Abstract:

Objective To investigate the effects of maternal fenvalerate exposure on sexual differentiation of male offspring rats. Methods Forty pregnant SD rats were randomly divided into three fenvalerate groups (treated with 2, 10 and 50 mg/kg fenvalerate respectively on day 12 to 18 of gestation by means of intragastric injection) and control group (treated with corn oil). The birth weight of all male and female offspring rats were measured on postnatal day 2. The body weight and anogenital distance of 25 male offspring rats randomly selected from each group were measured on postnatal day 4, 8, 12, 16, 20, 24 and 28. These 25 male offspring rats in each group were sacrificed on postnatal day 30, and organ coefficients of testis were calculated. Results There was no significant difference in birth weight of offspring rats between control group and fenvalerate groups (P>0.05). The body weight of male offspring rats in 2 mg/kg fenvalerate group was significantly higher than that of control group on postnatal day 8, 12 and 16 （P<0.05）, and the body weight of male offspring rats in 50 mg/kg fenvalerate group was significantly lower than that of control group on postnatal day 28（P<0.01）. The anogenital distance in fenvalerate groups was significantly shorter than that in control group on postnatal day 4, 8, and 12 （P<0.05 or P<0.01）, while there was no significant difference in anogenital distance between fenvalerate groups and control group on postnatal day 24 and 28 (P>0.05). The organ coefficients of testis in 10 mg/kg and 50 mg/kg fenvalerate groups were significantly lower than that of control group (P<0.05). Conclusion Maternal exposure to fenvalerate has definite effects on sexual differentiation of male offspring rats, which can shorten anogenital distance of male offspring rats in early stage after birth.

Key words: fenvalerate, sexual differentiation, anogenital distance, pregnancy, rat, male