Postnatal development of the tubular lamina propria and the intertubular tissue in the bovine testis

Abstract

The postnatal development of intertubular cells and vessels and of the tubular lamina propria was studied in three locations of perfusion-fixed bovine testes from 31 animals ranging from 4 to 78 weeks. The postnatal morphological differentiation of the testis is not uniform, regional differences have to be considered. The intertubular cell population is composed of mesenchyme-like cells, fibrocytes, Leydig cells, peritubular cells and mononuclear cells. In 4- and 8-week-old testes mesenchyme-like cells are the dominating element. These pluripotent cells proliferate by frequent mitoses and are the precursors of Leydig cells, contractile peritubular cells and fibrocytes. Morphologically differentiated Leydig cells are encountered throughout the entire period of postnatal development. In 4-week-old testes degenerating fetal and newly formed postnatal Leydig cells are seen in juxtaposition to each other. From the 8th week on, only postnatal Leydig cells are present. Between 16 and 30 weeks large-scale degeneration of prepuberal Leydig cells is observed. The Leydig cells that survive this degenerative phase constitute the long-lasting adult population. 20-30% (numerically) of all intertubular cells at all ages are free mononuclear cells. These are found as lymphocytes, plasma cells, monocytes, macrophages and light intercalated cells (LIC). The latter are monocyte-derived, Leydig cell-associated typical cells of the bovine testis. The differentiation of the two main components of the tubular lamina propria, (i) basal lamina and (ii) peritubular cell sheath, seems to be effected rather independent from each other and also from hormonal signals important for the development of the germinal cells. The laminated basal lamina reaches nearly 3 micron at 16 weeks and is later on continuously reduced. At 25 weeks the peritubular cells have transformed into contractile myofibroblasts. At this period the germinal epithelium is still in a prepuberal state.

Immunohistochemistry of the cytoskeleton in the excurrent ducts of the testis in birds of the Galloanserae monophyly

“…Coexpression of MF and IF systems occurs in all birds, to varying degrees and combinations, in the epithelium of the ED unit (actin and vimentin in the quail; actin, desmin, vimentin and cytokeratin in the domestic fowl; actin, vimentin and cytokeratin in the turkey; and actin and desmin in the duck). These observations on variations in IF immunoexpression are in consonance with similar observations made in myoid cell populations in the testicular capsule in mammals (Leeson and Forman 1981;Wrobel et al 1979Wrobel et al , 1988Maekawa et al 1996). The variations are considered not only to reflect species-specific differences in the degree of differentiation of the cells from fibroblasts to smooth muscle cells in the myoid layer of cells, but also to be a reflection of the finding that the smooth muscle cell is a heterogeneous cell that expresses both contractile and synthetic activities at opposite poles of the spectrum (Banks et al 2006).…”

Quantitative Aspects of Water Buffalo (Bubalus bubalis) Spermatogenesis.

“…Immediately after slaughter in Assiut (Egypt) abattoir, the testes were removed and fixed by vascular perfusion via the straight intratunical portion of the testicular artery. Following a rinsing procedure, the fixatives I and II of FORSSMANN et al (1977) were instilled at low, steady pressure (for details see WROBEL et al, 1978WROBEL et al, , 1988. Small blocks from seminiferous parenchyma were postfixed in solution II for 3-5h, washed in 0.2M phosphate buffer, osmicated (1% Os 04), dehydrated in a graded series of ethanol and embedded in ERL (SPURR, 1969).…”

Peritubular Myoid Cells in the Testis: Their Structure and Function.

“…Comparative studies on the organizations of the interstitial tissue have classified three or four patterns according to the occupied space of lymphatics, blood capillaries, Leydig cells and connective tissue cells (FAWCETT, 1973;FAWCETT et al, 1973). The postnatal development of the boundary tissue of the seminiferous tubule has been investigated in the mouse (Ross, 1967), rat (LEESON and LEESON, 1963;KORMANO and HOVATTA, 1972;PALOMBI et al, 1992), sheep (BUSTOS-OBREGON and COUROT, 1974), rabbit (LEESON and FORMAN, 1981), and bull (WROBEL et al, 1988).…”

“…However, STEGER et al (1994) have demonstrated that the myoid cells of the bull and ram do not contain desmin, but instead show vimentin, which is abundant in fibroblasts. These results might reflect species-specific differences in the degree of differentiation from fibroblasts to smooth muscle cells in the myoid cell population (BUSTOS-OBREGON and COUROT,1974;LEESON and FORMAN 1981;WROBEL et al, 1979WROBEL et al, , 1988. DAVIDOFF et al (1990) have reported that the inner three to four cellular layers in the lamina propria of the human seminiferous tubule show immunoreactivity for both desmin and vimentin, whereas the outermost one or two cellular layers have immunoreactivity only for vimentin.…”