ABSTRACT
OBJECTIVE: To investigate the effects of combined exposure to di(2-ethylhexyl) phthalate(DEHP) and bisphenol A(BPA) on glucose metabolism in female rats during gestational and lactation periods, and its possible mechanism. METHODS: Twenty-four specific pathogen free pregnant SD rats were randomly divided into control group, DEHP group, BPA group, and combined exposure group, with 6 rats in each group. From the 5 th day of gestation to the 21 st day after birth of the offspring, the rats in the DEHP group were treated with DEHP 600 mg/kg body weight(bw); rats in BPA group were treated with 80 mg/kg bw BPA, and rats in combined exposure group were treated with 600 mg/kg bw DEHP and 80 mg/kg bw BPA by intragastric perfusion, while the rats in the control group were given the same amount of corn oil, once per day. After exposure, maternal rats were sacrificed immediately. The levels of glucose metabolism related indicators in liver tissues and serum were examined, and the mRNA and protein expression of phosphatidylinositol 3-kinase(PI3 K)/protein kinase B(AKT) signaling pathway related factors in liver tissues were detected by real-time fluorescence quantitative polymerase chain reaction and Western blot. RESULTS: Except for the activity of phosphoenolpyruvate carboxykinase(PEPCK) in BPA group, the levels of liver glycogen and serum high density lipoprotein cholesterol(HDL-C) in rats of the 3 exposure groups decreased(P<0.05), while the activity of serum PEPCK and the level of low density lipoprotein cholesterol(LDL-C) increased(P<0.05) compared with rats in the control group. The levels of liver glycogen and serum HDL-C in the combined exposure group were lower than that in the BPA group(P<0.05), while the level of serum LDL-C were lower than that in DEHP group and BPA group(P<0.05). The levels of serum glycosylated serum protein, total cholesterol and triglyceride in the 4 groups were not statistically different when compared with each other(P>0.05). Except for the PI3 K protein in DEHP group, the mRNA and protein expression of PI3 K, AKT, and glucose transporter 4 in liver tissues of rats in the 3 exposure groups decreased(P<0.05), and the mRNA expression of forkhead box protein 1(Foxo1) decreased(P<0.05), but the protein expression of FOXO1 increased(P<0.05) compared with the control group. CONCLUSION: Exposure to DEHP or BPA during pregnancy and lactation can cause glucose metabolism disorders in rats. The combined exposure of DEHP and BPA has certain synergistic effect. This process may be achieved through the PI3 K/AKT signaling pathway.