Early Life Perfluorooctanoicacid (PFOA) Exposure Leads To Obesity In Adulthood And Therapeutic Effects Of Chlorogenic Acid In Mice

OBJECTIVE: Perfluorooctanoic acid(PFOA)is a new type of synthetic persistent organic pollutant that is widely used in industry and consumer products throughout the world and is commonly detected in humans and various environmental media.This study aims to explore the effects of exposure to PFOA in early life on adult obesity and its possible mechanisms using animal models,and to evaluate the therapeutic effects of chlorogenic acid(CGA)on PFOA-induced physiological and pathological changes.METHODS: Twenty-four pregnant female mice were randomly divided into three groups according to their body weight.In the third trimester(pregnancy from 14 days to 21 days),the following protocol was used for gavage every day:(1)control group(corn oil);(2)PFOA group(PFOA 0.05 mg/kg daily);(3)PFOA+CGA(0.05 mg/kg daily for PFOA and 100 mg/kg daily for CGA);After birth,male progeny are normally reared until weaning(21st days Age),the mother mice were sacrificed,and then the offspring male mice were intragastrically administrated to 12 weeks old and the body weight was recorded as follows:(1)control group(normal saline);(2)PFOA group(normal saline);(3)PFOA+CGA group(CGA 100 mg/kg daily).Automatic biochemical analyzer to detect changes in blood biochemical parameters;Small animal high field magnetic resonance imaging instrument to measure body composition;Metabolic cage instrument to measure metabolic conditions in real time;Transmission electron microscopy and light microscopy to check pathological changes;Western blot,immunofluorescence method and immunohistochemistry Methods Protein expression was detected;Illumina and PCR were used to detect gene expression and abundance of intestinal microflora;ultra high performance liquid chromatography was used to detect bile acid content;high performance liquid phase was used to detect PFOA residue.Result: The body weights showed that the mice exposed to PFOA in early life were significantly higher than that of the control group,and there was no significant in the weight of mice given CGA intervention compared with the control group.The highfield magnetic resonance imaging of small animals showed that the body fat content of mice in the PFOA group was higher than control group,and the body fat content of mice after CGA intervention was significantly reduced.The metabolic cage results showed the heat production rate of mice in the PFOA group was lower than control group,and there was no significant between the CGA intervention group and the control group.Blood biochemical results showed that the serum alanine aminotransferase(ALT),aspartate aminotransferase(AST),alkaline phosphatase(ALP)and triglyceride(TG)content were increased,while the high-density lipoprotein cholesterol(HDL-C)content and superoxide dismutase(SOD)were decreased in PFOA group.CGA intervention can effectively improve these changes.In abdominal adipose tissue,the volume of adipocytes were bigger in PFOA group than in control group,while the adipocytes volume of the CGA intervention group were similar to that of the control group.The genes expression of the inflammatory factors IL1?,IL6 and TNF? were increased,while the genes related to energy metabolism and fatty acid depletion including TGR5,PGC1? and MMP9 were decreased in the adipose tissue of the PFOA group.And the CGA intervention could partially alleviate this change.Intestinal histopathology,immunohistochemistry and PCR showed that the PFOA group had severe pathological lesions in the small intestine,and there was an infiltration of inflammatory cells.The expression of the inflammatory body-associated proteins NLRP3 and caspase-1 were increased,while the protein and gene expression levels of the intestinal barrier proteins ZO-1,claudin-1,connexin43,and claudin-5 were decreased.And these were improved in the CGA intervention group.In gut microbiota,the composition of the intestinal microbiota was changed in the PFOA group,and the mycobacterial families related to the production of short-chain fatty acids such as Fabriaceae and Rumenaceae appeared to be down-regulated in the PFOA group.The CGA intervention group was similar to control group.Liver histopathology and electron microscopy revealed that the PFOA group showed structural damage to the hepatocytes and the presence of inflammatory cell infiltration.The expression of the inflammatory body-associated proteins NLRP3 and caspase-1 were increased,and the mRNA levels of the inflammatory cytokines TNF? and IL-6 were also increased in PFOA group.The expression levels of LPS-related receptors CD14 and TRL4 were significantly increased in PFOA group,whereas the results in the CGA intervention group were nearly normal.Liver mRNA-seq results showed that the gene expression profiles of autophagy,insulin resistance,lipid metabolism,and bile acid secretion pathways were increased in PFOA group,whereas many genes in the CGA intervention group were more closely to the control group.In addition,the gene expression involved in lipogenesis and cholesterol production were increased,while the gene expression of ?-oxidation and nuclear receptors were decreased in the PFOA group.The gene expression of lipogenesis and cholesterol production were decreased and the gene expression of ?-oxidation and nuclear receptors were increased under the intervention of CGA.The gallbladder bile acids showed that the hydrophobicity of bile acids was increased in the PFOA group,but there was no significant between the CGA intervention group and the control group.CONCLUSIONS: PFOA exposure in early life leads to obesity and dyslipidemia in adulthood,and its main mechanism is to alter the composition of the intestinal bacteria,thereby affecting the normal function of the intestinal tract and its barrier function.Endotoxins such as LPS produced by the intestinal bacteria can invade the liver,adipose and other tissues through the enterohepatic circulatory or lymphatic system,causing systemic inflammatory including liver and adipose tissue,eventually leading to obesity.The CGA intervention can effectively maintain the integrity of the intestinal barrier function,so as to prevent its subsequent systemic chronic inflammation,prevent the occurrence of obesity,at the same time,CGA treatment of lipid metabolism disorders can not be ignored.