Postnatal development of Mongolian gerbil female prostate: An immunohistochemical and 3D modeling study

The impacts of exposure to bisphenol A in the adult female prostate Meriones unguiculatus

The female prostate is associated with the urogenital system and presents homology in morphological terms with the male prostate. Due to its responsiveness to endogenous hormones, this gland is under a constant risk of developing prostatic pathologies and neoplasia when exposed to certain exogenous compounds. Bisphenol A (BPA) is an endocrine disruptor found in different plastic and resin products. Studies have emphasized the effects of perinatal exposure to this compound on different hormone-responsive organs. However, there have been few studies highlighting the influence on female prostate morphology of perinatal exposure to BPA. The objective of this study was to describe the histopathological alterations caused by perinatal exposure to BPA (50 µg/kg) and 17-β estradiol (E2) (35 µg/kg) in the prostate of adult female gerbils. The results showed that E2 and BPA induced proliferative lesions in the female prostate and acted along similar pathways by modulating steroid receptors in the epithelium. BPA was also found to be a pro-inflammatory and pro-angiogenic agent. The impacts of both agents were marked in the prostatic stroma. An increase in the thickness of the smooth muscle layer and a decrease in AR expression were observed, but no alterations in the expression of ERα and ERβ, leading to estrogenic sensitivity of the prostate. However, a peculiar response of the female prostate was to diminish the collagen frequency under BPA exposure correlated to smooth muscle layer. These data therefore indicate the development of features related to estrogenic and non-estrogenic tissue repercussions by BPA perinatally exposure in gerbil female prostate.

Female Prostate Development: Morphological Analysis of the Budding Dynamic

The presence of the prostate in female mammals has long been known. However, pieces of information related to its development are still lacking. The aim of this study was to explore the budding dynamic during the initial prostate development in female gerbils. Pregnant females were timed, the fetuses were euthanized, and the urogenital sinus was dissected out between the embryonic days 20 and 24 (E20-E24 groups). Newborn pups (1-day-old; P1 group) underwent the same procedures. The female prostate development was based on epithelial buds which arose far from the paraurethral mesenchyme (PAM). The epithelial buds reached the PAM at prenatal day 24, crossing a small gap in the smooth muscle layer between the periurethral mesenchyme (PEM) and the PAM. Steroid nuclear receptors such as the androgen receptor and estrogen receptor alpha were localized in the PEM through the urethral wall, although some epithelial labeling was also present in the urogenital sinus epithelium (UGE). P63-positive cells were found only in the UGE, becoming restricted to the basal compartment after the 23rd prenatal day. The results showed that the gerbil female prostate exhibits a distinct budding pattern as compared to the male prostate development.

Inflammatory repercussions in female steroid responsive glands after perinatal exposure to bisphenol A and 17-β estradiol

The mammary gland (MG) and female prostate are plastic reproductive organs which are highly responsive to hormones. Thus, endocrine disruptors, such as bisphenol A (BPA) and exogenous estrogens, negatively affect glandular homeostasis. In addition to previously described alterations, changes in inflammatory markers expression also trigger the development of a microenvironment that contributes to tumor progression. The current work aimed to evaluate the inflammatory responses of the MG and prostate gland to BPA (50 µg/kg) and 17-β estradiol (35 µg/kg) exposure during the perinatal window of susceptibility. The results showed that at 6 months of age there was an increase in the number of phospho-STAT3 (P-STAT3) positive cells in the female prostate from animals perinatally exposed to 50 µg/kg BPA daily. In addition, the number of macrophages increased in these animals in comparison with nonexposed animals, as shown by the F4/80 marker. Despite an increase in the incidence of lobuloalveolar and intraductal hyperplasia, the MG did not show any difference in the expression of the four inflammatory markers evaluated: tumor necrosis factor-α, COX-2, P-STAT3, and F4/80. Analysis of both glands from the same animal led to the conclusion that exposure to endocrine disruptors during the perinatal window of susceptibility leads to different inflammatory responses in different reproductive organs. As the prostate is more susceptible to these inflammatory mechanisms, it is reasonable to affirm that possible neoplastic alterations in this organ are related to changes in the inflammatory pattern of the stroma, a characteristic that is not evident in the MG.

Explant culture: A relevant tool for the study of telocytes

Telocytes are cells present in the stroma of various tissues including the prostate. The detection of telocytes is still very much dependent on obtaining ultrastructural data that show the presence of telopodes, which are cytoplasmic projections that alternate between dilated regions, the podoms, and thin segments, the podomers. These structures are the distinctive characteristics of the telocytes. Thus, in vitro assays are important for the study of telocytes, which are more easily identified in culture, which also enables the experimental manipulation of these cells. The isolation of telocytes per se does not allow the analysis of the behavior of these cells in relation to other cell types in a given organ. In this sense, in the prostate, explants could be a useful tool for the study of telocytes. The present study obtained prostatic explants and evaluated the influence of recombinant proteins, scattering factor (SCF) and stromal-derived factor 1 (SDF-1), which could impact on the migration of CD34-positive cells. Telocytes migrate out of explants and SDF-1 stimulates the proliferation and formation of telocyte networks in vitro. Telocytes are not smooth muscle cell progenitors in the prostate; on the contrary, they are CD90- and CD44-negative cells and, hence, have limited progenitor capacity. The present study demonstrated that explants are useful tools to elucidate the nature of telocytes and their functions.

Prenatal exposure to finasteride promotes sex-specific changes in gerbil prostate development

Finasteride is a drug that is widely used in the treatment of benign prostatic hyperplasia, hair loss and even as a chemotherapeutic agent in the treatment of prostatic adenocarcinoma. However, its use is known to cause several side effects in adults and it can also cause changes in the embryonic development of the male prostate, which is a cause for concern given the possibility of the accumulation of finasteride in the environment. Nevertheless, no studies have investigated the effects of finasteride on the development of the prostate in females, which occurs in several species of mammals. To evaluate the effects of intrauterine exposure to finasteride (500μgkg-1 day-1) on postnatal prostate development in the Mongolian gerbil in the present study, we used immunohistochemistry, immunofluorescence, serological analysis and three-dimensional reconstruction techniques. Differences were observed in the effects of finasteride on periductal smooth muscle and cell proliferation between the sexes, as well as intersex differences in the presence of the androgen receptor, which was elevated in males, and the oestrogen receptor ERα, which was increased in females. Together, the data indicate that the female prostate has its own hormone dynamics and that there are sex-specific differences in the way in which the female prostate reacts to prenatal exposure to finasteride.

Postnatal exposure to finasteride causes different effects on the prostate of male and female gerbils

The development and maintenance of prostate function depend on a fine balance between oestrogen and androgen levels. Finasteride inhibits 5α-reductase, which is responsible for the conversion of testosterone into its most active form, dihydrotestosterone. Enzymes that metabolize these hormones have a highly relevant role in both the normal prostate metabolism and in the occurrence of pathological conditions. There are few studies on the impact of finasteride on male prostate development and fewer studies on the female prostate and possible intersexual differences. Therefore, we treated male and female gerbils from 7 to 14 days in postnatal life with a high dose of finasteride (500 μg/kg/day); the prostate complexes were then removed and submitted to immunohistochemistry, immunofluorescence and three-dimensional reconstruction. In addition, hormonal serum dosages were administered. Treatment with finasteride resulted in an increased thickness of the periductal smooth musculature in the prostate of both male and female gerbils, such as well as a reduction in the thickness of developing prostate alveoli in both sexes. In addition, intersexual differences were observed as increased epithelial proliferation and decreases in the number of developing alveoli in females. Together, the data indicate that postnatal exposure to finasteride causes greater changes in the female gerbil prostate than in the male.

Differences between male and female prostates in terms of physiology, sensitivity to chemicals and pathogenesis-A review in a rodent model

The prostate is a gland that is not exclusively present in males, being also found in females of several mammalian species, including humans. There is evidence that the prostate in both sexes is affected by the same pathologies such as prostatitis, benign alterations and even cancer. In view of the difficulties of manipulating the prostate gland, the Mongolian gerbil (Meriones unguiculatus), a rodent species with high incidence of functional prostates in females, is widely used in studies of the female prostate. However, despite knowing much about the similarities between the female and male prostate, little emphasis has been placed on the differences between them. This review investigates the intersex differences in prostate development, physiology and pathogenesis. The female prostate develops earlier than in males and studies indicate that it is more sensitive to oestrogens than the male prostate, as well as being more sensitive to exposure to xenoestrogens, such as Bisphenol A and methylparaben, with a higher susceptibility to benign lesions in the adult and senile prostate than in males. In addition, the female prostate is impacted by pregnancy and the oestrous cycle, and is also dependent on progesterone. The peculiarities of the female prostate raise concerns about the risk of it undergoing neglected changes as a result of environmental chemicals, since safe dosages are established exclusively for the male prostate.

Telocytes play a key role in prostate tissue organisation during the gland morphogenesis

Telocytes are CD34-positive interstitial cells, known to exert several functions, one of which is a role in tissue organisation, previously demonstrated by telocytes in the myocardium. The existence of telocytes in the prostate has recently been reported, however, there is a lack of information regarding the function of these cells in prostate tissue, and information regarding the possible role of these cells in prostatic development. This study used immunofluorescence techniques in prostate tissue and prostatic telocytes in culture to determine the relationship between telocytes and prostate morphogenesis. Furthermore, immunofluorescent labelling of telocytes was performed on prostate tissue at different stages of early postnatal development. Initially, CD34-positive cells are found at the periphery of the developing alveoli, later in the same region, c-kit-positive cells and cells positive for both factors are verified and CD34-positive cells were predominantly observed in the interalveolar stroma and the region surrounding the periductal smooth muscle. Fluorescence assays also demonstrated that telocytes secrete TGF-β1 and are ER-Beta (ERβ) positive. The results suggest that telocytes play a changing role during development, initially supporting the differentiation of periductal and perialveolar smooth muscle, and later, producing dense networks that separate alveoli groups and form a barrier between the interalveolar region and periurethral smooth muscle. We conclude that telocytes play a relevant role in prostate tissue organisation during postnatal development.