The Study Of Effects And Mechanism Of Di-(2-Ethylhexyl) Phthalate On Glucose And Lipid Metabolism In Mice

Di-(2-ethylhexyl)phthalate(DEHP)is an environmental endocrine disrupting chemical(EDC)and is the most used phthalate plasticizer.Because DEHP forms extremely weak non-covalent bonds with plastic,and with the production,use and abandonment of plastic,DEHP is highly precipitated from plastic products and is ubiquitous in the environment due to its non-degradable properties.As a persistent environmental pollutant,DEHP has toxic effects on several systems,such as the nervous system,reproductive system and cardiovascular system.Metabolic disorders have become a serious threat to human health.Approximately 25% of the world’s population has been affected by metabolic diseases.Metabolic disorders are caused by a number of factors,mainly dietary,behavioral,and environmental factors,such as unhealthy eating habits,sedentary lifestyles,lack of exercise,and exposure to environmental chemicals.Existing studies have shown that DEHP exposure is significantly associated with metabolic disorders.The toxic effects and safety assessment of phthalate plasticizers have become one of the important research hotspots in the fields of biotoxicology and environmental science.However,the effects and mechanisms of DEHP on glucose and lipid metabolism are still not fully understood.In this study,the effects of DEHP on glucose and lipid metabolism were investigated by combining in vivo and in vitro experiments.The study showed that DEHP exposure could cause liver injury and liver function disorder in mice,and glucose and lipid metabolism disorder in mice through insulin resistance,without affecting their insulin secretion levels and body weight changes.Through the glucose content,glucose production,lipid biochemical indicators and oil red O staining of hepatocytes,it was found that DEHP and MEHP can cause the disorder of glycolipid metabolism of hepatocytes,especially MEHP.These results reveal that DEHP exposure can cause glucose and lipid metabolism disorder.To investigate the mechanism of glucose and lipid metabolism disorders in mice caused by DEHP exposure,the study obtained differential genes through RNA-sequencing(RNA-seq)analysis,and functional pathway enrichment analysis revealed that inflammatory response,insulin resistance,gluconeogenesis and lipid synthesis pathways were involved in the glucose and lipid metabolism disorder caused by DEHP.Gene interaction,gene and disease correlation analysis and transcription factor prediction predicted that the transcription factor FoxO1 was the target of DEHP.In order to confirm these findings,The study found that DEHP could activate NFκB/MAPK signaling pathway to promote inflammatory response and cause insulin resistance,which in turn upregulated FoxO1,and the upregulated FoxO1 further promoted gluconeogenesis and lipid accumulation,causing disorders of glucose and lipid metabolism in mice by RT-q PCR and Western blot experiments.Through hepatocyte experiment,MEHP can up-regulate FoxO1 and cause glucose and lipid metabolism disorder.These results indicate that FoxO1 plays a key role in the disorder of glucose and lipid metabolism caused by DEHP.To further investigate FoxO1’s role in glucose and lipid metabolism disruption induced by DEHP exposure,FoxO1-specific inhibitors AS1842856(AS),metformin(Met)and entacapone(Ent)were selected as inhibitors for reverse inhibition validation.The results showed that AS significantly inhibited FoxO1 expression to ameliorate the increased gluconeogenesis and lipogenesis caused by MEHP treatment in hepatocytes,without affecting AKT phosphorylation levels.Both glucose and hepatic lipid metabolism were improved in mice treated with metformin or entacapone and DEHP.Metformin and entacapone also reduced organ damage caused by DEHP exposure.Metformin improved inflammation,activated AKT signaling pathways,and inhibited FoxO1 expression,leading to inhibition of gluconeogenesis,PGC-1β/SREBP1 c signaling pathway and upregulation of CYP7A1 expression,and ultimately reduced hyperglycemia and lipid accumulation.FoxO1 inhibition by metformin was largely attributed to metformin-inhibited inflammation response and AKT activation.Interestingly,entacapone reduced hyperglycemia and lipid accumulation induced by DEHP.However,this recovery was not dependent on AKT regulation,and alleviation of inflammation,suggesting entacapone could directly target FoxO1.Notably,entacapone exerts a weak effect on PGC1β/SREBP1c-mediated lipogenesis,while normalization of hepatic lipid metabolism was controlled by FoxO1up-regulated CYP7A1.Both metformin and entacapone can significantly inhibit FoxO1 to improve abnormal glucose and lipid metabolism caused by DEHP exposure.In conclusion,FoxO1 plays a key role in DEHP-induced disorders of glucose and lipid metabolism.The results of this study extend the understanding of the health risks caused by DEHP and establish a research basis for the metabolic toxicity of phthalate esters.In addition,this study also provides an experimental basis for targeting entacapone to FoxO1,which provides a new idea for regulating disorders of glucose and lipid metabolism.