| ObjectiveThe high-fat diet-induced obese rat and 3T3-L1 mouse preadipocyte were chosed as the momel to study the effect of arctigenin on reducing weight gain and blood lipids.The proliferation,differentiation,adipogensis and adipolysis were also abserved for exploring the mechanism of arctigenin controlling fat metabolism.Methods(1)The HFD-induced obese rat model was replicated and randomly divided into four groups:model control group,arctigenin low-dose group,and positive drug(atorvastatin)group.The rats fed with normal diet were normal control group.Each group consists of 8 rats.After intervention,the changes of body weight and organ weight were recorded,and the blood lipids level was measured.The pathological changes of liver cells and adipocytes were observed by slicing.(2)3T3-L1 preadipocytes in logarithmic growth period were treated with different concentrations of arctigenin(12.5-100 ?mol/L)for 48 h,and the cells proliferation was detected by CCK8 method.The adipogenic differentiation of 3T3-L1 preadipocytes was induced.During differentiation,arctigenin(25-100 ?mol/L)was added with induced medium for 8 days.The degree of adipocyte differentiation and lipid synthesis were measured by oil red 0 staining.The mRMA level of transcription factors relating adipogenic differentiation and their target genes was quantitatively assayed by real time fluorescence quantitative-polymerase chain reaction(RTFQ-PCR).(3)After 3T3-L1 preadipocytes were induced to differentiate into mature adipocytes,various concentrations of arctigeninwere added into cells for 48 h.The total cellular lipids,triglycerides and glycerol were quantitatively analyzed.,RT-PCR and Western blotting detection of The expression and activation of proteins involving in AMP-activated protein kinase(AMPK)signaling pathway.Results(1)Compared with model control group,the treatment by high-dose of arctigenin can significantly reduce body weight gain,the weight of epididymal fat and the liver index.The results also showed that there was a marked drop in the serum total cholesterol(TCHO)and triglyceride(TG).Contrarily,the concentration of high density lipoprotein cholesterol(HDL-L)was observably increasedin arctigenin high-dose group.The liver steatosis hepatocytes were significantly reduced.(2)Arctigenin had no significant effect on the proliferation of 3T3-L1 preadipocytes in the concentration range of 12.5-100 ?mol/L,but remarkably inhibited adipogenic differentiation.The adipogenic differentiation rate of 3T3-L1 preadipocytes was only 76.4%,46.5%and 18.7%of the control group at 25,50 and 100 ?mol/L.(3)Arctigenin significantly inhibited the total lipid and TG synthesis of mature adipocytes in the range of 25-100 ?mol/L,and inhibited the release of glycerol.(4)In the adipocyte differentiation process,arctigenin obviously down-regulated the mRNA level of three key transcription factor in adipocyte differentiation(including PPAR y,C/EBP a and SREBP-lc)and their corresponding target genes(including LPL,AP2,FAS,ACC,Adiponectin and LXR)in a dose-dependent manner.(5)Arctigenin significantly up-regulated the phosphorylation of AMPK,suggesting that the AMPK signaling pathway was activated.At the downstream of the signaling pathway,the expression levels of ACC,FAS,LPL,PPAR? and C/EBP a genesassociated with adipogensis and HSL related to adipolysis were down-regulated..Moreover,the activation of AMPK also resulted in an increase in the level of ACC phosphorylation.And the transcriptional level of the downstream gene(CPT-1)associated with fatty acid oxidation was up-regulated.ConclusionThis study demonstrates that arctigenin can inhibit lipogenesis,and lipolysis,and reduce weight and fat by activating the AMPK signaling pathway. |
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