Effects Of Arctiin And Arctigenin On Differentiation And Glucose And Lipid Metabolism Of3T3-L1Preadipocytes And The Mechanism Study

ObjectiveTo investigate the effects of arctiin and arctigenin on proliferation/differentiation and glucose/lipid metabolism of murine3T3-L1preadipocytes and study their possible mechanism.Methods3T3-L1preadipocytes were cultured with arctiin and arctigenin in different concentrations. Cell proliferation was analyzed by MTT method. The degree of differentiation was evaluated by oil red0staining and spectrophotography. To unravel the lipolysis and glucose consumption of3T3-L1preadipocytes were induced into adipocytes, the glycerol, free fatty acid and glucose in the supernatants were quantitatively assayed by glycerol phosphate oxidase-peroxidase method, colorimetry and glucose oxidase method respectively. The transcriptional and translational expression of peroxisome proliferators activated receptor γ (PPAR γ) gene and CCAAT enhancer binding protein α (C/EBPα) gene were detected by real time fluorescence quantitative-polymerase chain reaction (RTFQ-PCR) and western blot. The activity of fatty acid synthase (FAS) was determined by ultraviolet spectrophotography.ResultsIn a concentration range of12.5～100μ mol/L, arctiin and arctigenin did not exhibit remarkable influence on proliferation of3T3-L1preadipocytes (P>0.05), but significantly inhibited the cell differentiation and adipogenesis in a dose-dependent manner (P<0.01). At the same concentration, the inhibitory effect of arctigenin was stronger than that of arctiin (P<0.01or P<0.05) The release of glycerol and free fatty acid was obviously decreased with increasing dose of arctigenin within the range of25-100μ mol/L (P<0.01或P<0.05). In the highest concentration (100μmol/L) group, the content of glycerol and free fatty acid were28.7%and40.6%of that in control. Arctiin had no significant effect on the lipolysis in adipocytes (P>0.05)The data also showed that arctigenin and arctiin promoted the glucose consumption of adipocytes with the concentration from12.5to100μmol/L (P<0.01)The PPARγ and C/EBPa mRNA levels during differentiation of3T3-L1preadipocyte were decreased after the treatment with arctiin and arctigenin (F<0.01or P<0.05), and the inhibitory action accompanied with the dose effect relation. At the highest dosage (100μmol/L) of arctigenin and arctiin groups, the PPARγ and C/EBP a transcript level were just13.5%/6.3%and33.9%/8.4%of those in control respectively. Western blot gave the results similar to the RTFQ-PCR. It was indicated that arctiin and arctigenin could down-regulate the expression of PPARγ and C/EBPα gene both in the transcriptional and translational level.At the doses of12.5～100μ mol/L, arctiin and arctigenin effectively reduced the FAS activity of adipocytes (P<0.01or P<0.05). The FAS activities were lower in the arctigenin groups than in the arctiin groups at the same dosage (P<0.01or P<0.05)ConclusionArctiin and arctigenin inhibit the differentiation of3T3-L1preadipocytes, and increase the consumption of glucose in3T3-L1preadipocytes without cytotoxicity. Arctigenin suppresses the lipolysis in adipocytes. The decreased expression of PPARγ and C/EBP a, and depressed activity of FAS may be involved in the possible mechanism of arctiin and arctigenin.