Effects of cannabidiol on hepatic stellate cell activation and hepatic fibrosis induced by transforming growth factor beta1
BACKGROUND:Cannabidiol has anti-inflammatory,antioxidant,and other pharmacological effects,and has no mental activity,so the research in liver disease is increasing day by day,but its effect on transforming growth factor-β1/Smad signal transduction pathway in hepatic stellate cells is not clear.OBJECTIVE:To investigate the effect of cannabidiol on transforming growth factor-β1/Smad signal transduction pathway in hepatic stellate cells and its possible mechanism of anti-hepatic fibrosis.METHODS:(1)In vitro experiment:Rat hepatic stellate cell line(HSC-T6)was selected and cultured in six groups.The control group was routinely cultured for 24 hours.The simple drug group was cultured with cannabidiol for 24 hours.The modeling group was cultured with transforming growth factor β1 for 24 hours.The modeling+low-dose drug group,the modeling+high-dose drug group,and the modeling+positive control group were cultured with transforming growth factor β1 for 24 hours,1,5 μmol/L cannabidiol and silymarin were cultured for 24 hours.After culture,the mRNA expression of α-smooth muscle actin and type Ⅰ collagen,the levels of interleukin 1β and tumor necrosis factor α,and the protein expression of type Ⅰ collagen and transforming growth factor β1/Smad signal transduction pathway were detected in each group.(2)In vivo experiments:C57BL/6J mice were randomly divided into five groups with eight mice in each group.Models were not established in the sham operation group.The liver fibrosis models were established by biliary ligation in the modeling group,the modeling+low-dose drug group,the modeling+high-dose drug group,and the modeling+positive control group.At 3 weeks after the modeling,4,8 mg/kg cannabidiol or silymarin were injected intraperitoneally,once a day,for 7 consecutive days.After administration,the liver function,liver pathological morphology,expression levels of α-smooth muscle actin,type Ⅰ collagen,and transforming growth factor β1/Smad signal transduction pathway related protein were detected in each group.RESULTS AND CONCLUSION:(1)In vitro experiment:Compared with the control group,mRNA expression of α-smooth muscle actin and type Ⅰ collagen,interleukin 1β and tumor necrosis factor α,and protein expression of type Ⅰ collagen,transforming growth factor β1 and p-Smad2/3 in HSC-T6 cells were increased(P<0.05),while Smad7 protein expression was decreased(P<0.05)in the modeling group.Two doses of cannabidiol could improve the above changes in HSC-T6 cells induced by transforming growth factor β1,and the improvement was more obvious in the modeling+high-dose drug group.(2)In vivo experiment:Compared with sham operation group,the activities of serum alanine aminotransferase and aspartate aminotransferase were increased(P<0.05),inflammatory cell infiltration and collagen content in liver tissue were increased(P<0.05),and the transforming growth factor β1/Smad signal transduction pathway was activated;α-smooth muscle actin and type Ⅰ collagen expression levels were increased(P<0.05)in the modeling group.Two doses of cannabidiol could reduce the changes of the above indexes in the modeling mice,and the effect was more obvious in the modeling+high-dose drug group.(3)It is indicated that cannabidiol inhibits hepatic fibrosis by suppressing the activation of transforming growth factor-β1/Smad signal transduction pathway in hepatic stellate cells.