PDF(Pubmed)
Abstract：
BACKGROUND: Industrial progress has led to the omnipresence of chemicals in the environment of the general population, including reproductive-aged and pregnant women. The reproductive function of females is a well-known target of endocrine-disrupting chemicals. This function holds biological processes that are decisive for the fertility of women themselves and for the health of future generations. However, insufficient research has evaluated the risk of combined mixtures on this function. This study aimed to assess the direct impacts of a realistic exposure to eight combined environmental toxicants on the critical process of folliculogenesis.
METHODS: Female rabbits were exposed daily and orally to either a mixture of eight environmental toxicants (F group) or the solvent mixture (NE group, control) from 2 to 19 weeks of age. The doses were computed from previous toxicokinetic data to reproduce steady-state serum concentrations in rabbits in the range of those encountered in pregnant women. Ovarian function was evaluated through macroscopic and histological analysis of the ovaries, serum hormonal assays and analysis of the expression of steroidogenic enzymes. Cellular dynamics in the ovary were further investigated with Ki67 staining and TUNEL assays.
RESULTS: F rabbits grew similarly as NE rabbits but exhibited higher total and high-density lipoprotein (HDL) cholesterol levels in adulthood. They also presented a significantly elevated serum testosterone concentrations, while estradiol, progesterone, AMH and DHEA levels remained unaffected. The measurement of gonadotropins, androstenedione, pregnenolone and estrone levels yielded values below the limit of quantification. Among the 7 steroidogenic enzymes tested, an isolated higher expression of Cyp19a1 was measured in F rabbits ovaries. Those ovaries presented a significantly greater density/number of antral and atretic follicles and larger antral follicles without any changes in cellular proliferation or DNA fragmentation. No difference was found regarding the count of other follicle stages notably the primordial stage, the corpora lutea or AMH serum levels.
CONCLUSIONS: Folliculogenesis and steroidogenesis seem to be subtly altered by exposure to a human-like mixture of environmental toxicants. The antral follicle growth appears promoted by the mixture of chemicals both in their number and size, potentially explaining the increase in atretic antral follicles. Reassuringly, the ovarian reserve estimated through primordial follicles number/density and AMH is spared from any alteration. The consequences of these changes on fertility and progeny health have yet to be investigated.
METHODS: Female rabbits were exposed daily and orally to either a mixture of eight environmental toxicants (F group) or the solvent mixture (NE group, control) from 2 to 19 weeks of age. The doses were computed from previous toxicokinetic data to reproduce steady-state serum concentrations in rabbits in the range of those encountered in pregnant women. Ovarian function was evaluated through macroscopic and histological analysis of the ovaries, serum hormonal assays and analysis of the expression of steroidogenic enzymes. Cellular dynamics in the ovary were further investigated with Ki67 staining and TUNEL assays.
RESULTS: F rabbits grew similarly as NE rabbits but exhibited higher total and high-density lipoprotein (HDL) cholesterol levels in adulthood. They also presented a significantly elevated serum testosterone concentrations, while estradiol, progesterone, AMH and DHEA levels remained unaffected. The measurement of gonadotropins, androstenedione, pregnenolone and estrone levels yielded values below the limit of quantification. Among the 7 steroidogenic enzymes tested, an isolated higher expression of Cyp19a1 was measured in F rabbits ovaries. Those ovaries presented a significantly greater density/number of antral and atretic follicles and larger antral follicles without any changes in cellular proliferation or DNA fragmentation. No difference was found regarding the count of other follicle stages notably the primordial stage, the corpora lutea or AMH serum levels.
CONCLUSIONS: Folliculogenesis and steroidogenesis seem to be subtly altered by exposure to a human-like mixture of environmental toxicants. The antral follicle growth appears promoted by the mixture of chemicals both in their number and size, potentially explaining the increase in atretic antral follicles. Reassuringly, the ovarian reserve estimated through primordial follicles number/density and AMH is spared from any alteration. The consequences of these changes on fertility and progeny health have yet to be investigated.
摘要：
背景：工业进步导致一般人群的环境中化学物质无处不在，包括育龄妇女和孕妇。女性的生殖功能是内分泌干扰化学物质的众所周知的目标。这一功能拥有生物过程，对妇女本身的生育能力和后代的健康具有决定性作用。然而,没有足够的研究评估了混合混合物对这一功能的风险。这项研究旨在评估实际暴露于八种联合环境毒物对卵泡发育关键过程的直接影响。
方法：母兔每天口服八种环境毒物混合物（F组）或溶剂混合物（NE组，对照)从2到19周龄。根据先前的毒物动力学数据计算剂量，以在孕妇中遇到的范围内重现兔子的稳态血清浓度。通过卵巢的宏观和组织学分析评估卵巢功能，血清激素测定和类固醇生成酶表达的分析。用Ki67染色和TUNEL测定进一步研究卵巢中的细胞动力学。
结果：F兔的生长与NE兔相似，但在成年期表现出更高的总胆固醇和高密度脂蛋白（HDL）胆固醇水平。他们还提出了显著升高的血清睾酮浓度，而雌二醇，黄体酮,AMH和DHEA水平未受影响。促性腺激素的测量，雄烯二酮,孕烯醇酮和雌酮水平的值低于定量限。在测试的7种类固醇生成酶中，在F兔卵巢中检测到Cyp19a1的分离较高表达。这些卵巢表现出明显更大的窦和闭锁卵泡的密度/数量以及更大的窦卵泡，而细胞增殖或DNA片段没有任何变化。其他卵泡阶段的计数没有发现差异，特别是原始阶段，黄体或AMH血清水平。
结论：通过暴露于类似人类的环境毒物混合物，卵泡生成和类固醇生成似乎发生了微妙的改变。窦卵泡的生长似乎是由化学物质的数量和大小的混合物促进的，可能解释了闭锁窦卵泡的增加。令人放心的是，通过原始卵泡数量/密度和AMH估计的卵巢储备不受任何改变的影响。这些变化对生育力和后代健康的影响尚待研究。
方法：母兔每天口服八种环境毒物混合物（F组）或溶剂混合物（NE组，对照)从2到19周龄。根据先前的毒物动力学数据计算剂量，以在孕妇中遇到的范围内重现兔子的稳态血清浓度。通过卵巢的宏观和组织学分析评估卵巢功能，血清激素测定和类固醇生成酶表达的分析。用Ki67染色和TUNEL测定进一步研究卵巢中的细胞动力学。
结果：F兔的生长与NE兔相似，但在成年期表现出更高的总胆固醇和高密度脂蛋白（HDL）胆固醇水平。他们还提出了显著升高的血清睾酮浓度，而雌二醇，黄体酮,AMH和DHEA水平未受影响。促性腺激素的测量，雄烯二酮,孕烯醇酮和雌酮水平的值低于定量限。在测试的7种类固醇生成酶中，在F兔卵巢中检测到Cyp19a1的分离较高表达。这些卵巢表现出明显更大的窦和闭锁卵泡的密度/数量以及更大的窦卵泡，而细胞增殖或DNA片段没有任何变化。其他卵泡阶段的计数没有发现差异，特别是原始阶段，黄体或AMH血清水平。
结论：通过暴露于类似人类的环境毒物混合物，卵泡生成和类固醇生成似乎发生了微妙的改变。窦卵泡的生长似乎是由化学物质的数量和大小的混合物促进的，可能解释了闭锁窦卵泡的增加。令人放心的是，通过原始卵泡数量/密度和AMH估计的卵巢储备不受任何改变的影响。这些变化对生育力和后代健康的影响尚待研究。
