Objective To evaluate the reproductive toxicity to offspring rats induced by simazine exposure during early life stage.
Methods A total of 90 female and 45 male SD rats were allowed to mate in stainless steel cages with two females and one male per cage. Eighty pregnant rats in good condition were selected and divided into eight groups. Four groups received different doses of simazine during gestation and another four groups did during gestation-and-lactation. Each four groups included 0 mg/kg (3% starch solution, control), 12.5 mg/kg (low dose), 50.0 mg/kg (middle dose), and 200.0 mg/kg (high dose) groups. Litter numbers, numbers of litters alive, and weight of offspring were recorded. The dams were neutralized after weaning. Twenty offspring rats each group (10 females and 10 males) were raised until six months old and euthanized. Then we weighed main organs of the mother rats and reproductive organs of the offspring rats to calculate organ coefficients. ELISA was used to determine the serum sex hormone le vels of offspring rats. The reproductive toxicity to offspring rats by simazine exposure during early life stage was evaluated through statistical analysis.
Results There were no evident effects of simazine on the survival rate and weight of offspring. The 21-day survival rates of the middle and high dose groups' offspring with maternal gestational exposure and of the high dose groups' offspring with maternal gestational-and-lactational exposure were lower than those of corresponding control groups (P < 0.05). The testis organ coefficients of male offspring were significantly lower in the middle and high dose groups with maternal gestational exposure and gestational-andla ctational exposure than in the corresponding controls (P < 0.05); the testis organ coefficients of male offspring of three dose groups with gestational-and-lactational exposure were lower than those of corresponding groups with gestational exposure (P < 0.05). The ovary organ coefficient of female offspring of the high dose group with gestational-and-lactational exposure were lower than that of the control group (P < 0.05). For both exposure protocols, the testosterone levels of male offspring of the middle and high dose groups were lower than those of the corresponding control groups (P < 0.05); the levels of male offspring of the middle and high dose groups with gestational-and-lactational exposure were lower than corresponding groups with maternal gestational exposure (P < 0.05). For both exposure protocols, the 17-β estradiol levels of the high dose groups' female offspring were lower than those of corresponding control groups' (P < 0.05); only the 17-β estradiol level of female offspring of the high dose group with gestational-and-lactational exposure was lower than that with gestational exposure (P < 0.05).
Conclusion Simazine exposure during early life stage can affect the reproductive development of offspring rats.
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