Impact of perinatal bisphenol A and 17β estradiol exposure: Comparing hormone receptor response

Coconut oil reduces steroidogenic enzymes and imbalances estrogen receptors in the adrenal cortex of Mongolian gerbils

This study aims to verify the effects of prolonged ingestion of coconut oil on the adrenal glands of Mongolian gerbils. Mongolian gerbils were used as an experimental model due to the morphological similarity of the adrenal glands to those of primates. Male Mongolian gerbils, 3 months of age, were divided into three experimental groups (n = 12): an intact control group, which received no treatment, a gavage control group, which received 0.1 ml of water daily by gavage, and a coconut oil-treated group, which received 0.1 ml of coconut oil daily for 12 months. The results showed that prolonged consumption of coconut oil caused an increase in cell area and thickness of the zona reticularis and the accumulation of lipid droplets, as well as reducing the amount of steroidogenic enzymes, such as CYP17, 3BHSD, and 17BHSD. It was also observed that the oil increased the expression of estrogen receptor alpha and their isoforms. These alterations allow us to conclude that changes in the lipid diet can cause alterations in the morphophysiology of the adrenal gland and, consequently, impact its functionality.

Multiplex aptamer cluster detection platform and systems toxicology study for 17β-estradiol, bisphenol A, and diethylstilbestrol

Intake of 17β-estradiol (E2), bisphenol A (BPA), and diethylstilbestrol (DES) from food can contribute to endocrine disorders. Therefore, developing a sensitive method for the simultaneous detection of E2, BPA, and DES and understanding their combined effects on endocrine disruption are crucial. We developed a fluorescence aptasensing platform utilizing DNase I-assisted cyclic enzymatic signal amplification in conjunction with an aptamer/graphene oxide complex. Using PEG 20000 as a surface-blocking agent, the aptasensor achieved ultralow detection limits of 2.643, 0.3039, and 0.6996 for E2, BPA, and DES, respectively. The sensor demonstrated accurate detection in plastic bottled water at spiked levels of 10 and 100 ng/mL. Systems toxicology revealed 30 potential targets for mixture-induced endocrine disruption. Molecular docking showed binding affinities of E2, BPA, and DES for ESR1 of -9.94, -8.29, and - 8.98 kcal/mol, respectively. These results highlight the effectiveness of the aptasensor and provide valuable insights into endocrine disruption mechanisms.

Individual and combined effects of commercial glyphosate, atrazine and 2,4-D herbicides on the gerbil ventral prostate

Exposure to pesticides, individually or in a mixture, in drinking water is one of the main sources of human contamination, which causes adverse effects on the reproductive system. Our study aimed to investigate, the effects of a 90-day exposure to low concentrations of glyphosate (GLY), atrazine (ATZ), and 2,4-dichlorophenoxyacetic acid (2,4-D), in commercial formulations, on morphological, molecular, and hormonal parameters of the ventral prostate of gerbils (Meriones unguiculatus). The animals were exposed via drinking water to individual concentrations of GLY: 700 μg/L, ATZ: 3 μg/L, and 2,4-D: 70 μg/L, as well as to their mixture (MIX). Our findings showed an increase in prostatic complex relative weight in ATZ-exposed animals. Stereological and morphometric techniques indicated an increase in the percentage and thickness of muscular stroma, following an increase in the amount of collagen and reticular fibers in the MIX group. Histopathological analysis showed a decrease in the incidence of epithelial atrophy, subepithelial inflammation, and microacini in the MIX. On the other hand, ATZ-exposed animals showed an increase in hyperplasia and total prostatic intraepithelial neoplasia (PIN). The expression of caspase-3 decreased and estrogen receptor alpha (ERα) increased in the 2,4-D and MIX. Western blotting showed an increase in estrogen receptor beta (ERβ) expression in MIX-exposed animals. Testosterone levels decreased in animals from the GLY, ATZ and 2,4-D groups. Our findings provide evidence that individual or combined exposure to herbicides causes hormonal imbalance and morphological alterations, besides favoring the incidence of proliferative lesions in the prostate, predisposing the gland to more severe injuries.

Promoting effect of sunset yellow on N-methyl N-nitrosourea-induced rat mammary carcinogenesis: Implications of molecular mechanisms

BACKGROUND

Nowadays, the use of food additives, such as Sunset Yellow (SY), is growing, which attracted attention to the potential relationship between some diseases and food additives.

AIM

The study aimed to investigate the role of Sunset Yellow during chemically-induced mammary gland carcinogenesis in Sprague-Dawley rats.

MATERIAL AND METHODS

Three groups of female rats were intraperitoneally administered with N-methyl-N-nitrosourea (MNU). Group 1 was set on a basal diet. Group 2 was treated with 161.4 mg\kg\day Sunset Yellow (SY). Group 3 was given SY at 80.7 mg\kg\day. Groups 4-6 were not administered MNU; Group 4 received vehicles only. Groups 5 and 6 were administered SY similarly to groups 2 and 3 respectively.

RESULTS

Sunset Yellow at both doses exerted a significant dose-dependent increase in tumor incidences, multiplicities, volumes, and decreased tumor latency as compared with control. Immunolabeling indexes of the proliferating cell nuclear antigen, estrogen receptor alpha, and progesterone receptor were significantly increased after SY treatment. Oxidative stress markers, serum estrogen, progesterone, and prolactin levels were significantly modified by SY treatment. The mRNA expression of estrogen receptor alpha and epidermal growth factor was up-regulated in SY groups versus control.

CONCLUSION

Collectively, SY has significantly promoted MNU-induced mammary tumors in rats with underlying mechanisms correlating SY consumption with estrogen disruption and subsequent antioxidative stress discrepancy.

Gap junctions in polycystic ovary syndrome: Implications for follicular arrest

Gap junctions are specialized intercellular conduits that provide a direct pathway between neighboring cells, which are involved in numerous physiological processes, such as cellular differentiation, cell growth, and metabolic coordination. The effect of gap junctional hemichannels in folliculogenesis is particularly obvious, and the down-regulation of connexins is related to abnormal follicle growth. Polycystic ovary syndrome (PCOS) is a ubiquitous endocrine disorder of the reproductive system, affecting the fertility of adult women due to anovulation. Exciting evidence shows that gap junction is involved in the pathological process related to PCOS and affects the development of follicles in women with PCOS. In this review, we examine the expression of connexins in follicular cells of PCOS and figure out whether such communication could have consequences for PCOS women. While along with results from clinical and related animal studies, we summarize the mechanism of connexins involved in the pathogenesis of PCOS.

The Mongolian Gerbil as a Useful Experimental Model in Reproductive Biology

Ultimately, the Mongolian gerbils (Meriones unguiculatus) have acquired a relevant role in biological and biomedical experiments alongside other rodents. The use of gerbils in research has been mainly oriented to physiological and pharmacological studies, with special attention to nervous, digestive, and auditory systems as well as microbiology and parasitology. Ultimately, gerbils have also been applied for studying carcinogenesis in different organs and systems, since these animals show a natural propensity to develop spontaneous proliferative lesions, especially in steroid-responsive organs. This characteristic shed light on the reproductive aspects of this rodent model regarding morphological features in male and female individuals. This review of literature summarizes the significance of this model as an alternative to the use of inbred mice and rats in reproductive experimental research, highlighting recent findings. Gerbils have contributed to the expansion of knowledge in prostate biology in male and female individuals, providing studies related to prostatic morphogenesis and neoplasia. In the testes, spermiogenesis occurs in 15 steps, differently from other experimental models. Also, the complete maturation of the testis-epididymal complex occurs between the second and third months. Mammary gland alterations related to the estrous cycle and pregnancy were described, as well as its modulation under endogenous and exogenous estrogenic compounds. The ovaries frequently present ovarian cysts. Furthermore, this organ shows predominantly interstitial steroidogenic glands in the stroma, especially at aging. Adrenal gland shows a large size compared to other animals, presenting three distinct zones with a remarkable role in steroidogenesis.

Impairment of steroidogenesis and follicle development after bisphenol A exposure during pregnancy and lactation in the ovaries of Mongolian gerbils aged females

The ovaries regulate fertility and hormonal control in females, and aging is a crucial factor in this process, when ovarian function is drastically impacted. Exogenous endocrine disruptors may accelerate this process, acting as the main agents in decreased female fertility and hormonal imbalance, since they impact different features related to reproduction. In the present study, we demonstrate the implications of exposure of adult mothers to the endocrine disruptor bisphenol A (BPA) during pregnancy and lactation on their ovarian function during the transition to later in life (aging). The follicle population of BPA exposed ovaries showed impairment in the development of follicles to the mature stages, with growing follicles being halted in the early stages. Atretic and early-atretic follicles were also enhanced. Expression of estrogen and androgen receptors in the follicle population demonstrated impairment in signaling function: ERβ was highly expressed in follicles from BPA exposed females, which also showed a higher incidence of early atresia of developed follicles. ERβ1 wild-type isoform was also enhanced in BPA-exposed ovaries, compared to its variant isoforms. In addition, steroidogenesis was targeted by BPA exposure: aromatase and 17-β-HSD were reduced, whereas 5-α reductase was enhanced. This modulation was reflected in serum levels of estradiol and testosterone, which decreased in BPA-exposed females. Imbalances in steroidogenesis impair the development of follicles and play an important role in follicular atresia. Our study demonstrated that BPA exposure in two windows of susceptibility - gestation and lactation - had implications during aging, enhancing perimenopausal and infertile features.

Hormone receptor expression in aging mammary tissue and carcinoma from a rodent model after xenoestrogen disruption

AIMS

Hormone receptors are the main markers applied for prognosis of breast cancer subtypes. Among modulators, exogenous chemical agents known as endocrine disruptors interact with certain receptors, triggering molecular pathways or increasing their expression. Bisphenol A (BPA), a xenoestrogen, interacts with several hormone receptors. Thus, our aim was to characterize the hormone receptor status in the mammary gland (MG) of aged female Mongolian gerbils exposed to BPA in pregnancy and lactation.

METHODS

We evaluated the expression of receptors for estrogens (ERα and ERβ), progesterone (PR), prolactin (PRL-R), HER2/ErbB2, and androgen (AR) in normal and hyperplastic mammary tissue and in carcinomas developed after BPA exposure.

KEY FINDINGS

BPA-exposed MG presented increased ERα, whereas ERβ, PR, and PRL-R showed lower expression. AR and HER2/ErbB2 showed similar expression in normal and hyperplastic tissue from control, vehicle, and BPA groups. Both receptors were found in cytoplasm and nucleus in BPA-induced carcinoma. We demonstrate the presence of EZH2 expression, an epigenetic and epithelial-mesenchymal transition (EMT) marker, with a high H-score in BPA-exposed MG, which was associated with poor prognosis of cancer. Co-localization of ERα and EZH2 was present in normal and carcinoma features, corroborating the installation of ERα-positive mammary cancer associated with the EMT process. Enhanced EZH2 in BPA-exposed mammary tissue could decrease ERβ expression and promote tumorigenesis progress through HER2/ErbB2.

SIGNIFICANCE

The present study proposes the Mongolian gerbil as an experimental model for mammary carcinogenesis studies, based on BPA disruption that triggers a phenotype of increased ERα/HER2 positivity and depletion of ERβ/PR expression.

Impact of bisphenol A (BPA) on cells and tissues at the human materno-fetal interface

Bisphenol A (BPA) is an endocrine disruptor extensively used in the production of polycarbonate plastics and epoxy resins and a component of liquid and food containers. It is a hazard in the prenatal period because of its presence in the placenta, fetal membranes, amniotic fluid, maternal and fetal blood and its ability to cross the placenta and reach the fetus. Estimation of the risk of BPA exposure during in utero life is extremely important in order to prevent complications of pregnancy and fetal growth. This review describes in vitro models of the human materno-fetal interface. It also outlines the effects of BPA at doses indicated as "physiological", namely at the concentrations found in the general population, and at "supraphysiological" and "subphysiological" doses, i.e. above and below the physiological range. This work will help clarify the discrepancies observed in studies on the effects of BPA on human reproduction and pregnancy, and it will be useful for the choice of appropriate in vitro models for future studies aimed at identifying the potential impact of BPA on specific functional processes.

Molecular mechanisms of mammary gland remodeling: A review of the homeostatic versus bisphenol a disrupted microenvironment

Mammary gland (MG) undergoes critical points of structural changes throughout a woman's life. During the perinatal and pubertal stages, MG develops through growth and differentiation to establish a pre-mature feature. If pregnancy and lactation occur, the epithelial compartment branches and differentiates to create a specialized structure for milk secretion and nurturing of the newborn. However, the ultimate MG modification consists of a regression process aiming to reestablish the smaller and less energy demanding structure until another production cycle happens. The unraveling of these fascinating physiologic cycles has helped the scientific community elucidate aspects of molecular regulation of proliferative and apoptotic events and remodeling of the stromal compartment. However, greater understanding of the hormonal pathways involved in MG developmental stages led to concern that endocrine disruptors such as bisphenol A (BPA), may influence these specific development/involution stages, called "windows of susceptibility". Since it is used in the manufacture of polycarbonate plastics and epoxy resins, BPA is a ubiquitous chemical present in human everyday life, exerting an estrogenic effect. Thus, descriptions of its deleterious effects on the MG, especially in terms of serum hormone concentrations, hormonal receptor expression, molecular pathways, and epigenetic alterations, have been widely published. Therefore, allied to a didactic description of the main physiological mechanisms involved in different critical points of MG development, the current review provides a summary of key mechanisms by which the endocrine disruptor BPA impacts MG homeostasis at different windows of susceptibility, causing short- and long-term effects.

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.

Occurrence of contaminants of emerging concern in surface waters from Paraopeba River Basin in Brazil: seasonal changes and risk assessment

This study describes the application of gas chromatography coupled to mass spectrometry (GC-MS) to evaluate the occurrence of 12 CECs-contaminants of emerging concern (bisphenol A, diclofenac, 17β-estradiol, estriol, estrone, 17α-ethinylestradiol, gemfibrozil, ibuprofen, naproxen, 4-nonylphenol, 4-octylphenol, and acetaminophen) in surface waters from Paraopeba River Basin, Minas Gerais State, Brazil. The analytical procedure was validated and applied to 60 surface water samples collected across four sampling campaigns along the upper and middle watershed. Methods for CECs determination involved sample filtration, and solid-phase extraction (SPE) with subsequent derivatization of the target compounds prior to their analysis by GC-MS. The LOQ varied from 3.6 to 14.4 ng/L and extraction recoveries ranged from 46.1 to 107.1% for the lowest spiked concentration level (10 ng/L). The results showed a profile of spatial distribution of compounds, as well as the influence of rainfall. Ibuprofen (1683.9 ng/L), bisphenol (1587.7 ng/L), and naproxen (938.4 ng/L) occurred in higher concentrations during the rainy season, whereas during the dry season, the concentrations of bisphenol (1057.7 ng/L), estriol (991.0 ng/L), and estrone (978.4 ng/L) were highlighted. The risk assessment of human exposure shows that for most contaminants, the concentration is well below the estimated thresholds for chronic toxicity from water intake. However, estradiol and 17α-ethinylestradiol showed concentrations in the same order of magnitude as the guide values estimated for babies.

Effects of bisphenol A at the safe reference dose on abdominal fat deposition in aged hens

Bisphenol A (BPA) is an endocrine-disrupting chemical. Its influence on lipid homeostasis remains to be proven. In this study, the obese model of laying hens were induced using high-fat diet (HFD) to determine the lipid metabolism interference of BPA, especially its influence on estrogen receptors (ERs) and oxidative damage, at the dose of tolerable daily intake (TDI, 50 μg/kg body weight [BW]/day) and no observable adverse effect level (NOAEL, 5000 μg/kg BW/day). The results demonstrated that the TDI dose of BPA interacted with ERα more effectively than the NOAEL dose of BPA. The TDI dose of BPA increased the expression of ERα (esr1), which further changed the expression of lipid metabolism-related genes, such as cpt-1, lpl, creb1, and apov1. Furthermore, the abdominal fat rate, hematoxylin-eosin staining of adipocytes, and the average area of the hens were reduced. Therefore, the TDI dose of BPA played an estrogen-compensating role and weakened the effect of HFD on obesity in aged hens. By contrast, BPA at NOAEL dose exhibited great oxidative stress, which remarkably inhibited the activities of antioxidant-related enzymes (total superoxide dismutase and glutathione peroxidase) and promoted the excessive accumulation of lipid peroxidation products (malondialdehyde). Moreover, the increase in oxidative stress corresponded well with the increase in the expression of fat-forming genes (srebp-1, fas, acc, and ppar γ). That is, BPA at NOAEL may accelerate the process of fat formation.

Bisphenol A and benzophenone-3 exposure alters milk protein expression and its transcriptional regulation during functional differentiation of the mammary gland in vitro

The plastic monomer and plasticizer bisphenol A (BPA), and the UV-filter benzophenone-3 (BP3) have been shown to have estrogenic activities that could alter mammary gland development. Our aim was to analyze whether BPA or BP3 direct exposure affects the functional differentiation of the mammary gland using an in vitro model. Mammary organoids were obtained and isolated from 8 week-old virgin female C57BL/6 mice and were differentiated on Matrigel with medium containing lactogenic hormones and exposed to: a) vehicle (0.01% ethanol); b) 1 × 10^-9 M or 1 × 10^-6 M BPA; or c) 1 × 10^-12 M, 1 × 10^-9 M or 1 × 10^-6 M BP3 for 72 h. The mRNA and protein expression of estrogen receptor alpha (ESR1) and progesterone receptor (PR) were assessed. In addition, mRNA levels of PR-B isoform, glucocorticoid receptor (GR), prolactin receptor (PRLR) and Stat5a, and protein expression of pStat5a/b were evaluated at 72 h. The mRNA and protein expression of milk proteins and their DNA methylation status were also analyzed. Although mRNA level of PRLR and GR was similar between treatments, mRNA expression of ESR1, total PR, PR-B and Stat5a was increased in organoids exposed to 1 × 10^-9 M BPA and 1 × 10^-12 M BP3. Total PR expression was also increased with 1 × 10^-6 M BPA. Nuclear ESR1 and PR expression was observed in all treated organoids; whereas nuclear pStat5a/b alveolar cells was observed only in organoids exposed to 1 × 10^-9 M BPA and 1 × 10^-12 M BP3. The beta-casein mRNA level was increased in both BPA concentrations and 1 × 10^-12 M BP3, which was associated with hypomethylation of its promoter. The beta-casein protein expression was only increased with 1 × 10^-9 M BPA or 1 × 10^-12 M BP3. In contrast, BPA exposure decreased alpha-lactalbumin mRNA expression and increased DNA methylation level in different methylation-sensitive sites of the gene. Also, 1 × 10^-9 M BPA decreased alpha-lactalbumin protein expression. Our results demonstrate that BPA or BP3 exposure alters milk protein synthesis and its transcriptional regulation during mammary gland differentiation in vitro.