The Mechanism Of Dietary Tannic Acid Prevents High-fat-diet Induced Obesity In Mice

Obesity is one of the major diseases that threaten human health in recent years.Long-term high-fat diet is an important factor,which can cause obesity.Although weight control drugs and other measures can achieve the effect of weight control,they have more side effects.Therefore,functional foods with anti-obesity effects have attracted the favor of the public.Dietary tannic acid has many functions such as anti-inflammatory,anti-cancer,antioxidant and lipid-lowering,which widely distributed in various foods.It is very important to human health.Although plant polyphenols have a significant anti-obesity effect,the mechanism of dietary tannic acid on treating obesity is still unclear.In this paper,we investigate the effects of dietary tannic acid on body weight,blood glucose and lipid,the expression of glucose and lipid metabolism-related gene,intestinal mucosal barrier and the contents of fecal SCFAs in obese mice induced by a high-fat diet.By analyzing the mechanism of tannic acid on glucose and lipid metabolism in obese mice,it provides a new idea for the prevention and control of metabolic syndrome related to obesity.In this study,C57BL/6J male mice were fed high-fat diet to establish obesity model and randomly divided into 4 groups: normal control group(NC),high fat control group(HFD),50mg/kg/d tannic acid intervention group(HFD+TA(50mg/kg/d))and 150mg/kg/d tannic acid intervention group(HFD+TA(150mg/kg/d)).The weight and food intake of the mice were recorded weekly.After 8 weeks,the differences in blood glucose and lipids,organ quality,liver function damage and intestinal mucosal barrier destruction were compared among the groups.ELISA was used to detect the changes of INS,LEP,LPS,IL-6,TNF-α,Ig A,IgG,Ig E and IgM in the serum of mice.RT-PCR was used to detect the expression of PPAR-γ,LPL,FAS,SREBP,ACC,CPT-1,AMPK,PPAR-α,IL-6,TNF-α and other factors in the liver tissues of mice in each group.In addition,the expression of ZO-1,ZO-2,Occludin,IL-6,TNF-α and other genes in colon tissues were also detected.H&E staining sections were used to observe the changes of cell area in the adipose tissue of mice in each group.Inflammatory immersion,lipid accumulation and other pathological phenomena in liver tissues were observed by oil red O and H&E staining sections.The contents of fecal SCFAs of mice in each group were analyzed based on GC-MS targeted metabolomics.The results showed that tannic acid significantly reduced the body weight,liver and adipose tissue weight of mice on a long-term high-fat diet(P <0.05),as well as the contents of LEP,LPS,TC,TG,LDL-C and HDL-C in serum(P <0.05).Tannic acid reduced the levels of fasting and postprandial blood glucose in high-fat diet mice(P<0.05),and also reduced its serum INS content,which improved insulin resistance in obese mice,however,the intervention effect of 150mg/kg/d tannic acid dose was less than that of 50mg/kg/d.Tannic acid significantly improved the liver fatty lesions of high-fat diet mice,and decreased the contents of TC,TG,ALT,AST and AKP in the liver tissues in a dose-dependent manner(P <0.05).At the same time,after tannic acid intervention,the SOD enzyme activity in the liver increased significantly,and the MDA level was significantly reduced(P <0.05),which effectively improved the liver oxidative damage caused by obesity.The expression levels of PPAR-γ,LPL,FAS,SREBP and ACC in liver tissues of mice were decreased in a dose-dependent manner,while the expressions of CPT-1,AMPK and PPAR-α were increased to varying degrees(P <0.05),which showed that tannic acid improved the expression of genes related to glucose and lipid metabolism.Tannic acid increased the expression of ZO-1,ZO-2 and Occludin in the colon tissue of mice,and reduced the level of inflammation in the body(P <0.05).In addition,the tannic acid of 50mg/kg/d increased the content of SCFAs in the feces of high-fat diet mice,and regulated the content changes of various components of SCFAs to different degrees,thus regulating the energy and lipid metabolism of the body.However,the tannic acid of 150 mg/kg/d was not effective for this improvement.Dietary tannic acid can improve the integrity of the intestinal barrier function and reduce the inflammation level of the body by changing the content of fecal SCFAs in mice with high-fat diet,which improved the disorder of glucose and lipid metabolism in high-fat diet mice and inhibited the formation of obesity.