Li Hui, Kim Kwan Hee
School of Molecular Biosciences, Center for Reproductive Biology, Washington State University, Pullman, Washington 99164, USA.
Biol Reprod. 2003 Dec;69(6):1964-72. doi: 10.1095/biolreprod.103.018895. Epub 2003 Aug 6.
Di-(2-ethylhexyl) phthalate (DEHP) and its active metabolite, mono-(2-ethylhexyl) phthalate (MEHP), have been shown to cause reproductive toxicity in both developing and adult animals. In this study, we used organ cultures of fetal and neonatal rat testes to assess the in vitro effect of MEHP on seminiferous cord formation in Embryonic Day 13 (E13) testes and on the development of E18 and Postnatal Day 3 (P3) testes. Interestingly, MEHP had no effect on cord formation in the organ cultures of E13 testes, indicating that it has no effect on sexual differentiation of the indifferent gonad to testis. Consistently, the expression of a Sertoli cell-specific protein, mullerian inhibiting substance (MIS), or the number of gonocytes did not change in E13 testes after MEHP treatment. In contrast, MEHP decreased the levels of MIS and GATA-4 proteins in Sertoli cells and impaired Sertoli cell proliferation in the organ cultures of E18 and P3 testes. These results suggest that MEHP negatively influences proliferation and differentiation of Sertoli cells in both fetal and neonatal testes. In addition, MEHP treatment did not alter the number of gonocytes in E18 testes, whereas the number of gonocytes in P3 testes decreased in a dose-dependent manner, apparently due to enhanced apoptosis. These results suggest that MEHP adversely affects the gonocytes, which are mitotically active and undergoing migration and differentiation in neonatal testes, but it has no effect on fetal gonocytes that are mitotically quiescent.
邻苯二甲酸二（2-乙基己基）酯（DEHP）及其活性代谢物单（2-乙基己基）邻苯二甲酸酯（MEHP）已被证明会对发育中的动物和成年动物造成生殖毒性。在本研究中，我们使用胎鼠和新生鼠睾丸的器官培养物来评估MEHP对胚胎第13天（E13）睾丸生精索形成以及E18和出生后第3天（P3）睾丸发育的体外影响。有趣的是，MEHP对E13睾丸器官培养物中的索形成没有影响，这表明它对未分化性腺向睾丸的性分化没有影响。同样，在MEHP处理后的E13睾丸中，支持细胞特异性蛋白苗勒氏管抑制物质（MIS）的表达或生殖母细胞的数量没有变化。相比之下，MEHP降低了E18和P3睾丸器官培养物中支持细胞中MIS和GATA-4蛋白的水平，并损害了支持细胞的增殖。这些结果表明，MEHP对胎儿和新生睾丸中支持细胞的增殖和分化具有负面影响。此外，MEHP处理并未改变E18睾丸中生殖母细胞的数量，而P3睾丸中生殖母细胞的数量则呈剂量依赖性减少，这显然是由于细胞凋亡增加所致。这些结果表明，MEHP对新生睾丸中处于有丝分裂活跃状态并正在迁移和分化的生殖母细胞有不利影响，但对处于有丝分裂静止状态的胎儿生殖母细胞没有影响。
