【摘要】 目的研究青春期前苯甲酸雌二醇(EB)暴露对SD大鼠睾丸发育及功能的影响。方法21d龄雄性SD大鼠,随机分为EB0.1、100.0μg/(kg.d)2个实验组(AEa和AEb组)和1个对照组(AC组),于青春期前,即出生后第22d(PND22)实验组每日皮下注射相应剂量的EB,共14d,对照组仅注射溶媒(玉米油)。观察各组大鼠睾丸下降时间。于青春期晚期(PND50)、性成熟后(PND64)和成年期(PND130)分批处死各组大鼠,称量睾丸质量,测定大鼠血清睾酮浓度,观察睾丸形态学改变以及PND130大鼠附睾尾精子质量。结果AC、AEa和AEb组睾丸下降时间分别为出生后(27.00±0.89)d、(27.50±1.05)d和(43.17±1.72)d,其中AEb组较AC组明显延迟(P<0.01)。PND50时,与AC组比较,AEb组血清睾酮浓度明显降低(P<0.05),单侧睾丸质量减轻(P<0.01),生精小管发育较差、生精上皮中细胞数目减少、精子发生阻滞、间质细胞发育幼稚。PND64时,与AC组比较,AEb组单侧睾丸质量和睾丸组织形态学改变与PND50时类似,但总体较PND50时有所改善。PND130时,与AC组比较,各实验组与对照组比较,单侧睾丸质量和睾丸组织形态学改变无明显差异,但AEb组精子密度和精子活动率下降(P<0.05),a+b级精子比例降低(P<0.01)。结论青春期前小剂量EB暴露对SD大鼠睾丸发育及功能无明显影响,大剂量EB〔100.0μg/(kg.d)×14d〕暴露对大鼠睾丸发育及功能有明显的近期(PND50和PND64)和较远期(PND130)毒性作用,该毒性作用随鼠龄增长而逐渐减退,其机制可能与间质细胞和支持细胞的发育及功能受损相关。更多还原

【Abstract】 Objective To investigate the effects of prepubertal exposure to estradiol benzoate(EB)on the testicular development and function of SD rats.Methods Fifty four 21-day-old male SD rats were randomly and equally divided into 2 experimental groups(AEa and AEb,n=18 each)and one control group(AC,n=18).The rats in the experimental groups were injected(s.c.)with EB dissolved in corn oil at a dose of 0.1(AEa)and 100.0 μg/(kg·d)(AEb)respectively during prepuberty for 14 d 〔from postnatal day(PND)22 to PND 35〕.The rats in the control group received vehicle injections only.The testicular development of the rats was observed.The testes were harvested at the stages of late puberty(PND 50),sexual maturity(PND 64)and adulthood(PND 130)(n=6 at each stage).The serum testosterone,the weights and histology of the testes,and the quality of sperms in the epididymal cauda were examined.Results The testes of rats in group AEb descended at day 43.17±1.72,later than the rats in the AC group(27.00±0.89,P<0.01).At the stage of late puberty,the AEb group had lower serum testosterone than the AC group(P<0.05)and had less unilateral testes weights than the AC group(P<0.01).Compared with the AC group,the histological alteration of the testes of rats in the AEb group included seminiferous tubules maldevelopment,decreased cell numbers of seminiferous epithelia,spermatogenesis blocking and Leydig cells aplasia.At the stage of sexual maturity,the AEb group had less unilateral testes weight than the AC group(P<0.01)and maintained similar histological alterations of testes as at the stage of late puberty.At the stage of adulthood,no differences were observed among the three groups in the unilateral testes weights and the histological features of the testes(P>0.05).However,the AEb group had significant lower density and motility of sperms and percentage of grade a+b sperms in the epididymal cauda than the AC group(P<0.05).Conclusion Prepubertal exposure to low dose of EB does not affect the testicular development and function of SD rats,while high dose 〔100 μg/(kg·d)×14 d〕 exposure has significant short(PND 50 and 64)and long-term(PND 130)toxic effects.The toxic effects are associated with the damage of Leydig and Sertoli cells.更多还原