Effects of a phthalate metabolite mixture on both normal and tumoral human prostate cells.

Phthalates represent a group of substances used in industry that have antiandrogenic activity and are found in different concentrations in human urine and plasma. More than 8 million tons of phthalates are used each year, predominantly as plasticizers in polyvinyl chloride (PVC) products. Phthalates are widely used in everyday consumer products and improperly discarded into the environment. Furthermore, in vivo studies carried out in our laboratory showed that a mixture of phthalates, equivalent to the mixture used in this study, deregulated the expression of genes and miRNAs associated with prostatic carcinogenic pathways. Thus, this study was designed to establish an in vitro model to assess pathways related to cell survival, proliferation, apoptosis, and biosynthesis of miRNAs, using both normal and tumoral prostatic epithelial cells exposed to an environmentally relevant mixture of phthalate metabolites. Tumor (LNCaP) and normal (PNT-2) prostatic epithelial cell lines were exposed for 24 and 72 h to vehicle control or the phthalate mixture. The selected metabolite mixture (1000 µmol/L) consisted of 36.7% monoethyl phthalate (MEP), 19.4% mono(2-ethylhexyl) phthalate (MEHP), 15.3% monobutyl phthalate (MBP), 10.2% monoisobutyl phthalate (MiBP), 10.2% monoisononyl phthalate (MiNP), and 8.2% monobenzyl phthalate (MBzP). Gene expression was performed by qRT-PCR and cell migratory potential was measured using cell migration assays. Our results showed that the mixture of phthalates increased cell turnover, oxidative stress, biosynthesis, and expression of miRNAs in LNCaP cells; thus, increasing their cellular expansive and migratory potential and modulating tumor behavior, making them possibly more aggressive. However, these effects were less pronounced in benign cells, demonstrating that, in the short term, benign cells are able to develop effective mechanisms or more resistance against the insult.

Modulation of inflammatory and hormonal parameters in response to testosterone therapy: Effects on the ventral prostate of adult rats.

Testosterone is often recommended in the treatment of several aging-related conditions. However, there are still questions about the consequences of this therapy in terms of hormonal and inflammatory parameters that are crucial for prostate homeostasis. Thus, we investigate if the testosterone therapy (TT) modulates the hormone receptors and inflammatory cytokines in the ventral prostate of adult rats. Wistar rats aging 150 days were divided into two experimental groups (n = 10/group): T: received subcutaneous injections of testosterone cypionate (5 mg/kg body weight) diluted in corn oil every other day for 4 weeks; and C: received corn oil as vehicle. Animals were euthanized at 180 days old by decapitation. Blood was collected to obtain hormone and cytokines concentrations. The ventral prostate was dissected and processed for light microscope and molecular analyses. Relative ventral prostate weight and epithelial compartment were increased after TT. The number of intact and degranulated mast cells was reduced in the T group. Plasma testosterone, DHT and intraprostatic testosterone concentrations were higher in the T group. TT leads to an increase in cell proliferation and up-regulation of AR, ERß, PAR-4, and NRF2. Importantly, plasma concentration and tissue expression of IL-10 and TNF-α were higher after TT. In summary, these results indicate that TT can regulate inflammatory response, with impacts in cytokines and mast cell population, and modulates steroids receptors, important parameters for prostatic homeostasis.

Can resveratrol attenuate testicular damage in neonatal and adult rats exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin during gestation?

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is considered one of the most toxic dioxins. The effects of TCDD are exerted via binding to the aryl hydrocarbon receptor (AhR). The aim of the present study was to evaluate the possible protective effects of resveratrol, an AhR antagonist, against testicular damage caused by TCDD exposure during pregnancy. Pregnant female Sprague-Dawley rats were divided into four groups: a control group; a group treated with 1µgkg-1, p.o., TCDD on Gestational Day (GD) 15; a group treated with 20µgkg-1, p.o., resveratrol on GD10-21; and a group treated with both TCDD and resveratrol. Rats were weighed and killed, and neonatal testes were collected for histopathological analysis on Postnatal Day (PND) 1. At PND90, adult male rats were killed and the testes collected for histopathological analysis and determination of sperm count. Resveratrol had a protective effect against the effects of TCDD on Sertoli cell number in adult and neonate testes, as well as against the effects of TCDD on abnormal seminiferous tubules in adults. Combined administration of TCDD and resveratrol altered the kinetics of spermatogenesis and the proportion of neonatal testicular compartments compared with the control group In addition, combined TCDD and resveratrol treatment decreased seminiferous tubule diameter in adult male rats compared with the control group. In conclusion, resveratrol may protect against some TCDD-induced testicular damage, but, based on the parameters assessed, the administration of resveratrol and TCDD in combination may result in more severe toxicity than administration of either drug alone.

Dual action of high estradiol doses on MNU-induced prostate neoplasms in a rodent model with high serum testosterone: Protective effect and emergence of unstable epithelial microenvironment.

BACKGROUND: Estrogens are critical players in prostate growth and disease. Estrogen therapy has been the standard treatment for advanced prostate cancer for several decades; however, it has currently been replaced by alternative anti-androgenic therapies. Additionally, studies of its action on prostate biology, resulting from an association between carcinogens and estrogen, at different stages of life are scarce or inconclusive about its protective and beneficial role on induced-carcinogenesis. Thus, the aim of this study was to determine whether estradiol exerts a protective and/or stimulatory role on N-methyl-N-nitrosurea-induced prostate neoplasms. METHODS: We adopted a rodent model that has been used to study induced-prostate carcinogenesis: the Mongolian gerbil. We investigated the occurrence of neoplasms, karyometric patterns, androgen and estrogen receptors, basal cells, and global methylation status in ventral and dorsolateral prostate tissues. RESULTS: Histopathological analysis showed that estrogen was able to slow tumor growth in both lobes after prolonged treatment. However, a true neoplastic regression was observed only in the dorsolateral prostate. In addition to the protective effects against neoplastic progression, estrogen treatment resulted in an epithelium that exhibited features distinctive from a normal prostate, including increased androgen-insensitive basal cells, high androgens and estrogen receptor positivity, and changes in DNA methylation patterns. CONCLUSIONS: Estrogen was able to slow tumor growth, but the epithelium exhibited features distinct from a normal prostatic epithelium, and this unstable microenvironment could trigger lesion recurrence over time.

Impact of maternal and postnatal zinc dietary status on the prostate of pubescent and adult rats.

Zinc is important for cell physiology and alteration of its levels during development can modulate a series of biological events. The aim of this study was to investigate whether dietary zinc deficiency or supplementation during morphogenesis and early postnatal development could interfere in prostate maturation. Pregnant rats were exposed to a standard diet (NZ:35 mg Zn/kg chow), low-zinc diet (LZ:3 mg of Zn/kg chow) and zinc-supplemented diet (HZ:180 mg/Kg chow) from gestational day 10 (GD10) through postnatal day 21 (PND21). After weaning, male offspring were divided into three groups that were submitted to the same food conditions as their mothers until PND53. The animals were euthanized at PND53 and PND115. The ventral prostate was removed, weighed and its fragments were subjected to histological, western blot and zymography analysis. PND53: body and prostate weight were lower in LZ compared to NZ; the epithelial compartment was reduced while the stromal compartment was increased in LZ compared to NZ; there was an increase in the amount of collagen and reduction in AR and SIRT1 expression in LZ compared to NZ. PND115: body weight was lower in LZ compared to NZ and prostate weight was similar among the groups; peripheral physiological hyperplasia was observed, as well as an increased epithelial proliferation index and reduced PAR4 expression in LZ and HZ compared to NZ. Zinc deficiency during prostate morphogenesis and differentiation is potentially harmful to its morphology, however, by restoring the standard dietary environment, the gland responds to the new microenvironment independent of the previous dietary condition.

Long-term effects of perinatal exposure to low doses of cadmium on the prostate of adult male rats.

Developmental toxicity caused by environmental exposure to heavy metals during the perinatal period has raised questions about offspring health. Cadmium (Cd) is an endocrine-disrupting chemical with the potential to interfere with morphogenesis and susceptibility to diseases in reproductive organs. Taking into account that in the rat prostate morphogenesis occurs during the perinatal period, and that pregnant females absorb and retain more dietary Cd than their non-pregnant counterparts, it is important to understand the effects of perinatal Cd exposure on the adult rat prostate. Therefore this study investigated the effects of gestational and lactational Cd exposure on adult offspring rat prostate histopathology. Pregnant rats (n = 20) were divided into two groups: Control (treated with aqueous solution of sodium acetate 10 mg/l) and treated (treated with aqueous solution of cadmium acetate 10 mg/l) administered in the drinking water. After weaning, male offspring from different litters (n = 10) received food and water 'ad libitum'. The animals were euthanized at postnatal day 90 (PND90), the ventral prostates (VPs) were removed, weighed and examined histopathologically. Blood was collected for the measurement of testosterone (T) levels. Immunohistochemistry for androgen receptor (AR) and Ki67, and a TUNEL assay were performed. There were no differences in T levels, cell proliferation and apoptosis indexes, or AR immunostaining between the experimental groups. Stromal inflammatory foci and multifocal inflammation increased significantly in the treated group. These changes were associated with inflammatory reactive epithelial atypia and stromal fibrillar rearrangement. In conclusion, VP was permanently affected by perinatal Cd exposition, with increased incidence of inflammatory disorders with ageing.

Gestational and lactational exposition to Di-N-butyl-phthalate (DBP) increases inflammation and preneoplastic lesions in prostate of wistar rats after carcinogenic N-methyl-N-nitrosourea (MNU) plus testosterone protocol.

In the present study, it was evaluated the susceptibility of prostatic lesions in male adult rats exposed to Di-N-butyl-phthalate during fetal and lactational periods and submitted to MNU plus testosterone carcinogenesis protocol. Pregnant females were distributed into four experimental groups: CN (negative control); CMNU (MNU control); TDBP100 (100 mg/kg of DBP); TDBP500 (500 mg/kg of DBP). Females from the TDBP groups received DBP, by gavage, from gestation day 15 (GD15) to postnatal day 21 (DPN21), while C animals received the vehicle (corn oil). CMNU, TDBP100, and TDBP500 groups received a single intraperitoneal injection of MNU (50 mg/kg) on the sixth postnatal week. After that, testosterone cypionate was administered subcutaneously two times a week (2 mg/kg) for 24 weeks. The animals were euthanized on PND220. Distal segment fragments of the ventral (VP) and dorsolateral prostate (DLP) were fixed and processed for histopathological analysis. Protein extracts from ventral prostate were obtained, and western blotting was performed to AR, ERα, MAPK (ERK1/2), and pan-AKT. Stereological analysis showed an increase in the epithelial compartment in TDBP100 and TDBP500 compared to CN. In general, there was increase in the incidence of inflammation and metaplasia/dysplasia in the DBP-treated groups, mainly in DLP, compared to CN and CMNU. Proliferation index was significant higher in TDBP500 and PIN (prostatic intraepithelial neoplasia) was more frequent in this group compared to CMNU. Western blot assays showed an increase in the expressions of AR and MAPK (ERK1/2) in the TDBP100 compared to CN, and ERα and AKT expressions were higher in the TDBP500 group compared do CN. These results showed that different doses of DBP during prostate organogenesis in Wistar rats could increase the incidence of premalignant lesions in initiated rats inducing distinct biological responses in the adulthood. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1185-1195, 2016.

Gestational protein restriction delays prostate morphogenesis in male rats.

Maternal malnutrition due to a low-protein diet is associated with functional disorders in adulthood, which may be related to embryonic development failures. The effects of gestational protein restriction on prostate morphogenesis in male offspring were investigated. Pregnant rat dams were divided into normoprotein (NP; fed a normal diet containing 17% protein) and hypoprotein (LP; fed a diet containing 6% protein) groups. On the day of birth (PND1), anogenital distance and bodyweight were measured in male pups. Seven males per experimental group (one male per litter) were killed, and the pelvic urethra was evaluated. LP offspring showed a significant reduction in bodyweight and anogenital distance on PND1. On three-dimensional reconstruction of the prostate, the number of prostatic buds was lower in LP than in NP males. Mesenchymal cells surrounding the buds were androgen-receptor positive, and the quantity and intensity of nucleus immunoreactivity was decreased in LP. The proliferation index was lower in LP than in NP prostatic buds. Immunoreactivity for α-actin in mesenchymal cells and that for epidermal growth factor receptor in epithelial cells was higher in NP than in LP. Our findings demonstrate that maternal protein restriction delays prostatic morphogenesis, probably because of considerable disruption in the epithelium-mesenchyme interaction.

A new proposed rodent model of chemically induced prostate carcinogenesis: distinct time-course prostate cancer progression in the dorsolateral and ventral lobes.

BACKGROUND: Characterization of novel rodent models for prostate cancer studies requires evaluation of either spontaneous and carcinogen-induced tumors as well as tumor incidence in different prostatic lobes. We propose a new short-term rodent model of chemically induced prostate carcinogenesis in which prostate cancer progression occurs differentially in the dorsolateral and ventral lobes. METHODS: Adult gerbils were treated with MNU alone or associated with testosterone for 3 or 6 months of treatment. Tumor incidence, latency, localization, and immunohistochemistry (AR, PCNA, smooth muscle α-actin, p63, MGMT, and E-cadherin) were studied in both lobes. RESULTS: Comparisons between both lobes revealed that lesions developed first in the DL while the VL presented longer tumor latency. However, after 6 months, there was a dramatic increase in tumor multiplicity in the VL, mainly in MNU-treated groups. Lesions clearly progressed from a premalignant to a malignant phenotype over time and tumor latency was decreased by MNU + testosterone administration. Three-dimensional reconstruction of the prostatic complex showed that the DL developed tumors exclusively in the periurethral area and showed intense AR, PCNA, and MGMT immunostaining. Moreover, VL lesions emerged throughout the entire lobe. MNU-induced lesions presented markers indicative of an aggressive phenotype: lack of basal cells, rupture of the smooth muscle cell layer, loss of E-cadherin, and high MGMT staining. CONCLUSIONS: There are distinct pathways involved in tumor progression in gerbil prostate lobes. This animal provides a good model for prostate cancer since it allows the investigation of advanced steps of carcinogenesis with shorter latency periods in both lobes.

Early-life origin of prostate cancer through deregulation of miR-206 networks in maternally malnourished offspring rats.

The Developmental Origins of Health and Disease (DOHaD) concept has provided the framework to assess how early life experiences can shape health and disease throughout the life course. While maternal malnutrition has been proposed as a risk factor for the developmental programming of prostate cancer (PCa), the molecular mechanisms remain poorly understood. Using RNA-seq data, we demonstrated deregulation of miR-206-Plasminogen (PLG) network in the ventral prostate (VP) of young maternally malnourished offspring. RT-qPCR confirmed the deregulation of the miR-206-PLG network in the VP of young and old offspring rats. Considering the key role of estrogenic signaling pathways in prostate carcinogenesis, in vitro miRNA mimic studies also revealed a negative correlation between miR-206 and estrogen receptor α (ESR1) expression in PNT2 cells. Together, we demonstrate that early life estrogenization associated with the deregulation of miR-206 networks can contribute to the developmental origins of PCa in maternally malnourished offspring. Understanding the molecular mechanisms by which early life malnutrition affects offspring health can encourage the adoption of a governmental policy for the prevention of non-communicable chronic diseases related to the DOHaD concept.

Oral exposure to methylmercury modifies the prostatic microenvironment in adult rats.

Methylmercury (MeHg) is an environmental pollutant that is highly toxic to the central nervous system. As its effects on male reproductive system are poorly understood, this study was carried out to analyse the effects of MeHg on the rat prostate. To evaluate the MeHg toxicity on ventral prostate, three groups of adult male Wistar rats received oral doses of 0.5, 1.0 and 3.0 mg/kg MeHg, respectively, on a daily basis for 14 days. A fourth group was used as a control. The prostate weight was decreased in rats treated orally with 0.5 mg/kg MeHg compared to controls. Also, Hg concentration increased significantly in the prostate after treatments. There were reductions in serum testosterone levels and androgen receptor immunoreactivity in animals receiving 3.0 mg MeHg/kg. The stereological data showed changes in the prostatic epithelial, stromal and luminal compartments which varied according to the different doses. Histopathological alterations, such as chronic inflammation, stratified epithelial hyperplasia and epithelial inflammatory reactive atypia, were observed in the 0.5 mg/kg MeHg-treated group. Epithelial atrophy was observed in the 3.0 mg/kg MeHg-treated group. In conclusion, the MeHg affects prostatic homoeostasis resulting in histopathological changes that may be relevant in the pathogenesis of prostatic disease.

Chronic caffeine intake increases androgenic stimuli, epithelial cell proliferation and hyperplasia in rat ventral prostate.

Coffee intake has been associated with a low risk of developing cancer, including prostate cancer, which is one of the most commonly diagnosed cancer in men. However, few studies have evaluated the chronic effects of caffeine, which is the most abundant methylxanthine in coffee, on prostate morphology and physiology. In the present study, we investigated the effects of chronic, low-dose caffeine intake on rat prostate morphology from puberty to adulthood. Five-week-old male Wistar rats were randomized into two experimental groups: caffeine-treated (20 ppm in drinking water, n = 12) and control (n = 12). The ventral and dorsolateral prostates were dissected, weighted and submitted to morphological, morphometrical and immunohistochemical analysis of cellular proliferation, apoptosis and androgen receptor (AR) tissue expression. The testosterone (T) and dihydrotestosterone (DHT) concentrations were measured in the plasma. Our results show that caffeine intake increased the concentrations of T and DHT, organ weight, epithelial cell proliferation and AR tissue expression in the ventral prostatic lobe. All the ventral prostates from the caffeine-treated animals presented various degrees of epithelial and stromal hyperplasia. Our results suggest that chronic caffeine intake from puberty increases androgenic signalling and cell proliferation in the rat prostate gland and can be related to the development of benign prostatic hyperplasia.

Harmful effects of carbamazepine on the postnatal development of the rat ventral prostate.

BACKGROUND: Carbamazepine (CBZ) is a first-line antiepileptic drug (AED), although it is also used for the treatments of psychiatric disorders and neuropathic pain. The CBZ utilization has been associated with male reproductive damage, including hormonal alterations, sexual dysfunction and reduction of sperm quality. The wide and long-term use of the CBZ is a common schedule in children and adolescents and alters the testosterone level in adult rats and humans. The objective of this work was to evaluate the CBZ side effects on the ventral prostate of rats from pre-puberty to sexual maturation, since the prostate is an androgen-dependent organ. METHODS: Twenty three day-old male albino Wistar rats received CBZ diluted in propylene glycol (20 mg/Kg/i.p via). The treatment lasted 20, 40 and 70 days, according to the different stages of the rat sexual maturation. At the end of each treatment period, ventral prostates were removed and histologically processed. The prostate sections were submitted to the histopathological, morphological and stereological analyses using image analysis system. RESULTS: Reductions of the glandular epithelium, glandular lumen and fibromuscular stroma volume of the ventral prostate were observed in adult rats treated with CBZ since the weaning. Triggering and degranulation of mast cells were observed in the fibromuscular stroma of prepubertal and pubertal CBZ treated rats. CONCLUSIONS: The results suggest a direct effect of the CBZ on rat ventral prostate, evidenced by increase of mast cell and macrophage populations during pre-puberty and puberty causing a ventral prostate accentuated damage in the adult phase.

Multigenerational Effects of an Environmentally Relevant Phthalate Mixture on Reproductive Parameters and Ovarian miRNA Expression in Female Rats.

Phthalates are endocrine-disrupting chemicals used in many consumer products. Our laboratory previously developed an environmentally relevant phthalate mixture consisting of 6 phthalates and found that it disrupted female fertility in mice. However, it was unknown if maternal exposure to the mixture affects reproductive parameters and ovarian post-transcription in the F1 and F2 generation of female rats. Thus, we tested the hypothesis that maternal exposure to the phthalate mixture affects folliculogenesis, steroidogenesis, and ovarian microRNA (miRNA) in the F1 and F2 generations of female rats. Pregnant female rats were divided into 4 groups and orally dosed daily from gestational day 10 to postnatal day 21 with corn oil (control group), 20 µg/kg/day, 200 µg/kg/day, or 200 mg/kg/day of the phthalate mixture. Maternal exposure to the phthalate mixture impaired folliculogenesis in the F1 and F2 generations of female rats and affected steroidogenesis in the F1 generation of female rats compared to control. Further, the phthalate mixture altered ovarian expression of some genes related to the cell cycle and steroidogenesis compared to control in the F1 and F2 generations of female rats. The mixture also increased ovarian expression of rno-mir-184 that is involved with the oocyte maturation process. Collectively, our data show that maternal exposure to the phthalate mixture affects folliculogenesis and steroidogenesis in the F1 and F2 generations of female rats and alters ovarian miRNA expression in the F1 generation of female rats.

Exposure to aluminium chloride during the peripuberal period induces prostate damage in male rats.

Aluminium (Al) is an important metal, but it can be toxic including for prostate tissue. This study aimed to evaluate whether exposure to aluminium chloride (AlCl3) during the peripubertal period affects ventral prostate development in rats. Male Wistar rats (30 days old) were distributed into three experimental groups: control (sterile 0.9% saline solution), AL7 (7 mg AlCl3/kg) and AL34 (34 mg AlCl3/kg). Animals were treated intraperitoneally from postnatal day (PND) 36-66 (peripubertal period). At PND67, the animals were anaesthetized and euthanized. Blood was collected for testosterone levels. The ventral prostate (VP) was removed, weighed and processed for histochemistry and immunohistochemistry to detect androgen (AR) and Ki67. Stereological and histopathological analyses, mast cell counts, and determinations of myeloperoxidase (MPO) and N-acetyl glycosidase (NAG) activity and IL-6 levels were performed. The AL34 group presented a reduction in body weight and increase in MPO activity compared to the other groups. In both the AL7 and AL34 groups, there was reorganization of the prostatic tissue compartments. There was no significant difference in prostate weight, number of granulated or degranulated mast cells, or testosterone levels. In conclusion, the exposure to aluminium chloride during the peripubertal period impairs the prostatic development.

Prenatal exposure to a mixture of different phthalates increases the risk of mammary carcinogenesis in F1 female offspring.

Phthalates metabolites have been detected in the urine of pregnant and breastfeeding women. Thus, this study evaluated the adverse effects of maternal exposure to a mixture of six phthalates (Pth mix) on the mammary gland development and carcinogenesis in F1 female offspring. Pregnant female Sprague-Dawley rats were exposed daily to vehicle or Pth mix (35.22% diethyl-phthalate, 21.03% di-(2-ethylhexyl)-phthalate, 14.91% dibutyl-phthalate, 15.10% diisononyl-phthalate, 8.61% diisobutyl-phthalate, and 5.13% benzylbutyl-phthalate) by gavage at 20 µg/kg, 200 µg/kg or 200 mg/kg during gestational day 10 (GD 10) to postnatal day 21 (PND 21). After weaning (PND 22), some female offspring were euthanized for mammary gland analyses while other females received a single dose of N-methyl-N-nitrosourea (MNU, 50 mg/kg) or vehicle and then tumor incidence and multiplicity were recorded until PND 180. Maternal Pth mix exposure increased the number of Ki-67 and progesterone receptor-positive epithelial cells in the mammary gland from Pth mix 200 at µg/kg and 200 mg/kg groups. In addition, tumor incidence and mean number were higher only in Pth mix at 200 mg/kg when compared to the vehicle-treated group, and percentage of tumor-free animals was lower in Pth mix at 200 µg/kg and 200 mg/kg groups. The findings indicate that perinatal Pth mixture exposure increased susceptibility to MNU-induced mammary carcinogenesis in adult F1 female offspring.

Increased oxidative stress and cancer biomarkers in the ventral prostate of older rats submitted to maternal malnutrition.

The concept of Developmental Origins of Health and Disease (DOHaD) states that exposure to malnutrition early in life increase the incidence of non-communicable chronic diseases throughout the lifespan. In this study, a reduction in serum testosterone and an increase in estrogen levels were shown in older rats born to protein malnourished dams (6% protein in the diet) during gestation and lactation. Intraprostatic levels of reduced glutathione were decreased, while tissue expression of glutathione S-transferase pi and sulfiredoxin-1 were increased in these animals. Strong immunostaining for alfametilacil CoA racemase (AMACR), vascular endothelial growth factor-A (VEGF-A), and aquaporin-1 (AQP1) was also observed. In silico analysis confirmed commonly deregulated proteins in the ventral prostate of old rats and patients with prostate cancer. In conclusion, the increase in oxidative stress associated with an imbalance of sex hormones may contribute to prostate carcinogenesis in offspring, highlighting early-life malnutrition as a key risk factor for this malignance.

Tissue changes in senescent gerbil prostate after hormone deprivation leads to acquisition of androgen insensitivity.

The present study examined the response of the prostate epithelium of senescent gerbils submitted to orchiectomy and with or without steroidal blockade. Animals were divided into five groups, all surgically castrated except the control group composed of intact animals. In the experimental groups, doses of flutamide and/or tamoxifen were applied for 1, 3, 7 and 30 days postcastration. The structural methods applied reveal that castration, whether associated or not with anti-steroidal drugs, promoted short- and long-term decrease in wet and relative weights of the prostate. The quantitative decline of epithelial compartment proportion observed at the end of treatment was due to the sum of slight changes in the epithelium and lumen. The apoptotic index had risen significantly at 1 day and declined at 7 days postcastration. Androgen receptor (AR) expression decreased after 3 days of hormonal ablation, coinciding with the highest levels of apoptosis and cell proliferation observed in all treated groups. The majority of cells remained differentiated in all groups due to CK 8/18 expression. Some animals remained with injuries such as carcinomas and adenocarcinomas after hormonal ablation. In the latter a mixture of AR-positive and AR-negative cells was identified. Microinvasive carcinomas found in the group treated for 30 days consisted of PCNA-positive, inflammatory and non-proliferating cells. Low apoptosis incidence and bcl-2 positive cells were observed in these lesions. The treatments promoted a reduction of lesions in older gerbils, but treatment-resistant tumours will improve understanding of the events that lead to hormone resistance.

Prostate carcinogenesis induced by N-methyl-N-nitrosourea (mnu) in gerbils: histopathological diagnosis and potential invasiveness mediated by extracellular matrix components.

In the present study prostate lesions were induced in gerbils (Meriones unguiculatus) treated with a single N-methyl-N-nitrosourea (MNU) dose; thus, the incidence, latency and histology of these lesions were evaluated. Fibrillar elements of the extracellular matrix associated with microinvasive sites were also investigated. Animals were divided into 5 groups, including 2 control groups: (1) remained untreated; (2) received the corn oil vehicle (vehicle, 0.1 ml/application) and three different tumor induction regimens: (1) received MNU (30 mg/kg) and weekly testosterone (2 mg/kg) (MNU+testosterone); (2) received only MNU (30 mg/kg); (3) received weekly testosterone doses (2 mg/kg). After 3 and 6 months the animals were dissected and the prostates were evaluated morphologically, immunohistochemically and quantitatively. MNU plus androgen contributed to the development of prostatic intraepithelial neoplasia, microinvasive carcinoma and adenocarcinoma in gerbil prostate. However, these lesions occurred earlier in time in groups that received MNU and androgen compared to control animals as they over time also developed to a high extent microinvasive lesions. Cytochemistry and immunohistochemistry showed that these injuries were commonly associated with inflammatory cells whereas the epithelial cells presented proliferative activity. The alpha-methylacyl-CoA racemase (AMACR) expression in prostate cancer cells facilitated diagnosis of gerbil lesions. Testosterone, MNU and MNU+testosterone showed an increased epithelial volume, although the secretory activity was significantly suppressed mainly at neoplastic foci. In the prostatic stroma, reticular fibers increased significantly in MNU, MNU+testosterone and among the lesions found in these groups, while collagen fibers decreased at neoplastic sites. The disruption of the basement membrane was proven at malignant sites by ultrastructural analysis and type IV collagen and laminin degradation. The prostate carcinogenesis mediated by MNU and androgen stimulated the emergence of proliferative lesions in gerbils after short periods and showed the importance of a dynamic remodeling of stromal components for cellular invasiveness.

Functional and morphological reproductive aspects in male rats exposed to di-n-butyl phthalate (DBP) in utero and during lactation.

The potential adverse reproductive effects, with emphasis on the epididymis, of in utero and lactational exposure to 100 mg/kg/d di-n-butyl phthalate (DBP) in adult male rat offspring were investigated. The fetal testis histopathology was also determined. The selected endpoints included reproductive organ weights, sperm motility and morphology, sperm epididymal transit time, sperm quantity in the testis and epididymis, hormonal status, fetal testis and epididymal histopathology and stereology, and androgen receptor (AR), aquaporin 9 (AQP9), and Ki-67 immunoreactivities. Pregnant females were divided into two groups: control (C) and treated (T). The treated females received DBP (100 mg/kg/d, by gavage) from gestation day (GD) 12 to postnatal day (PND) 21, while control dams received the vehicle. Some pregnant dams were killed by decapitation on GD20, and testes from male fetuses were collected for histopathogy. Male rats from other dams were killed at PND 90. Fetal testes from treated group showed Leydig-cell clusters, presence of multinucleated germinative cells, and increase of the interstitial component. Testosterone levels and reproductive organ weights were similar between the treated and control adult groups. DBP treatment did not markedly affect relative proportions of epithelial, stromal, or luminal compartments in the epididymis; sperm counts in the testis and epididymis; sperm transit time; or sperm morphology and motility in adult rats. The AR and AQP9 immunoreactivities and proliferation index were similar for the two groups. These results showed that fetal testes were affected by DBP as evidenced by testicular histopathologic alterations, but reproductive parameters and epididymal structure/function were not significantly altered in the adult animals exposed to 100 mg/kg DBP in utero and during lactation.