The industrial chemical bisphenol A (BPA) interferes with proliferative activity and development of steroidogenic capacity in rat Leydig cells

Pregnenolone 16-Alpha Carbonitrile, an Agonist of Rodent Pregnane X Receptor, Regulates Testosterone Biosynthesis in Rodent Leydig Cells

Leydig cells (LCs) in the testes produce the male sex hormone testosterone (T). Several xenobiotics, including clinical drugs, supplements, and environmental chemicals, are known to disrupt T homeostasis. Notably, some of these xenobiotics are known to activate the pregnane X receptor (PXR), a ligand-dependent nuclear receptor. However, it is currently unknown whether PXR is expressed in LCs and whether PXR activation alters T synthesis in rodent LCs. Therefore, in this study, we sought to determine whether PXR is expressed in rodent LCs and whether pregnenolone 16-alpha carbonitrile (PCN), the prototype agonist of rodent PXR, regulates T biosynthesis in rodent LCs. Hormonal as well as protein and gene expression analyses were conducted in rat primary LCs and MA-10 mouse Leydig cells. Results showed that PXR was expressed at the mRNA and protein level in both rat primary LCs and MA-10 cells. Incubation of rat primary LCs with PCN resulted in a significant decrease in T secretion. This PCN-induced decrease in T secretion was associated with decreased protein expression of key steroidogenic enzymes such as 3β-HSD and CYP17A1. RNA-seq results from MA-10 cells showed that PCN down-regulated the transcripts of steroidogenic enzymes and proteins involved in the T synthesis pathway. Together, these results suggest that PCN, an agonist of rodent PXR, can regulate T biosynthesis in rodent LCs by down-regulating the expression of the steroidogenic enzymes involved in T biosynthesis. Our results are significant as they provide a potential novel mechanism for disruption of testosterone homeostasis by a variety of xenobiotics.

Bisphenol-A in Drinking Water Accelerates Mammary Cancerogenesis and Favors an Immunosuppressive Tumor Microenvironment in BALB-neuT Mice

Bisphenol-A (BPA), a synthetic compound ubiquitously present in the environment, can act as an endocrine disruptor by binding to both canonical and non-canonical estrogen receptors (ERs). Exposure to BPA has been linked to various cancers, in particular, those arising in hormone-targeted tissues such as the breast. In this study, we evaluated the effect of BPA intake through drinking water on ErbB2/neu-driven cancerogenesis in BALB-neuT mice, transgenic for a mutated ErbB2/neu receptor gene, which reproducibly develop carcinomas in all mammary glands. In this model, BPA accelerated mammary cancerogenesis with an increase in the number of tumors per mouse and a concurrent decrease in tumor-free and overall survival. As assessed by immunohistochemistry, BALB-neuT tumors were ER-negative but expressed high levels of the alternative estrogen receptor GPR30, regardless of BPA exposure. On the other hand, BPA exposure resulted in a marked upregulation of progesterone receptors in preinvasive tumors and of Ki67, CD31, and phosphorylated Akt in invasive tumors. Moreover, based on several infiltration markers of immune cells, BPA favored an immunosuppressive tumor microenvironment. Finally, in vitro cell survival studies performed on a cell line established from a BALB-neuT breast carcinoma confirmed that BPA's impact on cancer progression can be particularly relevant after chronic, low-dose exposure.

Effects of chronic dichlorodiphenyldichloroethylene exposure on testosterone secretion and steroidogenic pathway in the male gonad

Endocrine disrupting chemicals are present in the environment and/or in consumer products. These agents have the capacity to mimic and/or antagonize endogenous hormones and thus perturb the endocrine axis. The male reproductive tract expresses steroid hormone (androgen and estrogen) receptors at high levels and is a major target for endocrine disrupting chemicals. In this study, Long-Evans male rats were exposed to dichlorodiphenyldichloroethylene, a metabolite of dichlorodiphenyltrichloroethane and a chemical present in the environment, in drinking water at 0.1 and 10 μg/L for 4 weeks. At the end of exposure, we measured steroid hormone secretion and analyzed steroidogenic proteins, including 17β-hydroxysteroid dehydrogenase, 3β-hydroxysteroid dehydrogenase, steroidogenic acute regulatory protein, aromatase, and the LH receptor. We also analyzed Leydig cell apoptosis (poly-(ADP-ribose) polymerase) and caspase-3 in the testes. Testicular testosterone (T) and 17β-estradiol (E2) were both affected by exposure to dichlorodiphenyldichloroethylene by displaying altered steroidogenic enzyme expression. Dichlorodiphenyldichloroethylene exposure also increased the expression of enzymes mediating the pathway for programmed cell death, including caspase 3, pro-caspase 3, PARP, and cleaved PARP. Altogether, the present results demonstrate that dichlorodiphenyldichloroethylene directly and/or indirectly can target specific proteins involved in steroid hormone production in the male gonad and suggest that exposure to environmentally relevant dichlorodiphenyldichloroethylene levels has implications for male reproductive development and function.

Short-Term Exposure to Bisphenol A Does Not Impact Gonadal Cell Steroidogenesis In Vitro

Bisphenol A (BPA) is a ubiquitous, synthetic chemical proven to induce reproductive disorders in both men and women. The available studies investigated the effects of BPA on male and female steroidogenesis following long-term exposure to the compound at relatively high environmental concentrations. However, the impact of short-term exposure to BPA on reproduction is poorly studied. We evaluated if 8 and 24 h exposure to 1 nM and 1 µM BPA perturbs luteinizing hormone/choriogonadotropin (LH/hCG)-mediated signalling in two steroidogenic cell models, i.e., the mouse tumour Leydig cell line mLTC1, and human primary granulosa lutein cells (hGLC). Cell signalling studies were performed using a homogeneous time-resolved fluorescence (HTRF) assay and Western blotting, while gene expression analysis was carried out using real-time PCR. Immunostainings and an immunoassay were used for intracellular protein expression and steroidogenesis analyses, respectively. The presence of BPA leads to no significant changes in gonadotropin-induced cAMP accumulation, alongside phosphorylation of downstream molecules, such as ERK1/2, CREB and p38 MAPK, in both the cell models. BPA did not impact STARD1, CYP11A1 and CYP19A1 gene expression in hGLC, nor Stard1 and Cyp17a1 expression in mLTC1 treated with LH/hCG. Additionally, the StAR protein expression was unchanged upon exposure to BPA. Progesterone and oestradiol levels in the culture medium, measured by hGLC, as well as the testosterone and progesterone levels in the culture medium, measured by mLTC1, did not change in the presence of BPA combined with LH/hCG. These data suggest that short-term exposure to environmental concentrations of BPA does not compromise the LH/hCG-induced steroidogenic potential of either human granulosa or mouse Leydig cells.

Cucumeropsis mannii seed oil protects against Bisphenol A-induced testicular mitochondrial damages

There has been increasing search for the ameliorative properties of seed oils against toxicants. bisphenol A acts as an estrogenic endocrine-disrupting chemical capable of causing male infertility. This study aimed to explore Cucumeropsis mannii seed oil effects against mitochondrial damage in rats using bisphenol A. Forty-eight rats were randomly assigned to six groups (n = 6) of eight rats each and fed the same food and water for 6 weeks. The group A rats were given 1 mL olive oil, while the ones in group B were given bisphenol A at 100 mL/kg body weight via oral route. Group C received C. mannii seed oil 7.5 mL/kg body weight C. mannii seed oil, while group D, group E, and group F were pre-administered bisphenol A at 100 mL/kg body weight, followed by treatment with C. mannii seed oil at 7.5, 5, and 2.5 mL/kg body weight, respectively. Antioxidant enzymes, glutathione, reactive oxygen species, testicular volume, malondialdehyde, body weight, and testicular studies were done using standard methods. The results of the bisphenol A-administered group showed a significant decrease in the antioxidant enzymes, glutathione, body weight, and testicular volume with elevation in the levels of reactive oxygen species, malondialdehyde, and testicular indices. BPA + CMSO-treated group showed a significant increase in GPx activity compared with BPA-exposed rats. CMSO treatment significantly increased catalase activity in comparison with that of rats exposed to BPA. Remarkably, C. mannii seed oil and bisphenol A co-administration significantly reversed the abnormalities observed in the dysregulated biochemical biomarkers. Our findings suggest that C. mannii seed oil has considerable antioxidant potential which can be explored in therapeutic development against systemic toxicity induced by exposure to bisphenol A. Cucumeropsis mannii seed oil protects against bisphenol A-induced testicular mitochondria damages.

Cucumeropsis mannii seed oil ameliorates Bisphenol-A-induced adipokines dysfunctions and dyslipidemia

This study demonstrated the therapeutic potentials of Cucumeropsis mannii seed oil (CMSO) capable of alleviating BPA-induced dyslipidemia and adipokine dysfunction. In this study, we evaluated the effects of CMSO on adipokine dysfunctions and dyslipidemia in bisphenol-A (BPA)-induced male Wistar rats. Six-week-old 36 albino rats of 100-200 g weight were assigned randomly to six groups, which received varied doses of BPA and/or CMSO. The administration of BPA and CMSO was done at the same time for 42 days by oral intubation. The adipokine levels and lipid profile were measured in adipose tissue and plasma using standard methods. BPA induced significant (p < .05) increases in triglycerides, cholesterol, leptin, LDL-C, and atherogenic and coronary risk indices in adipose tissue and plasma, as well as a decrease in adiponectin and HDL-C levels in Group II animals. BPA administration significantly (p < .05) elevated Leptin levels and reduced adiponectin levels. BPA plus CMSO reduced triglycerides, cholesterol, leptin, LDL-C, and atherogenic and coronary risk indices while increasing adiponectin levels and HDL-C in adipose tissue and plasma (p < .05). The results showed that BPA exposure increased adipose tissue as well as serum levels of the atherogenic index, triglycerides, cholesterol, coronary risk index, LDL-C, leptin, and body weight with decreased adiponectin levels and HDL-C. Treatment with CMSO reduced the toxicities caused by BPA in rats by modulating the body weight, adiponectin/leptin levels, and lipid profiles in serum and adipose tissue. This study has shown that CMSO ameliorates BPA-induced dyslipidemia and adipokine dysfunctions. We suggest for further clinical trial to establish the clinical applications.

Expression and function of mitochondrial inhibitor factor-1 and TASK channels in adrenal cells

Adrenal medullary chromaffin (AMC) cells in the perinatal period and carotid body glomus cells after birth respond to hypoxia with catecholamine secretion. The hypoxia detection mechanism in such O2-sensitive cells is still not well defined. One hypothesis is that a decrease in cellular ATP may be involved in the hypoxia detection. This idea is based on ATP dependence of TASK channel activity that regulates the resting membrane potential and is suppressed by hypoxia in glomus cells. Mitochondrial ATPase inhibitor factor-1 (IF1), a physiological regulator of ATP synthase, helps prevent ATP hydrolysis under hypoxic conditions. In cells where IF1 expression is high, exposure to hypoxia is expected to have no effect on TASK channel activity. This possibility was electrophysiologically and immunocytochemically explored. Single channel recordings revealed that 36-pS TASK3-like channels contribute to the resting membrane potential in young rat adrenal cortical (AC) cells. TASK3-like channel activity in a cell-attached patch was not affected by bath application of mitochondrial inhibitors. Consistent with this finding, IF1-like immunoreactive material was well expressed in rat AC cells. In further support of our hypothesis, IF1-like immunoreactive material was well expressed in adult rat AMC cells that are known to be hypoxia-insensitive and minimally expressed in newborn AMC cells that are hypoxia-sensitive. These results provide evidence for the functional relevance of IF1 expression in excitability in O2-sensitive cells in response to mitochondrial inhibition.

Susceptibility of male reproductive system to bisphenol A, an endocrine disruptor: Updates from epidemiological and experimental evidence

Bisphenol A (BPA) is an omnipresent environmental pollutant. Despite being restrictions in-force for its utilization, it is widely being used in the production of polycarbonate plastics and epoxy resins. Direct, low-dose, and long-term exposure to BPA is expected when they are used in the packaging of food products and are used as containers for food consumption. Occupationally, workers are typically exposed to BPA at higher levels and for longer periods during the manufacturing process. BPA is a known endocrine disruptor chemical (EDC), that causes male infertility, which has a negative impact on human life from emotional, physical, and societal standpoints. To minimize the use of BPA in numerous consumer products, efforts and regulations are being made. Despite legislative limits in numerous nations, BPA is still found in consumer products. This paper examines BPA's overall male reproductive toxicity, including its impact on the hypothalamic-pituitary-testicular (HPT) axis, hormonal homeostasis, testicular steroidogenesis, sperm parameters, reproductive organs, and antioxidant defense system. Furthermore, this paper highlighted the role of non-monotonic dose-response (NMDR) in BPA exposure, which will help to improve the overall understanding of the harmful effects of BPA on the male reproductive system.

Current progress in treatment technologies for plastic waste (bisphenol A) in aquatic environment: Occurrence, toxicity and remediation mechanisms

Bisphenol-A (BPA) is a type of endocrine disrupting compound (EDC) that is being widely used in the production of polycarbonate and epoxy resins. In the last few years, human exposure to BPA has been extensively high due to the continuous increment in the Annual Growth Rate (AGR) of the BPA global market. The presence and transportation of BPA in the environment could cause serious damage to aquatic life and human health. This paper reviewed the literature on the exposure and toxicity mechanisms of BPA and advanced analytical techniques for the detection of BPA in the environment and human beings. The study indicated that BPA can cause damaging effects on numerous tissues and organs, including the reproductive system, metabolic dysfunction, respiratory system, immune system and central nervous system. On the basis of reported studies on animals, it appears that the exposure of BPA can be carcinogenic and responsible for causing a variety of cancers like ovarian cancer, uterine cancer, prostate cancer, testicular cancer, and liver cancer. This review paper focused mainly on the current progress in BPA removal technologies within last ten years (2012-2022). This paper presents a comprehensive overview of individual removal technologies, including adsorption, photocatalysis/photodegradation, ozonation/advance oxidation, photo-fenton, membranes/nanofilters, and biodegradation, along with removal mechanisms. The extensive literature study shows that each technology has its own removal mechanism and their respective limitations in BPA treatment. In adsorption and membrane separation process, most of BPA has been treated by electrostatic interaction, hydrogen boning and π-π interations mechanism. Whereas in the degradation mechanism, O* and OH* species have played a major role in BPA removal. Some factors could alter the removal potential and efficiency of BPA removal. This review paper will provide a useful guide in providing directions for future investigation to address the problem of BPA-containing wastewater treatment.

An insight into bisphenol A, food exposure and its adverse effects on health: A review

Bisphenol A (BPA) is a synthetic chemical widely employed to synthesize epoxy resins, polymer materials, and polycarbonate plastics. BPA is abundant in the environment, i.e., in food containers, water bottles, thermal papers, toys, medical devices, etc., and is incorporated into soil/water through leaching. Being a potent endocrine disrupter, and has the potential to alter several body mechanisms. Studies confirmed its anti-androgen action and estrogen-like effects, which impart many negative health impacts, especially on the immune system, neuroendocrine process, and reproductive mechanism. Moreover, it can also induce mutagenesis and carcinogenesis, as per recent scientific research. This review focuses on BPA's presence and concentrations in different environments, food sources and the basic mechanisms of BPA-induced toxicity and health disruptions. It is a unique review of its type because it focuses on the association of cancer, hormonal disruption, immunosuppression, and infertility with BPA. These issues are widespread today, and BPA significantly contributes to their incidence because of its wide usage in daily life utensils and other accessories. The review also discusses researched-based measures to cope with the toxic chemical.

Evaluation of Bisphenol A in Pregnant Women from 10 Caribbean Countries

Bisphenol A (BPA), a phenolic chemical incorporated into many plastic products, has been found to act as an endocrine disruptor that potentially is linked to adverse neurodevelopmental outcomes. Prenatal BPA concentration levels were assessed in 10 English-speaking Caribbean countries by randomly selecting 15 maternal urine samples from approximately 50 pregnant women samples collected in each island and then comparing the findings with comparable data from Canada and the U.S. BPA was detected in all samples ranging from a low geometric mean of 1.46 μg/L (St. Lucia) to a high of 4.88 μg/L (St. Kitts & Nevis). All of the Caribbean islands sampled had geometric mean concentration levels that were higher than those recorded in two Canadian biomonitoring surveys (1.26 μg/L and 0.80 μg/L) and the U.S. NHANES survey (1.39 μg/L). This first biomonitoring survey of BPA concentration levels in maternal urine samples taken from Caribbean countries clearly points to the need for Caribbean governments and public health officials to first engage in legislative and regulatory efforts to ban or minimize the importation and use of BPA products used the Caribbean and, second, to continue to conduct biomonitoring surveys so as to ensure that these laws and regulations are indeed leading to a decrease of BPA concentrations in Caribbean populations.

Knowledge Gap in Understanding the Steroidogenic Acute Regulatory Protein Regulation in Steroidogenesis Following Exposure to Bisphenol A and Its Analogues

The use of bisphenols has become extremely common in our daily lives. Due to the extensive toxic effects of Bisphenol A (BPA), the industry has replaced this endocrine-disrupting chemical (EDC) with its analogues, which have been proven to decrease testosterone levels via several mechanisms, including targeting the steroidogenic acute regulatory (StAR) protein. However, when exposed to BPA and its analogues, the specific mechanism that emerges to target StAR protein regulations remains uncertain. Hence, this review discusses the effects of BPA and its analogues in StAR protein regulation by targeting cAMP-PKA, PLC-PKC, EGFR-MAPK/ERK and Ca²⁺-Nur77. BPA and its analogues mainly lead to decreased LH in blood and increased ERK expression and Ca²⁺ influx, with no relationship with the StAR protein regulation in testicular steroidogenesis. Furthermore, the involvement of the cAMP-PKA, PLC-PKC, and Nur77 molecules in StAR regulation in Leydig cells exposed to BPA and its analogues remains questionable. In conclusion, although BPA and its analogues have been found to disrupt the StAR protein, the evidence in connecting the signaling pathways with the StAR regulations in testicular steroidogenesis is still lacking, and more research is needed to draw a solid conclusion.

The Male Reproductive System and Endocrine Disruptors

The male reproductive system is exposed to a great number of chemical substances which can interfere with the normal hormonal milieu and reproductive function; these are called endocrine disruptors (EDs). Despite a growing number of studies evaluating the negative effects of EDs, their production is continuously growing although some of which have been prohibited. The prevalence of poor semen quality, hypospadias, cryptorchidism, and testicular cancer have increased in the last decades, and recently, it has been postulated that these could all be part of a unique syndrome called testicular dysgenesis syndrome. This syndrome could be related to exposure to a number of EDs which cause imbalances in the hormonal milieu and oestrogenic over-exposure during the foetal stage. The same EDs can also impair spermatogenesis in offspring and have epigenetic effects. Although studies on animal and in vitro models have raised concerns, data are conflicting. However, these studies must be considered as the basis for future research to promote male reproductive health.

Gonadal sex steroid hormone secretion after exposure of male rats to estrogenic chemicals and their combinations

Environmental chemicals can interfere with the endocrine axis hence they are classified as endocrine disrupting chemicals (EDCs). Bisphenol S (BPS) is used in the manufacture of consumer products because of its superior thermal stability and is thought to be a safe replacement chemical for its analog bisphenol A (BPA). However, the safety profile of these compounds alone or in the presence of other EDCs is yet to be fully investigated. Also, the estrogenic chemical 17α-ethinyl estradiol (EE2) and a constituent of female oral contraceptives for women, is present in water supplies. To simulate concurrent exposure of the population to chemical mixtures, we investigated the effects of BPA, BPS, EE2, and their combinations on sex steroid secretion in the growing male rat gonad. Prepubertal and pubertal male rats at 21 and 35 days of age were provided test chemicals in drinking water (parts per billion) for 14 days. At termination of exposure, some individual chemical effects were modified by exposure to chemical combinations. Single chemical exposures markedly decreased androgen secretion but their combination (e.g., BPA + BPS + EE2) caused the opposite effect, i.e., increased Leydig cell T secretion. Also, the test chemicals acting alone or in combination increased testicular and Leydig cell 17β-estradiol (E2) secretion. Chemical-induced changes in T and E2 secretion were associated with altered testicular expression of the cholesterol side-chain cleavage (Cyp11a1) and 17β-hydroxysteroid dehydrogenase (Hsd17β) enzyme protein. Additional studies are warranted to understand the mechanisms by which single and chemical combinations impact function of testicular cells and disrupt their paracrine regulation.

Evaluation of post-adolescence exposure to bisphenol A on reproductive outcomes of male rodent models

The effect of post-adolescence bisphenol A (BPA) exposure on the reproductive system is not well-defined. We therefore performed this meta-analysis to elucidate the associations between post-adolescence BPA exposure and reproductive-related outcomes. A search was performed on the PubMed, EMBASE, and Web of science databases to identify relevant literature. The standardized mean differences (SMDs) and the 95 % confidence intervals (CIs) were measured by fixed-effects or random-effects models. Publication bias was assessed using funnel plots and Egger's regression test. A total of 40 studies were included in the final analysis. The results showed that post-adolescence BPA exposure was negatively associated with reproductive-related organ weighty (Testis weight: SMD: -0.61; 95 % Cl: -0.85, -0.36; epididymis weight; SMD: -0.43; 95 % Cl: -0.69, -0.17; seminal vesicles weight; SMD: -0.77; 95 % Cl: -1.05, -0.49) and sperm parameters (Sperm motility: SMD: -1.44; 95 % Cl: -1.95, -0.93; epididymal sperm concentration: SMD: -2.26; 95 % Cl: -2.79, -1.72; and abnormal sperm morphology: SMD: 2.41; 95 % Cl: 1.41, 2.86). Moreover, BPA exposure decreased the level of testosterone (T) and superoxide dismutase (SOD), but increased the ratio of serum estradiol (E2) to T. This systematic review demonstrates that post-adolescence exposure to BPA may adversely affect reproductive functions in male rodents.

Effects of Bisphenol A Released From Composite Fillings on Reproductive Hormone Levels in Men

Objectives

Composite resins are the most preferred filling material because of their excellent aesthetic qualities. However, a filling material should also be biocompatible as well as aesthetic. The aim of this study was to determine the serum and saliva bisphenol-A (BPA) levels and to examine the effects of serum BPA on reproductive hormone levels after healthy men were treated with composite fillings.

Methods

Eighteen healthy males each received 2 composite restorations. Saliva and blood samples of subjects were collected before resin application and 1 day and 1, 3, and 5 weeks after the resin was applied. BPA amounts in samples were detected using high-performance liquid chromatography (HPLC). Serum gonadotropins, testosterone, sex hormone binding globulin, free androgen index, and oestrogen levels were measured with radioimmunological assay kits. Statistical analysis of data was made using Friedman, Wilcoxon signed ranks and Mann-Whitney U tests (α = 0.05).

Results

The amount of BPA released from composite resins over time was not significantly elevated in either saliva or serum (P > 0.5). In addition, serum BPA levels were significantly higher than saliva BPA levels for both composites (P < .05), but saliva and serum BPA levels were not statistically different when comparing the 2 composites (P > .05).

Conclusions

BPA from composite resins used in this study did not significantly alter serum hormone levels.

Bisphenol A attenuates testosterone production in Leydig cells via the inhibition of NR1D1 signaling

Bisphenol A (BPA) is an endocrine-disrupting compound that impairs testosterone synthesis in male mammals. A circadian clock gene deficiency leads to diminished fertility and even infertility in male mice. However, whether circadian clock signaling pathways mediate the suppressive effect of BPA on testosterone synthesis in Leydig cells (LCs) remains unknown. The present study aims to detect the effect of BPA on cellular circadian clock and testosterone synthesis in mouse LCs, and examine the mechanisms underlying NR1D1 signaling. BPA treatment significantly attenuated the transcription levels of Nr1d1 and steroidogenic genes (Hsd3b2 and Hsd17b3) in TM3 cells, but increased other circadian clock gene levels (Per2 and Dbp). BPA treatment also significantly downregulated NR1D1 and StAR protein expression, but upregulated BMAL1 protein expression in TM3 cells. Furthermore, there was a marked decline in testosterone production in BPA-treated TM3 cells. Intraperitoneal injection of BPA profoundly reduced NR1D1 and StAR protein levels and steroidogenic gene transcription levels (Cyp11a1, Hsd3b2, and Hsd17b3), while enhancing BMAL1 protein and other circadian clock gene (Per2 and Dbp) levels in mouse testes. Notably, serum testosterone levels were also drastically reduced in BPA-treated mice. Moreover, SR9009, an NR1D1 agonist, augmented testosterone production in TM3 cells via elevated expression of steroidogenic genes (StAR, Cyp11a1 and Hsd17b3). Conversely, Nr1d1 knockdown inhibited testosterone accumulation and attenuated steroidogenic gene expression. Moreover, treatment with SR9009 partially reversed the BPA effect on the circadian clock and testosterone production. Taken together, our study demonstrates that BPA perturbs testosterone production, at least partially, via inhibiting NR1D1 signaling in LCs.

The impact of bisphenols on reproductive system and on offspring in pigs - A review 2011-2020

This study summarizes the knowledge about effects of bisphenol A (BPA) and its analogues on reproduction of pigs and some parameters of their offspring during period 2011-2020. Bisphenols are known as one of the most harmful environmental toxicants with endocrine-disrupting properties. One study in the reference period related to male reproductive system. Treatment with an antagonist of G-protein coupled estrogen receptor (GPER) - G15, and bisphenol A and its analogues, tetrabromobisphenol A (TBBPA) and tetrachromobisphenol A (TCBPA) diversely disrupted protein molecules controlling the biogenesis and function of microRNA in Leydig cells. Nine studies examined the effect of BPA, bisphenol S (BPS) or fluorene-9-bisphenol (BHPF) on female reproductive system. From the possible protective effect's point of view seems to be perspective the administration of melatonin in BPA-exposed oocytes. Finally, two studies were found to evaluate the maternal exposure to BPA on offspring's meat quality, muscle metabolism and oxidative stress. Administration of methyl donor improved antioxidant enzymes activity and reduced oxidative stress in piglets.

Co-administration of Selenium Nanoparticles and Metformin Abrogate Testicular Oxidative Injury by Suppressing Redox Imbalance, Augmenting Sperm Quality and Nrf2 Protein Expression in Streptozotocin-Induced Diabetic Rats

Selenium nanoparticles (SeNPs) and metformin (Met) elicit individually protective effects against testicular oxidative injury in diabetic rats. However, the combined effects of both compounds have not been investigated. We investigated the effects of SeNPs and Met individual/co-treatment on testicular oxidative injury in diabetic rats. Diabetes was induced by a single intraperitoneal administration of streptozotocin (STZ-40 mg/kg bwt). The rats were equally divided into 6 groups: Group one-non-diabetic; group two-diabetic untreated; and group six-non-diabetic received citrate buffer (2 mL/kg bwt), while group three, four, and five received SeNPs (0.1 mg/kg bwt), Met (50 mg/kg bwt), and SeNPs/Met combined respectively, for 42 days. Results revealed that SeNPs, as well as Met treatment significantly (p < 0.001), lowered blood glucose levels and improved relative organ weights in treated rats than those of the untreated group. Moreover, a synergistic effect was observed in the co-administration group. Additionally, combined treatment elicited better effect, in augmenting the pituitary and testicular hormone (LH, FSH, prolactin, and testosterone) levels, marker enzymes/protein associated with steroidogenesis (3-βHSD, 17-βHSD, and StAR protein), and sperm functional parameters than those of individual treatment groups, when compared with control. Furthermore, the combinatorial effects of SeNPs and Met surpassed their influence in attenuating testicular oxidative stress/inflammation and upregulation of Nrf2 protein expression in diabetic rats when compared with control. Overall, normal rats, co-treated with SeNPs and Met, did not reveal any deleterious effect. Therefore, SeNPs and Met combined treatment may better improve testes function in diabetic conditions than an individual regimen.

Bisphenols Threaten Male Reproductive Health via Testicular Cells

Male reproductive function and health are largely dependent on the testes, which are strictly regulated by their major cell components, i. e., Sertoli, Leydig, and germ cells. Sertoli cells perform a crucial phagocytic function in addition to supporting the development of germ cells. Leydig cells produce hormones essential for male reproductive function, and germ cell quality is a key parameter for male fertility assessment. However, these cells have been identified as primary targets of endocrine disruptors, including bisphenols. Bisphenols are a category of man-made organic chemicals used to manufacture plastics, epoxy resins, and personal care products such as lipsticks, face makeup, and nail lacquers. Despite long-term uncertainty regarding their safety, bisphenols are still being used worldwide, especially bisphenol A. While considerable attention has been paid to the effects of bisphenols on health, current bisphenol-related reproductive health cases indicate that greater attention should be given to these chemicals. Bisphenols, especially bisphenol A, F, and S, have been reported to elicit various effects on testicular cells, including apoptosis, DNA damage, disruption of intercommunication among cells, mitochondrial damage, disruption of tight junctions, and arrest of proliferation, which threaten male reproductive health. In addition, bisphenols are xenoestrogens, which alter organs and cells functions via agonistic or antagonistic interplay with hormone receptors. In this review, we provide in utero, in vivo, and in vitro evidence that currently available brands of bisphenols impair male reproductive health through their action on testicular cells.

Bisphenol A and Male Fertility: Myths and Realities

Bisphenol A (BPA) represents the main chemical monomer of epoxy resins and polycarbonate plastics. The environmental presence of BPA is widespread, and it can easily be absorbed by the human body through dietary and transdermal routes, so that more than 90% of the population in western countries display detectable BPA levels in the urine. As BPA is qualified as an endocrine disruptor, growing concern is rising for possible harmful effects on human health. This review critically discusses the available literature dealing with the possible impact of BPA on male fertility. In rodent models, the in vivo exposure to BPA negatively interfered with the regulation of spermatogenesis throughout the hypothalamic-pituitary-gonadal axis. Furthermore, in in vitro studies, BPA promoted mitochondrial dysfunction and oxidative/apoptotic damages in spermatozoa from different species, including humans. To date, the claimed clinical adverse effects on male fertility are largely based on the results from studies assessing the relationship between urinary BPA concentration and conventional semen parameters. These studies, however, produced controversial evidence due to heterogeneity in the extent of BPA exposure, type of population, and enrollment setting. Moreover, the cause-effect relationship cannot be established due to the cross-sectional design of the studies as well as the large spontaneous between- and within-subject variability of semen parameters. The best evidence of an adverse effect of BPA on male fertility would be provided by prospective studies on clinically relevant endpoints, including natural or medically assisted pregnancies among men either with different exposure degrees (occupational/environmental) or with different clinical conditions (fertile/subfertile).

Mouse testicular transcriptome after modulation of non-canonical oestrogen receptor activity

The aims of this study were to shed light on the role of G-protein-coupled membrane oestrogen receptor (GPER) and oestrogen-related receptor (ERR) in mouse testis function at the gene expression level, as well as the involvement of GPER and ERR in cellular and molecular processes. Male mice were injected (50µg kg-1,s.c.) with the GPER antagonist G-15, the ERRα inverse agonist XCT790 or the ERRβ/ERRγ agonist DY131. Next-generation sequencing (RNA-Seq) was used to evaluate gene expression. Bioinformatic analysis of read abundance revealed that 50, 86 and 171 transcripts were differentially expressed in the G-15-, XCT790- and DY131-treated groups respectively compared with the control group. Annotated genes and their protein products were categorised regarding their associated biological processes and molecular functions. In the XCT790-treated group, genes involved in immunological processes were upregulated. In the DY131-treated group, genes with increased expression were primarily engaged in protein modification (protein folding and small protein conjugation). In addition, the expression of genes recognised as oncogenes, such as BMI1 proto-oncogene, polycomb ring finger (Bmi1) and nucleophosphin 1 (Npm1), was significantly increased in all experimental groups. This study provides detailed information regarding the genetic changes in the testicular transcriptome of the mouse in response to modulation of non-canonical oestrogen receptor activity.

Gonadoprotective ability of Vincetoxicum arnottianum extract against bisphenol A-induced testicular toxicity and hormonal imbalance in male Sprague Dawley rats

Vincetoxicum arnottianum (Wight) of family Apocynaceae is a rich source of therapeutic alkaloids, phenolics and flavonoids. Study aims to evaluate the protective potential of methanol extract of Vincetoxicum arnottianum (VAM) on bisphenol A (BPA)-induced testicular toxicity in male Sprague Dawley rat. Quantitative analysis of VAM for total phenolic (TPC), total flavonoid (TFC) and total alkaloid content (TAC) along with HPLC analysis for polyphenolics was carried out. BPA-induced testicular toxicity was determined through analysis of antioxidant enzymes, DNA damages and testicular histopathology along with reproductive hormones in serum of rat. VAM was constituted of TFC (382.50 ± 1.67 μg GAE/mg), TPC (291.17 ± 0.82 μg RE/mg), TAC (16.5 ± 0.5%), ferulic acid (2.2433 μg/mg) and vanillic acid (2.1249 μg/mg). VAM co-administration to BPA-treated rats attenuated the toxic effects of BPA and restored the body and testis weights. Altered level of luteinizing hormone (LH), testosterone and follicle-stimulating hormone (FSH) in serum, and level of antioxidants (GSH, POD, CAT and SOD) and nitric oxide in testis tissues of BPA-induced toxicity were significantly restored by VAM. Histological and comet assay studies also sanctioned the protective potential of VAM in BPA-intoxicated rats. The presence of polyphenols and alkaloids might contribute towards the scavenging and ameliorative potential of VAM in testicular toxicity induced by BPA.

Hazards of bisphenol A (BPA) exposure: A systematic review of plant toxicology studies

The widespread use of bisphenol A (BPA) has led to its ubiquity in the natural environment. Thus, BPA is considered as a contaminant of emerging concern. Due to its widespread use, BPA has been detected in a range of soils and surface waters. This is of concern because BPA has been shown to elicit slight to moderate toxicity to plants. Based on current research and our own work, this paper reviews the toxic effects of BPA on plant growth and development, including effects at the macroscopic (e.g. seed germination, root, stem, and leaf growth) and microscopic (photosynthesis, uptake of mineral nutrient, hormone secretion, antioxidant systems, and reproductive genetic behavior) levels. Furthermore, this paper will discuss effects of BPA exposure on metabolic reactions in exposed plant species, and explore the use of high-efficiency plants in BPA pollution control (e.g. phytoremediation). Finally, this paper proposes some ideas for the future of BPA phytotoxicity research.

Bisphenols and Leydig Cell Development and Function

Bisphenol A (BPA) is a ubiquitous environmental pollutant, mainly from the production and use of plastics and the degradation of wastes related to industrial plastics. Evidence from laboratory animal and human studies supports the view that BPA has an endocrine disrupting effect on Leydig cell development and function. To better understand the adverse effects of BPA, we reviewed its role and mechanism by analyzing rodent data in vivo and in vitro and human epidemiological evidence. BPA has estrogen and anti-androgen effects, thereby destroying the development and function of Leydig cells and causing related reproductive diseases such as testicular dysgenesis syndrome, delayed puberty, and subfertility/infertility. Due to the limitation of BPA production, the increased use of BPA analogs has also attracted attention to these new chemicals. They may share actions and mechanisms similar to or different from BPA.

Effects of Bisphenols on Testicular Steroidogenesis

Over the last decades, the adverse effects of human exposure to the so-called "endocrine disruptors" have been a matter of scientific debate and public attention. Bisphenols are synthetic chemicals, widely used in the manufacture of hard plastic products. Bisphenol A (BPA) is one of the best-known environmental toxicants proven to alter the reproductive function in men and to cause other health problems. Consumer concern resulted in "BPA free" products and in the development of bisphenol analogs (BPA-A) to replace BPA in many applications. However, these other bisphenol derivatives seem to have effects similar to those of BPA. Although a number of reviews have summarized the effects of BPA on human reproduction, the purpose of this article is to review the effects of bisphenols on testicular steroidogenesis and to explore their mechanisms of action. Testicular steroidogenesis is a fine-regulated process, and its main product, testosterone (T), has a crucial role in fetal development and maturation and in adulthood for the maintenance of secondary sexual function and spermatogenesis. Contradictory outcomes of both human and animal studies on the effects of BPA on steroid hormone levels may be related to various factors that include study design, dosage of BPA used in in vitro studies, timing and route of exposure, and other confounding factors. We described the main possible molecular target of bisphenols on this complex pathway. We report that Leydig cells (LCs), the steroidogenic testicular component, are highly sensitive to BPA and several mechanisms concur to the functional impairment of these cells.

Dietary Biotin Supplementation Impairs Testis Morphology and Sperm Quality

Supplements containing pharmacological concentrations of biotin are commercially available over the counter. Classical toxicity studies have considered biotin administration as harmless; however, recent investigations have shown that biotin supplementation modifies tissue morphology without changes in toxicity markers, raising concerns about the consequences of morphological changes on tissues' functions and the safety of pharmacological concentrations of the vitamin. Testes are very sensitive to toxicants, and testicular histology is a reliable method to study its function. In this work, we investigated the effects of dietary biotin supplementation on testis morphology and spermatogenesis function using an experimental model, in which we have not observed unfavorable effects on other tissue functions or toxicity markers. Male BALB/cAnNHsd mice were fed a control or a biotin-supplemented diet (1.76 or 97.7 mg biotin/kg diet) for 8 weeks. Compared to the control group, the biotin-supplemented mice presented remarkable testis morphology changes, including increased spermatogonia layers; the cellular mechanism involved is related to increased proliferation. Sperm count and serum testosterone levels were not affected, but spermatozoa motility and morphology were significantly impaired in the biotin-supplemented mice. These results caution against the use of supplements with high concentrations of biotin and indicate that biotin's pharmacological effects on morphology need to be considered in toxicological studies.

Prenatal exposures to bisphenol A and di (2-ethylhexyl) phthalate disrupted seminiferous tubular development in growing male rats

Endocrine-disrupting compounds (EDCs) are found in the environment due to their use in industrial and manufacturing activities. Exposure of the population to bisphenol A (BPA) and di (2-ethylhexyl) phthalate (DEHP) is significant because they are present in many consumer products. EDCs target the reproductive tract because they express high levels of steroid hormone receptors, which act as transcriptional factors to regulate reproductive development. In the present study, timed-pregnant Long-Evans female rats (n = 8-10) were administered BPA and DEHP by oral gavage at 2.5 or 25 μg/kg body weight and 5 or 50 μg/kg body weight, respectively. Exposures to chemicals were limited to the period between gestational days 12 and 21 followed by assessment of testicular development in male offspring in the postnatal period. Leydig cells and Sertoli cells are the two major somatic cells present in the testis. The 17β-hydroxysteroid dehydrogenase (17β-HSD) steroidogenic enzyme is a marker for Leydig cell maturation, whereas transferrin is a marker for Sertoli cell differentiation. At day 10 post-partum, testes were obtained from cohorts of control and chemical-exposed male rats and processed to measure 17β-HSD and transferrin expression levels in western blots. Compared to control, 17βHSD enzyme protein was increased in BPA-treated rats but levels were decreased in animals exposed to DEHP (P < 0.05). Transferrin protein was decreased in male rats exposed to both BPA and DEHP compared to control animals (P < 0.05). To assess qualitative cellular changes within the spermatogenic epithelium, testes were obtained from separate cohorts of male rats at 35 days of age and processed for histopathological analysis. Results showed that prenatal exposures of male rats to BPA and DEHP caused disruption of the spermatogenic epithelium evident as disorganization and atrophy of seminiferous tubules as well as desquamation of germ cells into the tubular lumen. Together, results from the present study support the view that developmental exposures to environmentally relevant levels of BPA and DEHP are associated with disruptions of testicular cell development, which have implications for endocrine and exocrine functions of testis.

Do estrogens regulate lipid status in testicular steroidogenic Leydig cell?

In this study mouse Leydig cell (MA-10) were treated with G-protein coupled membrane estrogen receptor antagonist (G-15; 10 nM). Cells were analyzed by Western blotting for expression of estrogen-related receptors (ERRα, β and γ), steroidogenic markers (lutropin receptor; LHR and 3β-hydroxysteroid dehydrogenase; 3β-HSD) and lipid droplet markers (perilipin; PLIN and microtubule-associated protein 1 A/1B-light chain 3; LC3). Concomitantly, microscopic analyses by light microscope (immunofluorescent staining for lipid droplets, PLIN and LC3) as well as by electron microscope (for lipid droplet ultrastructure) were utilized. For analysis of cholesterol content, cAMP level and progesterone secretion, G-15, estrogen receptor (ER) antagonist (ICI 182,780; 10 μM), 17β-estradiol (10 mM) and, bisphenol A (BPA; 10 nM) were used alone or in combinations. We revealed no changes in ERRs expression but alterations in ERRβ and γ localization in G-15-treated cells when compared to control. Partial translocation of ERRβ and γ from the cell nucleus to cytoplasm was observed. Decreased expression of LHR, 3β-HSD, PLIN and LC3 was detected. Moreover, in treated cells large lipid droplets and differences in their distribution were found. Very strong signal of co-localization for PLIN and LC3 was found in treated cells when compared to control. In ultrastructure of treated cells, degenerating lipid droplets and double membrane indicating on presence of lipophagosome were observed. We found, that only (i) BPA and G-15 did not effect on cholesterol content, (ii) BPA, G-15 and ICI did not effect on cAMP level and (iii) BPA, ICI alone and in combination, and BPA with G-15 did not modulate progesterone secretion. These findings showed complex and diverse estrogen effects on mouse Leydig cells at various steps of steroid hormone production (cholesterol storage, release and processing). Lipid homeostasis and metabolism in these cells were affected by endogenous and exogenous estrogen, interactions of receptors (GPER, ER and ERR) and GPER and ER antagonists.

Do G-protein coupled estrogen receptor and bisphenol A analogs influence on Leydig cell epigenetic regulation in immature boar testis ex vivo?

Organotypic culture of testicular fragments from 7-day-old male pigs (Polish White Large) was used. Tissues were treated with an antagonist of G-protein coupled estrogen receptor (GPER) (G-15; 10 nM), and bisphenol A (BPA), and its analogs (TBBPA, TCBPA; 10 nM) alone or in combination and analyzed using electron and light (stainings for collagen fibers, lipid droplet and autophagy markers) microscopes. In addition, mRNA and protein abundances and localization of molecules required for miRNA biogenesis and function (Drosha, Exportin 5; EXPO5, Dicer, and Argonaute 2; AGO2) were assessed together with calcium ion (Ca²⁺) and estradiol concentrations. Regardless of GPER blockade and/or treatment with BPA, TBBPA and TCBPA, there were no changes in Leydig cell morphology. Also, there were no changes in lipid droplet content and distribution but there were changes in lipid and autophagy protein abundance. In the interstitial tissue, there was an increase of collagen content, especially after treatment with BPA analogs and G-15 + BPA. Independent of the treatment, there was downregulation of EXPO5 and Dicer genes but the Drosha and AGO2 genes were markedly upregulated as a result of treatment with G-15 + BPA and TCBPA, respectively. There was always a lesser abundance of EXPO5 and AGO2 proteins regardless of treatment. There was markedly greater abundances of Drosha after G-15 + BPA treatment, and this also occurred for Dicer after treatment with G-15 + TCBPA. Immunolocalization of miRNA proteins indicated there was a cytoplasmic-nuclear pattern in control and treated cells. There was an increase of Ca²⁺ concentrations after treatment with G-15 and BPA analogs. Estradiol secretion decreased after antagonist and chemical treatments when these were administered alone, however, there was an increase in estradiol secretion after treatment with combinations of these compounds.

Prenatal bisphenol a and phthalate exposure are risk factors for male reproductive system development and cord blood sex hormone levels

Bisphenol A (BPA) and phthalates can adversely affect the fetal development. However, observational studies on the effects of these chemicals on fetal male reproductive system are still limited. A hundred of umbilical cord blood samples were analyzed for the levels of BPA, di-2-ethylhexyl phthalate (DEHP), mono-2-ethylhexyl phthalate (MEHP), and sex hormones. After birth, male newborns underwent physical examination that included measurements of anogenital distance, stretched penile length (SPL), and penile width. BPA, DEHP and MEHP levels were detectable in ≈99% of cord blood samples. In covariate-adjusted models, cord blood BPA levels were inversely associated with SPL of newborns and positively associated with cord blood estradiol levels. In addition, there was a significant inverse relationship between cord blood DEHP levels and anogenital distance index of newborn males. Our results suggest that in utero BPA and DEHP exposure exerted adverse effects on fetal male reproductive development and cord blood estradiol levels.

Maternal bisphenol A exposure disrupts spermatogenesis in adult rat offspring

Bisphenol A (BPA) is an endocrine-disrupting chemical (EDC) that is widely used in the manufacturing of plastics and inner linings of food cans. Previously, it was reported that BPA disturbed the sexual dimorphic nucleus of the hypothalamus and delaying the onset of puberty attributed to an estrogenic action. In addition, BPA during the perinatal period increased LH serum concentrations in male offspring of dams at doses below the reproductive NOAEL (No Observable Adverse Effect Level) based upon World Health Organization guidelines. Based upon these findings, the objective of this study was to (1) determine the effects of perinatal treatment with low doses of BPA on regulation of spermatogenesis in adult offspring and (2) elucidate molecular mechanisms involved in the pathogenesis of gonadal dysfunction. The expression of genes related to spermatogenesis was disrupted with adverse consequences on sperm production, reserves, and function. Both BPA treated groups exhibited reduction in sperm production and epithelial height of seminiferous tubules, accompanied by diminished integrity of the acrosome and plasma membrane, decreased mitochondrial activity and increased incidence of morphological abnormalities. The sperm transit time was also slower. However, only in the group receiving the higher BPA dose was transcript expression of genes affected (reduced Ar and increased Esr1). It is of interest that serum testosterone levels were elevated in the same group where Ar was decreased. Data suggest that exposure to low BPA doses during hypothalamic sexual differentiation period produces permanent deleterious effects on spermatogenesis in adulthood.

Effects of Exposure to Bisphenol A during Pregnancy on the Pup Testis Function

Testosterone plays an important prenatal role in male testis development. Bisphenol A (BPA) exposure during pregnancy affects testosterone levels and germ cell apoptosis of male pups, but little information is available for the mechanism. The aim of the present study was to investigate the mechanism by which BPA alters testosterone levels and germ cell apoptosis. Pregnant female C57BL/6J mice, throughout gestation, had access to drinking water containing BPA at 5 and 50 μg/mL. Male pups were euthanized on postnatal days (PNDs) 1, 14, and 35. Relative to control, BPA exposure at 5 and 50 μg/ml decreased testosterone level, as measured by chemiluminescent immunoassay, on PND14. Real-time PCR indicated mRNA levels for steroidogenic acute regulatory protein (StAR), cholesterol side-chain cleavage enzyme (CYP11A1), and 3-β-hydroxysteroid dehydrogenase/△-5-4 isomerase (3β-HSD) were significantly lower in the BPA pups compared to control. Additionally, BPA increased the percentage of TUNEL-positive seminiferous tubules, decreased the mRNA level of Bcl-2, and increased Bax expression, indicative of increased apoptosis. These results suggest that BPA exposure in utero decreases the testosterone concentration by decreasing steroidogenic enzymes (StAR, CYP11A1, and 3β-HSD). Furthermore, BPA exposure increases the apoptosis of germ cells, which is associated with proapoptotic changes in the levels of Bcl-2 and Bax.

Decreased Capacity for Sperm Production Induced by Perinatal Bisphenol A Exposure Is Associated with an Increased Inflammatory Response in the Offspring of C57BL/6 Male Mice

Many previous studies have indicated the adverse effects of bisphenol A (BPA) on sperm production and quality; however, the mechanisms underlying BPA male reproductive toxicity have yet to be elucidated. The main purpose of this study was to investigate the effect of perinatal exposure to BPA on the spermatogenic capacity of male offspring, and to explore the possible influence of inflammatory responses in BPA reproductive toxicity. Twenty-one pregnant C57BL/6mice were randomly divided into three groups: a control group, a group receiving 0.2 μg/mL (LBPA), and a group receiving 2 μg/mL of BPA (HBPA), all via drinking water from gestational day 6 to the end of lactation. After weaning, one male mouse was randomly selected from each group (n = 7/group); these three mice were fed a normal diet and drinking water for 1 month. Levels of serum testosterone (T) and tumor necrosis factor (TNF)-α were then measured in all mice. Sperm count and the proportion of sperm malformation were also determined. The levels of Toll-like receptor 4 (TLR4), nuclear factor (NF)-κB, and aryl hydrocarbon receptor (AhR) protein expression in the testis tissue were determined. Analysis showed that the proportion of sperm malformation increased in the LBPA and HBPA groups (p < 0.05). Sperm count significantly decreased only in the HBPA group (p < 0.05), while the levels of serum TNF-α increased in the LBPA and HBPA groups (p < 0.05). Levels of serum T decreased significantly in the HBPA group, compared with controls (p < 0.05). Levels of TLR4 and NF-κB protein expression in the testis were significantly higher in the LBPA and HBPA groups (p < 0.05 or p < 0.01), while AhR protein expression was higher and seminiferous tubules in the testis showed more damage in the HBPA group compared to controls (p < 0.05 and p < 0.01, respectively). Our results showed that perinatal exposure to low or high doses of BPA decreased the capacity for spermatogenesis in male offspring, which may be associated with an inflammatory response activated by the TLR4/ NF-κB and AhR signaling pathways in the testis.

Effects of bisphenol A and its analogs on reproductive health: A mini review

Known endocrine disruptor bisphenol A (BPA) has been shown to be a reproductive toxicant in animal models. Its structural analogs: bisphenol S (BPS), bisphenol F (BPF), bisphenol AF (BPAF), and tetrabromobisphenol A (TBBPA) are increasingly being used in consumer products. However, these analogs may exert similar adverse effects on the reproductive system, and their toxicological data are still limited. This mini-review examined studies on both BPA and BPA analog exposure and reproductive toxicity. It outlines the current state of knowledge on human exposure, toxicokinetics, endocrine activities, and reproductive toxicities of BPA and its analogs. BPA analogs showed similar endocrine potencies when compared to BPA, and emerging data suggest they may pose threats as reproductive hazards in animal models. While evidence based on epidemiological studies is still weak, we have utilized current studies to highlight knowledge gaps and research needs for future risk assessments.

Bisphenol A exposure during early pregnancy impairs uterine spiral artery remodeling and provokes intrauterine growth restriction in mice

Endocrine disrupting chemicals are long suspected to impair reproductive health. Bisphenol A (BPA) has estrogenic activity and therefore the capacity of interfering with endocrine pathways. No studies dissected its short-term effects on pregnancy and possible underlying mechanisms. Here, we studied how BPA exposure around implantation affects pregnancy, particularly concentrating on placentation and uterine remodeling. We exposed pregnant female mice to 50 µg/kg BPA/day or 0.1% ethanol by oral gavage from day 1 to 7 of gestation. High frequency ultrasound was employed to document the presence and size of implantations, placentas and fetuses throughout pregnancy. Blood velocity in the arteria uterina was analyzed by Doppler measurements. The progeny of mothers exposed to BPA was growth-restricted compared to the controls; this was evident in vivo as early as at day 12 as analyzed by ultrasound and confirmed by diminished fetal and placenta weights observed after sacrificing the animals at day 14 of gestation. The remodeling of uterine spiral arteries (SAs) was considerably impaired. We show that short-term exposure to a so-called "safe" BPA dose around implantation has severe consequences. The intrauterine growth restriction observed in more than half of the fetuses from BPA-treated mothers may owe to the direct negative effect of BPA on the remodeling of uterine SAs that limits the blood supply to the fetus. Our work reveals unsuspected short-term effects of BPA on pregnancy and urges to more studies dissecting the mechanisms behind the negative actions of BPA during early pregnancy.

Mechanism of bisphenol AF-induced progesterone inhibition in human chorionic gonadotrophin-stimulated mouse Leydig tumor cell line (mLTC-1) cells

Bisphenol AF (BPAF) has been shown to inhibit testicular steroidogenesis in male rats. However, the precise mechanisms related to the toxic effects of BPAF on reproduction remain poorly understood. In the present study, a mouse Leydig tumor cell line (mLTC-1) was used as a model to investigate the mechanism of steroidogenic inhibition and to identify the molecular target of BPAF. Levels of progesterone and the concentration of cyclic adenosine monophosphate (cAMP) in cells exposed to BPAF were detected, and expression of key genes and proteins in steroid biosynthesis was assessed. The results showed that BPAF exposure decreased human chorionic gonadotrophin (hCG)-stimulated progesterone production in a dose-dependent manner. The 24-h IC₅₀ (half maximal inhibitory concentration) value for BPAF regarding progesterone production was 70.2 µM. A dramatic decrease in cellular cAMP concentration was also observed. Furthermore, BPAF exposure inhibited expression of genes and proteins involved in cholesterol transport and progesterone biosynthesis. Conversely, the protein levels of steroidogenic acute regulatory protein (StAR) were not altered, and those of progesterone were still decreased upon 22R-hydroxycholesterol treatment of cells exposed to higher doses of BPAF. Together, these data indicate that BPAF exposure inhibits progesterone secretion in hCG-stimulated mLTC-1 cells by reducing expression of scavenger receptor class B type I (SR-B1) and cytochrome P450 (P450scc) due to the adverse effects of cAMP. However, StAR might not be the molecular target in this process.

Protective Effect of Aloe vera Extract against Bisphenol A Induced Testicular Toxicity in Wistar Rats

Objective

Bisphenol A (BPA), an endocrine-disrupting chemical, has been considered as a possible risk factor for fertility because it induces testicular toxicity. Thus, we sought to analyze the effect of Aloe vera as plant with antioxidant properties on tissues and oxidative stress parameters in male rats.

Materials and Methods

In this experimental study, 50 adult male Wistar rats (200 ± 20 g) have been used in this 56 day study. Animals were completely randomized and divided into five groups: A₁(control), A₂(vehicle control), A3 (Aloe vera gel 300 mg/kg), B₁(BPA 20 µg/kg bw) and B₂(Aloe vera gel+ BPA). At the end of the study, the rats were anesthetized and 2 ml blood samples were obtained for evaluation of oxidative stress markers. Also, both testes were collected for histological examinations.

Results

BPA significantly decreased (P<0.05) body and testis weights. Seminiferous tubule diameter (STD) and height of seminiferous epithelium (HSE), were significantly decreased (P<0.05) in the groups receiving BPA as compared to the control. There was also a reduction in the quantity of spermatocyte and spermatids. Moreover, malondialdehyde (MDA) increased and thiol protein (G-SH) decreased. But, co-administration of Aloe vera with BPA accelerated the total antioxidant capacity and testicular tissue structure healing.

Conclusion

According to our findings, Aloe vera gel extract can overcome the damaging effects of BPA on the reproductive system of rats and protects rats’ testes against BPA-induced toxicity.

Neuroendocrine disruption in animal models due to exposure to bisphenol A analogues

Animal and human studies provide evidence that exposure to the endocrine disrupting chemical (EDC), bisphenol A (BPA), can lead to neurobehavioral disorders. Consequently, there is an impetus to identify safer alternatives to BPA. Three bisphenol compounds proposed as potential safer alternatives to BPA are bisphenol S (BPS), bisphenol F (BPF), and bisphenol AF (BPAF). However, it is not clear whether these other compounds are safer in terms of inducing less endocrine disrupting effects in animals and humans who are now increasingly coming into contact with these BPA-substitutes. In the past few years, several animal studies have shown exposure to these other bisphenols induce similar neurobehavioral disruption as BPA. We will explore in this review article the current studies suggesting these other bisphenols result in neuroendocrine disruptions that may be estrogen receptor-dependent. Current work may aide in designing future studies to test further whether these BPA-substitutes can act as neuroendocrine disruptors.

Gut Dysbiosis in Animals Due to Environmental Chemical Exposures

The gut microbiome consists of over 10³–10⁴ microorganism inhabitants that together possess 150 times more genes that the human genome and thus should be considered an “organ” in of itself. Such communities of bacteria are in dynamic flux and susceptible to changes in host environment and body condition. In turn, gut microbiome disturbances can affect health status of the host. Gut dysbiosis might result in obesity, diabetes, gastrointestinal, immunological, and neurobehavioral disorders. Such host diseases can originate due to shifts in microbiota favoring more pathogenic species that produce various virulence factors, such as lipopolysaccharide. Bacterial virulence factors and metabolites may be transmitted to distal target sites, including the brain. Other potential mechanisms by which gut dysbiosis can affect the host include bacterial-produced metabolites, production of hormones and factors that mimic those produced by the host, and epimutations. All animals, including humans, are exposed daily to various environmental chemicals that can influence the gut microbiome. Exposure to such chemicals might lead to downstream systemic effects that occur secondary to gut microbiome disturbances. Increasing reports have shown that environmental chemical exposures can target both host and the resident gut microbiome. In this review, we will first consider the current knowledge of how endocrine disrupting chemicals (EDCs), heavy metals, air pollution, and nanoparticles can influence the gut microbiome. The second part of the review will consider how potential environmental chemical-induced gut microbiome changes might subsequently induce pathophysiological responses in the host, although definitive evidence for such effects is still lacking. By understanding how these chemicals result in gut dysbiosis, it may open up new remediation strategies in animals, including humans, exposed to such chemicals.

Effect of bisphenol A on reproductive processes: A review of in vitro, in vivo and epidemiological studies

As bisphenol A (BPA) is characterized by a pronounced influence on human hormonal regulation, particular attention has been aimed at understanding its role in reproductive processes in males and females, as well as on fetal development. Owing to the increasing number of alarming reports on the negative consequences of the presence of BPA in human surroundings, more and more studies are being undertaken to clarify the negative effects of BPA on human reproductive processes. The aim of this work was to collect and summarize data on the influence of BPA exposure on reproductive health. Based on an analysis of selected publications it was stated that there is strong proof confirming that BPA is an ovarian, uterine and prostate toxicant at a level below the lowest observed adverse effect level (50 mg kg^-1 bodyweight) as well as a level below the proposed safe level (4 μg kg^-1 bodyweight). It seems there is also reliable evidence in relation to the negative effect of BPA on sperm quality and motility. Limited evidence also pertains to the case of the potential of BPA to affect polycystic ovary syndrome occurrence. Although in epidemiological studies this disease was common, in studies on animal models such results were still not confirmed. No unambiguous results of epidemiological studies and with animal models were obtained in relation to the evaluation of associations between BPA and implantation failure in women, evaluation of associations between BPA and sexual dysfunction in men, and impact of BPA on birth rate, birth weight and length of gestation. Copyright © 2017 John Wiley & Sons, Ltd.