Relationships between di-(2-ethylhexyl) phthalate exposure and lipid metabolism in adolescents: Human data and experimental rat model analyses

In recent years, the incidence of lipid metabolism disorders in adolescents has gradually increased, and the effects of DEHP on lipid metabolism have received widespread attention. In this study, 463 adolescents aged 16-19 years were enrolled as subjects. This study analyzed the associations between the urinary levels of DEHP metabolites (MEHP, MEOHP, MEHHP, MECPP, MCMHP, and ∑DEHP) and BMI, WHR, WtHR, VAI, LAP, the plasma levels of lipids (TC, TG, HDL-C, and LDL-C), and the peripheral blood leukocyte mRNA levels of SREBP-2, SR-BI, LDLR, and NR1H3. Animal experiments were performed to confirm and expand findings. Wistar rats were administered DEHP at 0, 5, 50, and 500 mg/kg/d for 8 weeks. The serum and liver levels of TC, TG, HDL-C, and LDL-C, and the liver mRNA and protein levels of SREBP-2, SR-BI, LDLR, and NR1H3 were measured. The results showed that WHR, VAI, and LAP were significantly positively associated with the urinary levels of MECPP and ∑DEHP; the plasma HDL-C level was significantly negatively associated with the levels of MECPP, MCMHP and ∑DEHP; the peripheral blood leukocyte mRNA levels of SREBP-2, NR1H3, and LDLR were significantly positively correlated with the MCMHP level; and the SR-BI mRNA level was significantly positively correlated with the levels of MECPP and MCMHP in adolescents. Moreover, the results of animal experiments showed that DEHP exposure significantly increased the serum levels of TC, HDL-C, and LDL-C in 500 mg/kg/d group, as well as the liver levels of TC and HDL-C, up-regulated SREBP-2 mRNA and protein expression in 50 and 500 mg/kg/d groups. DEHP exposure significantly down-regulated SR-BI and NR1H3 protein expression in the liver of the 500 mg/kg/d group rats. Our findings indicate that DEHP exposure can affect lipid metabolism in adolescents by regulating the expression of lipid metabolism-related genes.