Study On The Regulation And Mechanism Of Clostridium Butyricum On White Fat Metabolism In Mice

With the changes in lifestyle and dietary habits,the rates of overweight and obesity have been increasing dramatically in both children and adults,and obesity has become a common public health problem in developed and even developing countries.Both an increase in the number of adipocytes and an increase in the size of adipocytes can contribute to the development of obesity,so limiting the growth of adipocyte size and number is a key measure in the treatment and prevention of obesity.Clostridium butyricum(C.butyricum,CB)belongs to the genus Clostridium and is a resident bacterium in the human intestine.Studies have shown that C.butyricum can produce short-chain fatty acids,vitamin C,folic acid and other beneficial metabolites in the intestine.There are many reports on the use of C.butyricum in the treatment of intestinal diseases,but it is not clear whether it has any effect on fat metabolism.In this study,C57BL/6J mice were used as experimental materials to investigate the regulatory effect of C.butyricum on white fat metabolism in mice and its molecular mechanism.The main findings are as follows:(1)C.butyricum has an inhibitory effect on fat deposition.Mice were treated with C.butyricum by drinking water and sampled after 3 weeks to analyze the effect of C.butyricum.Results showed that C.butyricum treatment reduced body weight gain and white adipose tissue(WAT)weight,decreased white adipocyte volume,and down-regulated the expression of Pparγ,C/ebpα,Fas,Lpl and other adipogenic genes.(2)C.butyricum do not alter the intestinal flora composition of mice,but resulted in increased serum butyric acid levels.The intestinal flora of mice was analyzed by 16 S r RNA sequencing,and it was found that C.butyricum treatment did not change the intestinal flora composition of mice.Next,analysis of short-chain fatty acid content in the intestine and serum of mice by high performance liquid chromatography revealed that C.butyricum treatment caused a significant increase in serum butyric acid content in mice.We therefore hypothesized that butyric acid may be the main effector of C.butyricum in inhibiting fat deposition.(3)Butyric acid has an inhibitory effect on fat deposition.Because butyric acid is highly volatile,we used sodium butyrate to mimic the effect of butyric acid.Mice were treated with sodium butyrate by drinking water and sampled after 3weeks to analyze the effect of butyric acid on lipid metabolism.The results showed that butyric acid treatment slowed down body weight gain,decreased white adipose tissue volume,reduced adipocyte area,and decreased expression of adipogenesis-related genes such as Pparγ,C/ebpα,Fas,and Lpl.(4)C.butyricum and sodium butyrate increase the proportion of Treg cells in white adipose tissue.The percentage of Treg cells in white adipose tissue was detected using flow cytometry.The results showed that C.butyricum and butyric acid treatment increased the percentage of Treg cells in white adipose tissue of mice.To further verify the results,the expression of downstream target genes of Treg cells was detected by q PCR technique,and the expression of IL-10,TNF-β,and Wnt10 b were found to be significantly increased.(5)Wnt10b played an important role in fat deposition inhibition by C.butyricum and butyric acid.Wnt10b activates the Wnt signaling pathway and inhibits fat formation,so we hypothesize that Wnt10 b plays an important role in the inhibition of fat deposition by C.butyricum and butyric acid.In this study,we constructed Wnt10 b knockout mice and treated them with C.butyricum and butyric acid by drinking water.The results showed that in Wnt10 b knockout mice,C.butyricum and butyric acid treatment did not alter the rate of body weight gain,white adipose tissue volume,white adipocyte area,or the expression of adipogenesis-related genes.The fat deposition inhibitory effect of C.butyricum and butyric acid disappeared.(6)C.butyricum and butyric acid treatment can improve obesity and related metabolic diseases induced by high fat diet.In order to further verify the effects of C.butyricum and butyric acid treatment on obesity and related metabolic diseases in mice,a high fat diet was fed to mice to establish a mouse obesity model.In the high fat diet group,the mice were treated with C.butyricum and butyric acid,which slowed down the weight gain and reduced the fat deposition.The liver and glucose tolerance indexes of mice were also measured in this study,and the results showed that the liver indexes of obese mice decreased,the liver and serum concentrations of triglyceride(TG)and total cholesterol(THC)decreased,and the fasting blood glucose level decreased after C.butyricum and butyric acid treatment.In summary,C.butyricum induces Treg cell differentiation in white adipose tissue through its metabolite butyric acid,thereby promoting Wnt10 b expression,which inhibits fat deposition and improves obesity and related metabolic diseases.These findings provide new ideas for the prevention and treatment of obesity.