Inj ury of male reproductive system of rats by prepubertal exposure to exogenous estrogen and its natural process of tissue repair / 吉林大学学报(医学版)

ABSTRACT

Objective To investigate the influence of prepubertal exposure to estradiol benzoate (EB)in the male reproductive system of the rats and the natural process of tissue repair,and to clarify the possible mechanism of the reproductive toxicity of exogenous estrogen.Methods Ninety 2 1-day-old male Wistar rats were randomly divided into 2 experimental groups (low dose of EB group and high dose of EB group,n=30)and control group (n=30). The rats in the experimental groups were injected with EB dissolved in peanut oil at 15(low dose of EB group)and 15 000μg·kg-1 (high dose of EB group)respectively,the rats in control group received equal vehicle injection only,once every other day for two weeks from postnatal day(PND)21 to 34.All of them were normally fed after the drug usage was stopped.The testes were harvested at the stages of PND 60 and PND 125(n=15 at each stage).The serum levels testosterone of (T),follicle-stimulating hormone(FSH),luteinizing hormone(LH),prolactin (PRL)and estradiol(E2)of the rats in various groups were detected with radioimmunology method and the weights of the rats in various groups were recorded;the histological changes of the testes tissue were observed with light microscope.Results On PND60,compared with control group,the T levels in low dose of EB group and high dose of EB group were decreased(P0.05);the weights of testes were decreased(P0.05 ), and the weight of testes was decreased (P0.05),and the weight of testes was decreased(P<0.01);there was still no sperm in high dose of EB group, the number of sperms was increased in low dose of EB group, but it was still lower than that in control group.Conclusion EB is harmful to the reproductive system and can change the normal serum sex hormone levels,even induces the irreversible injury.