919 resultados para PROSTATE NEOPLASMS


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We have investigated epithelial cell proliferation and the rate of glandular recovery of the ventral prostate (VP) and seminal vesicle (SV) promoted by testosterone replacement (TR) in castration-induced regressed glands. Adult male Wistar rats were castrated and, after 21 days, they were treated with testosterone propionate (4 mg/kg/day). Intact (CT) and castrated rats without TR (CS) were also analysed. VP and SV were processed for histochemistry, morphometric-stereological analysis and immunocytochemistry to determine the PCNA index (PI). After 10 days of TR, the VP weight reached similar to 72% of the CT values, while the SV weight exceeded similar to 17% of the CT values. By the third day of TR, VP and SV presented a mean P1 of 34% and 94% for distal region and 14% and 22% for proximal region, respectively. SV also had more luminal cells PCNA-positive than VP, mainly in the distal region. The PI values fell on days 5, 7 and 10, but were still higher than CT. These findings indicate that epithelial cells from involuted SV are more responsive to TR than those from VP when Stimulated to proliferate and replace the luminal cell population, suggesting a different mechanism regulating cell proliferation in response to androgenic stimuli. (c) 2006 International Federation for Cell Biology. Published by Elsevier Ltd. All rights reserved.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Androgen deprivation causes the rat ventral prostate to reduce to 10% of its original size by 21 days after castration. The regressive changes result from the loss of epithelial cells by apoptosis and marked reorganization of the stroma. We have investigated whether these changes are accompanied by variations in heparanase expression. The ventral prostate of castrated rats was collected and processed for the quantification of heparan sulfate (HS), for the measurement of heparanase expression and its localization by reverse transcription/polymerase chain reaction, Western blotting, and immunohistochemistry, and for transmission electron microscopy (TEM). Absolute HS content decreased significantly as early as day 7 after surgery. Heparanase mRNA peaked 7 days after castration. The heparanase proenzyme (65 kDa) and the active form (50 kDa) were identified and peaked on day 7 after castration; this coincided with maximum HS-degrading activity. Heparanase was located to the basolateral surface of epithelial cells and in the adjacent stroma. After castration, staining for heparanase was reduced in the epithelium and increased in the stroma. TEM revealed that the peak of heparanase expression at day 7 after castration was associated with extensive changes in the basement membrane of the epithelium, endothelium and smooth muscle cells involving cell shrinkage and/or deletion by apoptosis. These results suggest that heparanase expression increases after castration and correlates with a decreased amount of HS. This variation in heparanase expression is involved in tissue remodeling and in the control of the regressive pattern after 1 week of androgen deprivation.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Prostate differentiation during embryogenesis and its further homeostatic state maintenance during adult life depend on androgens. Abundant biological data suggest that androgens play an important role in the development of the prostate cancer and other prostatic diseases. The objective of this work was to evaluate the effects of the testosterone supplementation in gerbil (a new experimental model) at different ages. Tissues from experimental animals were studied by histological and histochemistry procedures, androgen receptor immunohistochemistry assay, morphometric-stereological analysis, and transmission electron microscopy (TEM). After the treatment were observed increase of prostate weight and epithelium height in all ages studied. In some adult and aged treated animals, hyperplasic and displasic process were observed, including prostatic intraepithelial neoplasias and adenocarcinomas. Increase of the thickness of the smooth muscle cell (SMC) layer was observed in pubescent and adult animals and TEM revealed apparent SMC hypertrophy. An apparent increase in the frequency of blood vessels distributed by the subepithelial stroma in the treated animals was noticed. Reversion of the natural effects of aging on the prostate was observed in the aged treated animals in some acini of the gland. These data demonstrate that the gerbil prostate is susceptible to androgenic action at the studied ages and it can serve, for example, as experimental model to studies of prostate neoplasic process induction and hormonal therapy in aged animals.

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In this study, we evaluated the involvement of rat ventral prostate smooth muscle cells (SMC) in secretory activity and whether this function is modulated after castration. Cell morphology was examined at both light and electron microscopy levels and the organelles involved in secretory function were labeled by the zinc-iodide-osmium (ZIO) method at the ultrastructural level and their volume density was determined by stereology. Castration resulted in marked changes of the SMC, which adopted a spinous aspect and abandoned the layered arrangement observed in the prostates of non-castrated rats. The volume density of ZIO reactive organelles increased progressively after castration, reaching significantly higher levels 21 days after castration, Since previous studies have demonstrated that SMC express SMC markers (even 21 days after castration) and are able to respond to adrenergic stimulation, we concluded that differentiated SMC are able to shift from a predominantly contractile to a more synthetic phenotype without changing their differentiation status. (c) 2005 International Federation for Cell Biology. Published by Elsevier Ltd. All rights reserved.