| The lipid synthesis and decomposition of the body are in a state of dynamic balance.When the balance is broken,the lipid metabolism disorder will be caused,resulting in a variety of metabolic diseases,which has become a global health problem.Existing treatments include drug therapy,which has disadvantages such as high side effects or expensive treatment,and dietary intervention,which is relatively healthy and affordable.The role of gut microbiota and its metabolites in regulating lipid metabolism disorders has been widely reported,and more and more researchers have focused their attention on postbiotics.Postbiotics are rich in bioactive substances,which not only have the same health effect as probiotics,but also have a wider range of applications and forms because they do not require the number of viable bacteria.At present,there are few studies on the regulation of probiotics in lipid metabolism disorder.Therefore,in this paper,the probiotics with the effect of regulating lipid metabolism disorder were discovered through animal experiments,the effective substances of probiotics were preliminarily screened through cell experiments,the key effective substances of probiotics were further analyzed through metabolomics,and finally the key effective substances were verified through cell experiments.Specific research contents and results are as follows:(1)In this study,a high-fat diet was used to establish an animal model of visceral lipid metabolism disorder.During the entire experimental period,six postbiotics were used to intervene at low and high doses of 200 mg/kg mouse body weight and 800 mg/kg mouse body weight,respectively.The results showed that among the six postbiotics,the interventions of the postbiotics(CCFM1224)prepared by Lactobacillus paracasei CCFM1224 and the postbiotics(CCFM1219)prepared by Lactobacillus rhamnosus CCFM1219 significantly improved the symptoms of lipid metabolism disorder caused by high fat diet in a dose-dependent manner,including inhibiting weight gain,improving blood glucose regulation,reducing serum total cholesterol(TC),low density lipoprotein cholesterol(LDL-c),alanine aminotransferase(ALT),and aspartate aminotransferase(AST),improving liver steatosis and inflammation,inhibiting epididymal white fat cell hypertrophy and inflammation,inhibiting brown fat whiteness.Gene expression detection results showed that CCFM1224 and CCFM1219 regulate the disorder of visceral lipid metabolism by reducing the expression levels of related to lipid synthesis(liver:PPAR-γ,SREBP-1c and FASN,white fat: PPAR-γ),increasing the expression levels of genes related to lipid decomposition(liver: PPAR-α,ATGL and HSL,white fat: PPAR-α and HSL)and thermogenic genes(brown fat: PPAR-α,PGC1-α and UCP1).(2)In this study,an animal model of sebum metabolism disorder was established by oleic acid.During the whole experiment period,two effective postbiotics were used to intervene at the dose of 800 mg/kg mouse body weight.The results showed that the effective postbiotics interventions improved the symptoms related to sebum metabolism disorder of mice induced by oleic acid,including recovery of body weight gain,reduction of testicular coefficient,improvement of skin histopathologic status,reduction of skin lipid and pro-inflammatory cytokines,and reduction of serum testosterone and insulin content.Gene expression detection results showed that CCFM1224 and CCFM1219 regulate sebum metabolism disorder by reducing the expression levels of genes related to skin lipid synthesis(PPAR-γ,SREBP-1c and FASN)and increasing the expression levels of genes related to skin lipid decomposition(PPAR-α,ATGL and HSL).(3)In this study,free fatty acids(FFA)were used to establish the lipid accumulation model of Hep G2 cells,and the supernatant(S),exopolysaccharides(EPS)and inactivated bacteria(IB)of postbiotics were used for intervention.The results showed that EPS and IB of two effective postbiotics could significantly reduce the intracellular lipid accumulation and cell damage induced by FFA.The results of gene expression detection showed that the mechanism of action of EPS is to decrease the expression levels of genes related to lipid synthesis(PPAR-γ,SREBP-1c and FASN),and the mechanism of action of IB is to decrease the expression levels of genes associated with lipid synthesis(PPAR-γ,SREBP-1c and FASN)and increase the expression levels of genes associated with lipid decomposition(PPAR-α,CPT1 and ACOX1).We then used untargeted metabolomics to analyze mice livers in the study of visceral lipid metabolism disorders,two effective postbiotics,and the medium used to prepare postbiotics.The differential metabolites of liver(the level of metabolites was significantly lower in the modeling group than in the blank group,and significantly higher in the corresponding effective postbiotics high-dose intervention group than in the modeling group)and the differential metabolites significantly enriched in the effective postbiotics relative to the medium were compared to find the signature differential metabolites.Targeted metabolomics was used to detect the content of signature differential metabolites in IB,and it was found that the content of hexadecanedioic acid in IB of CCFM1224 and CCFM1219 was 1.848 and 1.914 μg/g,respectively,which may be the key effective substance of the effective postbiotics.Finally,the Hep G2 cell lipid accumulation model was used to verify that hexadecanedioic acid at 320μmol/L can significantly reduce the intracellular lipid accumulation and cell damage caused by FFA.Its mechanism of action is to decrease the expression levels of genes related to lipid synthesis(PPAR-γ,SREBP-1c and FASN)and increase the expression levels of genes related to lipid decomposition(PPAR-α,CPT1 and ACOX1).In conclusion,oral administration of CCFM1224 and CCFM1219 can not only regulate the visceral lipid metabolism disorder caused by high fat diet,but also regulate the sebum metabolism disorder caused by oleic acid.Further analysis showed that hexadecanedioic acid from IB may be the key effective substance of effective postbiotics in regulating lipid metabolism disorder,and it acts by inhibiting lipid synthesis and promoting lipid decomposition in cells. |
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