 ~ (-7) mol / L genistein for 48 h wasalso significantly decreased compared with the controls.CONCLUSION: Genistein influences proliferation of HSC, suppresses the expression of α-SMA in HSC and t inhibits the intensity of c-fos, c-jun and cyclin D_1expression of HSCs.Gen istein has therapeutic potential against liver fibrosis.