Molecular biological analysis of ontogenetical expression of inhibin in horse testis.

采用形态学、组织化学、免疫组织化学、超微结构和分子生物学的方法检测了马睾丸的个体发生变化，并对抑制素α-、βA-、β b亚基的表达进行了研究。精子发生始于2岁的春天，精子发生活性随着年龄的增长而下降，直至9岁。马睾丸发育过程中最显著的特征是色素细胞的出现和消失。这些细胞最早出现在3日龄的小马体内，到1岁体积逐渐增大。细胞数量在2月龄时达到最大值，逐渐减少，3岁后完全消失。根据其组织化学和超微结构特征，色素细胞可能是巨噬细胞吞噬的胎儿型间质细胞。免疫组化结果显示，抑制素α-、βA-和β b亚基不仅存在于Lydig细胞中，也存在于Sertoli细胞中。Lydig细胞的阳性染色强度大于Sertoli细胞。原位杂交制备地高辛标记的互补RNA探针，检测抑制素α-、βA-和β b亚基的细胞内信使RNA。抑制素α-、βA-和β b亚基在间质细胞和精原上皮基底区检测到信号。虽然由于该方法的局限性，无法在精管基底区确定信号的确切定位，但很可能支持细胞具有最高的可能性。然而，我们不能排除精原细胞。在产前和产后阶段，甚至在成年马，这些结果基本上是相似的。结果表明，抑制素α-亚基和抑制素/激活素βA-亚基和β b亚基不仅在支持细胞中表达，而且在间质细胞中表达水平高于支持细胞。此外，本研究表明，间质细胞是马睾丸中抑制素和/或激活素的主要来源。抑制素和/或激活素可能通过自分泌和/或旁分泌的方式对睾丸功能起调节作用，但其具体作用尚不清楚。少

Ontogenetical changes of horse testis were examined morphologically, histochemically, immunohistochemically, ultractructurally and molecular biologically with special reference to expression of inhibin α-, βA-, βB-subunits.Spermatogenesis initiated in the spring of 2 years old, and spermatogeneic activity appeared to inverase with age up to 9 years old. The most characteristic feature during development of horse testis is the appearance and disappearance of pigmented cells. These cells first appeared in 3-day old colt and gradually increased in volume up to 1 year old. The number of cells reached maximum at 2 months old, graduelly decreased, and completely disappered after 3 years old. According to their histochemical and ultrastructural feature, the pigmented cells might be macrophages phagocytized fetal types of Leydig cells.Immunohistochemically, inhibin α-, βA- and βB-subunits were found not only in Lydig cells but also in Sertoli cells, respectively. But their intensities of posit … More ive stainings were more intense in Lydig cells than in Sertoli cells.For in-situ hybrldization, digoxigenin-labelled comprementary RNA probes were prepared to detect intracellular messenger RNAS of inhibinα-, βA- and βB-subunits. Signals for inhibin α-, βA- and βB-subunits were detected in Leydig cells and the basal region of seminiferous epithelium. Although exact localization of the signals were could not identified in the basal region of the seminiferous tubules due to the limitation of this method, it may well be that Sertoli cells have the highest possibility. However we could not excluded the spermatogonia. During prenatal and postnatal stages and even in adult horses, these seults are fundamentally similar. The present results suggested that inhibin α-subunit and inhibin/activin βA- and βB-subunits were expressed not only in Sertoli cells but also in Lydig cells, and the expression level was higer in Leydig cells than in Sertoli cells. Furthermore this study suggested that Leydig cells are the major source of inhibin and/or activin in horse testis. Inhibin and/or activin may play reguration role of testicular function by autocrine and/or paracrine manner, but they are not known in detail. Less