Department of Animal Science, University of California Davis, Davis, California, USA.
Department of Applied Mathematics and Computer Science, Technical University of Denmark, Kongens Lyngby, Denmark.
J Endocrinol. 2020 Nov;247(2):153-168. doi: 10.1530/JOE-20-0126.
Follicle-stimulating hormone (FSH) is required for ovarian antral folliculogenesis and steroidogenesis, and there is increasing evidence that it may play critical roles in preantral follicle development. We hypothesized that preantral follicles begin responding to FSH as early as the primary stage of development. Our objectives were to establish whether the FSH receptor (FSHR) was expressed in bovine preantral follicles and to determine the effects of FSH in these follicles and the surrounding ovarian tissue. Preantral follicles were isolated from bovine ovaries and subjected to immunolocalization of FSHR. Ovarian cortical strips were cultured with FSH or vehicle for 2 or 4 days and subjected to RNA sequencing, hematoxylin/eosin staining and immunostaining for p42/44 MAPK. Finally, cortical strips were cultured for 4 days with FSH before Western blot analysis of total and phosphorylated p42/44 MAPK and total aromatase. We found greater FSHR labeling intensity per cell in preantral follicles at the primary stage compared to other stages (P < 0.05). FSH upregulated genes involved in energy metabolism and MAPK signaling and downregulated genes related to phagosome and allograft rejection in the ovarian cortex. Preantral follicles cultured in situ with FSH had greater expression of total p42/44 MAPK (P < 0.05), but no difference was detected in whole tissue Western blot for phosphorylated p42/44 MAPK or aromatase. We conclude that the FSHR is expressed in preantral follicles as early as the primary stage of development, and that FSH upregulates cell metabolism and activates MAPK signaling pathways in preantral follicles.
卵泡刺激素（FSH）是卵巢腔前卵泡发生和类固醇生成所必需的，越来越多的证据表明它可能在腔前卵泡发育中发挥关键作用。我们假设腔前卵泡早在初级发育阶段就开始对 FSH 产生反应。我们的目标是确定 FSH 受体（FSHR）是否在牛腔前卵泡中表达，并确定 FSH 对这些卵泡和周围卵巢组织的影响。从牛卵巢中分离腔前卵泡，并进行 FSHR 的免疫定位。将卵巢皮质条用 FSH 或载体培养 2 或 4 天，并进行 RNA 测序、苏木精/伊红染色和 p42/44 MAPK 的免疫染色。最后，在皮质条用 FSH 培养 4 天后，进行总和磷酸化 p42/44 MAPK 以及总芳香酶的 Western blot 分析。我们发现，与其他阶段相比，初级阶段的腔前卵泡中每个细胞的 FSHR 标记强度更高（P<0.05）。FSH 上调了与能量代谢和 MAPK 信号相关的基因，并下调了与卵巢皮质中的吞噬体和同种异体排斥相关的基因。与 FSH 在原位培养的腔前卵泡具有更高的总 p42/44 MAPK 表达（P<0.05），但在整个组织的磷酸化 p42/44 MAPK 或芳香酶的 Western blot 中没有差异。我们得出结论，FSHR 早在腔前卵泡的初级发育阶段就表达，并且 FSH 上调了腔前卵泡的细胞代谢并激活了 MAPK 信号通路。
