Stromal cell-derived factor 1 (SDF-1) increases the number of telocytes in ex vivo and in vitro assays.

Telocytes are interstitial cells that are present in various tissues, have long cytoplasmic projections known as telopodes, and are classified as CD34+ cells. Telopodes form extensive networks that permeate the stroma, and there is evidence that these networks connect several stromal cell types, giving them an important role in intercellular communication and the maintenance of tissue organisation. Data have also shown that these networks can be impaired and the number of telocytes reduced in association with many pathological conditions such as cancer and fibrosis. Thus, techniques that promote telocyte proliferation have become an important therapeutic target. In this study, ex vivo and in vitro assays were conducted to evaluate the impact on prostatic telocytes of SDF-1, a factor involved in the proliferation and migration of CD34+ cells. SDF-1 caused an increase in the number of telocytes in explants, as well as morphological changes that were possibly related to the proliferation of these cells. These changes involved the fusion of telopode segments, linked to an increase in cell body volume. In vitro assays also showed that SDF-1 enriched prostate stromal cells with telocytes. Altogether, the data indicate that SDF-1 may offer promising uses in therapies that aim to increase the number of telocytes. However, further studies are needed to confirm the efficiency of this factor in different tissues/pathological conditions.

Photodynamic therapy reduces cell viability, migration and triggers necroptosis in prostate tumor cells.

Prostate cancer is the most common cancer in American men, aside from skin cancer. As an alternative cancer treatment, photodynamic laser therapy (PDT) can be used to induce cell death. We evaluated the PDT effect, using methylene blue as a photosensitizer, in human prostate tumor cells (PC3). PC3 were subjected to four different conditions: DMEM (control); laser treatment (L-660 nm, 100 mW, 100 J.cm-2); methylene blue treatment (MB-25 µM, 30 min), and MB treatment followed by low-level red laser irradiation (MB-PDT). Groups were evaluated after 24 h. MB-PDT treatment reduced cell viability and migration. However, because MB-PDT did not significantly increase the levels of active caspase-3 and BCL-2, apoptosis was not the primary mode of cell death. MB-PDT, on the other hand, increased the acid compartment by 100% and the LC3 immunofluorescence (an autophagy marker) by 254%. Active MLKL level, a necroptosis marker, was higher in PC3 cells after MB-PDT treatment. Furthermore, MB-PDT resulted in oxidative stress due to a decrease in total antioxidant potential, catalase levels, and increased lipid peroxidation. According to these findings, MB-PDT therapy is effective at inducing oxidative stress and reducing PC3 cell viability. In such therapy, necroptosis is also an important mechanism of cell death triggered by autophagy.

High-lipid nutritional environment in different ontogenetic periods induce developmental programming of rat prostate at aging.

In brief: Maternal obesity plus high-fat diet in breastfeeding induces stromal hyperplasia and diffuse acinar atrophy in the rat prostate at aging, related to dyslipidemia and testosterone reduction. The high-lipid nutritional environment from intrauterine and throughout life favors the development of prostatic intraepithelial neoplasia and aggravated degenerative alterations in the gland. Abstract: Maternal obesity and high-fat diet (HFD) affect permanently prostate histophysiology in adulthood, but the consequences during aging are unknown. Here, we evaluated the prostate alterations in middle-aged rats subjected to a high-lipid nutritional environment (HLE) in different ontogenetic periods. Wistar rats (56 weeks of age) were assigned into groups exposed to standard nutrition (C) or HLE during gestation (G), gestation and lactation (GL), from lactation onward (L), from weaning onward (W) and from gestation onward (AL). HLE in the periods after weaning consisted of HFD (20% fat), and during gestation and lactation it also included previous maternal obesity induced by the HFD. HLE increased total cholesterol and triglyceride levels in all groups and led to insulin resistance in GL and AL and obesity in L. Serum testosterone levels decreased ~67% in GL, ~146% in L and W, and ~233% in AL. Histological and stereological analysis revealed an increment of the stromal compartment and collagen fibers in the prostates of all HLE groups, as well as degenerative lesions, such as cell vacuolation and prostate concretions. HLE aggravated acinar atrophy in G, GL, and L, and in AL it reached more than 50% of the prostate area for most animals. The foci of prostatic intraepithelial neoplasia increased in AL. Tissue expression of androgen receptor did not vary among groups, except for a higher stromal expression for G and GL. Even when restricted to gestation and lactation, HLE induces diffuse acinar atrophy in the aging prostate and worsens degenerative and premalignant lesions when it continues throughout life.

High-fat diet during sexual maturation induces hyperplastic differentiation of rat prostate and higher expression of AR45 isoform and ERα.

We examined the consequences of high-fat diet (HFD) on prostate histophysiology in two periods along sexual maturation of rats and the impact on the gland in adulthood. After weaning, male Wistar rats were fed a balanced diet (4 % fat-C3, C6, C9) or a HFD (20 % fat- HF3, HF6, HF9) for 3, 6 or 9 weeks. Fat deposit weights, blood glucose and levels of serum testosterone and estrogen were measured. Prostate was evaluated for histology, proliferative and apoptotic cell index, and for the expression of androgen (AR), estrogen receptors type α (ERα) and aromatase. HFD did not affect estrogen levels and elevated serum testosterone only in HF9. HFD reduced prostate weight in HF6 and increased it in adulthood (HF9) but relative prostate weight was unchanged among groups. Cell proliferation, height and density were higher in epithelium of all HFD-groups, compared to controls, featuring the epithelial hyperplasia. Epithelial apoptosis was lower in HF9. HF3 and HF9 exhibited higher expressions of ERα, indicating that HFD triggers a new activation of ERα expression in the acinar epithelium. The content of prostatic aromatase was also elevated in HF9. Increased numbers of AR-positive cells were observed in all HFD groups, and western blotting analysis showed an increase in the truncated form of 45 kDa (AR45) and a reduction in the expression of 110 kDa-AR for HF3 and HF9. In conclusion, excessive dietary fats during sexual maturation of rats led to developmental programming of the prostate, inducing a hyperplastic status with perturbations in AR isoforms expression and reactivation of ERα in adulthood, whose implications for posterior prostatic health could be detrimental.

Protective effect of the association of curcumin with piperine on prostatic lesions: New perspectives on BPA-induced carcinogenesis.

Bisphenol A (BPA) is a chemical agent which can exert detrimental effects on the male reproductive system, especially the prostate gland. In this study we described the efficacy of the dietary agent curcumin, alone or combined with piperine, to suppress the impact of BPA on the prostate. Adult gerbils were divided into nine experimental groups (n = 7 each group), regarding control (water and oil), exposed to BPA (50 µg/kg/day in water) or curcumin (100 mg/kg) and/or piperine (20 mg/kg). To evaluate the effects of the phytotherapic agents, the other groups received oral doses every two days, BPA plus curcumin (BCm), piperine (BP), and curcumin + piperine (BCmP). BPA promoted prostatic inflammation and morphological lesions in ventral and dorsolateral prostate lobes, associated with an increase in androgen receptor-positive cells and nuclear atypia, mainly in the ventral lobe. Curcumin and piperine helped to minimize these effects. BPA plus piperine or curcumin showed a reduction in nuclear atypical phenotype, indicating a beneficial effect of phytochemicals. Thus, these phytochemicals minimize the deleterious action of BPA in prostatic lobes, especially when administered in association. The protective action of curcumin and piperine consumption is associated with weight loss, anti-inflammatory potential, and control of prostate epithelial cell homeostasis.

Docosahexaenoic acid differentially modulates the cell cycle and metabolism- related genes in tumor and pre-malignant prostate cells.

Prostate cancer (PCa) has different molecular features along progression, including androgen profile, which is associated to therapy inefficiency leading to more aggressive phenotype. Docosahexaenoic acid (DHA) has antiproliferative and pro-apoptotic properties in different cancers associated to cell metabolism modulation. The latter is of particular interest since metabolic reprogramming is one of PCa hallmarks, but is not clear how this occurs among disease progression. Therefore, we evaluated DHA antiproliferative potential in distinct androgenic backgrounds associated to metabolism modulation and androgen-regulated genes. For this purpose, pre-malignant PNT1A and tumor AR-positive 22rv1, and AR-negative PC3 cells were incubated with DHA at 100 µM-48 h. DHA reduced at least 26% cell number for all lineages due to S-phase decrease in AR-positive and G2/M arrest in AR-negative. Mitochondrial metabolic rate decreased in PNT1A (~38%) and increased in tumor cells (at least 40%). This was associated with ROS overproduction (1.6-fold PNT1A; 2.1 22rv1; 2.2 PC3), lipid accumulation (3-fold PNT1A; 1.8 22rv1; 3.6 PC3) and mitochondria damage in all cell lines. AKT, AMPK and PTEN were not activated in any cell line, but p-ERK1/2 increased (1.5-fold) in PNT1A. Expression of androgen-regulated and nuclear receptors genes showed that DHA affected them in a distinct pattern in each cell line, but most converged to metabolism regulation, response to hormones, lipids and stress. In conclusion, regardless of androgenic or PTEN background DHA exerted antiproliferative effect associated to cell cycle impairment, lipid deregulation and oxidative stress, but differentially regulated gene expression probably due to distinct molecular features of each pathologic stage.

Effect of glucose and palmitate environment on proliferation and migration of PC3-prostate cancer cells.

Recent studies have been trying to find out how diet and metabolic changes such as dyslipidaemia, hyperglycaemia, and hyperinsulinaemia can stimulate cancer progression. This investigation aimed to evaluate the effect of high concentrations of fatty acids and/or glucose in tumour prostate cells, focusing on the proliferation/migration profile and oxidative stress. PC3 cells were treated with high concentration of saturated fatty acid (palmitate, 100 µM), glucose (220 mg/dL), or both for 24 or 48 h. Results demonstrated that PC3 cells showed a significant increase in proliferation after 48 h of treatment with glucose and palmitate+glucose. Cell proliferation was associated with reduced levels of AMPK phosphorylation in glucose group at 24 and 48 h of treatment, while palmitate group presented this result only after 48 h of treatment. Also, there was a significant increase in cell migration between time 0 and 48 h after all treatments, except in the control. Catalase activity was increased by palmitate in the beginning of treatment, while glucose presented a later effect. Also, nitrite production was increased by glucose only after 48 h, and the total antioxidant activity was enhanced by palmitate in the initial hours. Thus, we conclude that the high concentration of the saturated fatty acid palmitate and glucose in vitro influences PC3 cells and stimulates cellular activities related to carcinogenesis such as cell proliferation, migration, and oxidative stress in different ways. Palmitate presents a rapid and initial effect, while a glucose environment stimulates cells later on, maintaining high levels of cell proliferation.

Maternal supplementation with corn oil associated or not with di-n-butyl phthalate increases circulating estradiol levels of gerbil offspring and impairs sperm reserve.

This study evaluated the consequences of gestational exposure to di-n-butyl phthalate (DBP) for testicular steroidogenesis and sperm parameters of the adult gerbil and the interference of corn oil (co), a vehicle widely used for administration of liposoluble agents, on DBP effects. Pregnant gerbils received no treatment or were treated from gestational day 8 to 23 via gavage with 0.1 mL/day of co only or containing DBP (100 mg/kg/day). Maternal co intake enhanced serum estradiol levels and testicular content of ERα, and reduced sperm reserve of adult offspring. Gestational DBP exposure caused dyslipidemia, increased serum and intratesticular estradiol levels and reduced sperm reserve and motility. Thus, maternal co supplementation alters circulating estradiol and impairs sperm quantity and quality of offspring. Gestational DBP exposure alters lipid metabolism and testicular steroidogenesis and worsens the negative effects of co on the sperm reserve and motility of gerbil. Therefore, co interferes with the reproductive response to DBP.

Pathological lesions and global DNA methylation in rat prostate under streptozotocin-induced diabetes and melatonin supplementation.

Chronic hyperglycemia increases production of reactive oxygen species, which favors carcinogenesis. The association between diabetes and prostate cancer is controversial. Melatonin has antioxidant, anti-inflammatory, and antiproliferative properties. We investigated whether low doses of melatonin prevent the tissue alterations caused by diabetes and alter prostate histology of healthy rats. We also investigated whether experimental diabetes promoted the development of pathological lesions in the ventral prostate of rats. Melatonin was provided in drinking water (10 µg/kg/day) from age 5 weeks until the end of experiment. Diabetes was induced at 13 weeks by administration of streptozotocin (40 mg/kg, ip). Rats were euthanized at 14 or 21 weeks. Histological and stereological analyses were carried out and the incidence and density of malignant and pre-malignant lesions were assessed. Immunohistochemical assays of α-actin, cell proliferation (PCNA), Bcl-2, glutathione S-transferase (GSTPI), and DNA methylation (5-methylcytidine) were performed. Melatonin did not elicit conspicuous changes in the prostate of healthy animals; in diabetic animals there was a higher incidence of atrophy (93%), microinvasive carcinoma (10%), proliferative inflammatory atrophy, PIA (13%), prostatitis (26%), and prostate intraepithelial neoplasia, PIN (20%) associated with an increase of 40% in global DNA methylation. Melatonin attenuated epithelial and smooth muscle cell (smc) atrophy, especially at short-term diabetes-and normalized incidence of PIN (11%), inflammatory cells infiltrates, prostatitis (0%) and PIA (0%) at long-term diabetes. MLT was effective in preventing inflammatory disorders and PIN under diabetic condition. Although MLT has antioxidant action, it did not influence DNA methylation and not avoid carcinogenesis at low doses.

Corticosterone influences gerbil (Meriones unguiculatus) prostatic morphophysiology and alters its proliferation and apoptosis rates.

Glucocorticoids (GCs) are hormones that are widely used in medicine; but although side effects are generally recognised, little is known about the precise mechanisms that is implicated in many of these side effects. Furthermore, GCs are highly correlated with stress and behaviour disorders. This study evaluated the effects of the glucocorticoid corticosterone on the ventral prostate of the Mongolian gerbil. Male gerbils (Meriones unguiculatus) (n = 5) received intraperitoneal injections of saline or corticosterone in doses of 0.5 mg/kg/day and 1.5 mg/kg/day for 5 days; while some of the animals were killed immediately after the treatment, the others were killed 5 days after the treatment period. The data show that corticosterone influences the structure and functionality of this organ. This hormone has anti-proliferative and anti-apoptotic properties in the prostate. In addition, the frequencies of the androgen (AR), oestrogen (ERα, ERß) and glucocorticoid (GR) receptors changed. The frequencies of AR, GR and ERß decreased in the Ct1/5 group; in the groups with rest period, the frequencies of GR increased and ERß decreased in the epithelium. Changes in the proliferative index, apoptotic index and receptor activity may have contributed to the emergence of prostatic morphological alterations, such as the presence of cellular debris and inflammatory cells. Different doses of corticosterone had variable effects on the prostate, with a higher dose showing subtler effects and a lower dose showing more striking effects. The corticosterone effects on nuclear receptors were reverted or attenuated after a rest period, which was not observed for proliferation and apoptosis. In summary, we have demonstrated that corticosterone might influence the prostatic morphophysiology and that these changes may be linked in some way to the altered receptor distribution.

Role of the TNF-α receptor type 1 on prostate carcinogenesis in knockout mice.

BACKGROUND: TNF-α is a key cytokine involved in prostate carcinogenesis and is mediated by the TNF-α receptor type 1 (TNFR-1). This receptor triggers two opposite pathways: cell death or cell survival and presents a protective or stimulator role in cancer. Thus, the purpose of this study was to evaluate the role of TNF signaling in chemically induced prostate carcinogenesis in mice. METHODS: C57bl/6 wild type (WT) and p55 TNFR-1 knockout mice (KO) were treated with mineral oil (control) or N-methyl N-nitrosurea (MNU) in association with testosterone (MNU+T, single injection of 40 mg/kg and weekly injection 2 mg/kg, respectively) over the course of 6 months. After this induction period, prostate samples were processed for histological and biochemical analysis. RESULTS: MNU+T treatment led to the development of prostate intraepithelial neoplasia (PIN) and adenocarcinoma (PCa) in both WT and KO animals; however, the incidence of PCa was lower in KO group than in WT. Cell proliferation analysis showed that PCNA levels were significantly lower in the KO group, even after carcinogenesis induction. Furthermore, the prostate of KO animals had lower levels of p65 and p-mTOR after treatment with MNU+T than WT. There was also a decrease in prostate androgen receptor levels after induction of carcinogenesis in both KO and WT mice. Regarding the extracellular matrix in the prostate, KO mice had higher levels of fibronectin and lower levels of matrix metalloproteinase 2 (MMP2) after carcinogenesis. Finally, there was a similar increase in apoptosis in both groups after carcinogenesis, indicating that the TNAFr1 pathway in prostate carcinogenesis presented proliferative, and not apoptotic, stimuli. CONCLUSIONS: TNF-α, through its receptor TNFR-1, promoted cell proliferation and cell survival in prostate by activation of the AKT/mTOR and NFKB pathway, which stimulated prostate carcinogenesis in chemically induced mice. Prostate 76: 917-926, 2016. © 2016 Wiley Periodicals, Inc.

Differential ontogenetic exposure to obesogenic environment induces hyperproliferative status and nuclear receptors imbalance in the rat prostate at adulthood.

BACKGROUND: Experimental data indicate that high-fat diet (HFD) may alter proliferative activity and prostate health. However, the consequences of HFD exposure during different periods of ontogenetic development on prostate histophysiology remain to be elucidated. Herein, we compare the influence of obesogenic environment (OE) due to maternal obesity and HFD at different periods of life on proliferative activity and nuclear receptors frequency in the rat ventral prostate and a possible relationship with metabolic and hormonal alterations. METHODS: Male Wistar rats (19 weeks old), treated with balanced chow (Control group-C; 3% high-fat, 3.5 Kcal/g), were compared with those exposed to HFD (20% high-fat, 4.9 kcal/g) during gestation (G-maternal obesity), gestation and lactation (GL), from post-weaning to adulthood (WA), from lactation to adulthood (LA) and from gestation to adulthood (GA). After the experimental period, the ventral prostate lobes were removed and analyzed with different methods. RESULTS: Metabolic data indicated that G and GL rats became insulin resistant and WA, LA, and GA became insulin resistant and obese. There was a strong inverse correlation between serum testosterone (∼133% lower) and leptin levels (∼467% higher) in WA, LA, and GA groups. Estrogen serum levels increased in GA, and insulin levels increased in all groups, especially in WA (64.8×). OE-groups exhibited prostatic hypertrophy, since prostate weight increased ∼40% in G, GL, LA, and GA and 31% in WA. As indicated by immunohistochemistry, all HFD-groups except G exhibited an increase in epithelial cell proliferation (PCNA-positive) and a decrease in frequency of AR- and ERß-positive epithelial cells; there was also an increment of ERα-positive stromal cells in comparison with control. Cells containing PPARγ increased in both epithelium and stroma of all OE groups and those expressing LXRα decreased, particularly in groups OE-exposed during gestation (G, GL and GA). CONCLUSIONS: OE leads to prostate hypertrophy regardless of the period of development and, except when restricted to gestation, leads to a hyperproliferative status which was correlated to downregulation of AR and LXRα and upregulation of ERα and PPARγ signaling.

Sexual maturation of the Mongolian gerbil (Meriones unguiculatus): a histological, hormonal and spermatic evaluation.

This study determined the phases of sexual development of the male Mongolian gerbil (Meriones unguiculatus) based on an integrative analysis of testicular morphology, hormonal data and sperm parameters. Male gerbils were analysed at 1, 7, 14, 21, 28, 35, 42, 50, 60, 70, 90, 100 and 120 days of age. Body, testicular and epididymal weights increased up to Day 70, 60 and 90, respectively. The impuberal phase, characterised by the presence of gonocytes, extended until Day 14. The prepubertal period lasted until Day 42, when puberty was achieved and a drastic increase in serum testosterone levels, mature adult Leydig cells and elongated spermatids was observed. Gerbils at 60 days of age showed a remarkable number of spermatozoa in the testis, epididymidis caput/corpus and cauda, and at Day 70 the maximum daily sperm production was reached. However, the gerbil may be considered sexually mature only from Day 90 onward, when sperm reserves become stable. The total transit time of spermatozoa along the epididymis of sexually mature gerbils was 11 days, with 1 day in the caput/corpus and 10 days in the cauda. These data cover a lacuna regarding the reproductive parameters of this rodent and provide foundations for its use in testicular toxicology studies.

Histopathological alterations in the prostates of Mongolian gerbils exposed to a high-fat diet and di-n-butyl phthalate individually or in combination.

Both high-fat diet and exposure to endocrine-disrupting chemicals have been implicated in susceptibility to pathological prostate lesions, but the consequences of combining the two have not yet been examined. We evaluated the effects of gestational and postnatal exposure to a high-fat diet (20% fat) and low doses of di-n-butyl phthalate (DBP; 5mg/kg/day), individually or in combination, on the tissue response and incidence of pathological lesions in the ventral prostate of adult gerbils. Continuous intake of a high-fat diet caused dyslipidemia, hypertrophy, and promoted the development of inflammatory, premalignant and malignant prostate lesions, even in the absence of obesity. Life-time DBP exposure was obesogenic and dyslipidemic and increased the incidence of premalignant prostate lesions. Combined exposure to DBP and a high-fat diet also caused prostate hypertrophy, but the effects were less severe than those of individual treatments; combined exposure neither induced an inflammatory response nor altered serum lipid content.

Prostate hyperplasia caused by long-term obesity is characterized by high deposition of extracellular matrix and increased content of MMP-9 and VEGF.

Recent studies have shown a positive association of cancer and obesity, but the morphological and molecular mechanisms involved in this relationship are still unknown. This study analysed the impact of long-term obesity on rat prostate, focusing on stromal changes. Male adult Wistar rats were treated with high-fat diet to induce obesity, while the control group received a balanced diet. After 30 weeks of feeding, the ventral prostate was analysed by immunohistochemistry for cell proliferation, smooth muscle α-actin, vimentin, chondroitin sulphate and metalloproteinases (MMP-2 and 9). The content of androgen receptor (AR), oestrogen receptors (ERs) and vascular endothelial growth factor (VEGF) was measured by Western blotting, and activity of catalase and Glutathione-S-Transferase (GST) were quantified by enzymatic assay. Long-term obesity decreased testosterone plasma levels by 70% and resulted in stromal prostate hyperplasia, as evidenced by increased collagen fibres. Such stromal hyperplasia was associated with increased number of blood vessels and raised VEGF content, and increased expression of chondroitin sulphate, vimentin, α-actin and MMP-9. In spite of the high cell density in prostate, the proliferative activity was lower in the prostates of obese rats, indicating that hyperplasia was established during the early phases in this obesity model. AR levels increased significantly, whereas the ERα decreased in this group. Moreover, the levels of catalase and GST were changed considerably. These findings indicate that long-term obesity, besides disturbing the antioxidant control, causes intense stromal remodelling and release of factors that create an environment that can promote proliferative disorders in the gland, culminating with diffuse hyperplasia.

Budding process during the organogenesis of the ventral prostatic lobe in Mongolian gerbil.

The prostate is a mammalian gland that shows a complex process of organogenesis. Here, a morphological study to characterize the organogenesis of the ventral prostate lobe in male gerbils was conducted. The urogenital sinus (UGS) was dissected out and processed for paraffin embedding. Histological sections were subjected to cytochemical, immunofluorescence, immunohistochemical, and three-dimensional reconstruction techniques. We found that the first ventral buds emerged from the ventral urethral epithelium between the days 20 and 21 of prenatal life, reaching the ventral mesenchymal pad and initiating the branching process on the first day of postnatal life. The buds presented a V-shaped elongation, suggesting that the smooth muscle layer (SML) plays an important role during budding events. Indeed, whereas the androgen receptor (AR) was preferentially found in the UGS mesenchyme (UGM), estrogen receptor alpha (ERα) was localized in both the UGM and in the emerging buds. This study characterized the morphological aspects of the budding process in a different rodent from rat and mice, serving as a new model for future studies on developmental biology of the prostate.

Effects of exposure to estradiol and estradiol plus testosterone on the Mongolian gerbil (Meriones unguiculatus) female prostate.

The female prostate is a differentiated organ found in several mammal species, including humans and rodents. This gland has been related to important functions on female reproductive biology. Although the factors, which regulate prostate's development and activity are not well known, its functionality has been related to steroid hormones. It is well established that cyclic changes of estradiol and progesterone levels promote histophysiological adaptations of the whole female body. In contrast, only a few is found about those adaptations in female prostate. Thus, this study aimed to evaluate the effect of estradiol and estradiol + testosterone association on gerbil female prostate in order to verify, which hormonal associations are necessary to its homeostasis. For this, adult females had the ovaries surgically removed. After recovering, they received estradiol and estradiol + testosterone doses through 30 days, each 48 h. The prostatic tissue underwent morphological and morphometric-estereological analysis. Hormonal restriction caused great gland involution and decreased secretory activity, aspects that were reverted by exposure to estradiol and estradiol + testosterone. However, these hormones were not able to re-establish the normal prostate histoarchitecture. The immunoreaction of steroid receptors (ER-α, ER-ß, and AR) responded differently among the experimental and control groups, and PCNA assay showed a decrease in epithelial cell proliferation within groups that had hormone privation. Therefore, we conclude that estradiol and testosterone are able to influence prostate morphophysiology and the maintenance of gland homeostasis depends on a balance among these and other hormones.

Estrogen receptors alpha and beta in male and female gerbil prostates.

The Mongolian gerbil (Meriones unguiculatus, Gerbilinae: Muridae) is useful for prostate studies, because both males and females spontaneously develop prostatic disorders with age. Estrogens regulate prostate homeostasis via two estrogen receptors, ER alpha (ESR1) and ER beta (ESR2), but the cellular distribution and regulation of these receptors in the gerbil prostate has not been described. Both receptors were localized by immunohistochemistry in the ventral prostate of intact male and female gerbils, in males 7 and 21 days after castration, and in females treated with testosterone for 7 and 21 days. In male and female adult gerbils, ER alpha was detected mainly in prostatic stromal cells, whereas ER beta was present mostly in secretory and basal cells. More ER alpha-positive stromal cells were found in females than in males, as was a reduction toward the male value in females treated with testosterone. Castration did not alter ER alpha expression. Testosterone was necessary for maintenance of ER beta in the male prostate epithelium: ER beta expression declined markedly in prostates of males older than 1 yr, and castration of 4-mo-old males caused a reduction in ER beta to levels seen in 1-yr-old males. Because ER beta is an antiproliferative receptor, its loss with age may predispose the aging gerbil to proliferative diseases of the prostate.

High-fat diet obesity associated with insulin resistance increases cell proliferation, estrogen receptor, and PI3K proteins in rat ventral prostate.

In this study, we evaluated the effects of obesity and insulin resistance induced by a high-fat diet on prostate morphophysiology, focusing on cell proliferation, expression of androgen (AR) and estrogen receptors (ER) and proteins of the insulin signaling pathway. Adult male Wistar rats were fed a high-fat diet (20% fat) for 15 weeks, whereas control animals received a balanced diet (4% fat). Both groups were then divided and treated for 2 weeks with 1 mg/kg body weight/day of the aromatase inhibitor letrozole or vehicle only. The ventral prostate was analyzed with immunohistochemical, histopathological, stereological, and Western blotting methods. Obese rats showed insulin resistance, hyperinsulinemia, and reduced plasma testosterone levels. The incidence of prostatic intraepithelial neoplasia (PIN) was 2.7 times higher in obese rats and affected 0.4% of the gland compared with 0.1% PIN areas found in control rats. Obesity doubled cell proliferation in both prostate epithelium and stroma. AR content decreased in the prostate of obese rats and estrogen receptor beta (ERß) increased in this group. Protein levels of insulin receptor substrate 1 and protein kinase B diminished in the obese group, whereas phosphatidylinositol 3-kinase (PI3K) increased significantly. Most structural changes observed in the prostate of obese rats normalized after letrozole treatment, except for increased stromal cell proliferation and ERß expression, which might be associated with insulin resistance. This experimental model of obesity and insulin resistance induced by a high-fat diet increases cell proliferation in rat prostate. Such alterations are associated with decreased levels of AR and increased ERß and PI3K proteins. This change can facilitate the establishment of proliferative lesions in rat prostate.

Exposure to ethinylestradiol during prenatal development and postnatal supplementation with testosterone causes morphophysiological alterations in the prostate of male and female adult gerbils.

Steroids perform significant functions in prostatic development and growth, so that interferences of this equilibrium may predispose the gland to the development of diseases during the life. Embryonic and neonatal exposure to xenoestrogens, many of them with endocrine-disrupting potential, has been related to the induction of disturbances in reproductive system organs. Thus, this study aimed to analyse morphological and immunocytochemical aspects of prostate in both male and female adult gerbils either exposed to ethinylestradiol during the prenatal phase (pregnant females received 10 µg/kg, by gavage) (EE group) or exposed to testosterone (1 mg/kg) during the postnatal period (EE/T group). Serological analysis revealed a rise in estradiol levels in adult males and females of the EE group. A higher incidence of prostatic intraepithelial neoplasia (PIN) was observed in the male and female prostate of the treated groups, besides an increase in collagen and reticular fibres. Immunocytochemistry showed an increase in prostatic epithelial cells immunoreactive to AR and a presence of a smooth muscle layer, evidenced by α actin, in injured regions this way absent in prostatic epithelial buds. These pieces of evidence suggest that the alterations verified in the prostate in adulthood of both sexes may be due to the high oestrogen levels. Either males or females of the EE/T group showed normalized estradiol levels, although prostatic lesions could be observed. While the prostatic gland of male gerbils was more affected than the female prostate, this study showed that the exposure to EE during this critical period of development disrupts the prostate of both sexes in terms of prostatic lesions.