The Mechanism Of Conjugated Linoleic Acid Isomer T10 And C12-CLA In Reducing Fat And Losing Weight In DIO Mice

The global incidence of obesity has been showing a trend of rapid growth.It is a major health challenge,and it is also a predisposing factor for diseases such as non-alcoholic fatty liver and type 2 diabetes.Heredity is the congenital factor leading to obesity,while environmental related problems,abnormal endocrine regulation,inflammation,intestinal flora,activity and other factors are the acquired factors leading to obesity.Conjugated linoleic acid(CLA)as a food functional additive has been approved by the US FDA to be added to various foods.Its unique lipid-lowering physiological function makes CLA a hot spot in current weight loss research,but most of the current research uses A mixture of CLA isomers,not a single isomer.Therefore,this subject has studied the mechanism of the single isomer t10,c12-CLA on lipid catabolism,laying a foundation for the realization of the specific function and high-value development and utilization of CLA products.Objective In-depth study of the lipid-lowering regulatory mechanism of t10,c12-CLA on high-fat diet-induced obesity.The experimental research is divided into two parts: the first part,to establish an obese mouse model induced by a high-fat diet,through technical means to detect the apparent indicators of obese mice after t10,c12-CLA intervention,and in-depth study of the synthesis and decomposition mechanism of liver lipids and epididymal fat in obese mice,to explore the effect of t10,c12-CLA on the body fat accumulation of obese mice;the second part is to explore the effect of t10,c12-CLA on the species abundance and diversity of the intestinal flora of obese mice from the intestinal flora of mice impact,verify whether t10,c12-CLA can improve the body fat accumulation of mice by affecting the intestinal flora.Methods The mice were fed 60% fat feed(HFD)for 6 weeks.After successful modeling,the mice were randomly divided into groups,and then the mice were given conjugated linoleic acid isomers at 100 mg/kg and 400 mg/kg respectively.The body undergoes a 6-week intervention.After t10,c12-CLA intervention:(1)Monitor the weekly weight,food intake and other apparent indicators of the mice,and detect the blood lipid levels of TC,TG,HDLC and LDLC in the serum of the mice.Hematoxylin-eosin staining was used to observe the morphology of mouse liver and epididymal fat,and molecular biology methods(q RT-PCR,WB)were used to explore the lipid-lowering mechanism and the inflammatory mechanism caused by obesity in obese mice.(2)Through 16 S r DNA amplicon sequencing,the population structure,community diversity and function prediction of gut microbes in obese mice were analyzed and studied.Results(1)After 6 weeks of intervention,compared with the negative control group,the weight,Lee’s index,food intake,the levels of four indicators of blood lipids,and fat cell hypertrophy of mice in the t10,c12-CLA intervention group were significantly reduced(P < 0.05).In terms of liver lipid synthesis and metabolism,the expression of lipid synthesis-related genes Gpat,Dgat,Pap,Vldl,Acc1,Fas,Hmgr and Cyp7 a in the t10,c12-CLA intervention group was significantly decreased(P < 0.05),lipid transport and decomposition the expressions of related genes Hsl,Atgl,Pparα,Cpt-1,Ampk,Acox and Scp2 were significantly up-regulated(P < 0.05).In terms of the synthesis and decomposition of epididymal adipose tissue,the expression of Wnt and Cebp α in the t10,c12-CLA intervention group were significantly reduced(P < 0.01),and the transcription level of Gsk 3β m RNA was significantly up-regulated(P < 0.01).In terms of inflammatory metabolic mechanism,the expression of pro-inflammatory factor NfκB in the t10,c12-CLA intervention group was significantly reduced(P < 0.05),and the expression of anti-inflammatory factor IκB was significantly increased(P < 0.05).(2)Compared with the negative control group,the α diversity(Shannon index,Simpson index and Chao1 index)and β diversity of the intestinal flora of mice in the t10,c12-CLA intervention group and the abundance of dominant flora such as Lachnospiraceae,Desulfouibrionales and Bacteroidetes significantly increased(P < 0.05),while the expression function of "arginine and proline metabolism" pathway,"methane metabolism" pathway,"pentose,glucuronic acid conversion" pathway and "pyruvate metabolism" pathway was significantly upregulated,And the abundance of harmful bacteria such as Firmicutes,Erysipelotrichia and Erysipelotrichales was significantly reduced(P < 0.05).Conclusions(1)t10,c12-CLA activates the expression of downstream target genes Ppars and Srebp-1c by up-regulating the transcription of AMPK,further regulating the transcription of downstream lipid synthesis and metabolism genes,and reducing the accumulation of lipids in the liver.The activation of Wnt/β-catenin pathway reduces the production of white fat,and it co-regulates lipid metabolism in mice with AMPK pathway.At the same time,t10,c12-CLA can inhibit the expression of inflammation-related factors induced by obesity and enhance the body’s immunity.(2)t10,c12-CLA can increase the diversity of intestinal flora,improve the structure of intestinal flora in mice,reduce the ratio of Firmicutes/Bacteroridetes in high-fat diet mice,and reduce lipid accumulation.At the same time,it increases the abundance of butyrate-producing Lachnospiraceae and other beneficial bacteria,reduces harmful bacteria,and is beneficial to the intestinal barrier.The significance of this topic is to comprehensively study the effects of t10,c12-CLA on HFD-induced obese mice on food intake,lipid metabolism and intestinal flora,and further clarify the pathway regulation mechanism of t10,c12-CLA on lipid catabolism in obese mice.This not only helps explain the lipid-lowering and weight-loss functions of t10 and c12-CLA,but also has important guiding significance for the development of medical foods for lipid metabolism disorders.