Hayward S W, Baskin L S, Haughney P C, Foster B A, Cunha A R, Dahiya R, Prins G S, Cunha G R
Department of Anatomy, University of California, School of Medicine, San Francisco 94143-0452, USA.
Acta Anat (Basel). 1996;155(2):94-103. doi: 10.1159/000147794.
The prostate and seminal vesicle (SV) are androgen-dependent secretory glands of the male genital tract. They produce the bulk of the seminal secretions. The object of the present study was to examine and document the ontogeny of stromal maturation in the rat anterior and ventral prostate and SV. These organs have a loosely organized cellular mesenchyme during fetal development. During prostatic development the mesenchyme condensed to form smooth muscle sheaths immediately surrounding the epithelium, with looser connective tissue between individual ducts. In the SV, a loose connective tissue layer called the lamina propria lies between the epithelium and developing muscle. Smooth muscle alpha-actin, myosin, desmin, laminin, vinculin, vimentin and androgen receptor (AR) expression were examined by immunocytochemical methods during the pre- and postnatal developmental periods. The first marker to be detected was vimentin, which was initially found throughout the mesenchyme. During development vimentin became mostly restricted to the interductal tissue of the prostate and the lamina propria of the SV. Smooth muscle markers were expressed in an orderly sequence in a proximal to distal manner along prostatic ducts, from the urethra towards the tips. Expression of alpha-actin was followed by vinculin, myosin, desmin, and laminin. These markers became localized to the developing smooth muscle sheaths and were not expressed in the interductal tissue of the prostate or the lamina propria of the SV. Organ culture experiments demonstrated that androgens were required for the differentiation of smooth muscle sheaths. Castration of adult rats demonstrated that androgens were required to maintain smooth muscle differentiation. In castrates, the stroma was relatively thicker but less dense than in intact animals. Following castration, expression of the smooth muscle markers was lost sequentially in the reverse order of their expression during development. In long-term castrates alpha-actin, vimentin and a small amount of vinculin were detected. AR were first detected in the urogenital sinus mesenchyme immediately surrounding the epithelium at 16 days of gestation. As development progressed expression of AR became more widespread, and postnatally was found throughout the mesenchyme. As maturation of smooth muscle occurred, stromal expression of AR became localized to the muscular sheath immediately surrounding the epithelium. In the prostate the interductal connective tissue displayed very low levels of AR expression. In the SV, AR were also observed in the lamina propria. In summary, stromal differentiation and dedifferentiation in the rat prostate and SV were found to be androgen-dependent processes with ordered sequential ontogenic expression of specific markers.
前列腺和精囊是男性生殖道中依赖雄激素的分泌腺。它们产生大部分精液分泌物。本研究的目的是检查并记录大鼠前列腺前叶和腹叶以及精囊中基质成熟的个体发生过程。在胎儿发育期间，这些器官具有组织松散的细胞间充质。在前列腺发育过程中，间充质浓缩形成紧邻上皮的平滑肌鞘，各导管之间有较疏松的结缔组织。在精囊中，上皮和发育中的肌肉之间有一层称为固有层的疏松结缔组织层。采用免疫细胞化学方法检测出生前和出生后发育阶段平滑肌α-肌动蛋白、肌球蛋白、结蛋白、层粘连蛋白、纽蛋白、波形蛋白和雄激素受体（AR）的表达。首先检测到的标志物是波形蛋白，最初在整个间充质中都能发现。在发育过程中，波形蛋白大多局限于前列腺的导管间组织和精囊的固有层。平滑肌标志物沿前列腺导管从尿道向尖端以近端到远端的方式按顺序表达。α-肌动蛋白表达后依次是纽蛋白、肌球蛋白、结蛋白和层粘连蛋白。这些标志物定位于发育中的平滑肌鞘，在前列腺的导管间组织或精囊的固有层中不表达。器官培养实验表明，雄激素是平滑肌鞘分化所必需的。成年大鼠去势表明，雄激素是维持平滑肌分化所必需的。在去势大鼠中，基质比完整动物相对更厚但密度更低。去势后，平滑肌标志物的表达按其在发育过程中表达的相反顺序依次丧失。在长期去势大鼠中可检测到α-肌动蛋白、波形蛋白和少量纽蛋白。AR在妊娠16天时首先在紧邻上皮的泌尿生殖窦间充质中被检测到。随着发育的进行，AR的表达变得更广泛，出生后在整个间充质中都能发现。随着平滑肌的成熟，AR的基质表达定位于紧邻上皮的肌鞘。在前列腺中，导管间结缔组织的AR表达水平非常低。在精囊中，固有层中也观察到AR。总之，发现大鼠前列腺和精囊中基质分化和去分化是依赖雄激素的过程，具有特定标志物的有序个体发生顺序表达。
