Bisphenol AF Exposure Research Articles

New insights into the effect of bisphenol AF exposure on maternal mammary glands at various stages of gestation in mice

Bisphenol AF (BPAF) is the most estrogenic compound among BPA analogs. Mammary glands (MDs) are special organs that undergo repeated cycles of structural development, metabolism, and functional differentiation. Gestation is a sensitive window for MDs. In the present study, plug-positive CD-1 mice were exposed to vehicle (Veh) or 300 μg/kg BPAF through oral gavage every second day during gestation, and maternal MDs were collected from different developmental windows at 9.5, 13.5, and 18.5 d of gestation (gestation day [GD]9.5, GD13.5 and GD18.5). The results showed that gestational BPAF exposure induced a significantly elevated MD density at GD18.5. Non-target metabolomics analysis was used to screen for tyrosine, valine, ornithine, proline, threonine, phenylalanine and asymmetrical dimethylarginine (ADMA) amino acids, which changed significantly at all time points. Furthermore, the mRNA expression levels of genes related to these amino acids also changed significantly. Additionally, amino acid levels in BPAF-treated MGs at GD18.5 were related to the serum ammonia concentration of the corresponding offspring. These results provide a comprehensive view of the adverse effects of BPAF exposure during gestation on the maternal MG structure and function, which may affect milk components during lactation. Moreover, higher amino acids content may lead to amino acid imbalance or hyperammonemia in newborns.

Oxidative Stress and Apoptosis in Bisphenol AF–Induced Neurotoxicity in Zebrafish Embryos

Bisphenol AF (BPAF) is a structural counterpart of bisphenol A (BPA) that is utilized in the food and beverage industry. The present study has investigated the potential mechanisms in BPAF-induced neurotoxicity in zebrafish embryos. The BPAF concentrations (0.03, 0.1, 0.3, and 1.0 µM) had no obvious effect on hatching, mortality, and body length of zebrafish larvae; while curved tail and pericardial edema were observed in the 1.0 μM group at 72 and 96 hpf. Locomotor activity of the larvae (at 120 hpf) significantly decreased from dark-light, but increased from light-dark transitions, in BPAF groups (0.1 μM, 0.3 μM and 1.0 μM). Acridine orange result showed that BPAF significantly increased green fluorescence protein intensity (22.6%) in the 1.0 μM group. Consistently, the induced apoptosis significantly upregulated caspase 3 in 0.3 μM (1.95 fold) and 1.0 μM (2.26 fold); and bax in folds of 1.60- and 1.78 in 0.3 μM and 1.0 μM, respectively; while bcl-2 expression was significantly decreased in 0.3 μM (0.72-fold) and 1.0 μM (0.53-fold). Additionally, increased ROS concentrations in 0.3 μM (27%) and 1.0 μM (61.4%) resulted in suppressed SOD and CAT activities. Moreover, qPCR results depicted that BPAF (0.3 μM and 1.0 μM) significantly altered the normal dopaminergic signalling where dat was upregulated, while drd2a and th1 were downregulated, in a concentration-dependent manner. Aberrations in dopamine-related genes were congruous with the dysregulations in neurodevelopment genes (sox11b, pax6a, syn2a, and rob2). Our findings suggest that BPAF-evoked oxidative stress and apoptosis could translate into phenotypical behavioral and neurodevelopmental abnormalities. These highlights could provide theoretical reference for risk assessment and early indicator to BPAF exposure. This article is protected by copyright. All rights reserved. © 2022 SETAC.

Association of serum bisphenol AF concentration with depressive symptoms in adolescents: A nested case–control study in China

BackgroundAs an important alternative to bisphenol A (BPA), bisphenol AF (BPAF) is widely used and can be detected in multiple human biological samples. However, there are few studies on neurotoxicity of BPAF at present. In particular, no epidemiological studies have investigated BPAF in relation to depressive symptoms in adolescents. Here, our study aimed to evaluate the associations between serum BPAF concentrations and depressive symptoms in adolescents. MethodsA nested case-control study within an ongoing longitudinal prospective adolescent cohort that was established in Huaibei, China was conducted. A total of 175 participants who had new-onset depressive symptoms (cases) and 175 participants without depressive symptoms (controls) were included. Serum BPAF concentrations was measured using ultra–high–performance liquid chromatography–tandem mass spectrometry. The associations between BPAF exposure and the risk of depressive symptoms in adolescents were assessed using conditional logistic regression. The dose-response relationship between BPAF level and depressive symptoms was estimated using restricted cubic spline analyses. ResultsIn this study, the detection rate of serum BPAF was 100%, and the median (interquartile range, IQR) serum BPAF concentration was 5.24 (4.41–6.11) pg/mL in the case group and 4.86 (4.02–5.77) pg/mL in the control group (P = 0.009). Serum BPAF exposure was a risk factor for depressive symptoms (odds ratio (OR)= 1.132, 95% confidence interval (CI):1.013–1.264). After adjustment for all for confounders, compared with the low–exposure group, the high–exposure group had a 2.806-fold increased risk of depressive symptoms (OR=2.806, 95% CI: 1.188–6.626). Stratified analysis by sex revealed that males were more vulnerable to BPAF exposure than females. After adjustment for all confounders, compared with the low-exposure group, the relative risk of depressive symptoms in the high-exposure group was 3.858 (95% CI: 1.118–12.535) for males, however, no significant association between BPAF exposure and depressive symptoms was found in females. In addition, there was a marked linear association between BPAF exposure and the risk of depressive symptoms in the total population and in males. ConclusionsThe adolescents in this study were widely exposed to low levels of BPAF. A significant positive association was found between serum BPAF levels and the risk of depressive symptoms. The association was significantly modified by sex, and males were more vulnerable to BPAF exposure than females.

In utero bisphenol AF exposure causes fetal Leydig cell dysfunction and induces multinucleated gonocytes by generating oxidative stress and reducing the SIRT1/PGC1α signals

Bisphenol AF (BPAF) is one of the primary alternatives of bisphenol A. It has been ubiquitously detected in the environment and is an emerging endocrine disrupting compound. However, the effects of BPAF exposure on fetal Leydig cells and germ cells and the underlying mechanisms remain largely unknown. To this end, pregnant Sprague-Dawley rats were exposed to 10, 50, and 200 mg/kg/d BPAF by gavage from gestational days 14 to 21. The neonatal rats were sacrificed on day 1 at birth. The results showed that serum testosterone levels were significantly decreased at 50 and 200 mg/kg/d, the expression of Scarb1, Star, Cyp17a1, Hsd17b3, and Dhh and their proteins were markedly down-regulated at 50 and 100 mg/kg/d. BPAF exposure also significantly increased the incidence of multinucleated gonocytes at 200 mg/kg/d. We further detected significant increase of testicular malondialdehyde levels and reduction of antioxidants, including SOD1, SOD2, and CAT at 50 and/or 200 mg/kg/d. Furthermore, BPAF markedly reduced the levels of SIRT1 and PGC1α at 200 mg/kg/d while significantly increased AMPK phosphorylation in the testes at 50 and 200 mg/kg/d. In conclusion, our results provide novel in vivo data that BPAF can induce fetal Leydig cell dysfunction by interfering with steroidogenic networks and induce the formation of multinucleated gonocytes after suppressing the antioxidant defense system and reducing SIRT1 and PGC1α signals and increasing the phosphorylation of AMPK, which highlights the potential health risk of environmental exposure to BPAF in inducing male reproductive tract malformation.

Sex-dependent and long-lasting effects of bisphenol AF exposure on emotional behaviors in mice

We recently reported that maternal exposure to bisphenol AF (BPAF), an environmental endocrine disruptor (EED), induced significant alterations in emotional behaviors in offspring mice during adolescence in a sex-dependent manner. However, the effects of adult BPAF exposure and the potential long-lasting effects of maternal exposure to BPAF on offspring mice are still unknown. The present study aimed to investigate the neurobehavioral effects of adult and maternal exposure to BPAF, intragastrically (0.4, 4 mg•kg−1, i.g.), by using a series of classic emotional behavioral tests, mainly referring to depression, anxiety, and memory. The results showed that adult BPAF exposure significantly attenuated anxiety- and depression-like behaviors in adult male mice, while increasing anxiety-like behaviors, promoting novel object recognition memory formation, and impairing contextual fear conditioning memory formation in adult female mice. Maternal exposure to BPAF induced anxiety-like effects and anti-depression-like effects in male offspring mice during adulthood, while maternal BPAF exposure increased anxiety- and depression-like behaviors in female offspring mice during adulthood. Our present findings indicate that BPAF exposure significantly affects emotional behaviors in adult/offspring mice in a sex-dependent manner and that female adult mice are more likely to have adverse consequences to BPAF exposure during adulthood, even during early life stages.

Intergenerational toxic effects of parental exposure to bisphenol AF on offspring and epigenetic modulations in zebrafish

Bisphenol AF (BPAF), an endocrine-disrupting chemical, has been detected in various environmental media because of its wide industrial applications. Meanwhile, substances that are known to be toxic to the reproductive system have been observed to interfere with the development of the offspring following parental exposure. This study was aimed at determining the gender-dependent intergenerational effects of BPAF on offspring development following either paternal or maternal exposure of adult zebrafish to an environmental concentration of BPAF. Four-month-old zebrafish (F0) were exposed to 10 μg/L of BPAF for 28 days, the developmental endpoints of F1 embryos were then tested without further treatment with BPAF. The results show that paternal BPAF exposure decreased the hatching rate, increased mortality, and shortened the body lengths of F1 larval offspring. In addition, it changed DNA and m6A RNA methylation gene expression levels in F0 testes and F1 larvae. Although maternal exposure increased mortality and enhanced antioxidant enzyme activities in F1 larvae, only DNA methylation gene expression was altered in F0 ovaries and F1 larvae. In addition, a short term BPAF exposure of zebrafish embryos from 4 h post-fertilization (hpf) until 120 hpf similarly impaired the early development of the larvae but only at a level relatively higher than 10 μg/L; and DNA and RNA methylation gene expression was regulated to some extent in BPAF exposure groups. Overall, our results indicate the gender-specific effects of BPAF on offspring development and epigenetic modulations, suggesting a relatively high susceptibility within the exposure window during gametogenesis and early embryonic developmental stages to environmental chemicals.

Bisphenol AF exposure causes fasting hyperglycemia in zebrafish (Danio rerio) by interfering with glycometabolic networks.

Bisphenol AF (BPAF), one of the main alternatives to bisphenol A, has been frequently detected in various environmental media, including the human body, and is an emerging contaminant. Epidemiological investigations have recently shown the implications of exposure to BPAF in the incidence of diabetes mellitus in humans, indicating that BPAF may be a potential diabetogenic endocrine disruptor. However, the effects of BPAF exposure on glucose homeostasis and their underlying mechanisms in animals remain largely unknown, which may limit our understanding of the health risks of BPAF. To this end, zebrafish (Danio rerio), an emerging and valuable model in studying animal glycometabolism and diabetes, were exposed to environmentally relevant concentrations (5 and 50μg/L) and 500μg/L BPAF for 28 d. Several key toxicity endpoints of blood glucose metabolism were detected in our study, and the results showed significantly increased fasting blood glucose levels, hepatic glycogen contents and hepatosomatic indexes and decreased muscular glycogen contents in the BPAF-exposed zebrafish. The results of quantitative real-time PCR showed the abnormal expression of genes involved in glycometabolic networks, which might promote hepatic gluconeogenesis and inhibit glycogenesis and glycolysis in the muscle and/or liver. Furthermore, the failure of insulin regulation, including plasma insulin deficiency and impaired insulin signaling pathways in target tissues, may be a potential mechanism underlying BPAF-induced dysfunctional glycometabolism. In summary, our results provide novel in vivo evidence that BPAF can cause fasting hyperglycemia by interfering with glycometabolic networks, which emphasizes the potential health risks of environmental exposure to BPAF in inducing diabetes mellitus.

Perinatal low-dose bisphenol AF exposure impairs synaptic plasticity and cognitive function of adult offspring in a sex-dependent manner

Bisphenol AF (BPAF), a kind of the ideal substitutes of Bisphenol A (BPA), has frequently been detected in environmental media and biological samples. Numerous studies have focused on the reproductive toxicity, cardiotoxicity and endocrine disrupting toxicity of BPAF. However, little evidence is available on neurodevelopmental toxicity of BPAF. Here, our study is to evaluate the effect of perinatal BPAF exposure (0, 0.34, 3.4 and 34 mg/kg body weight/day, correspond to Ctrl, low-, medium- and high-dose groups) on the cognitive function of adult mouse offspring. This study firstly found that perinatal BPAF exposure caused cognitive impairments of mouse offspring, in which male offspring was more sensitive than female offspring in low- and medium-dose BPAF groups. Furthermore, the dendritic arborization and complexity of hippocampal CA1 and DG neurons in male offspring were impaired in all BPAF groups, and these effects were only found in high-dose BPAF group for female offspring. The damage of BPAF to dendritic spines, and the structural basis of learning and memory, was found in male offspring but not in females. Correspondingly, perinatal BPAF exposure significantly downregulated the expressions of hippocampal PSD-95 and Synapsin-1 proteins, and male offspring was more vulnerable than female offspring. Meanwhile, we explored the alteration of hippocampal estrogen receptors (ERs) to explain the sex specific impairment of cognitive function in low- and medium-dose BPAF groups. The results showed that perinatal BPAF exposure significantly decreased the expression of ERα in male offspring in a dose-dependent manner, but not in female offspring. In addition, we found that perinatal BPAF exposure can disordered the balance of oxidation and antioxidation in hippocampus of male offspring. In summary, perinatal low-dose bisphenol AF exposure impairs synaptic plasticity and cognitive function of adult offspring in a sex-dependent manner. The present results provide a pierce of potential mechanism of BPAF-caused neurodevelopmental toxicity.

Bisphenol AF induces apoptosis via estrogen receptor beta (ERβ) and ROS-ASK1-JNK MAPK pathway in human granulosa cell line KGN.

Bisphenol AF (BPAF) is an emerging environmental pollutant. Although BPAF is widely spread in the environment and human surroundings, its interference with ovarian function has not been fully elucidated. The aim of this study was to identify the mechanism underlying the effect of BPAF on the apoptosis of KGN cells, which maintain the physiological characteristics of ovarian granulosa cells. Our results indicated that BPAF induces KGN cell apoptosis in a concentration- and time-dependent manner. Meanwhile, BPAF exposure significantly promoted the expression of pro-apoptotic proteins, including Bax, Bid and Bak, while the expression of anti-apoptotic proteins, such as Bcl-2, Bcl-xL and Mcl-1, decreased significantly. We further detected a significant increase in intracellular ROS levels in response to high concentrations of BPAF exposure. After blocking the corresponding pathway, it was found that ROS mediates ASK1 and JNK activation. Furthermore, the role of Ca2+ overload and estrogen receptor β (ERβ) in BPAF-induced KGN cell apoptosis was also confirmed by using inhibitors. These results suggest that BPAF has potential reproductive toxicity for females, and ROS-ASK1-JNK axis may play a key role in BPAF-induced ovarian dysfunction. In addition, Ca2+ overload and ERβ pathway activation may also be an important mechanism of reproductive toxicity of BPAF.

Comparative toxicokinetics of bisphenol S and bisphenol AF in male rats and mice following repeated exposure via feed

We investigated the plasma toxicokinetic behavior of free (parent) and total (parent and conjugated forms) of bisphenol S (BPS) and bisphenol AF (BPAF) in plasma of adult male rats and mice following exposure via feed for 7 days to BPS (338, 1125, and 3375 ppm) or BPAF (338, 1125, and 3750 ppm). In rats, the exposure concentration-normalized maximum concentration [Cmax/D (ng/mL)/(ppm)] and area under the concentration time curve [AUC/D (h × ng/mL)/(ppm)] for free was higher for BPS (Cmax/D: 0.476–1.02; AUC/D: 3.58–8.26) than for BPAF (Cmax/D: 0.017–0.037; AUC/D:0.196–0.436). In mice, the difference in systemic exposure parameters between free BPS (Cmax/D: 0.376–0.459; AUC/D: 1.52–2.54) and free BPAF (Cmax/D: 0.111–0.165; AUC/D:0.846–1.09) was marginal. Elimination half-lives for free analytes (4.41–10.4 h) were comparable between species and analogues. When systemic exposure to free analyte was compared between species, in rats, BPS exposure was slightly higher but BPAF exposure was much lower than in mice. BPS and BPAF were highly conjugated; total BPS AUC values (rats ≥18-fold, mice ≥17-fold) and BPAF (rats ≥127-fold, mice ≥16-fold) were higher than corresponding free values. Data demonstrated that there are analogue and species differences in the kinetics of BPS and BPAF.

Transcriptomic analysis of bisphenol AF on early growth and development of zebrafish (Danio rerio) larvae

Bisphenol AF (BPAF), an alternative to bisphenol A, is widely detected in aquatic environments. Owing to health concerns, the toxic effects of BPAF on organisms are drawing attention. The present study aims to evaluate the toxicity of BPAF, combining the results of omics techniques and experiment. Employing transcriptome sequencing (RNA-seq), we obtained 391, 648, 512, and 545 differentially expressed genes (DEGs) in 0.1, 1, 10, and 100 μg/L BPAF-exposed zebrafish larvae, respectively. Gene ontology (GO) analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment revealed the early development, stimulus-response, and MAPK signaling pathway were significantly affected by BPAF. In addition, five hub genes (fgf3, fgf4, map2k1, myca, and casp3b) were highlighted as the key genes in MAPK signaling pathway using the protein-protein interaction network. Therefore, the RNA-seq results showed that early development and stimulus-response were the main processes affected by BPAF, which was consistent with our morphological and pathological results. The hatching rate of zebrafish embryos in 1 and 10 μg/L BPAF groups was significantly inhibited, and the oxidative stress indexes, including the level of total antioxidant capacity (T-AOC), superoxide dismutase (SOD), and lipid peroxidation (LPO), were significantly increased by the 100 μg/L BPAF treatment. Moreover, the activity of alkaline phosphatase (AKP) was significantly decreased in all BPAF exposure groups. In conclusion, exposure to BPAF at environmental relevant concentrations affected the early development and immune system of zebrafish larvae by modulating MAPK signaling pathway, and our results provide solid evidence for the future studies on the toxicity of bisphenols.

Oxidative stress in bisphenol AF-induced cardiotoxicity in zebrafish and the protective role of N-acetyl N-cysteine

Research has shown that there is a relationship between bisphenol A (BPA) exposure and the incidence of cardiovascular diseases. However, the effect of bisphenol AF (BPAF), a main substitute for BPA, on heart development remains unclear. In this study, the cardiotoxicity of BPAF was evaluated in zebrafish in vivo and in human cardiac myocytes (HCMs) in vitro. Our results showed that BPAF at a concentration of 200 μg/L results in cardiotoxicity, including a reduced number of cardiomyocytes and endocardial cells in the heart, and reduced heart size in two transgenic zebrafish models (myl7:: dsred2-nuc and fli1a::nGFP). An increase in apoptosis was observed along with antioxidant enzyme inhibition and lipid peroxidation. In addition, the mRNA expression levels of several key genes involved in cardiac development were suppressed by BPAF treatment. In the HCM cell model, BPAF at 2 mg/L induced reactive oxygen species generation, antioxidant enzyme inhibition, mitochondrial dysfunction and oxidative DNA damage. These adverse outcomes can be attenuated by the antioxidant N-acetyl-L-cysteine (NAC), suggesting that oxidative stress is involved in BPAF-induced cardiotoxicity. These data indicated that BPAF exposure increased oxidative stress and apoptosis and that it suppressed the expression of genes involved in cardiac development, which may play crucial roles in the mechanisms of BPAF-induced cardiotoxicity.

Use of embryonic stem cell-derived cardiomyocytes to study cardiotoxicity of bisphenol AF via the GPER/CAM/eNOS pathway

Bisphenol AF (BPAF) is a derivative of bisphenol A (BPA) that is widely used in fluorinated polymers, fluorinated rubber, electronic equipment, plastic optical fibers, etc. Studies have shown that BPAF exposure is associated with a number of diseases; however, little is known about the effects of BPAF on cardiomyocytes. We investigated the impact of chronic exposure to BPAF on cardiomyocytes derived from embryonic stem cells (ESCs). The present study showed that chronic exposure to various concentrations of BPAF (0, 8, 200 and 1000 ng/ml) induces cardiomyocyte hypertrophy. The ratios of microfilaments to mitochondrial length and the ratio of microfilaments to cell nuclei and MYH7b levels indicate that BPAF exposure alters the morphology of the cells and mitochondria. Furthermore, BPAF exposure at concentrations from 8 to 1000 ng/ml results in an increase in G protein-coupled estrogen receptor (GPER) expression. Additionally, our results suggest that these effects of BPAF mediate cardiomyocyte hypertrophy apparently due to an increase in the production of reactive nitrogen species (RNS) via an increase in endothelial NO synthase (eNOS). These results imply that ESC-based myocardial differentiation can be an excellent cellular model to study BPAF-induced cardiotoxicity at the cellular and molecular levels.

The role of chorion around embryos in toxic effects of bisphenol AF exposure on embryonic zebrafish (Danio rerio) development

Bisphenol AF (BPAF) has been found ubiquitously in the environment and attributed to the population degradation of the fish community. It was proved that the susceptibilities of fish to BPAF exposure are diverse in different developing stages. However, the role of embryonic chorion under BPAF exposure remains unknown. In the study, model organism zebrafish (Danio rerio) was adopted to carry out the embryo acute toxicity tests (OECD No. 236) combined with microinjection (MI, at the blastula) and dechorionation (DC, at the pharyngula) techniques and non-treatment (NT-1, NT-2) for investigating the role of chorion around embryos. The results showed that the BPAF exposure could considerably contribute to the growth-retardation, delayed hatching, pericardial edema, yolk sac edema, non-inflated swimming bladder and death. The embryos in the MI-ZR group which soaked to ZR embryo medium after microinjected with BPAF solutions were hardly affected. While the mortalities and malformation rates in the MI-BPAF (the embryos were injected with BPAF and soaked in BPAF solution) and NT-1 (the embryos were not injected but soaked in BPAF solution) increased significantly with time and dose. Under BPAF soaking exposure, the dechorionated embryos in the DC (the embryos were dechorionated and soaked in BPAF solution) were significantly sensitive in comparison with the parallel undechorionated embryos in the NT-2 (the embryos were not dechorionated but soaked in BPAF solution). The 96 h LC50 values of MI-BPAF, NT-1, DC and NT-2 were 1.61, 1.68, 0.27, 1.30 mg L−1, respectively. The results indicate that the chorion has good permeability for BPAF passing through it at the earlier stage of zebrafish embryonic development, but becomes an effective barrier for protecting embryos over time. Moreover, zebrafish are more sensitive to BPAF exposure at embryos-to-larvae development. Thus, BPAF exposure hazards the development of zebrafish embryos and larvae. Waterborne BPAF exposure might pose serious risks to aquatic organisms and break the balance of aquatic ecosystem.

Bisphenol AF compromises blood-testis barrier integrity and sperm quality in mice

The profound influence of environmental chemicals on human health including inducing life-threatening gene mutation has been publicly recognized. Being a substitute for the extensively used endocrine-disrupting chemical BPA, Bisphenol AF (BPAF) has been known as teratogen with developmental toxicities and therefore potentially putting human into the risk of biological hazards. Herein, we deciphered the detrimental effects of BPAF on spermatogenesis and spermiotiliosis in sexual maturity of mice exposing to BPAF (5, 20, 50 mg/kg/d) for consecutive 28 days. BPAF exposure significantly compromises blood-testis barrier integrity and sperm quantity and quality in a dose-dependent manner. Sperms from BPAF exposure mice are featured by severe DNA damage, altered SUMOylation and ubiquitination dynamics and interfered epigenetic inheritance with hypermethylation of H3K27me3 presumably due to the aggregation of cellular reactive oxygen species (ROS). Furthermore, BPAF treatment (50 μM for 24 h) compromises cytoskeleton architecture and tight junction permeability in primary cultured Sertoli cells evidenced by dysfunction of actin regulatory proteins (e.g. Arp3 and Palladin) via activation of ERK signaling, thereby perturbing the privilege microenvironment created by Sertoli cells for spermatogenesis. Overall, our study determines BPAF is deleterious for male fertility, leading to a better appreciation of its toxicological features in our life.

Use of a Mouse Model of Experimentally Induced Endometriosis to Evaluate and Compare the Effects of Bisphenol A and Bisphenol AF Exposure.

Background:Endometriosis is a gynecological disease affecting 1 in 10 women of reproductive age. Endometriosis incidence has risen; however, whether this rise is due to disease awareness or environmental contamination is not known.Objective:The objective of this study was to determine if bisphenol A (BPA) or bisphenol AF (BPAF) potentiate the development of endometriosis and if hormonal status alters how toxicant exposure affects disease.Methods:A mouse model of endometriosis, where minced uterine tissue is injected into the peritoneal cavity of a host mouse, was used to examine the effects of BPA and BPAF on endometriosis lesion development in ovariectomized and hormonally intact mice. BPA and BPAF were delivered through diet to include no-observed-adverse-effect-level (NOAEL) and the low-observed-adverse-effect-level (LOAEL) exposure levels. After six weeks (at necropsy), lesions, ovaries, and blood were collected to examine characteristics, gene expression, and hormonal regulation.Results:BPA and BPAF treatments affected endometriosis in a manner specific to dose and hormonal status of the host mouse. Estrogen and endometriosis-mediated differences in lesion target gene expression also depended on hormonal status. In intact mice, ovarian steroidogenic pathways were disrupted, progesterone levels were lowered, and atretic oocyte numbers were higher with toxicant exposure. BPAF, more so than BPA, resulted in more endometriosis lesion growth, but both toxicants disrupted normal ovarian signaling.Conclusion:These findings further our understanding of the effects and hormonal impacts of BPA and BPAF on endometriosis perturbation in ovariectomized and hormonally intact mice. BPAF appeared to be similar if not more estrogenic than BPA and may be affecting an environmental contribution of the increased incidence of endometriosis. https://doi.org/10.1289/EHP3802

Serum concentrations of bisphenol A and its alternatives in elderly population living around e-waste recycling facilities in China: Associations with fasting blood glucose

In the present study, concentrations of bisphenol A (BPA) and its six alternatives were quantified in serum samples collected from elder population living around an e-waste recycling facilities as well as an reference area in China. BPA, bisphenol AF (BPAF), and bisphenol F (BPF) were frequently detected (detection rates: > 65%) in serum samples collected from residents living near e-waste dismantling facilities, with geometric mean (GM) concentrations of 3.2, 0.0074, and 0.062 ng/mL, respectively. The detection frequencies of other four bisphenols (BPs) in serum samples were lower than 25%, regardless of the sampling areas. Significant difference (Mann−Whitney U−test, p < 0.05) was observed in the serum concentration of BPA, but not BPAF and BPF, between the e-waste recycling and reference areas. This finding indicated e-waste dismantling activities are correlated with human BPA exposure. Significant higher (p < 0.05) detection rates of donors who had abnormal fasting blood glucose (FBG) levels were found in e-waste recycling areas (45%) than those found in reference area. Our results suggested BPA and BPAF exposure might associated with abnormal FBG in participants living in e-waste sites. To our knowledge, this study is first determination of BPs in serum samples and assessment of health risk of elderly people from BPs exposure in e-waste dismantling area.

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.

Developmental Effects and Estrogenicity of Bisphenol A Alternatives in a Zebrafish Embryo Model.

In order to understand the negative effects of bisphenol A (BPA) alternatives comprehensively, zebrafish embryos were used to assess the lethality, developmental effects, and estrogenic activity of bisphenol analogues. The in silico estrogenic activities of bisphenol analogues were assayed by binding simulation. According to our results, the lethality of bisphenol analogues decreased in order of bisphenol AF (BPAF) > BPA > bisphenol F (BPF) > bisphenol S (BPS). BPAF and BPF induced significant effects on zebrafish embryos, including decreased heart rate, hatching inhibition, and teratogenic effects. The binding potentials of bisphenol analogues toward zebrafish ERs (zfERS) decreased in the following order: BPAF > BPA > BPF > BPS. Among the three subtypes of zfERs, zfERβ2 showed the highest binding activity toward the bisphenols, followed by zfERα and zfERβ1. In vivo estrogenic activity tests showed that BPAF, BPA, and BPF significantly enhanced the protein levels of ERα along with the mRNA levels of esr1, esr2a, esr2b, and vtg1 in zebrafish embryos. Esr2b showed the strongest response to BPAF and BPA exposure among the three esrs. In contrast, BPS did not significantly regulate ER protein level or ER transcription. In conclusion, BPAF showed the highest lethality, developmental effects, and estrogenic activity (both in silico and in vivo) followed by BPA and BPF. BPS showed the weakest toxicity and estrogenic activity. zfERβ2 might act as the main target among the three ER subtypes of zebrafish after exposure to BPAF and BPA.

Bisphenol AF negatively affects oocyte maturation of mouse in vitro through increasing oxidative stress and DNA damage

Bisphenol AF (BPAF) is commonly used in industry production as a substitute for Bisphenol A (BPA). Many studies showed that BPAF negatively affect some physiological processes in humans and animals. However, the effects of BPAF on oocyte maturation and its possible mechanisms are sparsely understood. In the present study, we found that 100 μM BPAF exposure affect oocyte maturation with a decreased first polar body extrusion (PBE) rate. Immunofluorescence study displayed that BPAF exposure disrupt the spindle morphology through affecting the function of microtubule organizing centers (MTOCs), which was confirmed by the dysfunction of γ-tubulin and phosphorylated mitogen-activated protein kinase (p-MAPK). As shown by reactive oxygen species (ROS) accumulation, BPAF exposure also induced oxidative stress. Moreover, DNA damage was significantly increased after BPAF exposure, which may be caused by oxidative stress. In addition, histone modification statuses were changed after BPAF exposure, as shown by western blot with decreased expression of H3K9me3 and H3K27ac. Collectively, our current work demonstrated the possibility of BPAF to negatively impact female fertility and revealed the mechanisms that BPAF disrupted mouse oocyte maturation by affecting cytoskeletal dynamics, inducing oxidative stress, increasing DNA damage, and changing the status of epigenetic modifications. This finding can help develop the potential therapies to alleviate oxidative damage to preserve fertility in people who are often exposed to BPAF environment.