摘要目的 探讨增塑剂邻苯二甲酸二(2-乙己基)酯(DEHP)于性腺发育的关键时期作用于孕鼠(0),研究F1-F3代隐睾跨代遗传的演变情况及各代睾丸基因组DNA甲基化转移酶水平的改变情况.方法 妊娠SD大鼠随机分为两组:正常对照组和DEHP实验组,实验组自妊娠第七天(GD7)到第十九天(GD19)持续经口予以DEHP 750 mg·kg-1 ·d-1灌胃,观察子代隐睾发生情况,雌鼠受孕率;记录大鼠体重和睾丸、附睾重量以及AGD值,观察精子数量和质量;观察连续三代大鼠睾丸组织形态的演变情况,检测DNA甲基化转移酶变化情况.结果 孕鼠在孕期(GD7-GD19)暴露于DEHP,第一代(F1)隐睾发生率为30％,第二代(F2)隐睾发生率为12.5％,第三代(F3)未见隐睾发生;交配实验F1代受孕率50％,F2代75％,F3代100％;HE染色发现F1代睾丸生精上皮明显萎缩,生精细胞少,F2代有所改善,F3代形态趋于正常.Real Time-PCR、免疫组化和Western Blot表明DNA甲基化转移酶的表达随着遗传代数的增加而上调,差异有统计学意义.结论 DEHP损伤大鼠雄性生殖功能,通过改变DNA甲基化转移酶的表达,继而导致基因组印记甲基化修饰模式改变并遗传给下一代,从而使子代雄性生殖系统发育的关键性印记基因作用失衡,并最终导致子代产生隐睾,可能是导致生殖系统损害的重要毒理机制之一.

abstractsObjective To investigate the role of DEHP in the critical period of gonadal development in pregnant rats (F0),and study the evolution of F1-F3 generation of inter-generational inheritance of cryptorchidism and the alteration of DNA methyltransferase enzyme levels in testis.Methods Pregnant SD rats were randomly divided into two groups:normal control group and DEHP experimental group.From pregnancy 7 d to 19 d,experimental group was sustained to gavage DEHP 750 mg· kg-1· d-1,observed the incidence of cryptorchidism in offspring and examnined the pregnancy rate of female rats through mating experiments.After maturation (PND80),recorded the rat's weight of body,testes,epididymis and AGD value,detected the sperm number and quality.Subsequently,we examined the evolution morphological and DNA methyltransferase changes of testicular tissue for 3 generation rats by HE and Western Blot.Results DEHP successfully induced cryptorchidism occurrence in offspring during pregnancy.The incidence of cryptorchidism in F1 was 30％,in F2 was 12.5％,and there is no cryptorchidism occurrence in F3.Conception rate 50％ mating experiment shows in the F1,F2 generation of 75％,the F3 generation by 100％.HE staining showed that the seminiferous epithelium of F1 generation was atrophy and with a few sperrnatogenic cell,F2 generation had improved,F3 generation was tend to be normal.The DNA methyltransferase expression was up-regulated with the increase of generations by Real Time-PCR,immunohistochemistry and Western Blot.Conclusions DEHP damages male reproductive function in rats,affects expression of DNA methyltransferase enzyme,which in turn leads to genomic imprinting methylation pattern changes and passed on to the next generation,so that the offspring of male reproductive system critical role in the development of imprinted genes imbalances,and eventually leads to child produced offspring cryptorchidism.This may be an important mechanism of reproductive system damage.