| 1,3-Diacylglycerol(1,3-DAG)is formed by esterification of two fatty acid molecules at the sn-1 and sn-3 positions of glycerol,respectively.The taste and texture of DAG are not much different from those of ordinary triglyceride(TAG)edible oil.Because it is not hydrolyzed into 2-MAG in the intestine and will not be esterified into TAG in intestinal epithelial cells,the digestion,absorption and metabolism characteristics of 1,3-DAG oil are essentially different from those of TAG oil.The special structure makes it have the potential to improve postprandial blood lipids,increase fatty acid oxidation,reduce lipid storage,and regulate intestinal flora.However,so far,there is a lack of systematic research on the mechanism of 1,3-DAG lipid reduction.In view of this,this paper takes ob / ob leptin gene knockout mice as the research object,and studies the regulation of different doses of 1,3-DAG on fat synthesis and decomposition and the regulation of intestinal microorganisms,in order to clarify the mechanism of 1,3-DAG exerting health effects and provide theoretical basis for its popularization and application.The main results of this thesis are as follows :(1)The effects of different doses of 1,3-DAG on body weight,blood lipid levels,and white fat morphology in ob/ob mice were studied.The results showed that 1,3-DAG had high antiobesity potential.Compared with TAG,1,3-DAG could effectively delay the weight gain of obese mice.The serum total cholesterol(p<0.05),triglyceride(p<0.05),and low-density lipoprotein cholesterol(p<0.05)in the 40% 1,3-DAG group were significantly reduced,and the triglyceride(p<0.05)in the 80% 1,3-DAG group was significantly reduced.Significantly increased serum high-density lipoprotein cholesterol(p<0.05)levels in different doses of 1,3-DAG groups;from the tissue sections of subcutaneous fat and abdominal fat,1,3-DAG diet significantly reduced the size of adipocytes,and the improvement effect of 40% 1,3-DAG group was significantly better than that of 80% 1,3-DAG group.(2)The effects of different doses of 1,3-DAG on lipid metabolism,browning,and secretory function of white adipose tissue were studied.In sebum,compared with TAG,different doses of1,3-DAG significantly down-regulated the gene expression of fatty acid synthase(FAS),and significantly up-regulated the gene expression of hormone-sensitive esterase(HSL),acyl-Co A oxidase(ACOX)and lipoprotein lipase(LPL).In abdominal fat,compared with TAG,different doses of 1,3-DAG significantly down-regulated the gene expression of FAS,LPL,stearoyl-Co A desaturase(SCD),and ACOX.Compared with the TAG group,the 40% 1,3-DAG group significantly up-regulated the gene expression levels of peroxisome proliferator-activated receptorγ(PPARγ),uncoupling protease 1(UCP-1)and silencing regulatory protein 1(SIRT1)in subcutaneous fat and abdominal fat.Different doses of 1,3-DAG could significantly increase the gene expression of adiponectin in subcutaneous fat and abdominal fat in a dose-dependent manner.1,3-DAG may prevent lipid metabolism disorders by promoting lipolysis,fatty acid β oxidation and inhibiting lipid production.It may promote the browning of white fat through the SIRT1/PPARγ/UCP-1 pathway,thereby promoting fat energy consumption and heat production.it may improve lipid metabolism by improving the secretory function of white adipose tissue.(3)To study the effects of different doses of 1,3-DAG on liver lipid metabolism and related mechanisms.The results of PCR showed that compared with TAG,the expression of GAPT in the genes related to fat synthesis in the 40% 1,3-DAG group was significantly decreased,and the expression of PPARα was significantly increased.The expression of the fatty acid transporter gene FATP2 was decreased.Compared with TAG,the expression levels of fatty acid oxidation-related genes(CPT-1,ACOX),lipolysis-related genes(HSL,ATGL),and fat synthesis-related genes(SCD,GPAT)were significantly decreased in 80% 1,3-DAG group.The results of lipidomics showed that compared with TAG,the 40% 1,3-DAG group significantly increased the contents of sphingolipids,sterols,deoxycholic acid,and phospholipids,and significantly decreased the contents of phosphatidic acid and lignoceric acid.Compared with TAG,the 80% 1,3-DAG group significantly increased the contents of sphingolipids,steroid conjugates,and phospholipids,and significantly decreased the contents of fatty acids and fatty acid conjugates,monoglycerides,and phosphatidylcholine.It indicated that different doses of 1,3-DAG may affect lipid composition by affecting lipid metabolism.(4)To study the regulation of different doses of 1,3-DAG on intestinal microorganisms in ob/ob mice.The effects of different doses of 1,3-DAG on intestinal microbial diversity and community composition in ob/ob mice were investigated using 16 S r RNA sequencing technology.Studies have shown that different doses of 1,3-DAG significantly affected the community composition of intestinal microflora compared with TAG.Under the 80% 1,3-DAG diet,the number of microorganisms and the number of different species increased relatively.Different doses of 1,3-DAG can reduce the accumulation of lipids in the body and improve the body’s inflammation by increasing the intestinal flora beneficial to the improvement of obesity,such as Lactobacillus,Bifidobacterium,Clostridium,etc.,thereby alleviating obesity.The correlation analysis of lipidomics and gut microbiota showed that gut microbiota may play an important role in the regulation of lipid metabolism by 1,3-DAG.In summary,long-term consumption of different doses of 1,3-DAG can achieve the effect of weight loss and lipid reduction by improving lipid metabolism and regulating intestinal flora. |
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