Dioxin perturbs, in a dose- and time-dependent fashion, steroid secretion, and induces apoptosis of human luteinized granulosa cells
Dioxin perturbs, in a dose- and time-dependent fashion, steroid secretion, and induces apoptosis of human luteinized granulosa cells
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DOI：
10.1210/en.139.10.4373
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发表时间：
1998-10-01
期刊：
影响因子：
4.8
通讯作者：
Hutz, RJ
中科院分区：
文献类型：
--
作者：
Heimler, I;Rawlins, RG;Hutz, RJ
二恶英（2，3，7，8-四氯二苯并对二恶英; TCDD）是一大类环境污染物中毒性最大的同类物。几项研究表明，接触TCDD会降低大鼠的生殖力和排卵率，并增加猴子子宫内膜异位症的发病率。最近的研究表明，TCDD的内分泌干扰作用至少部分是由卵巢的直接作用引起的。虽然涉及TCDD诱导毒性的因素仍在调查中，一些研究表明，TCDD诱导程序性细胞死亡，或凋亡，在各种组织中，并可能在卵巢中以类似的方式发挥作用。在本研究中，我们着手评估在体外TCDD对类固醇分泌的影响，特别是雌二醇-17 β（E-2）和孕酮，由人类黄体化颗粒细胞（LGC），并进一步确定是否TCDD是能够诱导这种细胞类型的凋亡。从参与体外受精计划的妇女获得人LGC。培养基中加入或不加入三种不同浓度的TCDD和底物[雄烯二酮（A（4））或双烯醇酮]。在4、8、12、24、36和48 h收集培养基并通过RIA测定。在24和48小时，固定LGC，通过原位免疫荧光技术评估DNA片段化。透射电子显微镜也进行了LGC后24和48小时与TCDD。与对照组相比，TCDD在所有测试浓度（3.1 pM，3.1 nM和3.1 μ M）下，在8，12和24 h时显著降低了培养基中E-2的积累。在36和48小时，TCDD治疗（在3.1 μ M）引起的E-2显着增加，与对照组相比。TCDD对E-2的影响可被A（4）消除。TCDD处理没有改变孕酮的积累。细胞凋亡增加，在24小时与3.1 μ M的TCDD，没有明显的影响，在3.1 nM。然而，到48小时，TCDD以剂量依赖性方式增加细胞凋亡。透射电子显微镜显示，在LGC与3.1 μ M TCDD在24和48小时的超微结构的差异。总的来说，本研究的结果表明，TCDD通过消耗A（4）前体干扰E-2的分泌，并以剂量和时间依赖的方式增加人LGC的凋亡细胞死亡。
Dioxin (2,3,7,8-tetrachlorodibenzo-p-dioxin; TCDD) is the most toxic congener of a large class of environmental pollutants. Several studies have shown that TCDD exposure reduced fecundity and ovulatory rate in rats and increased the incidence of endometriosis in monkeys. Recent work suggests that TCDD's endocrine-disrupting effects are, at least in part, caused by a direct action at the ovary. Although the factors involved in TCDD-induced toxicity are still under investigation, several studies have shown that TCDD induces programmed cell death, or apoptosis, in various tissues and may act in a similar fashion in the ovary. In the present study, we set out to evaluate the in, vitro effects of TCDD on steroid secretion, specifically estradiol-17 beta (E-2) and progesterone, by human luteinized granulosa cells (LGC), and to further determine whether TCDD is capable of inducing apoptosis in this cell type. Human LGC were obtained from women participating in an in vitro fertilization program. Medium, with or without three different concentrations of TCDD and substrates [androstenedione (A(4)) or pregnenolone], was added to each culture. The media were collected at 4, 8, 12, 24, 36, and 48 h and were assayed by RIA. At 24 and 48 h, the LGC were fixed for assessment of DNA fragmentation via an in situ immunofluorescence technique. Transmission electron microscopy was also performed on LGC after 24 and 48 h with TCDD. TCDD, at all concentrations tested (3.1 pM, 3.1 nM, and 3.1 mu M), significantly reduced E-2 accumulation in the media at 8, 12, and 24 h, compared with controls. At 36 and 48 h, TCDD treatment (at 3.1 mu M) caused a significant increase in E-2, compared with controls. The effect of TCDD on E-2 was abolished with the addition of A(4). TCDD treatment did not alter progesterone accumulation. Apoptosis increased at 24 h with 3.1 mu M TCDD, with no apparent effect at 3.1 nM. By 48 h, however, TCDD increased apoptosis in a dose-dependent manner. Transmission electron microscopy showed ultrastructural differences in LGC with 3.1 mu M TCDD at 24 and 48 h. Collectively, the results of the present study suggest that TCDD perturbs E-2 secretion by depletion of A(4) precursor and increases apoptotic cell death of human LGC in a dose- and time-dependent fashion.