Effect of di-2-ethylhexyl phthalate on oocyte development potential

Abstract

Objective To investigate the effect of di-2-ethylhexyl phthalate (DEHP) on oocyte development potential and its mechanism. Methods Forty 3-week old female KM mice were randomly divided into 4 groups (n=10, each), including control group (corn oil), the low-, medium-, and high-dose DEHP groups (300 mg/kg, 600 mg/kg, 1200 mg/kg). Mice of 4 groups were orally administered with corn oil (control) or DEHP daily for 6 weeks (5 d per week), respectively. After the treatment, female mice in each group were given ovulation induction and cooped up with male mice. The fertilized eggs were collected to observe the cleavage rate and blastocyst formation rate. Meanwhile, the levels of Ca2+ and reactive oxygen species (ROS) of oocytes in each group were detected with the Ca2+ fluorescence probe (Fluo-4 AM) and ROS assay kit, then the differences were compared. Results Compared with control group, the cleavage rate and blastocyst formation rate of the low-, medium- and high-dose DEHP groups decreased, and the differences were statistically significant (P all<0.05). The levels of Ca2+ and ROS in oocytes increased with the increase of DEHP dosage. Compared with control group and the low-dose DEHP group, the levels of Ca2+ and ROS in oocytes of the medium- and high-dose DEHP groups were significantly higher, and the differences were statistically significant (P all<0.05). Conclusion DEHP can increase the levels of Ca2+ and ROS in mouse oocytes, reduce the quality of oocytes, and affect the early embryonic development. Key words: Oocyte; di-2-ethylhexyl phthalate; Calcium ion; Reactive oxygen species