Yoshimura Shiori, Omotehara Takuya, Nakata Hiroki, Birch Lynn A, Prins Gail S, Ichimura Koichiro, Itoh Masahiro
Department of Anatomy, Tokyo Medical University, Shinjuku-Ku, Tokyo, Japan.
Department of Anatomy and Life Structure, Juntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-Ku, Tokyo, 113-8421, Japan.
Cell Tissue Res. 2025 Jan;399(1):85-96. doi: 10.1007/s00441-024-03931-5. Epub 2024 Nov 23.
The rete ovarii and epoophoron in females are homologous structures of the rete testis and efferent/epididymal duct in males and are derived from the developing rete cells and mesonephric tubules, respectively. Sex steroid hormones play a critical role in reproductive function for both sexes, and we recently reported expression patterns of sex steroid receptors in developing male reproductive tracts. However, their expression patterns in females remain unclear. We, therefore, investigated the three-dimensional structure and expression patterns of sex steroid receptors in the rete ovarii and epoophoron of fetal and adult female mice. In adult females, the epoophoron was not adherent to the rete ovarii. The rete ovarii had a bursa-like structure, with its extra-ovarian region protruding toward the epoophoron. A marker for mesonephric tubules, PAX2 (Paired box 2), was detected in the epoophoron and a small population of epithelial cells in the extra-ovarian rete ovarii. These epithelial cells expressed estrogen receptor and androgen receptor. During development, mesonephric tubules were adherent to the rete ovarii at first, but as the development proceeded, the continuity was lost due to the interruption of the tubule rather than separation between the tip of the tubule and rete ovarii. These findings suggest that epithelial cells, originating from the mesonephric tubules, persist even in the adult rete ovarii with maintained expressions of receptors for estrogen and androgen.
女性的卵巢网和卵巢冠分别是男性睾丸网和输出小管/附睾管的同源结构，分别来源于发育中的网细胞和中肾管。性类固醇激素对两性的生殖功能都起着关键作用，我们最近报道了性类固醇受体在发育中的雄性生殖道中的表达模式。然而，它们在女性中的表达模式仍不清楚。因此，我们研究了胎儿和成年雌性小鼠卵巢网和卵巢冠中性类固醇受体的三维结构和表达模式。在成年雌性中，卵巢冠不附着于卵巢网。卵巢网具有囊状结构，其卵巢外区域向卵巢冠突出。在卵巢冠和卵巢外网的一小部分上皮细胞中检测到中肾管的标志物PAX2（配对盒2）。这些上皮细胞表达雌激素受体和雄激素受体。在发育过程中，中肾管最初附着于卵巢网，但随着发育的进行，由于小管的中断而不是小管尖端与卵巢网之间的分离，连续性丧失。这些发现表明，源自中肾管的上皮细胞即使在成年卵巢网中也会持续存在，并维持雌激素和雄激素受体的表达。
