Inhibitory Effect Of Osthole On Alcohol-induced Fatty Liver And Its Mechanisms In Murine

Aim: To examine the inhibitory effect of osthole on alcohol-induced fatty liver in mice and investigate the potential mechanisms. Methods: A mouse model with alcoholic fatty liver was induced by orally feeding 52 % erguotou wine by gavage when they were simultaneously treated with osthole 10, 20, 40 mg/kg for 4 weeks. Whereafter, the lipids in serum and hepatic tissue, the levels of malondialdehyde (MDA), superoxide dismutase (SOD), reduced glutathione hormone(GSH), tumor necrosis factor-α(TNF-α) in hepatic tissue, hepatic weight coefficient and its histological evaluation were measured. Expression of PPARα/γmRNA, DGAT mRNA, HMG-CoA reductase mRNA and CYP7A mRNA in hepatic tissues of alcoholic fatty liver mice were examined by RT-PCR. BRL cells were cultured in RPMI 1640 and divided into six groups as follows: RPMI 1640, RPMI 1640 with 25, 50, 100, 200μg/mL osthole and 200μg/mL lipanthyl, respectively. After incubation with drugs for 24 hours, total RNA was isolated and used for measurement of PPARα, DGAT, HMG-CoA reductase and CYP7A mRNA expression using RT-PCR analysis. In order to demonstrate whether the mechanisms of osthole are associated with the pathway of PPARα, BRL cells were divided into 4 groups as follows: RPMI 1640, PRMI 1640 with 200μg/mL osthole, RPMI 1640 with 1μmol/L MK886 (a PPARαinhibitor), RPMI 1640 with 1μmol/L MK886 plus 200μg/mL osthole (BRL cells were preincubated with MK886 (1μmol/L) for 2 hours). After osthole was added to cells and incubated for 24 hours, total RNA was isolated and used for measurement of PPARα-regulated target gene expression. Results: After treatment with osthole 10-40 mg/kg for 4 weeks, the levels of serum total cholesterol (TC), triglyceride (TG), coefficient of hepatic weight, and the hepatic tissue contents of TC and TG were significantly decreased(P<0.01), the levels of MDA and TNF-αin liver were also decreased(P<0.05 or P<0.01), while the GSH in liver was increased(P<0.01). Importantly, the histological evaluation of liver specimens demonstrated that osthole dramatically decreased lipid accumulation. Osthole could significantly increase the mRNA expression of PPARα/γand CYP7A(P<0.05 or P<0.01), decrease the mRNA expression of DGAT and HMG-CoA reductase in hepatic tissues of alcoholic fatty liver mice(P<0.05 or P<0.01). In vitro, Osthole could also increase the mRNA expression PPARαand CYP7A(P<0.05 or P<0.01), decrease the mRNA expression of DGAT and HMG-CoA reductase in cultured-BRL cells(P<0.05 or P<0.01). And after pretreatment with PPARαinhibitor (MK886) for 2 hours, the effects of osthole on mRNA expression of DGAT, HMG-CoA reductase and CYP7A were completely cancelled. Conclusion: Osthole had inhibitory effect on alcohol-induced fatty liver in mice, the mechanisms might be associated with its anti-oxidation,anti-inflammation and regulation of the mRNA expression of DGAT, HMG-CoA reductase and CYP7A via increasing PPARα/γmRNA expression.