Reproductive and developmental toxi-city of methoxychlor in pregnant mice and their foetuses

AIM: To explore the effects of methoxychlor (MXC) on reproduction and development in mice. METHODS: The pregnant mice were administered by oral gavage with MXC at different doses of 0, 20, 100 and 200 mg/kg during day 12-17 of pregnancy. Meanwhile, other pregnant mice as a control group were gavaged sesame oil solvent in the same manner. The changes in body mass and number of corpora lutea of the pregnant mice were observed; and the body mass and anogenital distance (AGD) of their F1 foetuses were recorded, too. The concentrations of estradiol (E_2 ) and progesterone (P) in sera of the pregnant mice were determined using radioimmunoassay. RESULTS: Reproductive toxicity: with the increase of the administered MXC dose, the nidation quantity decreased, the AGD in the male foetuses exhibited shorter than that in the controls, and the concentrations of E_2 and P in sera went up. Significant differences in these indexes were found between the MXC treated groups and the control group (P0.05). Developmental toxicity: with the increase of the administered MXC dose, the gained weights of pregnant mice reduced, the quantity of live fetuses decreased, and the incidence of adverse pregnancy outcome (fetal death, absorption) went up. The difference among the different-dose MXC groups and the control group were significant difference (P0.05). CONCLUSION: MXC can disrupt reproductive function, thereby resulting in dysgenesis and maldevelopment in mice.