Castration induced changes in dog prostate gland associated with diminished activin and activin receptor expression

This study was conducted to evaluate the effect of androgen ablation on dog prostate gland structure and the proliferation capacity of the prostatic cells and their association with the expression of Activin A and Activin RIIA receptor. The effect of androgen on the prostate gland was compared in intact and castrated dogs after one and two weeks. Specific primary antibodies were used to immunolocalize activin-A, activin receptor type II A and the proliferation marker (PCNA). The results showed that the glandular acini of the prostate gland of intact dogs are lined by tall columnar secretory cells and less abundant flattened basal cells and surrounded by a thin fibromuscular tissue. The cytoplasm of the glandular cells exhibited an intense immunoreaction for activin A and activin RIIA receptor while basal cells expressed PCNA. Castration induced a remarkable atrophy of the prostatic acini associated with a progressive loss of secretory epithelial cells, which showed a dramatic decrease to complete disappearance of Activin A and Activin RIIA receptor immunoreactions. The remaining cells of the atrophied acini continue to express PCNA and the inter-acinar fibromuscular tissue showed a remarkable increase in its mass and are induced to express PCNA. These results indicated that androgen is required for the survival of epithelial cells and to maintain growth-quiescent fibromuscular cells, while basal cell proliferation is androgen independent. The changes in the Activin A and Activin RIIA receptor localization and their association with the dynamic pattern of prostate gland regression after castration suggested that Activin A and Activin RIIA receptor expression are androgen dependent.     

Epithelial-mesenchymal interactions in prostatic development. I. morphological observations of prostatic induction by urogenital sinus mesenchyme in epithelium of the adult rodent urinary bladder

Tissue recombinants of embryonic urogenital sinus mesenchyme (UGM) and epithelium of the urinary bladder (urothelium, BLE) of adult rats and mice were grown for 3-30 d in male syngeneic hosts. Short-term in vivo growth indicated that prostatic morphogenesis is initiated as focal outgrowths from the basal aspect of the adult urothelium. The solid epithelial buds elongate, branch, and subsequently canalize, forming prostatic acini. After 30 d of growth in the male hosts, prostatic acini exhibit secretory activity. The marked changes in urothelial morphology induced by the UGM are accompanied by the expression of fine- structural features indicative of secretory function (rough endoplasmic reticulum, Golgi apparatus, and secretory granules). During this process, urothelial cells express prostatic histochemical markers (alkaline phosphatase, nonspecific esterase, glycosaminoglycans) and prostate-specific antigens. The expression within BLE of prostatic characteristics is associated with the loss of urothelial characteristics. These data indicate that adult urothelial cells retain a responsiveness to embryonic mesenchymal inductors. Furthermore, mesenchyme-induced changes in urothelial cytodifferentiation appear to be coupled to changes in functional activity.     

Glyceraldehyde-3-phosphate dehydrogenase expression during apoptosis and proliferation of rat ventral prostate.

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is a multifunctional enzyme known to play a critical role in neuronal apoptosis. We undertook the current studies to determine whether GAPDH also plays a role in prostate epithelial cell apoptosis in response to androgen deprivation. To do so, we analyzed GAPDH staining by immunohistochemistry during castration-induced involution and androgen-induced regeneration of rat ventral prostate. We found that GAPDH was undetectable in secretory epithelial cells at baseline and that staining did not increase in the epithelium during the period of peak apoptosis from 1 to 3 days after castration. However, GAPDH levels did increase within nuclei of some basal epithelial cells 5 days after castration and within the cytoplasm of all secretory epithelial cells 7 days after castration. GAPDH was also abundant within the cytoplasm of secretory epithelial cells during the period of maximal cell proliferation from 2 to 3 days after androgen replacement and was clearly apparent within nuclei of some epithelial cells 4 days after androgen replacement. Our studies suggest that GAPDH plays multiple roles during prostate epithelial cell apoptosis and proliferation.     

The ultrastructure of the accessory sex organs of the male rat

Summary The fine structure of the nuclei of epithelial cells of the dorsal lobe of the rat prostate were studied 2, 3, 5, 7 and 21 days after castration. The nucleolus appears to undergo a progressive disorganisation with partial fragmentation and dispersion of its normal components.Changes in the nucleoplasm were primarily reflected by a condensation of chromatin, particularly along the nuclear membrane and adjacent to the nucleolus. Later, different types of intranuclear inclusions were observed.After 21 days, the nuclei were characterized by an irregular outline with large indentation. Within the nucleoplasm aggregates of coarse granular chromatin were found. No cell necrosis was observed, indicating that androgen deprivation results in a remodeling of the cell to a less active state with marked cellular alterations and cessation of secretion, but apparently with some of their basic functions still intact.Injections of testosterone completely reverse the castrated-induced alterations.The changes observed are assumed to be due to the withdrawal of the androgenic stimulus, with a direct influence on the secretory function of the cell. The findings support the view that the stimulating secretory effect of androgen is mediated via an intranuclear androgen receptor, probably located in the nucleolus-associated-chromatin. It is also proposed that the secretory function of the epithelial cells of the prostatic complex, initiated by androgens, may be regulated by an intranuclear secretory center.     

Histology,ultrastructure, and seasonal variations in the bulbourethral gland of the African straw-colored fruit bat Eidolon helvum

We studied the morphological characteristics and seasonal changes of the bulbourethral gland of Eidolon helvum in a typical African tropical environment. Forty-eight bulbourethral glands were examined using gross anatomical, histological, histochemical, and ultrastructural techniques during the early rainy, late rainy, and peak dry seasons. The pear-shaped bilateral bulbourethral glands were located extra-abdominally in the inguinal region. Trabeculae from the capsule divided the parenchyma into numerous lobules of tubuloalveolar glandular acini. The mucosa was covered by a simple columnar epithelium consisting up of principal secretory cells, columnar dense cells and basal cells, which were progressively pronounced during the dry season. The principal cells contained eosinophilic granules, which were PAS positive while the dense cells did not show affinity for the stains. The mean gross weights, acini diameters, and epithelial heights were greater during the rainy season than the dry season. Ultrastructural evaluation showed that the cytoplasm of the principal cells contained well-developed Golgi complexes, rough endoplasmic reticulum, mitochondria, and secretory vesicles of varying electron densities and sizes. The secretory vesicles were numerous during the early rainy season, decreased during the late rainy season and were scanty during the peak dry season. The simple columnar epithelium observed during the rainy season was replaced by an undefined stratified epithelium during the dry season, and this was associated with cellular degenerations and regenerations. In conclusion, E. helvum has a typical mammalian bulbourethral gland, with a unique cell type, the dense cell whose functions are not well-understood. The gland exhibits cyclical seasonal variation in structure and secretory activity; being active during the early rainy season (breeding season), and showing the lowest activity during the dry season (non-breeding season). Glandular epithelial cell renewal occurs during the dry season in preparation for the next breeding season.     

Different patterns of filipin-sterol labeling in prostate nuclear membranes from normal and castrated rats

Filipin was used as cytochemical probe for sterol detection in freeze-fractured prostate nuclear membranes from rats under different hormonal conditions. Isolated prostate acini and nuclei were fixed in glutaraldehyde and post-treated with filipin, according to Robinson and Karnovsky (1980). In general, most plasma and intracellular cytoplasmic membranes displayed a marked response to filipin in either epithelial and stromal cells from normal and castrated animals. Nuclear membranes from epithelial secretory cells were systematically negative to filipin labeling in normal animals, although after castration a positive response was detected. Stromal nuclear membranes were labeled both in normal and castrated animals. Filipin-treated isolated nuclei displayed the same overall labeling pattern but there was a different distribution of induced deformations relative to intact cell nuclei. These observations indicate that: a) nuclear membranes from different cell types have different responses to filipin; b) a change in the molecular organization of nuclear membranes from prostate secretory cells follow castration; c) nuclei isolation affects the distribution of filipin induced deformations on the membranes.     

TGF-β1 induces an age-dependent inflammation of nerve ganglia and fibroplasia in the prostate gland stroma of a novel transgenic mouse

TGF-β1 is overexpressed in wound repair and in most proliferative disorders including benign prostatic hyperplasia and prostate cancer. The stromal microenvironment at these sites is reactive and typified by altered phenotype, matrix deposition, inflammatory responses, and alterations in nerve density and biology. TGF-β1 is known to modulate several stromal responses; however there are few transgenic models to study its integrated biology. To address the actions of TGF-β1 in prostate disorders, we targeted expression of an epitope tagged and constitutively active TGF-β1 via the enhanced probasin promoter to the murine prostate gland epithelium. Transgenic mice developed age-dependent lesions leading to severe, yet focal attenuation of epithelium, and a discontinuous basal lamina. These changes were associated with elevated fibroplasia and frequency of collagenous micronodules in collapsed acini, along with an induced inflammation in nerve ganglia and small vessels. Elevated recruitment of CD115+ myeloid cells but not mature macrophages was observed in nerve ganglia, also in an age-dependent manner. Similar phenotypic changes were observed using a human prostate epithelium tissue recombination xenograft model, where epithelial cells engineered to overexpress TGF-β1 induced fibrosis and altered matrix deposition concurrent with inflammation in the stromal compartment. Together, these data suggest that elevated TGF-β1 expression induces a fibroplasia stromal response associated with breach of epithelial wall structure and inflammatory involvement of nerve ganglia and vessels. The novel findings of ganglia and vessel inflammation associated with formation of collagenous micronodules in collapsed acini is important as each of these are observed in human prostate carcinoma and may play a role in disease progression.     

Secretory cell activity in the hamster seminal vesicle following castration. A morphometric ultrastructural study

The ultrastructure of hamster seminal vesicle epithelium was studied 7, 14, 21 and 28 days after castration using a stereological approach. The results show that castration promotes epithelial reorganization, mainly characterized by reduced epithelial cell size and number, decreased rough endoplasmic reticulum and Golgi complex, increased lysosomes and lipid droplets, increased apical secretory granule size and number, and increased intracellular secretory products per average epithelial cell. It is concluded that after testosterone withdrawal the secretory activity of hamster seminal vesicle epithelial cells, although reduced, is not abolished, and that exocytosis is relatively more reduced than secretory protein production. We suggest that an extracellular androgen source is responsible for secretory activity not being lost in the epithelial cells of castrated hamster seminal vesicle.     

Epithelial-stromal transition of MMP-7 immunolocalization in the rat ventral prostate following bilateral orchiectomy

Epithelial cells from involuting rat ventral prostate (VP) express Matrilysin (MMP-7) mRNA. Herein, we investigated by immunohistochemistry the MMP-7 protein location and its association with tissue changes following castration in the VP. Normal and castrated adult male Wistar rats were sacrificed at different times after surgery. VP was examined by immunocytochemistry and immunoprecipitation. Castration promoted a shrinking of prostate ducts with an extensive stromal remodeling. In the VP from normal rats, MMP-7 immunoreactivity was found in epithelial secretory granules. Three days after castration, immunostaining for MMP-7 was found in both the epithelial secretory granules and in the stroma just below the epithelium, mainly at the distal ductal tips. At seven and 21 days after castration, the immunostaining for MMP-7 was found only in the stromal space. Immunoprecipitation confirmed the specificity of the primary antibody by rescuing a pro-enzyme form (28kDa) in the prostate extracts. The present results suggest that MMP-7 participates in the epithelial-stromal interface remodeling of the ventral prostate during the involution achieved by castration, probably in the degradation of components of the epithelial basement membrane.     

Blockage of cell-to-cell communication within pancreatic acini is associated with increased basal release of amylase

To assess whether junctional coupling is involved in the secretory activity of pancreatic acinar cells, dispersed rat acini were incubated for 30 min in the presence of either heptanol (3.5 mM) or octanol (1.0 mM). Exposure to either alkanol caused a marked uncoupling of the acinar cells which, in control acini, were extensively coupled. Uncoupling was associated with an increased basal release of amylase that was at least twice that of controls. By contrast, carbamylcholine (10(-5) M)-induced maximal amylase secretion, cytosolic pH, and free Ca2+, as well as the structure of gap junctions joining the acinar cells, were unaffected. Both uncoupling and the alteration of basal secretion were already observed after only 5 min of exposure to heptanol, they both persisted throughout the 30-min exposure to the alkanols, and were reversible after removal of either heptanol or octanol. Since neither of the two uncouplers appeared to alter unspecifically the secretory machinery and the nonjunctional membrane of acinar cells, the data are consistent with the view that junctional coupling participates in the control of the basal secretion of acinar cells.     

Histogenesis and morphogenesis of epidermoid metaplasia in hamster tracheal organ explant culture

The formation of epidermoid metaplasia was studied in hamster tracheal epithelium in long-term serum-free organ explant culture. Explants were cultured up to 5 weeks in CMRL 1066 with antibiotics and amphotericin B. At 3 weeks there were rare small foci of epidermoid metaplasia and they became larger and more numerous at 4 and 5 weeks. Three dimensional reconstructions from serial sections demonstrated that the small deep-seated foci were discrete and did not reach the epithelial surface, whereas the larger foci were expansive and involved the full thickness of the explant epithelium. Each small focus consisted of a few swollen electron-lucent basal cells attached to the basal lamina, covered by a layer of flattened electron-dense secretory cells which formed a tight-fitting cap over the basal cells. The altered secretory cells displayed moderately well-developed rough endoplasmic reticulum and tonofilament bundles. During the early stages of formation the deep-seated metaplastic foci were completely covered by a layer of normal appearing cuboidal to low-columnar secretory and ciliated cells. Expansion of the metaplastic foci occurred by addition of flattened, electron-dense secretory cells to the cap so that multiple layers of altered secretory cells covered a core of basal cells, analogous to the structure of an onion. The secretory cells became cornified and with time the foci broke through the columnar mucociliary surface layer. In well-advanced foci, the uppermost cornified squames (metaplastic secretory cells) exfoliated into the tracheal lumen. The study emphasizes similarities and differences between the morphogenesis and histogenesis of epidermoid metaplasia in vivo and in vitro.(ABSTRACT TRUNCATED AT 250 WORDS)     

The development of the guinea pig gallbladder epithelial cells. II. Electron microscopical and enzymhistochemical investigations (author's transl)]

The development of the guinea pig gallbladder epithelium follows a distinct time schedule. During the first phase (up to 30th day of intrauterine life) the epithelial cells increase in number. They remain small and undifferentiated. In the second phase, from the 30th to the 44th day, cytodifferentiation is a dominating feature. The epithelial cells increase in height, the nuclei become more basal, the cells acquire their final zonal structure and the cell organelles exhibit their characteeristic appearance. Weak enzyme activities can be observed. In the third phase, from the 45th day until birth, there is functional differentiation and the adult pattern of enzyme distribution is established. Glycogen appears first on day 29, increases in amount and then disappears by day 57. There is a marked development of the Golgi apparatus associated with increased synthesis of secretory material. Between the 59th embryonic day and the 6th day of life mucoid cells with different functional states appear in the gallbladder epithelium. Later on these cells can be visualized only in the depths of the invaginations. After birth the epithelial cells become more columnar and by 10 days after birth the adult appearance of the epithelium is fully established.     

Ultrastructure of bovine parotid glands

Bovine parotid glands exhibit outstanding structural differences when compared with those of non-ruminant mammals. The acini are tortuous, branched and lined with cells of different heights, imparting a scalloped appearance to acinar lumina. Numerous microvilli, ca. 1.5 μ in length, extend into the lumina and intercellular canaliculi. Intercellular canaliculi measure ca. 3 μ in diameter and interweave in close association with intercellular tissue spaces. Intercellular tissue spaces are separated from the extraacinar spaces across a basal lamina only, whereas junctional complexes guard canaliculi from direct continuity with tissue spaces and/or extraacinar spaces. Flattened cytoplasmic lamellae extend from adjacent acinar cells and loosely interdigitate with one another across the tissue spaces. Acinar cells contain more mitochondria and less granular endoplasmic reticulum than parotid glands of non-ruminant mammals. Two types of secretory material, in the form of inclusions which vary in size and electron density, are present in the acinar cells. Intercalated ducts connect acini with striated ducts which in turn, empty into collecting ducts located between gland lobules. In terms of frequency of “basal infoldings” and numbers of mitochondria, striated ducts of calf parotid glands are not as well developed as those of certain other salivary glands. Myoepithelial cells are most often present at junctions of acini and intercalated ducts where they may attach to both acinar and ductal epithelium. Nerve “terminals” were not observed on the epithelial side of basement membranes in relation to the secretory cells.     

Differentiation of the golden hamster oviduct epithelial cells during postnatal development: an electron microscopic study

The ultrastructural changes in the process of differentiation of the epithelial cells of the golden hamster oviduct during postnatal development were investigated by means of electron microscopy. In the epithelium of the ampulla of the neonatal oviducts, no differentiated ciliated cells or secretory cells were identified. In these undifferentiated cells, free ribosomes were well developed, but rough endoplasmic reticulum (RER) and the Golgi apparatus were undeveloped. Cells undergoing ciliogenesis were first identified at 3.5 days after birth, and some ciliated cells appeared at 4.5 days. In the nonciliated cells, marked changes in the organelles were observed at this time. Subsequently, some nonciliated cells containing well-developed RER and Golgi apparatus were observed at 9.5 to 10.5 days after birth, and a few mature secretory cells were observed at 10.5 days. An increase in secretory granules occurred in the secretory cells at 12.5-15.5 days after birth. Many fully mature ciliated and secretory cells were observed at 15.5 days after birth. After 20.5 days after birth, the epithelium was identical with that of the adult golden hamster. Quantitative data indicated that the differentiation of ciliated cells began earlier and took place over a more extended period of time than did that of the secretory cells in the golden hamster oviduct during postnatal development.     

Scanning electron microscopy of isolated epithelium of the murine gastrointestinal tract: morphology of the basal surface and evidence for paracrinelike cells

By using the method of Bjerknes and Cheng, isolated murine gastrointestinal epithelial sheets were prepared for scanning electron microscopy. Examination of isolated epithelium from fundic stomach revealed numerous branched gastric glands. Parietal cells were easily detected bulging from the basal surface of the glandular epithelium. The basal surface membrane of parietal cells appeared smooth, with only sparse microvilluslike projections, whereas adjacent glandular cells had numerous 1- to 2-micron fingerlike projections which interdigitated laterally with similar processes from adjacent cells. Occasionally, paracrinelike cells having long cytoplasmic processes ranging from 10 to 20 micron in length were observed on the basal epithelial surface of the stomach and the colon, but not the small intestine. In isolated intestinal epithelia, the basal surface of crypt epithelial cells showed extensive cytoplasmic interdigitations, but no distinct morphology permitting recognition of individual cell types. Various stages of intestinal crypt bifurcation were seen. Craterlike spaces in the basal surface of crypt epithelium, presumably due to migrating leukocytes, were also numerous. Examination of the luminal surface of the isolated intestinal epithelium revealed that intimate associations between epithelium and mucosal-associated microorganisms were maintained, thus suggesting that minimal alterations in surface morphology were incurred by epithelial isolation. These observations on epithelial structure suggest that isolated gastrointestinal epithelia may be well suited for physiological studies of epithelial function and interactions with the microbial flora.     

Par-1b is required for morphogenesis and differentiation of myoepithelial cells during salivary gland development

The salivary epithelium initiates as a solid mass of epithelial cells that are organized into a primary bud that undergoes morphogenesis and differentiation to yield bilayered acini consisting of interior secretory acinar cells that are surrounded by contractile myoepithelial cells in mature salivary glands. How the primary bud transitions into acini has not been previously documented. We document here that the outer epithelial cells subsequently undergo a vertical compression as they express smooth muscle α-actin and differentiate into myoepithelial cells. The outermost layer of polarized epithelial cells assemble and organize the basal deposition of basement membrane, which requires basal positioning of the polarity protein, Par-1b. Whether Par-1b is required for the vertical compression and differentiation of the myoepithelial cells is unknown. Following manipulation of Par-1b in salivary gland organ explants, Par-1b-inhibited explants showed both a reduced vertical compression of differentiating myoepithelial cells and reduced levels of smooth muscle α-actin. Rac1 knockdown and inhibition of Rac GTPase function also inhibited branching morphogenesis. Since Rac regulates cellular morphology, we investigated a contribution for Rac in myoepithelial cell differentiation. Inhibition of Rac GTPase activity showed a similar reduction in vertical compression and smooth muscle α-actin levels while decreasing the levels of Par-1b protein and altering its basal localization in the outer cells. Inhibition of ROCK, which is required for basal positioning of Par-1b, resulted in mislocalization of Par-1b and loss of vertical cellular compression, but did not significantly alter levels of smooth muscle α-actin in these cells. Overexpression of Par-1b in the presence of Rac inhibition restored basement membrane protein levels and localization. Our results indicate that the basal localization of Par-1b in the outer epithelial cells is required for myoepithelial cell compression, and Par-1b is required for myoepithelial differentiation, regardless of its localization.     

Fine structure of the seminal vesicle epithelium of the mouse and golden hamster

The seminal vesicle epithelium of the mouse and golden hamster was examined by light microscopy and by transmission and scanning electron microscopy. By transmission electron microscopy, in the seminal vesicle epithelium of both animals secretory epithelial cells which consisted of mostly light and a few dark cells were observed. The epithelial cells possessed secretory granules which contained a densely stained core. The secretory granules in the mouse epithelium reacted weakly with periodic acid-Schiff (PAS) stain and were slightly stained with alcian blue (AB), and those in the golden hamster exhibited strongly positive reactions with PAS and AB. The nuclei in the mouse tissue were spherical or ovoid, and those in the golden hamster tissue had a few lobes. By scanning electron microscopy, the apical surfaces of most of the epithelial cells were commonly flat or domed, and those of some epithelial cells protruded into the lumen as apocrine-like processes, or possessed small and large orifices. Besides the epithelial cells, there were cells characterized by pseudopodium-like cytoplasmic projections, a few membranous structures, an irregular nucleus, and cytoplasm containing a few dense bodies, in the basal portions of the epithelial cells, or between the basal lamina and the epithelial cells. These cells of the two species were similar in their features.     

Fine structure of the midgut of Sinopanorpa tincta (Navás) (Mecoptera: Panorpidae)

Fine structure of the midgut and degeneration of the midgut epithelium of the scorpionfly Sinopanorpa tincta (Navás) adults were investigated using light microscopy and scanning and transmission electron microscopy. The results show that the tubular midgut lacks gastric caeca and is composed of an outer longitudinal and an inner circular muscle layer, a basal lamina, an epithelium and a lumen from the outside to inside. A peritrophic membrane was not found in the lumen. A mass of nodules was observed on the surface of the basal lamina. Three types of cells were recognized in the epithelium: digestive, secretory, and regenerative cells. The digestive cells contain irregular-shaped infoldings in the basal membrane and two types of microvilli in the apical membrane. The secretory cells are characterized by irregular shape and large quantities of secretory granules in the basal cytoplasm. The regenerative cells are triangular in shape and distributed only in the nodules. The epithelial cells are degenerated through programmed cell-death mechanisms (apoptosis and necrosis). The type, function, and degeneration of the epithelial cells of the midgut are briefly discussed.     

Rat endometrial stromal-epithelial response to estrogen infusion

Morphologic changes at the interface of rat endometrial luminal epithelial cells and the stromal cells immediately adjacent were examined and correlated with hypertrophy of the epithelial cells during estradiol (E2) infusion (1 microgram E2/24 h). While the lamina densa in castrate endometrium was thread-like, it became thicker and apparently more granular in some areas below the luminal epithelium during E2 infusion. However, no changes were seen in the intensity of laminin-like immunoreactivity at various time points up to 96 hours after beginning infusion, suggesting that these alterations were due to changes in nonlaminin components. The stromal cells adjacent to the basal lamina in the castrate state had cell processes extending toward the epithelium that terminated on the basal lamina. Under estrogen infusion, stromal cell bodies migrated close to and became oriented along the basal lamina. No interruptions were seen in the lamina densa or in the laminin-like immunoreactivity in the basal lamina. Thus, there were no direct morphologic interactions between epithelial and stromal cells induced by estrogen. Some of the stromal cells developed a dilated rough endoplasmic reticulum and some developed multiple elaborate processes within 41 hours after minipump implantation. Within 28 hours, nuclear hypertrophy had occurred in 15% of the epithelial cell layer. If interactions occur between stromal and epithelial cells, and morphologic evidence presented here suggests they do, then all such interactions are through an intact lamina densa-laminin layer, and any chemical mediators affecting cells on opposite sides of the lamina densa must migrate through it.