Boutin E L, Battle E, Cunha G R
Department of Anatomy, University of California-San Francisco 94143-0452.
Differentiation. 1992 Mar;49(2):101-7. doi: 10.1111/j.1432-0436.1992.tb00774.x.
The epithelium of the mammalian vagina arises from two distinct germ layers, endoderm from the urogenital sinus and mesoderm from the lower fused Müllerian ducts. While previously it has been reported that neonatal vaginal epithelium can be induced to differentiate as uterus, which normally develops from the middle portion of the Müllerian ducts, it has not been determined whether this ability is shared by both mesoderm- and endoderm-derived vaginal epithelia. To test if germ layer origin influences the ability of vaginal epithelium to undergo uterine differentiation, we have isolated sinus-derived and Müllerian-derived vaginal epithelia from newborn mice, combined them with uterine mesenchyme, and grown them for 4 weeks in female mice. Mesoderm-derived Müllerian vaginal epithelium in combination with uterine mesenchyme formed the simple columnar epithelium typical of uterus. Similar results were obtained with neonatal cervical epithelium, another mesodermal Müllerian duct derivative. On the other hand, sinus vaginal epithelium combined with uterine mesenchyme formed small cysts lined by a stratified squamous vaginal-like epithelium. This epithelium never showed evidence of cycling between the cornified and mucified states as is typically seen in vaginal epithelium combined with vaginal stroma. These results indicate that the ability of epithelium to form uterus is limited to mesoderm-derived epithelia and suggest that endoderm-derived sinus vaginal epithelium cannot undergo the typical differentiative modifications in response to the hormonal fluctuations of the estrous cycle when associated with uterine stroma.
哺乳动物阴道的上皮组织起源于两个不同的胚层，泌尿生殖窦的内胚层和下方融合的苗勒管的中胚层。虽然此前有报道称，新生小鼠的阴道上皮可被诱导分化为子宫组织（子宫通常由苗勒管中部发育而来），但尚未确定中胚层和内胚层来源的阴道上皮是否都具备这种能力。为了测试胚层起源是否会影响阴道上皮向子宫分化的能力，我们从新生小鼠中分离出泌尿生殖窦来源和苗勒管来源的阴道上皮，将它们与子宫间充质结合，并在雌性小鼠体内培养4周。中胚层来源的苗勒管阴道上皮与子宫间充质结合后，形成了典型的子宫单层柱状上皮。另一种中胚层苗勒管衍生物——新生小鼠宫颈上皮，也得到了类似结果。另一方面，泌尿生殖窦来源的阴道上皮与子宫间充质结合后，形成了由分层鳞状阴道样上皮衬里的小囊肿。这种上皮从未表现出在角化和黏液化状态之间循环的迹象，而这在阴道上皮与阴道基质结合时通常可见。这些结果表明，上皮形成子宫的能力仅限于中胚层来源的上皮，并提示当与子宫基质相关时，内胚层来源的泌尿生殖窦阴道上皮无法响应发情周期的激素波动而进行典型的分化修饰。
