Therapeutic Effect Of Osthole On Alcohol-induced Fatty Liver In Mice And Its Mechanisms

Aim: The aim of our study was to examine the therapeutic effect of osthole on alcohol-induced fatty liver in mice and investigate its potential mechanisms of the treatment. Methods: A mouse model of alcoholic fatty liver in vivo was established by orally feeding 56 % alcohol (erguotou), the therapeutic effect of osthole on alcoholic fatty liver and its lipid-regulation and anti-oxidation were observed. The effects of osthole on mRNA expressions of PPARα, CYP2E1, CPT1A and DGAT in mouse hepatic tissues were determined by reverse transcription polymerase chain reaction (RT-PCR). Rat hepatocyte line (BRL cell) was used in vitro experiments, after adaptive cultured with RPMI1640 medium, these cells were treated with serum-free medium containing 25, 50, 100, 200μg/ml osthole or with serum-free medium containing 200μg/ml lipanthyl for 24 h, and the mRNA expressions of PPARα, CYP2E1, CPT1A and DGAT in cells were then detected by RT-PCR. In order to further clarify whether the roles of osthole were related to the PPARα-mediated pathway, we also observed the changes of CPT1A, DGAT and CYP2E1 gene expressions in BRL cells after the cells were pretreated with PPARαinhibitor MK886 1μmol/L for 2 h. Results: After treatment with osthole 10, 20 and 40 mg/kg for 6 weeks, the serum TC, TG, low density lipoprotein-cholesterol (LDL-C), and hepatic tissue contents of TC, TG and MDA in osthole-treated groups were significantly decreased (P<0.05 or P<0.01),while the hepatic SOD level was significeantly increased as compared with model group (P<0.05 or P<0.01), but GSH-PX level was no significant change between groups.Importantly,the histological evaluation of liver demonstrated that osthole dramatically decreased lipid accumulation. Moreover, RT-PCR results showed that the osthole could significeantly increased the mRNA expressions of PPARαand CPT1A (P<0.05 or P<0.01), and decreased the mRNA expressions CYP2E1 and DGAT in mouse liver tissues (P<0.01). In vitro, osthole at 50～200μg/ml could also increase the expressions of PPARa mRNA and CPT1A mRNA (P<0.05 or P<0.01), and decrease the expressions of CYP2E1 mRNA and DGAT mRNA (P<0.05 or P<0.01) in rat hepatocytes, and after pretreatment with PPAR a inhibitor MK886 for 2 h, the effects of osthole on mRNA expressions of CYP2E1, CPT1A and DGAT were reduced or cancelled. Conclusion: Osthole was effective in treating mouse alcoholic fatty liver, and its main mechanisms might be related to regulating fat metabolism and oxidative stress related genes DGAT, CPT1A and CYP2E1 expression via increasing the expression of PPARαgene.