Effects Of Gestational And Lactational Exposure To Propylparaben On The Reproductive System Of Offspring Mice

Objective: To investigate the effects of parental pregnancy and lactation exposure to parabens(PrPB)on the reproductive health of offspring.Methods: Female C57BL/6j pregnant mice with reproductive age were selected and exposed to parabens by feeding method.The exposure period was from the first day of gestation to the end of lactation.According to the different doses of PrPB in the feed,it was divided into blank control group,low-dose group and high-dose group,with doses of 0mg/kg,600mg/kg and 3000mg/kg respectively.The offspring of pregnant mice were observed,and the effects of PrPB exposure on the general health of the offspring were evaluated by calculating the sex ratio,organ coefficient,and monitoring the hair quality and body weight.By using HE staining of ovarian paraffin sections,ovarian follicles were counted,the estrous cycle of sexual maturity was monitored,serum sex hormone levels were measured,and ovarian function of female offspring was evaluated.The expression of nitrotyrosine(NTY)and 4-hydroxynonenal(4-HNE)in ovarian tissue sections was analyzed by immunohistochemistry to explore the possible mechanisms of PrPB affecting ovarian function.The reproductive function of male progeny was evaluated by counting sperm motility,deformity rate and mortality,and determining the serum testosterone levels.Results:(1)PrPB exposure may affect the sex of the offspring.There was no significant difference in the number of litters in the three groups,but the proportion of males and females was changed,showing an upward trend with the increase of exposure dose.(2)PrPB affected the growth and development of the pups in a certain period of time,and the difference among the groups after the lactation was not obvious.The birth weight of the female offspring in the low-dose group was decreased compared with the control group.At the time of lactation,the weight of the male offspring in the two exposed groups manifested an upward trend with the increase of exposure dose compared with the control group,but there was no statistical difference in the females.At the exual maturity stage,there was no statistical difference in the offspring body weight of the exposed groups compared with the control group.Also,there was no statistically significant difference in the organ coefficient at the sexual maturity time among the three groups.(3)PrPB exposure has an impact on the reproductive health of female pups.The number of follicles at all levels of total follicles in the ovary of female progeny at 1 week of age were not significantly different among the three groups.There were no significant differences in the uterus and ovarian coefficient and the number of ovarian follicles at all levels and the total number of follicles in the ovary at 12 weeks of sexual maturity time,and the serum progesterone was elevated in the high-dose group.(4)PrPB exposure has an impact on reproductive health in male offspring.Sperm count showed that the sperm deformity rate and mortality were increased with the increase of exposure dose,and the sperm motility rate was decreased with no statistical difference.The serum testosterone level in the exposed groups was not significantly different from the control group.(5)Immunohistochemistry experiments showed that the ovarian oxidative stress level of the offspring was increased.Conclusions: Female mice exposed to a certain amount of parabens during pregnancy and lactation could induce the various degrees of effects on reproductive health in the offspring,both female and male.The investigation suggests that it may affect the ovarian function of female pups by affecting the level of oxidative stress.