In vitro follicle development from cryopreserved ovarian tissue could become an invaluable assisted reproduction technology for women with early ovarian failure. The challenge lies in producing, from small follicles present in the ovarian cortex, high-quality mature oocytes able to sustain embryo development. In vivo, an optimal combination of hormones and other factors coordinates the development of follicles and their enclosed oocyte. We have investigated the effect of the leukaemia inhibitory factor (LIF) cytokine, alone or in combination with FSH, on sheep in vitro follicle development from the preantral stage onwards. LIF did not alter follicle growth or antrum formation, but it modulated the differentiation of granulosa cells, as revealed by decreased production of anti-Müllerian hormone and abolished FSH-induced stimulation of oestradiol secretion. This modulatory role was also reflected in the abundance of mRNA from 35 genes, analysed by reverse-transcription coupled to microfluidic quantitative PCR. LIF stimulated or at least maintained the expression of genes involved in the dialogue between the oocyte and granulosa cells, through gap junctions (GJA4 encoding connexin 37) or paracrine signalling (Bone morphogenetic protein 15, KIT ligand and their receptors). Finally, the presence of both LIF and FSH during follicle growth strongly improved oocyte meiotic competence: most oocytes (56%) underwent subsequent nuclear maturation, a significant increase compared with their counterparts from follicles of similar size (550–900 µm) cultured with FSH only (28%) or developed in vivo (9%). Their ability to sustain embryo development remains to be evaluated. Combined supplementation with FSH and LIF certainly merits investigation with human follicles.

中文翻译：

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白血病抑制因子调节绵羊体外窦前至窦卵泡发育过程中颗粒细胞的分化并提高卵母细胞减数分裂能力

冷冻保存的卵巢组织的体外卵泡发育可能成为早期卵巢功能衰竭女性的一项宝贵的辅助生殖技术。挑战在于从卵巢皮质中的小卵泡中产生能够维持胚胎发育的高质量成熟卵母细胞。在体内，激素和其他因素的最佳组合协调卵泡及其封闭卵母细胞的发育。我们研究了白血病抑制因子 (LIF) 细胞因子，单独或与 FSH 联合，对从前腔期开始的绵羊体外卵泡发育的影响。LIF 不改变卵泡生长或胃窦形成，但它调节颗粒细胞的分化，正如通过减少抗苗勒管激素的产生和消除 FSH 诱导的雌二醇分泌刺激所揭示的那样。这种调节作用也反映在来自 35 个基因的 mRNA 丰度中，通过与微流体定量 PCR 结合的逆转录分析。LIF 通过间隙连接（GJA4 编码连接蛋白 37）或旁分泌信号（骨形态发生蛋白 15、KIT 配体及其受体）刺激或至少维持参与卵母细胞和颗粒细胞之间对话的基因的表达。最后，在卵泡生长过程中 LIF 和 FSH 的存在大大提高了卵母细胞的减数分裂能力：大多数卵母细胞 (56%) 经历了随后的核成熟，与仅用 FSH 培养 (28%) 或体内发育 (9%) 的类似大小 (550–900 µm) 的卵泡相比，显着增加。它们维持胚胎发育的能力仍有待评估。FSH 和 LIF 的联合补充剂当然值得对人类卵泡进行研究。