Chronology of events accompanying follicular atresia in hypophysectomized ewes. Changes in levels of steroidogenic enzymes, connexin 43, insulin-like growth factor II mannose 6 phosphate receptor, extracellular matrix components, and matrix metalloproteinases
Chronology of events accompanying follicular atresia in hypophysectomized ewes. Changes in levels of steroidogenic enzymes, connexin 43, insulin-like growth factor II mannose 6 phosphate receptor, extracellular matrix components, and matrix metalloproteinases
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DOI：
10.1095/biolreprod58.1.175
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发表时间：
1998-01-01
影响因子：
3.6
通讯作者：
Monniaux, D
中科院分区：
文献类型：
--
作者：
Huet, C;Monget, P;Monniaux, D
在动情周期卵泡期末期切除垂体的母羊中，研究了已知在卵泡闭锁期间改变的一些蛋白质水平变化的时间顺序。这项研究是通过定量免疫组织化学和酶谱分析对通常注定排卵的大窦卵泡（直径 > 3.5 毫米）进行的，在垂体消融后 24、36 或 72 小时恢复。通过比较完整母羊的健康卵泡来跟踪闭锁的过程，早期闭锁卵泡在垂体切除后24小时恢复，明显闭锁卵泡在垂体切除后36小时恢复，晚期闭锁卵泡在垂体切除后72小时恢复。垂体切除引起的最早的闭锁事件是在卵泡膜中检测到的，包括纤连蛋白水平的强烈下降（p < 0.001) 和胰岛素样生长因子-II/甘露糖 6 磷酸 (IGF-II/M6P) 受体 (p < 0.05)，发生在垂体消融后的第一个 24 小时内。在完整动物中，在早期闭锁卵泡的卵泡膜中观察到类似的变化，表明这些变化可能是与卵泡闭锁发生有关的重要事件。同时，早在垂体切除术后24小时，滤泡内基质金属蛋白酶-2和-9的水平就显示出增加，并且在垂体切除术后72小时观察到进一步增加。这些早期事件之后，垂体切除后 36 小时，颗粒细胞中的 P450 芳香酶消失（p < 0.05），并且内膜中的 P450 17 α-羟化酶水平和颗粒细胞中的间隙连接蛋白 connexin-43 水平逐渐降低；垂体切除术后 72 小时，这些标记物在闭锁晚期卵泡中仍可检测到。颗粒细胞层内纤连蛋白、IV 型胶原、层粘连蛋白和 IGF-II/M6P 受体水平的增加 (p < 0.05) 仅在闭锁晚期阶段才显着，表明这些变化可能是闭锁的结果而不是原因。
The chronology of changes in levels of some proteins known to be altered during atresia of ovarian follicles was studied in ewes hypophysectomized at the end of the follicular phase of the estrous cycle. This study was performed by quantitative immunohistochemistry and zymography on large antral follicles (diameter > 3.5 mm) normally destined to ovulate, recovered 24, 36, or 72 h after pituitary ablation. The process of atresia was followed by comparing healthy follicles from intact ewes, with early atretic follicles recovered 24 h after hypophysectomy, clearly atretic follicles recovered 36 h after hypophysectomy, and late atretic follicles recovered 72 h after hypophysectomy.The earliest events of atresia induced by hypophysectomy were detected in theca and consisted of a strong decrease in levels of fibronectin (p < 0.001) and insulin-like growth factor-II/mannose 6 phosphate (IGF-II/M6P) receptors (p < 0.05), occurring within the first 24 h following pituitary ablation. In intact animals, similar changes were observed in theca of early atretic follicles, suggesting that these changes may be important events involved in the onset of follicular atresia.In parallel, intrafollicular levels of matrix metalloproteinase-2 and -9 were shown to increase as early as 24 h after hypophysectomy, and a further increase was observed until 72 h after hypophysectomy. These early events were followed by the disappearance of P450 aromatase in granulosa cells 36 h after hypophysectomy (p < 0.05), and a progressive decrease in levels of P450 17 alpha-hydroxylase in the theca interna and of gap junction protein connexin-43 in granulosa cells; these markers were still detectable in late atretic follicles 72 h after hypophysectomy.The increase in levels of fibronectin, type IV collagen, laminin, and IGF-II/M6P receptors within granulosa cell layers (p < 0.05) was significant only in late atretic stages, suggesting that these changes may be consequences rather than causes of atresia.