Effects Of Exposure To Di(2-ethylhexyl) Phthalate During Pregnancy On Obesity And Metabolism In Offspring Mice

Di-(2-ethylhexyl)phthalate(DEHP),a representative compound of phthalate esters(PAEs),is widely used in plastic consumer goods,food packaging,polyvinyl chloride,children’s toys,medical equipment,cosmetics,detergents and fragrances,and other fields.In China,DEHP is the largest general plasticizer for production and consumption.Therefore,the safety issue of DEHP with an endocrine disruptor-like estrogen effect has received increasing attention.Epidemiological studies have shown that PAEs exposure is closely related to childhood obesity.Whether in the economic developed or developing countries,obesity and overweight are rapidly growing at an alarming rate globally,which has become a serious problem in the global medical and public health in the 21 st century.The focus on childhood overweight and obesity has also been on the rise in recent years.Overweight and obese children in China are more than 12 million,accounting for one over thirteen of the world "fat child",which suggests that childhood obesity in China has a period of rapid epidemic.Without prevention and control in time,it will soon be developed to a higher level of developed countries.However,domestic and foreign academics have relatively late research on DEHP exposure to offspring during pregnancy,and research reports are also very limited at present.Objective: This study evaluated the effects of exposure to DEHP during pregnancy on offspring obesity and screened for metabolomic variation via metabolomics,which may provide new clues and theoretical basis for DEHP to be used as a potential environment-induced obesity factor to induce offspring obesity.Methods: 1.8-week-old female ICR mice were oral gavaged DEHP using different doses(0.2,2,and 20 mg/kg/day)from 7 days before mating to give birth to offsping(28 days)to study different doses of DEHP on the effect of offspring obesity.2.To assess the phenotype of DEHP pregnancy exposure on the obese mice through nuclear magnetic resonance imaging(MRI),intraperitoneal glucose tolerance test(ip GTT),intraperitoneal insulin resistance test(ip ITT),metabolic cage monitoring,etc.3.Through metabonomics screening DEHP pregnancy exposure to the offspring of obese mice induced key differences in metabolic small molecule metabolism and metabolic pathways,build differential metabolic profiles,provide a new biometabolism marker for obese mice induced by DEHP pregnancy exposure Material and theoretical basis.4.Screening key differences metabolic small molecules and metabolic pathways to build metabolic profiles through metabonomics in the obese mice livers,and then provide new biometabolism markers and theoretical basis for obese offspring mice induced by DEHP pregnancy exposure.Results: 1.After 28 days of maternal oral gavage,there was no significant difference in the average daily intake per cage of female/male offspring in each dose groups.When body weight of DEHP-treated dams were 12 weeks old,body weights of male mice in the low-,medium-,and high-dose groups were significantly higher than those in the control group.The difference was statistically significant,especially in the low-dose group(P=0.0008,P<0.05).The female middle-dose-treated group was significantly higher than the control group in the 12-week-old(P=0.0020,P<0.05).2.There was no significant difference in the glucose tolerance level and insulin resistance level in the 12-week-old low-dose treatment male mice group,body fat ratio(P=0.0003,P<0.05),serum total cholesterol(TC)(P=0.0079,P<0.05),high-density lipoprotein(HDL-C)(P=0.0190,P<0.05),low-density lipoprotein(LDL-C)(P=0.0392,P<0.05)and glucose(GLU)levels(P=0.0014,P<0.05)were higher than those in the control group.The heat production during the light cycle was lower than that of the control group(P=0.0443,P<0.05).The presence and accumulation of fat droplets in the liver of the low-dose treatment male offspring was significantly greater than that in the control group.Whereas in the female medium-treated group,glucose tolerance level(P=0.0108,P<0.05),body fat ratio(P=0.0094,P<0.05)were significantly higher than the control group,insulin tolerance level was no significantly difference.3.Metabolomics analysis showed that 46 and 44 metabolic small molecules in lowand medium-dose of DEHP pregnancy exposures(P<0.05),respectively.The five differentially metabolized small molecules such as thymidine,N-acetylglutamate,thymidine,inosine,and 8-hydroxydeoxyguanosine were changed in both treatment groups;Metabo Analyst 3.0 database was used to enrichment analyze metabolism pathways of metabolic small molecules,and 8 metabolic pathways were significantly changed in both treatment groups,namely the biosynthesis of tea phenols,pyrimidine metabolism,purine metabolism,niacin and niacinamide metabolism,steroid hormones,citric acid cycle,methionine metabolism and tyrosine metabolism pathway.Conclusion: 1.DEHP pregnancy exposure can lead to a series of changes in the weight of offspring mice,abdomen fat pad accumulation,abnormal metabolic indicators such as triglyceride and blood glucose.The effect is more significant in low-dose-treated male offspring mice.2.At the same time,metabolomics reveals the effect of DEHP pregnancy exposure on hepatic metabolism of offspring mice,and thus a more comprehensive understanding of the effect of DEHP pregnancy exposure on obesity and metabolic profile variation in offspring mice.Our study provides a new clue and theoretical basis for DEHP acted as a potential environmental induced obesity factor.