Methoxychlor directly affects ovarian antral follicle growth and atresia through Bcl-2-and Bax-mediated pathways
Methoxychlor directly affects ovarian antral follicle growth and atresia through Bcl-2-and Bax-mediated pathways
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DOI：
10.1093/toxsci/kfi276
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发表时间：
2005-11-01
影响因子：
3.8
通讯作者：
Flaws, JA
中科院分区：
文献类型：
--
作者：
Miller, KP;Gupta, RK;Flaws, JA
甲氧滴滴涕（MXC）是一种有机氯农药和生殖毒性物质。虽然体内研究表明MXC暴露会增加窦状卵泡闭锁，部分原因是改变了细胞凋亡调节因子（Bcl-2和Bax），但他们并没有区分MXC是通过直接还是间接机制来实现这一目的。因此，我们利用体外卵泡培养系统来测试MXC对有腔卵泡直接有毒的假设，以及抗凋亡Bcl-2的过表达或促凋亡Bax的缺失保护有腔卵泡免受MXC诱导的毒性。从野生型（WT）、Bcl-2过表达（Bcl-2 OE）或Bax缺陷（Bax KO）小鼠中分离窦状卵泡，并将其暴露于二甲基亚砜（对照）或MXC（1-100 μ g/ml）96小时。每24小时测量卵泡直径以评估生长。96 h后，对卵泡进行组织学评价，或收集用于Bcl-2和Bax mRNA水平的定量PCR分析。与对照组相比，MXC（10-100 μ g/ml）在72和96 h显著抑制窦卵泡生长，并在96 h增加闭锁（100 μ g/ml）。此外，MXC在48-96 h之间增加Bax mRNA水平，并在96 h降低Bcl-2 mRNA水平。虽然MXC从72 h开始抑制WT窦卵泡的生长，但直到96 h才抑制Bcl-2 OE或Bcl-2 KO卵泡的生长。与对照组相比，MXC还增加了小型和大型WT和MXKO窦状卵泡的闭锁，但与对照组相比，MXC并未增加大型Bcl-2 OE窦状卵泡的闭锁。这些数据表明MXC部分通过Bcl-2和Bax通路直接抑制卵泡生长，部分通过Bcl-2通路增加闭锁。
Methoxychlor (MXC) is an organochlorine pesticide and reproductive toxicant. While in vivo studies indicate that MXC exposure increases antral follicle atresia, in part by altering apoptotic regulators (Bcl-2 and Bax), they do not distinguish whether MXC does so via direct or indirect mechanisms. Therefore, we utilized an in vitro follicle culture system to test the hypothesis that MXC is directly toxic to antral follicles, and that overexpression of anti-apoptotic Bcl-2, or deletion of pro-apoptotic Bax, protects antral follicles from MXC-induced toxicity. Antral follicles were isolated from wild-type (WT), Bcl-2 overexpressing (Bcl-2 OE), or Bax deficient (BaxKO) mice, and exposed to dimethylsulfoxide (control) or MXC (1-100 mu g/ml) for 96 h. Follicle diameters were measured every 24 h to assess growth. After 96 h, follicles were histologically evaluated for atresia or collected for quantitative PCR analysis of Bcl-2 and Bax mRNA levels. MXC (10-100 mu g/ml) significantly inhibited antral follicle growth at 72 and 96 h, and increased atresia (100 mu g/ml) compared to controls at 96 h. Furthermore, MXC increased Bax mRNA levels between 48-96 h and decreased Bcl-2 mRNA levels at 96 h. While MXC inhibited growth of WT antral follicles beginning at 72 h, it did not inhibit growth of Bcl-2 OE or BaxKO follicles until 96 h. MXC also increased atresia of small and large WT and BaxKO antral follicles over controls, but it did not increase atresia of large Bcl-2 OE antral follicles over controls. These data suggest that MXC directly inhibits follicle growth partly by Bcl-2 and Bax pathways, and increases atresia partly through Bcl-2 pathways.