Effect of vitamin E on reproductive function in the mice treated with 2,3,7,8-tetrachlorodibenzo-p-dioxin

The study was conducted to determine the effects of vitamin E on reproductive performance in mice treated with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). The 75 female and 40 male mice were randomly assigned into five groups. The levels of both TCDD and vitamin E given by gavage were 0 and 0 (Control group), 100 and 0 (experimental group I), 100 and 20 (experimental group II), 100 and 100 (experimental group III), and 100 ng/kg/day and 500 mg/kg/day (experimental group IV), respectively. Males and females were mixed to mate at the ratio of 1:2 after 4-week experiment. The gavage treatments were continued until the end of gestation in female mice after mating. The results showed that the litter number, survival rate, and body weight at birth of offspring in experimental group I had significantly decreased, and the females' pregnancy rate and pup sex ratio in experimental group I had the decreasing tendencies when compared with the control group. The litter number in experimental group III, survival rate in experimental group II and III, body weight at birth in experimental group III and IV exhibited significant increase compared with experimental group I. The female pregnancy rate in both experimental group III and IV recovered to 100%, but there were no significant differences when compared with experimental group I. The pups' sex ratio had a gradually increasing tendency with increase of vitamin E level, but there was no significant difference among experimental group I-IV. The results suggest that TCDD could induce reproductive toxicity in mice, whereas vitamin E alleviated adverse effects on reproductive performance in mice caused by TCDD.