Department of Anatomy, Tokyo Medical University, Shinjuku-ku, Tokyo, Japan.
Dev Dyn. 2020 Jun;249(6):754-764. doi: 10.1002/dvdy.155. Epub 2020 Feb 10.
Spermatozoa in mammals develop in seminiferous tubules in a testis and are transported through the male reproductive tract. Their developmental origins are, however, different from each other; the seminiferous tubules are testicular (gonadal) structure but the subsequent ducts stem from the mesonephros. Although some mechanisms should function for the connection between these ducts, there are few reports on them. In the present study, basic information such as timing, localization, and cell types involved in the connection was obtained by sequential immunohistochemistry.
At the time when the undifferentiated gonad differentiates into the testis or ovary, Adrenal-4 binding protein/steroidogenic factor-1 (Ad4BP/SF-1)-positive gonadal cells were noted in the mesonephric tubules (MT) in both sexes. At an earlier stage, although Ad4BP/SF-1-positive coelomic epithelial cells were adjacent to the MT, a basal membrane around them was not observed.
The connection between the testis cords and MT is suggested to be induced between Ad4BP/SF-1-positive gonadal cells and the MT before sex differentiation in a sex-independent manner.
哺乳动物的精子在睾丸的曲细精管中发育，并通过男性生殖道运输。然而，它们的发育起源彼此不同；曲细精管是睾丸（性腺）结构，而随后的导管则源自中肾。尽管应该有一些机制来连接这些导管，但关于它们的报道很少。在本研究中，通过连续免疫组织化学获得了连接的基本信息，如时间、定位和涉及的细胞类型。
在未分化的性腺分化为睾丸或卵巢时，两性的中肾管（MT）中均出现肾上腺 4 结合蛋白/类固醇生成因子 1（Ad4BP/SF-1）阳性性腺细胞。在更早的阶段，尽管 Ad4BP/SF-1 阳性的体腔上皮细胞与 MT 相邻，但它们周围没有基底膜。
在性别分化之前，以性别独立的方式，提示 Ad4BP/SF-1 阳性性腺细胞与 MT 之间诱导了睾丸索和 MT 之间的连接。
