Cumulus cells have an important role to play in the final preparation of the oocyte before ovulation. During the final phase of follicular differentiation, FSH levels are low and LH maintains follicular growth; however, it is not known if at that time LH has an influence on cumulus cells inside the follicle. In humans, LH is often inhibited to avoid a premature ovulatory LH surge. This procedure provides a tool to investigate the role of LH in follicular development. In this study, we investigated the impact of suppressing LH using the GnRH antagonist cetrorelix during an ovarian coasting stimulation protocol on the transcriptome of bovine cumulus cells (CC). Oocytes were collected twice from 6 dairy cows. For the first collection, the cows received FSH twice daily for 3 d, followed by FSH withdrawal for 68 h as a control protocol. For the second collection, the same stimulation protocol was used, but the cows also received, starting on day 2 of FSH stimulation, a GnRH antagonist once a day until recovery of the cumulus-oocyte complexes (COC). Half of the COC were subjected to in vitro maturation, fertilization, and culture to assess blastocyst rates. The other half of the COC underwent microarray analysis (n = 3 cows, 2 treatments, 6 oocyte collections) and qRT-PCR (n = 6 cows: 3 microarray cows +3 other cows, 2 treatments, 12 oocyte collections). The differential expression of specific genes was confirmed by RT-qPCR: decrease of ATP6AP2, SC4MOL, and OSTC and increase of PTGDS in the LH-inhibited condition. The global transcriptomic analysis of cumulus cells demonstrated that the inhibition of LH secretion may decrease survival and growth of the follicle. Moreover, the results suggested that LH may be important to cumulus for the maintenance of cellular mechanisms such as global RNA expression, protein and nucleic acid metabolism, and energy production. These results support the hypothesis that LH support is important during the final part of follicle maturation through its influence on the cumulus cells.

卵泡细胞在排卵前的卵母细胞最终制备中起着重要作用。在卵泡分化的最后阶段，FSH水平低，LH维持卵泡生长。然而，尚不知道那时LH是否对卵泡内的卵丘细胞有影响。在人类中，LH经常被抑制，以避免过早排卵的LH激增。该程序提供了研究LH在卵泡发育中作用的工具。在这项研究中，我们调查了在卵巢滑行刺激方案期间使用GnRH拮抗剂西曲瑞克抑制LH对牛卵丘细胞（CC）转录组的影响。从6头奶牛中收集两次卵母细胞。对于第一个采集，奶牛每天两次接受FSH，持续3 d，然后作为控制方案，将FSH停药68 h。对于第二次采集，使用了相同的刺激方案，但是从FSH刺激的第二天开始，母牛还接受了GnRH拮抗剂，每天一次，直到卵母细胞复合物（COC）恢复。将一半的COC进行体外成熟，受精和培养以评估胚泡率。COC的另一半进行了微阵列分析（n = 3头母牛，2种处理，6个卵母细胞收集）和qRT-PCR（n = 6头母牛：3例微阵列母牛+ 3头其他母牛，2种处理，12个卵母细胞收集）。通过RT-qPCR证实了特定基因的差异表达：LH抑制条件下ATP6AP2，SC4MOL和OSTC的降低以及PTGDS的升高。对卵丘细胞的整体转录组学分析表明，抑制LH分泌可能会降低卵泡的存活和生长。此外，结果表明，LH对于积云可能对于维持细胞机制（例如全局RNA表达，蛋白质和核酸代谢以及能量产生）很重要。这些结果支持以下假设：LH支持在卵泡成熟的最后阶段通过影响卵丘细胞而很重要。