Purpose

We investigated whether expression of activator proteins that control follicle reserve and growth change after ovarian tissue vitrification and re-transplantation. Moreover, we assessed whether inhibition of mTOR signaling pathway by rapamycin would protect primordial follicle reserve after ovarian tissue freezing/thawing and re-transplantation.

Methods

Fresh control, frozen/thawed, fresh-transplanted, frozen/thawed and transplanted, rapamycin/control, rapamycin fresh-transplanted, and rapamycin frozen-thawed and transplanted groups were established in rats. After freezing and thawing process, two ovaries were transplanted into the back muscle of the same rat. After 2 weeks, grafts were harvested, fixed, and embedded into paraffin block. Normal and atretic primordial/growing follicle count was performed in all groups. Ovarian tissues were evaluated for the dynamic expressions of Gdf-9, Bmp-15, KitL, Lif, Fgf-2, and p-s6K using immunohistochemistry, and H-score analyses were done.

Results

Primordial follicle reserve reduced almost 50% after ovarian tissue re-transplantation. Expression of Gdf-9 and Lif increased significantly in primordial and growing follicles in frozen-thawed, fresh-transplanted, and frozen/thawed and transplanted groups, whereas expression of Bmp-15, KitL, and Fgf-2 decreased in primordial follicles. Freezing and thawing of ovarian tissue solely significantly increased p-s6K expression in primordial follicles, and on the other hand, suppression of mTORC1 pathway using rapamycin preserved the primordial follicle pool.

Conclusion

Altered expressions of activator proteins that regulate primordial follicle reserve and growth may lead to primordial follicle loss and rapamycin treatment can protect ovarian reserve after ovarian tissue cryopreservation/transplantation.

中文翻译：

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在卵巢组织冷冻保存/移植和雷帕霉素预防原始卵泡丢失后，控制卵泡储备的激活蛋白的表达发生改变。

目的

我们研究了在卵巢组织玻璃化和再移植后控制卵泡储备和生长的激活蛋白的表达是否发生变化。此外，我们评估了雷帕霉素对 mTOR 信号通路的抑制是否会保护卵巢组织冻融和再移植后的原始卵泡储备。

方法

在大鼠中建立新鲜对照、冷冻/解冻、新鲜移植、冷冻/解冻和移植、雷帕霉素/对照、雷帕霉素新鲜移植和雷帕霉素冻融和移植组。经过冷冻和解冻过程，将两个卵巢移植到同一只大鼠的背部肌肉中。2周后，收获移植物，固定并包埋在石蜡块中。在所有组中进行正常和闭锁原始/生长卵泡计数。使用免疫组织化学评估卵巢组织的 Gdf-9、Bmp-15、KitL、Lif、Fgf-2 和 p-s6K 的动态表达，并进行 H-score 分析。

结果

卵巢组织再移植后原始卵泡储备减少了近 50%。Gdf-9 和 Lif 在冻融、新鲜移植、冻融和移植组的原始和生长卵泡中的表达显着增加，而 Bmp-15、KitL 和 Fgf-2 在原始卵泡中的表达降低。卵巢组织的单独冷冻和解冻显着增加了原始卵泡中 p-s6K 的表达，另一方面，使用雷帕霉素抑制 mTORC1 通路保留了原始卵泡池。

结论

调节原始卵泡储备和生长的激活蛋白表达的改变可能导致原始卵泡丢失，而雷帕霉素治疗可以保护卵巢组织冷冻/移植后的卵巢储备。