SummaryThis study evaluated the effects of leptin on primordial follicle survival and activation after in vitro culture of ovine ovarian tissue and if leptin acts through the phosphatidylinositol-3-kinase/protein kinase B (PI3K/Akt) pathway. Ovarian fragments were fixed for histology (fresh control) or cultured for 7 days in control medium (α-MEM+) alone or supplemented with leptin (1, 5, 10, 25 or 50 ng/ml). Follicle morphology, activation and apoptosis were analyzed. Next, the fragments were cultured in the medium that showed the best results in the absence or the presence of the PI3K inhibitor (LY294002), and immunohistostaining of p-Akt protein was assessed. After culture, the percentage of normal follicles decreased (P < 0.05) in all treatments compared with the fresh control. Moreover, control medium and 1 ng/ml leptin had similar (P > 0.05) percentages of normal follicles, which were significantly higher than those in other treatments. However, culture with 1 ng/ml leptin maintained apoptosis similarly (P > 0.05) to that of the fresh control and lower (P < 0.05) than that in α-MEM+. Leptin did not influence follicle activation (P > 0.05) compared with the control medium (α-MEM+). Culture in 1 ng/ml leptin with LY294002 decreased the normal follicles and increased apoptosis, inhibited follicle activation (P < 0.05), and reduced p-Akt immunostaining, compared with the medium containing 1 ng/ml leptin without PI3K inhibitor. In conclusion, leptin at 1 ng/ml reduces apoptosis and promotes the activation of primordial follicles compared with the fresh control after in vitro culture of ovine ovarian tissue possibly through the PI3K/Akt pathway.

中文翻译：

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瘦素通过培养的绵羊卵巢组织中的磷脂酰肌醇-3-激酶/蛋白激酶 B 途径减少细胞凋亡并促进原始卵泡的活化

总结本研究评估了瘦素对原始卵泡存活和激活后的影响。体外绵羊卵巢组织的培养和瘦素是否通过磷脂酰肌醇-3-激酶/蛋白激酶 B (PI3K/Akt) 途径起作用。卵巢碎片被固定用于组织学（新鲜对照）或在对照培养基（α-MEM）中培养 7 天+) 单独或补充瘦素（1、5、10、25 或 50 ng/ml）。分析卵泡形态、活化和凋亡。接下来，将片段在不存在或存在 PI3K 抑制剂 (LY294002) 时显示最佳结果的培养基中培养，并评估 p-Akt 蛋白的免疫组织染色。培养后，正常卵泡的百分比下降（磷< 0.05) 在所有处理中与新鲜对照相比。此外，对照培养基和 1 ng/ml 瘦素具有相似的 (磷> 0.05) 正常卵泡的百分比，显着高于其他治疗组。然而，用 1 ng/ml 瘦素培养同样能维持细胞凋亡（磷> 0.05) 与新鲜对照相比更低 (磷< 0.05) 比 α-MEM+. 瘦素不影响卵泡激活（磷> 0.05) 与对照培养基 (α-MEM+）。用 LY294002 在 1 ng/ml 瘦素中培养可减少正常卵泡并增加细胞凋亡，抑制卵泡活化 (磷< 0.05)，与含有 1 ng/ml 瘦素且不含 PI3K 抑制剂的培养基相比，p-Akt 免疫染色减少。总之，与新鲜对照相比，1 ng/ml 的瘦素可减少细胞凋亡并促进原始卵泡的活化。体外绵羊卵巢组织的培养可能通过 PI3K/Akt 途径。