Sheep is usually a monovular animal; superovulation technology is used to increase the number of offspring per individual and shorten generation intervals. To date, mature FSH superstimulatory treatments have been successfully used in sheep breeding, but much remains unknown about genes, pathways, and biological functions involved in follicular development. Therefore, in this study, we performed transcriptome profiling of small follicles (SFs; 2–2.5 mm), medium follicles (MFs; 3.5–4.5 mm), and large follicles (LFs; > 6 mm) in Mongolian ewes after FSH superstimulation. Furthermore, we identified differentially expressed genes and performed Kyoto Encyclopedia of Genes and Genomes pathway and Gene Ontology enrichment analyses in 3 separate pairwise comparisons. We found that ovarian steroidogenesis was significantly enriched in the SFs versus MFs analysis; the associated genes, cytochrome P450 family 19 (CYP19) and Hydroxy-delta-5-steroid dehydrogenase 3 beta- and steroid delta-isomerase 1 (HSD3B1), were significantly upregulated. Moreover, proline metabolism, glutathione metabolism, and PPAR signaling pathways were significantly enriched in the LFs versus SFs analysis; the associated genes, glutamate-cysteine ligase modifier subunit (GCLM) and cystathionine gamma-lyase (CTH), were significantly upregulated, whereas peroxisome proliferator-activated receptor gamma (PPARγ) was significantly downregulated. In summary, our study provides basic data and possible biological direction to further explore the molecular mechanism of sheep follicular development after FSH superstimulation.

绵羊通常是单排动物；超数排卵技术用于增加每个个体的后代数量并缩短世代间隔。迄今为止，成熟的 FSH 超刺激疗法已成功用于绵羊育种，但关于卵泡发育所涉及的基因、途径和生物学功能仍有许多未知。因此，在本研究中，我们对蒙古母羊在 FSH 过度刺激后的小卵泡（SF；2-2.5 毫米）、中卵泡（MF；3.5-4.5 毫米）和大卵泡（LF；> 6 毫米）进行了转录组分析。此外，我们确定了差异表达的基因，并在 3 个单独的成对比较中进行了京都基因和基因组途径和基因本体论富集分析。我们发现在 SFs 与 MFs 分析中，卵巢类固醇生成显着丰富；相关基因，细胞色素 P450 家族 19 (CYP19 ) 和羟基-δ -5-类固醇脱氢酶 3 β- 和类固醇 δ-异构酶 1 ( HSD3B1 ) 显着上调。此外，脯氨酸代谢、谷胱甘肽代谢和 PPAR 信号通路在 LFs 与 SFs 分析中显着丰富；相关基因，谷氨酸-半胱氨酸连接酶修饰亚基（GCLM）和胱硫醚γ-裂解酶（CTH）显着上调，而过氧化物酶体增殖物激活受体γ（PPARγ）显着下调。综上所述，本研究为进一步探讨FSH过度刺激后绵羊卵泡发育的分子机制提供了基础数据和可能的生物学方向。