Effect of perinatal and postnatal bisphenol A exposure to the regulatory circuits at the hypothalamus–pituitary–gonadal axis of CD-1 mice

Azoospermia and multi-organ damage in juvenile rats exposed to α-Terpineol from weaning to sexual maturity

This study aimed to evaluate the repeated oral administration of α-terpineol in juvenile Wistar rats over a 70-day period. The objective was to assess the potential systemic and reproductive toxicity of α-terpineol when administered by gavage at doses of 75, 150, and 300 mg/kg/day to juvenile Wistar rats for 70 days from postnatal day 24. The control group received corn oil for 70 days. During the study, various parameters were evaluated, including clinical signs, body weight, food intake, neurobehavioral observations, haematology, serum biochemistry, organ weights, steroidogenic gene expression, and histopathological examination. No toxicity-related changes were observed in body weight, food intake, neurobehavioral observations, or steroidogenic gene expression. However, sperm evaluation revealed a complete absence of sperm and delayed sexual maturation. Total cholesterol was significantly elevated in both sexes, and serum testosterone was reduced at the 150 and 300 mg/kg doses. Microscopic examination showed severe pathological changes in the testes, epididymis, liver, and kidneys of both males and females. After the 14-day recovery period, total cholesterol levels returned to the normal range, but no recovery was observed in the other organs. The no-observed-adverse-effect level was 75 mg/kg/day for male rats based on the histopathological findings in the testes, liver, and kidneys, and for female rats based on the kidney and liver histopathology.

Neurotoxic effects of perinatal exposure to Bisphenol F on offspring mice

Bisphenols constitute a diverse group of endocrine-disrupting chemicals (EDCs) that impact hormone activity. Bisphenol F (BPF) is commonly used as a substitute for Bisphenol A (BPA). The disruption of the immune system by EDCs during embryonic brain development has been suggested as a plausible factor to neurodevelopmental disorders. We investigated the neurotoxic effects of perinatal exposure to BPF on offspring mice. Female mice were exposed to BPF through their drinking water on day 0.5 of pregnancy, and this exposure continued until the offspring mice were weaned, throughout the perinatal period. Our findings revealed that exposure to BPF hindered both growth and neurodevelopment in offspring mice, with a more pronounced effect observed in males. Additionally, transcriptomic analysis was conducted on the brains of male offspring mice exposed to high doses of BPF. In summary, our study indicates that perinatal exposure to BPF results in neurodevelopmental impairments in male offspring mice, linked to oxidative stress, inflammatory responses, and immune dysregulation. These findings underscore that BPF may not be a safe substitute for BPA. Thus, there is a pressing need to reevaluate the current regulation of BPF.

The effect of endocrine-disrupting chemicals in follicular fluid: The insights from oocyte to fertilization

Endocrine-disrupting chemicals (EDCs) exhibited the detriment in female reproductive health. Our objective was to investigate the individual and mixture effects of EDCs present in follicular fluid, the environment in which oocytes grow and develop, on early reproductive outcomes. We recruited 188 women seeking reproduction examination from the Study of Exposure and Reproductive Health (SEARCH) cohort between December 2020 and November 2021. We assessed the concentrations of 7 categories of 64 EDCs in follicular fluid, and measured early reproductive outcomes, including retrieved oocytes, mature oocytes, normal fertilized oocytes, and high-quality embryos. In this study Monomethyl phthalate (MMP) (2.17 ng/ml) were the compounds found in the highest median concentrations in follicular fluid. After adjusting for multiple testing, multivariate regression showed that multiple EDCs were significantly negatively associated with early assisted reproduction outcomes. For example, MMP showed a significant negative correlation with the number of high quality embryos (β: -0.1, 95 % CI: -0.15, -0.04). Specifically, eight types of EDCs were significantly negatively associated with four early assisted reproductive outcomes (β range: -0.2 ∼ -0.03). In the mixed exposure model, we found that mixtures of EDC were significantly negatively correlated with all four outcomes. In the quantile g-computation (QGCOMP) model, for each interquartile range increase in the concentration of EDC mixtures, the number of oocytes retrieved, mature oocytes, normally fertilized oocytes, and high-quality embryos decreased by 0.46, 0.52, 0.77, and 1.2, respectively. Moreover, we identified that phthalates (PAEs) predominantly contributed to the negative effects. Future research should validate our findings.

Novel insights into the role of bisphenol A (BPA) in genomic instability

Bisphenol A (BPA) is a phenolic chemical that has been used for over 50 years in the manufacturing of polycarbonate and polyvinyl chloride plastics, and it is one of the highest volume chemicals produced worldwide. Because BPA can bind to and activate estrogen receptors, studies have mainly focused on the effect of BPA in disrupting the human endocrine and reproductive systems. However, BPA also plays a role in promoting genomic instability and has been associated with initiating carcinogenesis. For example, it has been recently shown that exposure to BPA promotes the formation of single stranded DNA gaps, which may be associated with increased genomic instability. In this review, we outline the mechanisms by which BPA works to promote genomic instability including chromosomal instability, DNA adduct formation, ROS production, and estrogen receptor (ER) activation. Moreover, we define the ways in which BPA promotes both carcinogenesis and resistance to chemotherapy, and we provide critical insights into future directions and outstanding questions in the field.

High Levels of BPA and BPF Exposure during Pregnancy Are Associated with Lower Birth Weight in Shenyang in Northeast China

Animal studies indicate that bisphenol A (BPA) has obesogenic effects. Recent experiments reported similar endocrine-disrupting effects of bisphenol F (BPF) and bisphenol S (BPS), which are substitutes of BPA. The aim of this study was to investigate the exposure levels of these bisphenols in pregnant women and their effects on the physical development of infants aged 0-12 months. This study recruited pregnant women who gave birth at a hospital between February 2019 and September 2020. Urine samples from these pregnant women in the third trimester of pregnancy were detected by using ultrahigh-performance liquid chromatography-triple quadruple mass spectrometry. Follow-ups at 6 and 12 months of age were conducted by telephone by pediatricians using a structured questionnaire. Multiple linear regressions were used to determine the associations between bisphenol concentrations and infant weight. A total of 113 mother-child pairs had complete questionnaires and urine samples as well as data on newborns aged 6 months and 12 months. The detection rates of urinary BPA, BPF, and BPS in pregnant women were 100, 62.83, and 46.02%, respectively. Their median levels are 5.84, 0.54, and 0.07 μg/L, respectively. Increased urinary BPA and BPF concentrations during pregnancy were significantly associated with lower birth weight (standardized regression coefficients [β] = -0.081 kg, 95% confidence interval [CI]: -0.134 to -0.027; β = -0.049 kg, 95% CI: -0.097 to -0.001). In addition, urinary BPA and BPF concentrations during pregnancy were positively associated with weight growth rate from 0 to 6 months (β = 0.035 kg/mouth, 95% CI: 0.00-0.064; β = 0.028 kg/mouth, 95% CI: 0.006-0.050), especially in female infants (β = 0.054 kg/mouth, 95% CI: 0.015-0.093; β = 0.035 kg/mouth, 95% CI: 0.005-0.065). Therefore, maternal BPA and BPF levels during pregnancy were negatively correlated with birth weight and positively correlated with the growth rate of infant weight at 0-6 months of age, especially in female infants.

Toxicological Impact of Bisphenol A on Females' Reproductive System: Review Based on Experimental and Epidemiological Studies

The study encompassing research papers documented in the last two decades pertaining to the possible influence of bisphenol A (BPA) on the fertility of females are appraised with emphasis on the influence of BPA in reproductive organs (uterus and ovaries) and pregnancy outcomes including discussion on the reproductive process (implantation, estrous cycle, hormone secretion); outcomes reveal a connection amongst BPA and female infertility. Ovary, uterus, and its shape as well as function can alter a person's ability to become pregnant by influencing the hypothalamus-pituitary axis in the ovarian model. Additionally, implantation and the estrous cycle may be affected by BPA. However, more research is warranted to comprehend the underlying action mechanisms and to promptly identify any imminent reproductive harm.

The impact of water pollution on the health of older people

Water pollution exerts a negative impact on the health of both women and men, inducing hormonal changes, accelerating aging, and consequently leading to the premature onset of age-related health problems. Water pollutants can in general be classified as chemical (both organic and inorganic), physical, and biological agents. Certain chemical pollutants have been found to disrupt hormonal balance by blocking, mimicking, or disrupting functions within the intricate homeostasis of the human body. Moreover, certain water pollutants, including specific pesticides and industrial chemicals, have been associated with neurological and psychiatric disorders, such as mood swings, depression, cognitive decline, and anxiety, impacting both women and men. Water pollution is also associated with physical ailments, such as diarrhea, skin diseases, malnutrition, and cancer. Exposure to specific pollutants may promote premature menopause and vasomotor symptoms, elevate the risk of cardiovascular disease, and reduce bone density. In men, exposure to water pollution has been shown to reduce LH, FSH, and testosterone serum levels. The oxidative stress induced by pollutants prompts apoptosis of Sertoli and germ cells, inhibiting spermatogenesis and altering the normal morphology and concentration of sperm. Environmental estrogens further contribute to reduced sperm counts, reproductive system disruptions, and the feminization of male traits. Studies affirm that men generally exhibit a lower susceptibility than women to hormonal changes and health issues attributed to water pollutants. This discrepancy may be attributed to the varied water-related activities which have traditionally been undertaken by women, as well as differences in immune responses between genders. The implementation of effective measures to control water pollution and interventions aimed at safeguarding and enhancing the well-being of the aging population is imperative. The improvement of drinking water quality has emerged as a potential public health effort with the capacity to curtail the onset of cognitive impairment and dementia in an aging population.

Mechanistic Insights into Bisphenol A-Mediated Male Infertility: Potential Role of Panax Ginseng Extract

Male infertility is identified by the inability of a man to successfully impregnate his fertile female partner, even following a year of regular unprotected sexual intercourse. About half of all infertility cases are attributed to what is known as "male factor" infertility. The escalating prevalence of male infertility in the contemporary era across the globe can be largely attributed to environmental pollution, which is the common etiological factor due to the ubiquitous presence of the environmental contaminants. Bisphenol A is recognized as an endocrine-disrupting chemical that has adverse effects on both male and female reproductive systems. On the other hand, numerous studies have demonstrated that Panax ginseng possessed the potential to improve male infertility parameters; promote spermatogenesis, recover the quality and motility of sperm and enhance testicular functions as it acted as a natural androgen supplement. The objective of this review is to offer a summary of the findings obtained from the current research data on the insult of bisphenol A (BPA) on male infertility and its supposed mode of action, as well as shed light on the potent ameliorative role of Panax ginseng extract, with a special focus on the mechanism behind its action. This review delivers a clear understanding of BPA mechanism of action on male infertility and the presumed risks deriving from its exposure. Also, this review provides evidence for the functional role of Panax ginseng extract in restoring male fertility.

Syringin alleviates bisphenol A-induced spermatogenic defects and testicular injury by suppressing oxidative stress and inflammation in male zebrafish

Syringin (SRG) is a bioactive principle possessing extensive activities including scavenging of free radicals, inhibition of apoptosis, and anti-inflammatory properties. However, its effects on spermatogenic defects and testicular injury as well as the underlying mechanisms are still unclear. This study aims to investigate the protective effect of SRG on testis damage in zebrafish and explore its potential molecular events. Zebrafish testicular injury was induced by exposure to bisphenol A (BPA) (3000 μg/L) for two weeks. Fish were treated with intraperitoneal injection of SRG at different doses (5 and 50 mg/kg bodyweight) for two more weeks under BPA induction. Subsequently, the testis and sperm were collected for morphological, histological, biochemical and gene expression examination. It was found that the administration of SRG resulted in a significant protection from BPA-caused impact on sperm concentration, morphology, motility, fertility rate, testosterone level, spermatogenic dysfunction and resulted in increased apoptotic and reactive oxygen species' levels. Furthermore, testicular transcriptional profiling alterations revealed that the regulation of inflammatory response and oxidative stress were generally enriched in differentially expressed genes (DEGs) after SRG treatment. Additionally, it was identified that SRG prevented BPA-induced zebrafish testis injury through upregulation of fn1a, krt17, fabp10a, serpina1l and ctss2. These results indicate that SRG alleviated spermatogenic defects and testicular injury by suppressing oxidative stress and inflammation in male zebrafish.

Bisphenol A: Unveiling Its Role in Glioma Progression and Tumor Growth

Gliomas represent the most common and lethal category of primary brain tumors. Bisphenol A (BPA), a widely recognized endocrine disruptor, has been implicated in the progression of cancer. Despite its established links to various cancers, the association between BPA and glioma progression remains to be clearly defined. This study aimed to shed light on the impact of BPA on glioma cell proliferation and overall tumor progression. Our results demonstrate that BPA significantly accelerates glioma cell proliferation in a time- and dose-dependent manner. Furthermore, BPA has been found to enhance the invasive and migratory capabilities of glioma cells, potentially promoting epithelial-mesenchymal transition (EMT) characteristics within these tumors. Employing bioinformatics approaches, we devised a risk assessment model to gauge the potential glioma hazards associated with BPA exposure. Our comprehensive analysis revealed that BPA not only facilitates glioma invasion and migration but also inhibits apoptotic processes. In summary, our study offers valuable insights into the mechanisms by which BPA may promote tumorigenesis in gliomas, contributing to the understanding of its broader implications in oncology.

Rapamycin protects Sertoli cells against BPA-induced autophagy disorders

Bisphenol A (BPA) is a well-known environmental contaminant that can negatively impact reproductive function. Disruption of autophagy is implicated in BPA-induced cell injury, the specific molecular mechanisms through which BPA affects autophagy in Sertoli cells are still unknown. In the present study, TM4 cells were exposed to various doses of BPA (10, 100, and 200 μM), and the results indicated that BPA exposure led to the accumulation of autophagosomes, this change was accompanied by increased expression of p-mTOR and decreased expression of Atg12, a protein involved in regulating autophagy initiation. Additionally, BPA exposure upregulated the expression levels of p62, a protein involved in autophagic degradation. The inhibition of autophagy initiation and autophagic degradation contributes to the accumulation of autophagosomes. Further studies showed that BPA exposure didn't affect the expression of the lysosome protein LAMP1; however, decreased cytoplasmic retention of acridine orange in TM4 cells may explain the disruption of autophagy. The role of rapamycin and chloroquine (CQ), an autophagy inhibitor that impairs lysosomal degradation also confirmed the effect of BPA on autophagy regulation. Specifically, rapamycin can protect Sertoli cells against BPA-induced cell injury by promoting autophagy. These findings contribute to our understanding of the mechanisms underlying reproductive toxicity caused by BPA.

Bisphenol-A disturbs hormonal levels and testis mitochondrial activity, reducing male fertility

STUDY QUESTION

How does bisphenol-A (BPA) influence male fertility, and which mechanisms are activated following BPA exposure?

SUMMARY ANSWER

BPA exposure causes hormonal disruption and alters mitochondrial dynamics and activity, ultimately leading to decreased male fertility.

WHAT IS KNOWN ALREADY

As public health concerns following BPA exposure are rising globally, there is a need to understand the exact mechanisms of BPA on various diseases. BPA exposure causes hormonal imbalances and affects male fertility by binding the estrogen receptors (ERs), but the mechanism of how it mediates the hormonal dysregulation is yet to be studied.

STUDY DESIGN SIZE DURATION

This study consisted of a comparative study using mice that were separated into a control group and a group exposed to the lowest observed adverse effect level (LOAEL) (n = 20 mice/group) after a week of acclimatization to the environment. For this study, the LOAEL established by the US Environmental Protection Agency of 50 mg/kg body weight (BW)/day of BPA was used. The control mice were given corn oil orally. Based on the daily variations in BW, both groups were gavaged every day from 6 to 11 weeks (6-week exposure). Before sampling, mice were stabilized for a week. Then, the testes and spermatozoa of each mouse were collected to investigate the effects of BPA on male fertility. IVF was carried out using the cumulus-oocyte complexes from female hybrid B6D2F1/CrljOri mice (n = 3) between the ages of eight and twelve weeks.

PARTICIPANTS/MATERIALS SETTING METHODS

Signaling pathways, apoptosis, and mitochondrial activity/dynamics-related proteins were evaluated by western blotting. ELISA was performed to determine the levels of sex hormones (FSH, LH, and testosterone) in serum. Hematoxylin and eosin staining was used to determine the effects of BPA on histological morphology and stage VII/VIII testicular seminiferous epithelium. Blastocyst formation and cleavage development rate were evaluated using IVF.

MAIN RESULTS AND THE ROLE OF CHANCE

BPA acted by binding to ERs and G protein-coupled receptors and activating the protein kinase A and mitogen-activated protein kinase signaling pathways, leading to aberrant hormone levels and effects on the respiratory chain complex, ATP synthase and protein-related apoptotic pathways in testis mitochondria (P < 0.05). Subsequently, embryo cleavage and blastocyst formation were reduced after the use of affected sperm, and abnormal morphology of seminiferous tubules and stage VII and VIII seminiferous epithelial cells (P < 0.05) was observed. It is noteworthy that histopathological lesions were detected in the testes at the LOAEL dose, even though the mice remained generally healthy and did not exhibit significant changes in BW following BPA exposure. These observations suggest that testicular toxicity is more than a secondary outcome of compromised overall health in the mice due to systemic effects.

LARGE SCALE DATA

Not applicable.

LIMITATIONS REASONS FOR CAUTION

Since the protein expression levels in the testes were validated, in vitro studies in each testicular cell type (Leydig cells, Sertoli cells, and spermatogonial stem cells) would be required to shed further light on the exact mechanism resulting from BPA exposure. Furthermore, the BPA doses employed in this study significantly exceed the typical human exposure levels in real-life scenarios. Consequently, it is imperative to conduct experiments focusing on the effects of BPA concentrations more in line with daily human exposures to comprehensively assess their impact on testicular toxicity and mitochondrial activity.

WIDER IMPLICATIONS OF THE FINDINGS

These findings demonstrate that BPA exposure impacts male fertility by disrupting mitochondrial dynamics and activities in the testes and provides a solid foundation for subsequent investigations into the effects on male reproductive function and fertility following BPA exposure, and the underlying mechanisms responsible for these effects. In addition, these findings suggest that the LOAEL concentration of BPA demonstrates exceptional toxicity, especially when considering its specific impact on the testes and its adverse consequences for male fertility by impairing mitochondrial activity. Therefore, it is plausible to suggest that BPA elicits distinct toxicological responses and mechanistic endpoints based on the particular concentration levels for each target organ.

STUDY FUNDING/COMPETING INTERESTS

This work was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2018R1A6A1A03025159). No competing interests are declared.

Bisphenol A contamination in aquatic environments: a review of sources, environmental concerns, and microbial remediation

The production of polycarbonate, a high-performance transparent plastic, employs bisphenol A, which is a prominent endocrine-disrupting compound. Polycarbonates are frequently used in the manufacturing of food, bottles, storage containers for newborns, and beverage packaging materials. Global production of BPA in 2022 was estimated to be in the region of 10 million tonnes. About 65-70% of all bisphenol A is used to make polycarbonate plastics. Bisphenol A leaches from improperly disposed plastic items and enters the environment through wastewater from plastic-producing industries, contaminating, sediments, surface water, and ground water. The concentration BPA in industrial and domestic wastewater ranges from 16 to 1465 ng/L while in surface water it has been detected 170-3113 ng/L. Wastewater treatment can be highly effective at removing BPA, giving reductions of 91-98%. Regardless, the remaining 2-9% of BPA will continue through to the environment, with low levels of BPA commonly observed in surface water and sediment in the USA and Europe. The health effects of BPA have been the subject of prolonged public and scientific debate, with PubMed listing more than 17,000 scientific papers as of 2023. Bisphenol A poses environmental and health hazards in aquatic systems, affecting ecosystems and human health. While several studies have revealed its presence in aqueous streams, environmentally sound technologies should be explored for its removal from the contaminated environment. Concern is mostly related to its estrogen-like activity, although it can interact with other receptor systems as an endocrine-disrupting chemical. Present review article encompasses the updated information on sources, environmental concerns, and sustainable remediation techniques for bisphenol A removal from aquatic ecosystems, discussing gaps, constraints, and future research requirements.

Different types of bisphenols alter ovarian steroidogenesis: Special attention to BPA

Endocrine disruptors such as bisphenol A (BPA) and some of its analogues, including BPS, BPAF, and BPE, are used extensively in the manufacture of plastics. These synthetic chemicals could seriously alter the functionality of the female reproductive system. Although the number of studies conducted on other types of bisphenols is smaller than the number of studies on BPA, the purpose of this review study was to evaluate the effects of bisphenol compounds, particularly BPA, on hormone production and on genes involved in ovarian steroidogenesis in both in vitro (human and animal cell lines) and in vivo (animal models) studies. The current data show that exposure to bisphenol compounds has adverse effects on ovarian steroidogenesis. For example, BPA, BPS, and BPAF can alter the normal function of the hypothalamic-pituitary-gonadal (HPG) axis by targeting kisspeptin neurons involved in steroid feedback signals to gonadotropin-releasing hormone (GnRH) cells, resulting in abnormal production of LH and FSH. Exposure to BPA, BPS, BPF, and BPB had adverse effects on the release of some hormones, namely 17-β-estradiol (E2), progesterone (P4), and testosterone (T). BPA, BPE, BPS, BPF, and BPAF are also capable of negatively altering the transcription of a number of genes involved in ovarian steroidogenesis, such as the steroidogenic acute regulatory protein (StAR, involved in the transfer of cholesterol from the outer to the inner mitochondrial membrane, where the steroidogenesis process begins), cytochrome P450 family 17 subfamily A member 1 (Cyp17a1, which is involved in the biosynthesis of androgens such as testosterone), 3 beta-hydroxysteroid dehydrogenase enzyme (3β-HSD, involved in the biosynthesis of P4), and cytochrome P450 family 19 subfamily A member 1 (Cyp19a1, involved in the biosynthesis of E2). Exposure to BPA, BPB, BPF, and BPS at prenatal or prepubertal stages could decrease the number of antral follicles by activating apoptosis and autophagy pathways, resulting in decreased production of E2 and P4 by granulosa cells (GCs) and theca cells (TCs), respectively. BPA and BPS impair ovarian steroidogenesis by reducing the function of some important cell receptors such as estrogens (ERs, including ERα and ERβ), progesterone (PgR), the orphan estrogen receptor gamma (ERRγ), the androgen receptor (AR), the G protein-coupled estrogen receptor (GPER), the FSHR (follicle-stimulating hormone receptor), and the LHCGR (luteinizing hormone/choriogonadotropin receptor). In animal models, the effects of bisphenol compounds depend on the type of animals, their age, and the duration and dose of bisphenols, while in cell line studies the duration and doses of bisphenols are the matter.

Molecular insights underlying the adverse effects of bisphenol A on gonadal somatic cells' steroidogenic activity

Bisphenol A (BPA) exposure may impair gonadal steroidogenesis, although the underlying mechanism is not well known. Hereby, we assessed BPA action on human primary granulosa (hGC) and mouse Leydig cells (BLTK-1) proliferation, cytotoxicity, hormone secretion, and steroidogenic enzyme/receptor gene profile. hGC and BLTK-1 cells were stimulated with increasing concentrations of BPA (10^-12 M to 10^-4 M for cell proliferation assay, 10^-8 M to 10^-4 M for LDH-cytotoxicity assay, and 10^-9 M to 10^-5 M for hormone secretion and genes expression analysis). BPA at low concentrations (pM - nM) did not affect cell proliferation in either cell type, although was toxic at higher (µM) concentrations. BPA stimulation at low nM concentrations decreased the production of estradiol (E₂) and testosterone (T) in BLTK-1, E_2, and progesterone in hGCs. BPA down-regulated Star, Cyp11a1, and Hsd17b3, but up-regulated Cyp19a1, Esr1, Esr2, and Gpr30 expression in BLTK-1 cells. In hGC, BPA down-regulated STAR, CYP19A1, PGRMC1, and PAQR7 but up-regulated ESR2 expression. Estrogen receptor degrader fulvestrant (FULV) attenuated BPA inhibition of hormone production in both cell lines. FULV also blocked the BPA-induced Gpr30 up-regulation in BLTK-1 cells, whereas in hGC, failed to reverse the down-regulation of PGRMC1, STAR, and CYP19A1. Our findings provide novel mechanistic insights into environmentally-relevant doses of BPA action through both nuclear estrogen receptor-dependent and independent mechanisms affecting cultured granulosa and Leydig cell steroidogenesis.

Impact of Microplastics and Nanoplastics on Livestock Health: An Emerging Risk for Reproductive Efficiency

Pollution due to microplastics and nanoplastics is one of the major environmental issues of the last decade and represents a growing threat to human and animal health. In aquatic species, there is a large amount of information regarding the perturbation of marine organisms; instead, there are only a few studies focusing on the pathophysiological consequences of an acute and chronic exposure to micro- and nanoplastics in mammalian systems, especially on the reproductive system. There are several studies that have described the damage caused by plastic particles, including oxidative stress, apoptosis, inflammatory response, dysregulation of the endocrine system and accumulation in various organs. In addition to this, microplastics have recently been found to influence the evolution of microbial communities and increase the gene exchange, including antibiotic and metal resistance genes. Special attention must be paid to farm animals, because they produce food such as milk, eggs and meat, with the consequent risk of biological amplification along the food chain. The results of several studies indicate that there is an accumulation of microplastics and nanoplastics in human and animal tissues, with several negative effects, but all the effects in the body have not been ascertained, especially considering the long-term consequences. This review provides an overview of the possible adverse effects of the exposure of livestock to micro- and nanoplastics and assesses the potential risks for the disruption of reproductive physiological functions.

Mitochondrial oxidative damage by co-exposure to bisphenol A and acetaminophen in rat testes and its amelioration by melatonin

OBJECTIVE

Human exposure to multiple xenobiotics, over various developmental windows, results in adverse health effects arising from these concomitant exposures. Humans are widely exposed to bisphenol A, and acetaminophen is the most commonly used over-the-counter drug worldwide. Bisphenol A is a well-recognized male reproductive toxicant, and increasing evidence suggests that acetaminophen is also detrimental to the male reproductive system. The recent recognition of male reproductive system dysfunction in conditions of suboptimal reproductive outcomes makes it crucial to investigate the contributions of toxicant exposures to infertility and sub-fertility. We aimed to identify toxicity in the male reproductive system at the mitochondrial level in response to co-exposure to bisphenol A and acetaminophen, and we investigated whether melatonin ameliorated this toxicity.

METHODS

Male Wistar rats were divided into six groups (n=10 each): a control group and groups that received melatonin, bisphenol A, acetaminophen, bisphenol A and acetaminophen, and bisphenol A and acetaminophen with melatonin treatment.

RESULTS

Significantly higher lipid peroxidation was observed in the testicular mitochondria and sperm in the treatment groups than in the control group. Levels of glutathione and the activities of catalase, glutathione peroxidase, glutathione reductase, and manganese superoxide dismutase decreased significantly in response to the toxicant treatments. Likewise, the toxicant treatments significantly decreased the sperm count and motility, while significantly increasing sperm mortality. Melatonin mitigated the adverse effects of bisphenol A and acetaminophen.

CONCLUSION

Co-exposure to bisphenol A and acetaminophen elevated oxidative stress in the testicular mitochondria, and this effect was alleviated by melatonin.

Gestational bisphenol A exposure advances puberty onset in female offspring: Critical time window identification

Increasing evidence shows that the early onset of puberty in female offspring may be caused by maternal prenatal exposure to bisphenol A (BPA) during pregnancy; however, the critical time window of maternal prenatal BPA exposure remains unknown. Here, we identify the critical time window of gestational BPA exposure that induces early onset of puberty in female offspring. Pregnant CD-1 mice were gavaged with BPA (8 mg/kg) daily during the early gestational stage (GD1-GD6), middle gestational stage (GD7-GD12) or late gestational stage (GD13-GD18). We show that maternal BPA exposure during the early and middle gestational stages could advance the vaginal opening time and increase the serum levels of kisspeptin-10 and GnRH in the female offspring at PND 34. Mechanistically, maternal BPA exposure during early and middle gestation could significantly increase CpG island methylation in the Eed gene promoters but reduce the mRNA expression of Eed in the hypothalamus tissues of the female offspring. In conclusion, the critical period of maternal BPA exposure-induced early onset of puberty in female offspring is early and middle gestation; this BPA-induced early onset of puberty might be partly attributed to epigenetic programming of the Eed gene in the hypothalamus. This study provides important insights regarding the relationship and the mechanisms between BPA and offspring pubertal development.

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.

Endocrine disrupting chemicals: effects on pituitary, thyroid and adrenal glands

BACKGROUND

In recent years, scientific research has increasingly focused on Endocrine Disrupting Chemicals (EDCs) and demonstrated their relevant role in the functional impairment of endocrine glands. This induced regulatory authorities to ban some of these compounds and to carefully investigate others in order to prevent EDCs-related conditions. As a result, we witnessed a growing awareness and interest on this topic.

AIMS

This paper aims to summarize current evidence regarding the detrimental effects of EDCs on pivotal endocrine glands like pituitary, thyroid and adrenal ones. Particularly, we directed our attention on the known and the hypothesized mechanisms of endocrine dysfunction brought by EDCs. We also gave a glimpse on recent findings from pioneering studies that could in the future shed a light on the pathophysiology of well-known, but poorly understood, endocrine diseases like hormone-producing adenomas.

CONCLUSIONS

Although intriguing, studies on endocrine dysfunctions brought by EDCs are challenging, in particular when investigating long-term effects of EDCs on humans. However, undoubtedly, it represents a new intriguing field of science research.

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.

Disturbance in Some Fertility Biomarkers Induced and Changes in Testis Architecture by Chronic Exposure to Various Dosages of Each of Nonylphenol or Bisphenol A and Their Mix

This investigation was conducted to demonstrate the potential impacts of different doses of Bisphenol A (BPA) or Nonylphenol (NP) and their mixtures on some biological activities in male albino rats. Seventy male albino rats were allocated to the control group (GI) and were given 1 mL of ethanol. G II and G III were given 100 mg/kg of each of BPA and NP, G IV and G V were given 25 mg/kg of each of BPA and NP, G VI was given a high dose of BPA and NP, and G VII was given a low dose of BPA and NP. All animals were treated orally for 60 days. Serum biomarkers of oxidative stress, antioxidants, immune-inflammatory mediators, and apoptotic markers were determined, as well as a histopathological examination of the testis at the end of the experimental period. The results obtained showed a pronounced increase in malondialdehyde (MDA), protein carbonyl (PC), and 4-hydroxynonenol (4-HNE), concomitant with a significant reduction in serum Superoxide dismutase (SOD), catalase enzyme (CAT), and total antioxidant capacity (TAC) in all treated groups. A significant elevation in TNF Alpha, TNF Beta, and Caspase 3 serum was recorded individually and in the groups treated with high doses. The disturbance is represented by histological damage in the testis in the germinal epithelium and a decrease in spermatozoa inside the lumen of seminiferous tubules. The effects on testis tissues were dose-dependent, pronounced in mixture doses, and remarkable in higher doses. In conclusion, exposure to BPA and NP strongly impacts antioxidants, immune-inflammatory mediators, and testis tissue architecture. Furthermore, the data from this investigation support the idea that exposure to BPA and NP in daily life has multiple damages.

Environmental disruption of reproductive rhythms

Reproduction is a key biological function requiring a precise synchronization with annual and daily cues to cope with environmental fluctuations. Therefore, humans and animals have developed well-conserved photoneuroendocrine pathways to integrate and process daily and seasonal light signals within the hypothalamic-pituitary-gonadal axis. However, in the past century, industrialization and the modern 24/7 human lifestyle have imposed detrimental changes in natural habitats and rhythms of life. Indeed, exposure to an excessive amount of artificial light at inappropriate timing because of shift work and nocturnal urban lighting, as well as the ubiquitous environmental contamination by endocrine-disrupting chemicals, threaten the integrity of the daily and seasonal timing of biological functions. Here, we review recent epidemiological, field and experimental studies to discuss how light and chemical pollution of the environment can disrupt reproductive rhythms by interfering with the photoneuroendocrine timing system.

Effects of Bisphenol A on reproductive toxicity and gut microbiota dysbiosis in male rats

Bisphenol A (BPA) is an environmental endocrine disruptor. Recent studies have shown an association between decreased spermatogenesis and gut microbiota alteration. However, the potential associations and mechanisms of BPA exposure on spermatogenesis, hormone production, and gut microbiota remain unknown. This study aims to investigate BPA-induced male reproductive toxicity and the potential link with gut microbiota dysbiosis. Male Sprague Dawley rats were exposed to BPA at different doses by oral gavage for thirty consecutive days. The extent of testicular damage was evaluated by basic parameters of body weight and hematoxylin-eosin (H&E) staining. Next, we determined the mRNA levels and protein levels of apoptosis, histone-related factors, and mammalian target of rapamycin (mTOR) pathway in testes. Finally, 16 S rDNA sequencing was used to analyze gut microbiota composition after BPA exposure. BPA exposure damaged testicular histology, significantly decreased sperm count, and increased sperm abnormalities. In addition, BPA exposure caused oxidative stress and cell apoptosis in testes. The levels of histone (H2A, H3) were significantly increased, while ubiquitin histone H2A (ub-H2A) and ubiquitin histone H2B (ub-H2B) were markedly reduced. Furthermore, BPA activated the PI3K and AKT expression, but the protein expressions of mTOR and 4EBP1 in testes were inhibited significantly. Additionally, the relative abundance of class Gammaproteobacteria, and order Betaproteobacteriales was significantly higher when treated with a high dose of BPA compared to the control group, which was negatively correlated with testosterone level. This study highlights the relationship between BPA-induced reproductive toxicity and gut microbiota disorder and provides new insights into the prevention and treatment of BPA-induced reproductive damage.

Early programming of reproductive health and fertility: novel neuroendocrine mechanisms and implications in reproductive medicine

BACKGROUND

According to the Developmental Origins of Health and Disease (DOHaD) hypothesis, environmental changes taking place during early maturational periods may alter normal development and predispose to the occurrence of diverse pathologies later in life. Indeed, adverse conditions during these critical developmental windows of high plasticity have been reported to alter the offspring developmental trajectory, causing permanent functional and structural perturbations that in the long term may enhance disease susceptibility. However, while solid evidence has documented that fluctuations in environmental factors, ranging from nutrient availability to chemicals, in early developmental stages (including the peri-conceptional period) have discernible programming effects that increase vulnerability to develop metabolic perturbations, the impact and eventual mechanisms involved, of such developmental alterations on the reproductive phenotype of offspring have received less attention.

OBJECTIVE AND RATIONALE

This review will summarize recent advances in basic and clinical research that support the concept of DOHaD in the context of the impact of nutritional and hormonal perturbations, occurring during the periconceptional, fetal and early postnatal stages, on different aspects of reproductive function in both sexes. Special emphasis will be given to the effects of early nutritional stress on the timing of puberty and adult gonadotropic function, and to address the underlying neuroendocrine pathways, with particular attention to involvement of the Kiss1 system in these reproductive perturbations. The implications of such phenomena in terms of reproductive medicine will also be considered.

SEARCH METHODS

A comprehensive MEDLINE search, using PubMed as main interface, of research articles and reviews, published mainly between 2006 and 2021, has been carried out. Search was implemented using multiple terms, focusing on clinical and preclinical data from DOHaD studies, addressing periconceptional, gestational and perinatal programming of reproduction. Selected studies addressing early programming of metabolic function have also been considered, when relevant.

OUTCOMES

A solid body of evidence, from clinical and preclinical studies, has documented the impact of nutritional and hormonal fluctuations during the periconceptional, prenatal and early postnatal periods on pubertal maturation, as well as adult gonadotropic function and fertility. Furthermore, exposure to environmental chemicals, such as bisphenol A, and maternal stress has been shown to negatively influence pubertal development and gonadotropic function in adulthood. The underlying neuroendocrine pathways and mechanisms involved have been also addressed, mainly by preclinical studies, which have identified an, as yet incomplete, array of molecular and neurohormonal effectors. These include, prominently, epigenetic regulatory mechanisms and the hypothalamic Kiss1 system, which likely contribute to the generation of reproductive alterations in conditions of early nutritional and/or metabolic stress. In addition to the Kiss1 system, other major hypothalamic regulators of GnRH neurosecretion, such as γ-aminobutyric acid and glutamate, may be targets of developmental programming.

WIDER IMPLICATIONS

This review addresses an underdeveloped area of reproductive biology and medicine that may help to improve our understanding of human reproductive disorders and stresses the importance, and eventual pathogenic impact, of early determinants of puberty, adult reproductive function and fertility.

Review on bisphenol A and the risk of polycystic ovarian syndrome: an insight from endocrine and gene expression

Bisphenol A (BPA) is one of the most widely studied endocrine disrupting chemicals because of its structural similarity to 17-β estradiol; its ability to bind as an agonist/antagonist to estrogen receptors elicits adverse effects on the functioning of the metabolic and endocrinal system. Therefore, BPA has been thoroughly scrutinized concerning its disruption of pathways like lipid metabolism, steroidogenesis, insulin signaling, and inflammation. This has resulted in reports of its correlation with various aspects of cardiovascular diseases, obesity, diabetes, male and female reproductive disorders, and dysfunctions. Among these, the occurrence of the polycystic ovarian syndrome (PCOS) in premenopausal women is of great concern. PCOS is a highly prevalent disorder affecting women in their reproductive age and is clinically characterized by hyperandrogenism, ovulatory dysfunction, and polycystic ovarian morphology, along with metabolism-related dysfunctions like hyperinsulinemia, obesity, and insulin resistance. In this review, we analyzed certain researched effects of BPA, while focusing on its ability to alter the expression of various significant genes like GnRH, AdipoQ, ESR1, StAR, CYP11A1, CYP19A1, and many more involved in the pathways and endocrine regulation, whose disruption is commonly associated with the clinical manifestations of PCOS.

Blood Transcriptome Analysis Reveals Gene Expression Differences between Yangtze Finless Porpoises from Two Habitats: Natural and Ex Situ Protected Waters

The Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis, YFP) is a critically endangered small odontocete species, mainly distributed in the middle and lower reaches of the Yangtze River, Poyang Lake, and Dongting Lake. Under the influence of human activities, many factors are threatening the survival and reproduction of YFPs in their natural habitat. Ex situ conservation is of great significance to strengthen the rescuing conservation of YFPs by providing suitable alternative habitats and promoting the reproduction and growth of the ex situ population. To reveal the differences in gene expression of YFPs in natural and ex situ protected waters, and to investigate the effects of environmental factors on YFPs and their mechanisms, we performed transcriptome sequencing for blood tissues of YFPs collected from natural waters and ex situ protected waters. Using RNA-seq we identified 4613 differentially expressed genes (DEGs), of which 4485 were up-regulated and 128 were down-regulated in the natural population. GO analysis showed that DEGs were significantly enriched in entries related to binding, catalytic activity, and biological regulation; KEGG analysis showed that DEGs were enriched mainly in signal transduction, endocrine system, immune system, and sensory system-related pathways. Further analysis revealed that water pollution in natural waters may affect the hormone secretion of YFPs by altering the expression pattern of endocrine genes, thus interfering with normal endocrine activities; noise pollution may induce oxidative stress and inflammatory responses in YFPs, thus impairing the auditory function of YFPs. This study provides a new perspective for further research on the effect of habitat conditions on the YFPs and suggests that improving the habitat environment may help in the conservation of YFPs.

Killing two birds with one stone: Pregnancy is a sensitive window for endocrine effects on both the mother and the fetus

Pregnancy is a complex process requiring tremendous physiological changes in the mother in order to fulfill the needs of the growing fetus, and to give birth, expel the placenta and nurse the newborn. These physiological modifications are accompanied with psychological changes, as well as with variations in habits and behaviors. As a result, this period of life is considered as a sensitive window as impaired functional and physiological changes in the mother can have short- and long-term impacts on her health. In addition, dysregulation of the placenta and of mechanisms governing placentation have been linked to chronic diseases later-on in life for the fetus, in a concept known as the Developmental Origin of Health and Diseases (DOHaD). This concept stipulates that any change in the environment during the pre-conception and perinatal (in utero life and neonatal) period to puberty, can be "imprinted" in the organism, thereby impacting the health and risk of chronic diseases later in life. Pregnancy is a succession of events that is regulated, in large part, by hormones and growth factors. Therefore, small changes in hormonal balance can have important effects on both the mother and the developing fetus. An increasing number of studies demonstrate that exposure to endocrine disrupting compounds (EDCs) affect both the mother and the fetus giving rise to growing concerns surrounding these exposures. This review will give an overview of changes that happen during pregnancy with respect to the mother, the placenta, and the fetus, and of the current literature regarding the effects of EDCs during this specific sensitive window of exposure.

Effects of prenatal and lactational bisphenol a and/or di(2-ethylhexyl) phthalate exposure on male reproductive system

Bisphenol A (BPA) and phthalates are abundantly used endocrine disrupting chemicals (EDCs). The aim of this study was to evaluate the effects of single and combined exposures to BPA and/or di(2-ethylhexyl) phthalate (DEHP) in prenatal and lactational period on rat male reproductive system in later stages of life. Pregnant Sprague-Dawley rats were divided randomly to four groups (n = 3/group): Control (corn oil); DEHP (30 mg/kg/day); BPA (50 mg/kg/day); and BPA+ DEHP (30 mg/kg/day DEHP and 50 mg/kg/day BPA). Groups exposed to EDCs through 6-21 gestational days and lactation period by intragastric lavage. Male offspring (n = 6/group) from each mother were fed till adulthood and were then euthanized. Later, reproductive hormones, sperm parameters, and oxidative stress parameters were determined. In conclusion, we can suggest that prenatal and lactational exposure to BPA and DEHP may cause adverse effects in male reproductive system in later stages of life especially after combined exposure.

Maternal and developmental toxicity of Bisphenol-A in SWR/J mice

Bisphenol-A (BPA), an organic compound with two phenol functional groups, is a widely used industrial plasticizer with known estrogenic properties. It is used in the manufacture of epoxy resins and polycarbonate plastics. This study was designed to evaluate and assess the possible toxicity arising from the oral administration of BPA to pregnant mice. Pregnant SWR/J mice (15 mice/group) were administrated oral doses of BPA (125, 250 and 500 mg/kg/day) over the course of five-day intervals during gestation (D1-5, D6-10 and D11-15), while control groups received only corn oil. The results indicated that BPA was associated with a reduction in the body weight of the pregnant mice from around 2–3 days after administration until the end of gestation. The greatest effects were evident when the BPA was given during the later stages of pregnancy, and with higher doses. They also showed marked reduction in food intake and, to a lesser extent, in water intake. Furthermore, doses of BPA induced a reduction in implantation sites, lower foetal body weight and increased mortality rates. Abortion and foetal resorption rates were not affected by BPA administration, however. The above findings were concluded by discussing the possible mechanisms involved in producing these effects.

The hazardous threat of Bisphenol A: Toxicity, detection and remediation

Bisphenol A (or BPA) is a toxic endocrine disrupting chemical that is released into the environment through modern manufacturing practices. BPA can disrupt the production, function and activity of endogenous hormones causing irregularity in the hypothalamus-pituitary-gonadal glands and also the pituitary-adrenal function. BPA has immuno-suppression activity and can downregulate T cells and antioxidant genes. The genotoxicity and cytotoxicity of BPA is paramount and therefore, there is an immediate need to properly detect and remediate its influence. In this review, we discuss the toxic effects of BPA on different metabolic systems in the human body, followed by its mechanism of action. Various novel detection techniques (LC-MS, GC-MS, capillary electrophoresis, immunoassay and sensors) involving a pretreatment step (liquid-liquid microextraction and molecularly imprinted solid-phase extraction) have also been detailed. Mechanisms of various remediation strategies, including biodegradation using native enzymes, membrane separation processes, photocatalytic oxidation, use of nanosorbents and thermal degradation has been detailed. An overview of the global regulations pertaining to BPA has been presented. More investigations are required on the efficiency of integrated remediation technologies rather than standalone methods for BPA removal. The effect of processing operations on BPA in food matrices is also warranted to restrict its transport into food products.

Combinational exposure to Bisphenol A and a high-fat diet causes trans-generational Malfunction of the female reproductive system in mice

Bisphenol A (BPA) is a common endocrine disruptor and a high-fat diet (HFD) also affects fertility. However, little is known about the long-term consequences of simultaneous exposure to BPA and a HFD on reproductive health. Herein, we assessed the effects of maternal exposure to BPA in combination with a HFD on reproductive function in subsequent generations of female mice and evaluated its effects on the hypothalamic-pituitary-gonadal axis. We found that the combination of maternal exposure to BPA and a HFD led to increased urine BPA levels, precocious puberty, altered estrous cyclicity, decreased follicle numbers, and altered hypothalamic Kiss1 methylation status in F1 and F2 mice. Therefore, we demonstrated that maternal exposure to BPA in combination with a HFD exerts a trans-generational effect on female reproduction.

Caffeic acid mitigates aflatoxin B1-mediated toxicity in the male rat reproductive system by modulating inflammatory and apoptotic responses, testicular function, and the redox-regulatory systems

Aflatoxin B1 (AFB₁ ) is a toxic metabolite of public health concern. The present study investigates the protective effects of caffeic acid (CA) against AFB₁ -induced oxidative stress, inflammation, and apoptosis in the hypothalamus, epididymis, and testis of male rats. Five experimental rat cohorts (n = 6) were treated per os for 28 consecutive days as follows: Control (Corn oil 2 ml/kg body weight), AFB1 alone (50μg/kg), CA alone (40 mg/kg) and the co-treated rat cohorts (AFB₁ : 50μg/kg + CA1: 20 or 40 mg/kg). Following sacrifice, the biomarkers of hypothalamic, epididymal, and testicular toxicities, antioxidant enzyme activities, myeloperoxidase (MPO) activity, as well as levels of nitric oxide (NO), reactive oxygen and nitrogen (RONS) species and lipid peroxidation (LPO) were analysed spectrophotometrically. Besides, the concentration of tumour necrosis factor-alpha (TNF-α), Bcl-2 and Bax proteins were assessed using ELISA. Results showed that the AFB₁ -induced decrease in biomarkers of testicular, epididymal and hypothalamic toxicity was significantly (p < .05) alleviated in rats coexposed to CA. Moreover, the reduction of antioxidant status and the increase in RONS and LPO were lessened (p < .05) in rats co-treated with CA. AFB₁ mediated increase in TNF-α, Bax, NO and MPO activity were reduced (p< .05) in the hypothalamus, epididymis, and testis of rats coexposed to CA. In addition, Bcl-2 levels were reduced in rats treated with CA dose-dependently. Light microscopic examination showed that histopathological lesions severity induced by AFB₁ were alleviated in rats coexposed to CA. Taken together, the amelioration of AFB₁ -induced neuronal and reproductive toxicities by CA involves anti-inflammatory, antioxidant, antiapoptotic mechanisms in rats. PRACTICAL APPLICATIONS: The beneficial antioxidant effects of caffeic acid (CA) are attributed to CA delocalized aromatic rings and free electrons, easily donated to stabilize reactive oxygen species. We report in vivo findings on CA and AfB1 mediated oxidative stress and reproductive dysfunction in rats. CA conjugated esters including chlorogenic acids are widely distributed in plants, and they act as a dietary source of natural defense against infections. CA can chelate heavy metals and reduce production of damaging free radicals to cellular macromolecules. Along these lines, CA can stabilize aflatoxin B1-epoxide as well and avert deleterious conjugates from forming with deoxyribonucleic acids. Hence CA, as a dietary phytochemical can protect against the damaging effects of toxins including aflatoxin B1 that contaminate food. CA dose-dependently abated oxidative, inflammatory, and apoptotic stimuli, improved functional characteristics of spermatozoa and reproductive hormone levels, and prevented histological alterations in experimental rats' hypothalamus and reproductive organs brought about by AFB1 toxicity.

A Putative Adverse Outcome Pathway Network for Disrupted Female Pubertal Onset to Improve Testing and Regulation of Endocrine Disrupting Chemicals

The average age for pubertal onset in girls has declined over recent decades. Epidemiological studies in humans and experimental studies in animals suggest a causal role for endocrine disrupting chemicals (EDCs) that are present in our environment. Of concern, current testing and screening regimens are inadequate in identifying EDCs that may affect pubertal maturation, not least because they do not consider early-life exposure. Also, the causal relationship between EDC exposure and pubertal timing is still a matter of debate. To address this issue, we have used current knowledge to elaborate a network of putative adverse outcome pathways (pAOPs) to identify how chemicals can affect pubertal onset. By using the AOP framework, we highlight current gaps in mechanistic understanding that need to be addressed and simultaneously point towards events causative of pubertal disturbance that could be exploited for alternative test methods. We propose 6 pAOPs that could explain the disruption of pubertal timing by interfering with the central hypothalamic trigger of puberty, GnRH neurons, and by so doing highlight specific modes of action that could be targeted for alternative test method development.

A review of the endocrine disrupting effects of micro and nano plastic and their associated chemicals in mammals

Over the years, the vaste expansion of plastic manufacturing has dramatically increased the environmental impact of microplastics [MPs] and nanoplastics [NPs], making them a threat to marine and terrestrial biota because they contain endocrine disrupting chemicals [EDCs] and other harmful compounds. MPs and NPs have deleteriouse impacts on mammalian endocrine components such as hypothalamus, pituitary, thyroid, adrenal, testes, and ovaries. MPs and NPs absorb and act as a transport medium for harmful chemicals such as bisphenols, phthalates, polybrominated diphenyl ether, polychlorinated biphenyl ether, organotin, perfluorinated compounds, dioxins, polycyclic aromatic hydrocarbons, organic contaminants, and heavy metals, which are commonly used as additives in plastic production. As the EDCs are not covalently bonded to plastics, they can easily leach into milk, water, and other liquids affecting the endocrine system of mammals upon exposure. The toxicity induced by MPs and NPs is size-dependent, as smaller particles have better absorption capacity and larger surface area, releasing more EDC and toxic chemicals. Various EDCs contained or carried by MPs and NPs share structural similarities with specific hormone receptors; hence they interfere with normal hormone receptors, altering the hormonal action of the endocrine glands. This review demonstrates size-dependent MPs' bioaccumulation, distribution, and translocation with potential hazards to the endocrine gland. We reviewed that MPs and NPs disrupt hypothalamic-pituitary axes, including the hypothalamic-pituitary-thyroid/adrenal/testicular/ovarian axis leading to oxidative stress, reproductive toxicity, neurotoxicity, cytotoxicity, developmental abnormalities, decreased sperm quality, and immunotoxicity. The direct consequences of MPs and NPs on the thyroid, testis, and ovaries are documented. Still, studies need to be carried out to identify the direct effects of MPs and NPs on the hypothalamus, pituitary, and adrenal glands.

The Impact of Endocrine-Disrupting Chemicals in Male Fertility: Focus on the Action of Obesogens

The current scenario of male infertility is not yet fully elucidated; however, there is increasing evidence that it is associated with the widespread exposure to endocrine-disrupting chemicals (EDCs), and in particular to obesogens. These compounds interfere with hormones involved in the regulation of metabolism and are associated with weight gain, being also able to change the functioning of the male reproductive axis and, consequently, the testicular physiology and metabolism that are pivotal for spermatogenesis. The disruption of these tightly regulated metabolic pathways leads to adverse reproductive outcomes. The permanent exposure to obesogens has raised serious health concerns. Evidence suggests that obesogens are one of the leading causes of the marked decline of male fertility and key players in shaping the future health outcomes not only for those who are directly exposed but also for upcoming generations. In addition to the changes that lead to inefficient functioning of the male gametes, obesogens induce alterations that are “imprinted” on the genes of the male gametes, establishing a link between generations and contributing to the transmission of defects. Unveiling the molecular mechanisms by which obesogens induce toxicity that may end-up in epigenetic modifications is imperative. This review describes and discusses the suggested molecular targets and potential mechanisms for obesogenic–disrupting chemicals and the subsequent effects on male reproductive health.

Multi- and Transgenerational Outcomes of an Exposure to a Mixture of Endocrine-Disrupting Chemicals (EDCs) on Puberty and Maternal Behavior in the Female Rat

BACKGROUND

The effects of endocrine-disrupting chemicals (EDCs) on fertility and reproductive development represent a rising concern in modern societies. Although the neuroendocrine control of sexual maturation is a major target of EDCs, little is known about the potential role of the hypothalamus in puberty and ovulation disruption transmitted across generations.

OBJECTIVES

We hypothesized that developmental exposure to an environmentally relevant dose of EDC mixture could induce multi- and/or transgenerational alterations of sexual maturation and maternal care in female rats through epigenetic reprograming of the hypothalamus. We investigated the transmission of a disrupted reproductive phenotype via the maternal germline or via nongenomic mechanisms involving maternal care.

METHODS

Adult female Wistar rats were exposed prior to and during gestation and until the end of lactation to a mixture of the following 13 EDCs: di-n-butyl phthalate (DnBP), di(2-ethylhexyl) phthalate (DEHP), bisphenol A (BPA), vinclozolin, prochloraz, procymidone, linuron, epoxynaxole, dichlorodiphenyldichloroethylene, octyl methoxynimmate, 4-methylbenzylidene camphor (4-MBC), butylparaben, and acetaminophen. Perinatally exposed offspring (F1) were mated with unexposed males to generate germ cell (F2) and transgenerationally exposed (F3 and F4) females. Sexual maturation, maternal behavior, and hypothalamic targets of exposure were studied across generations.

RESULTS

Germ cell (F2) and transgenerationally (F3) EDC-exposed females, but not F1, displayed delayed pubertal onset and altered folliculogenesis. We reported a transgenerational alteration of key hypothalamic genes controlling puberty and ovulation (Kiss1, Esr1, and Oxt), and we identified the hypothalamic polycomb group of epigenetic repressors as actors of this mechanism. Furthermore, we found a multigenerational reduction of maternal behavior (F1-F3) induced by a loss in hypothalamic dopaminergic signaling. Using a cross-fostering paradigm, we identified that the reduction in maternal phenotype was normalized in EDC-exposed pups raised by unexposed dams, but no reversal of the pubertal phenotype was achieved.

DISCUSSION

Rats developmentally exposed to an EDC mixture exhibited multi- and transgenerational disruption of sexual maturation and maternal care via hypothalamic epigenetic reprogramming. These results raise concerns about the impact of EDC mixtures on future generations. https://doi.org/10.1289/EHP8795.

Bisphenol A and male murine reproductive system: finding a link between plasticizer and compromised health

The global burden of male infertility is rising at an alarming rate affecting the lives of millions in terms of physical, emotional and societal perspectives. Among several existing endocrine disrupting chemicals, bisphenol A (BPA) has been reported by many to inflict male reproductive toxicity in different experimental models, especially in mice. This review article critically discusses the overall reproductive toxicity of BPA with a special note to its ubiquitous existence, contamination route, effects on the reproductive system and toxicity mechanisms in male mice. Disturbed redox status in germ cells and spermatozoa plays a pivotal role in BPA induced male reproductive toxicity. In this context, the involvement of mitochondria and endoplasmic reticulum is also of grave importance. Induction of caspase-dependent apoptosis is the extreme consequence that leads to deterioration of cellular parameters. Besides the oxidative cellular and histoarchitectural damages, perturbed endocrine regulation, subsequent impaired hormonal and cellular genesis program, epigenetic alterations and inflammation cumulatively reflect poor sperm quality leading to compromised reproduction. Moreover, several key issues have also been highlighted that, if addressed, will strengthen our understanding of BPA mediated male reproductive toxicity.

Environmental Factors-Induced Oxidative Stress: Hormonal and Molecular Pathway Disruptions in Hypogonadism and Erectile Dysfunction

Hypogonadism is an endocrine disorder characterized by inadequate serum testosterone production by the Leydig cells of the testis. It is triggered by alterations in the hypothalamic–pituitary–gonadal axis. Erectile dysfunction (ED) is another common disorder in men that involves an alteration in erectile response–organic, relational, or psychological. The incidence of hypogonadism and ED is common in men aged over 40 years. Hypogonadism (including late-onset hypogonadism) and ED may be linked to several environmental factors-induced oxidative stresses. The factors mainly include exposure to pesticides, radiation, air pollution, heavy metals and other endocrine-disrupting chemicals. These environmental risk factors may induce oxidative stress and lead to hormonal dysfunctions. To better understand the subject, the study used many keywords, including “hypogonadism”, “late-onset hypogonadism”, “testosterone”, “erectile dysfunction”, “reactive oxygen species”, “oxidative stress”, and “environmental pollution” in major online databases, such as SCOPUS and PUBMED to extract relevant scientific information. Based on these parameters, this review summarizes a comprehensive insight into the important environmental issues that may have a direct or indirect association with hypogonadism and ED in men. The study concludes that environmental factors-induced oxidative stress may cause infertility in men. The hypothesis and outcomes were reviewed critically, and the mechanistic approaches are applied through oxidant-sensitive pathways. This study also provides reccomendations on future therapeutic interventions and protective measures against such adverse environmental factors-induced hypogonadism and ED.

Multigenerational and transgenerational impact of paternal bisphenol A exposure on male fertility in a mouse model

STUDY QUESTION

How does paternal exposure to bisphenol A (BPA) affect the fertility of male offspring in mice in future generations?

SUMMARY ANSWER

Paternal exposure to BPA adversely affects spermatogenesis, several important sperm functions and DNA methylation patterns in spermatozoa, which have both multigenerational (in F0 and F1) and partial transgenerational (mainly noticed in F2, but F3) impacts on the fertility of the offspring.

WHAT IS KNOWN ALREADY

BPA, a synthetic endocrine disruptor, is used extensively to manufacture polycarbonate plastics and epoxy resins. Growing evidence suggests that exposure to BPA during the developmental stages results in atypical reproductive phenotypes that could persist for generations to come.

STUDY DESIGN, SIZE, DURATION

CD-1 male mice (F0) were treated with BPA (5 or 50 mg/kg body weight per day (bw/day)) or ethinylestradiol (EE) (0.4 μg/kg bw/day) for 6 weeks. Control mice were treated with vehicle (corn oil) only. The treated male mice were bred with untreated female mice to produce first filial generation (F1 offspring). The F2 and F3 offspring were produced similarly, without further exposure to BPA.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Histological changes in the testis along with functional, biochemical and epigenetic (DNA methylation) properties of spermatozoa were investigated. Subsequently, each parameter of the F0-F3 generations was compared between BPA-treated mice and control mice.

MAIN RESULTS AND THE ROLE OF CHANCE

Paternal BPA exposure disrupted spermatogenesis by decreasing the size and number of testicular seminiferous epithelial cells, which eventually led to a decline in the total sperm count of F0-F2 offspring (P < 0.05). We further showed that a high BPA dose decreased sperm motility in F0-F2 males by mediating the overproduction of reactive oxygen species (F0-F1) and decreasing intracellular ATP (F0-F2) in spermatozoa (P < 0.05). These changes in spermatozoa were associated with altered global DNA methylation patterns in the spermatozoa of F0-F3 males (P < 0.05). Furthermore, we noticed that BPA compromised sperm fertility in mice from the F0-F2 (in the both dose groups) and F3 generations (in the high-dose group only). The overall reproductive toxicity of BPA was equivalent to or higher (high dose) than that of the tested dose of EE.

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

Further research is required to determine the variables (e.g. lowest BPA dose) that are capable of producing changes in sperm function and fertility in future generations.

WIDER IMPLICATIONS OF THE FINDINGS

These results may shed light on how occupational exposure to BPA can affect offspring fertility in humans.

STUDY FUNDING/COMPETING INTEREST(S)

This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (Grant No. NRF-2018R1A6A1A03025159). M.S.R. was supported by Korea Research Fellowship Program through the NRF funded by the Ministry of Science and ICT (Grant No. 2017H1D3A1A02013844). There are no competing interests.

Antioxidant effect of Vitamin E on the male rat reproductive system by a high oral dose of Bisphenol-A

Among researchers, environmental pollutants and their contribution to male fertility are still being discussed. The use of antioxidants manages to boost the reproductive system with the scavenging of free radicals. This study aimed to investigate the inhibiting function of Vitamin E (VE) on Bisphenol-A (BPA) toxicity in the male rats’ reproductive system. Male rats were divided into 4 groups: control (negative control) group, BPA group treated by 250 mg/kg/day (positive control), VE group treated by 150 mg/kg/day (comparative control) and BPA + VE group that received both doses at the same time (Oral treatment by gavage; 56 days). Sperm parameters, testicular tissue morphometric and biochemical tests were evaluated. Sperm count, motility, viability, normal morphology, sperm tail length, spermatogenesis index and serum testosterone levels significantly decreased in the BPA group compared to the control group. Versus a significant enhancement in the positive-TUNEL germinal cells and serum malondialdehyde (MDA) levels were observed. Moreover, BPA exhibited no effect on sperm maturity and DNA integrity. In the simultaneous treatment group (BPA + EV), VE could improve and regulate all the mentioned parameters within the control group range. As mentioned, there was a significant difference in the results in the positive control group compared to the negative control group. But these data improved significantly in the BPA + VE. It can be concluded that in this group, VE was able to overcome the toxicity caused by positive control in their simultaneous treatment and maintain the data at the negative control group range. Therefore, no significant change was observed in the BPA + VE group compared to the negative control group.

Bisphenol A and Metabolites in Meat and Meat Products: Occurrence, Toxicity, and Recent Development in Analytical Methods

Bisphenol A (BPA) is a commonly used compound in many industries and has versatile applications in polycarbonate plastics and epoxy resins production. BPA is classified as endocrine-disrupting chemical which can hamper fetal development during pregnancy and may have long term negative health outcomes in humans. Dietary sources, main route of BPA exposure, can be contaminated by the migration of BPA into food during processing. The global regulatory framework for using this compound in food contact materials is currently not harmonized. This review aims to outline, survey, and critically evaluate BPA contamination in meat products, including level of BPA and/or metabolites present, exposure route, and recent advancements in the analytical procedures of these compounds from meat and meat products. The contribution of meat and meat products to the total dietary exposure of BPA ranges between 10 and 50% depending on the country and exposure scenario considered. From can lining materials of meat products, BPA migrates towards the solid phase resulting higher BPA concentration in solid phase than the liquid phase of the same can. The analytical procedure is comprised of meat sample pre-treatment, followed by cleaning with solid phase extraction (SPE), and chromatographic analysis. Considering several potential sources of BPA in industrial and home culinary practices, BPA can also accumulate in non-canned or raw meat products. Very few scientific studies have been conducted to identify the amount in raw meat products. Similarly, analysis of metabolites and identification of the origin of BPA contamination in meat products is still a challenge to overcome.

Prenatal and pubertal exposure to 17α-ethinylestradiol disrupts folliculogenesis and promotes morphophysiological changes in ovaries of old gerbils (Meriones unguiculatus)

17α-Ethinylestradiol is an endocrine-disrupting chemical that make up most contraceptive pills and can be found in the environment. Exposure to ethinylestradiol in different development periods may promote changes in morphophysiological parameters of reproductive and endocrine organs. Considering that the effects of low doses (15 µg/kg/day) of ethinylestradiol in ovaries from 12-month-old female gerbils (Meriones unguiculatus) were investigated. Four experimental groups used were control (without treatment), EE/PRE (treated from the 18th to the 22nd gestational day), EE/PUB (treated from the 42nd to the 49th day of life), and EE/PRE-PUB (treated in the both periods). The animals were euthanized at 12 months. Testosterone and 17β-estradiol levels were measured. The ovaries were stained with Hematoxylin and Eosin, Periodic Acid Schiff, and Gomori's Trichome. The follicles, corpus luteum, interstitial gland, lipofuscin, ovarian epithelium, and tunica albuginea were analyzed. Estradiol was higher in EE/PRE and EE/PUB groups, while testosterone was higher only in EE/PUB group. The main changes in follicle count occurred in EE/PUB and EE/PRE-PUB groups, with higher primordial follicle count and lower maturation of follicles. The corpus luteum was more evident in EE/PRE group. No differences were found in atretic follicles count. A higher area occupied by interstitial gland cells and lipofuscin deposit in these cells was noted in EE/PUB and EE/PRE-PUB groups. Higher epithelium height and thicker tunic albuginea were showed in treated groups. These results suggest that exposure to doses of EE2 in prenatal and pubertal periods of the development leads to morphological changes in senile ovaries.

Fighting Bisphenol A-Induced Male Infertility: The Power of Antioxidants

Bisphenol A (BPA), a well-known endocrine disruptor present in epoxy resins and polycarbonate plastics, negatively disturbs the male reproductive system affecting male fertility. In vivo studies showed that BPA exposure has deleterious effects on spermatogenesis by disturbing the hypothalamic–pituitary–gonadal axis and inducing oxidative stress in testis. This compound seems to disrupt hormone signalling even at low concentrations, modifying the levels of inhibin B, oestradiol, and testosterone. The adverse effects on seminal parameters are mainly supported by studies based on urinary BPA concentration, showing a negative association between BPA levels and sperm concentration, motility, and sperm DNA damage. Recent studies explored potential approaches to treat or prevent BPA-induced testicular toxicity and male infertility. Since the effect of BPA on testicular cells and spermatozoa is associated with an increased production of reactive oxygen species, most of the pharmacological approaches are based on the use of natural or synthetic antioxidants. In this review, we briefly describe the effects of BPA on male reproductive health and discuss the use of antioxidants to prevent or revert the BPA-induced toxicity and infertility in men.

Cellular and molecular features of EDC exposure: consequences for the GnRH network

The onset of puberty and the female ovulatory cycle are important developmental milestones of the reproductive system. These processes are controlled by a tightly organized network of neurotransmitters and neuropeptides, as well as genetic, epigenetic and hormonal factors, which ultimately drive the pulsatile secretion of gonadotropin-releasing hormone. They also strongly depend on organizational processes that take place during fetal and early postnatal life. Therefore, exposure to environmental pollutants such as endocrine-disrupting chemicals (EDCs) during critical periods of development can result in altered brain development, delayed or advanced puberty and long-term reproductive consequences, such as impaired fertility. The gonads and peripheral organs are targets of EDCs, and research from the past few years suggests that the organization of the neuroendocrine control of reproduction is also sensitive to environmental cues and disruption. Among other mechanisms, EDCs interfere with the action of steroidal and non-steroidal receptors, and alter enzymatic, metabolic and epigenetic pathways during development. In this Review, we discuss the cellular and molecular consequences of perinatal exposure (mostly in rodents) to representative EDCs with a focus on the neuroendocrine control of reproduction, pubertal timing and the female ovulatory cycle.

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.

Identification of the Bisphenol A (BPA) and the Two Analogues BPS and BPF in Cryptorchidism

OBJECTIVE

to explore the association of plasma concentrations of bisphenol A (BPA), bisphenol S (BPS), and bisphenol F (BPF) with unilateral cryptorchidism. In addition, to analyze selected demographic and intraoperative characteristics.

DESIGN

Retrospective analysis to determine plasma concentrations of total BPA, BPS and BPF using gas chromatography - mass spectrometry (GC-MS) among prepubertal boys with cryptorchidism and prebupertal male control subjects. During operation, the size, turgor and location of the cryptorchid testes were assessed.

MAIN OUTCOME MEASURE

Plasma concentrations of total BPA, BPS and BPF.

RESULTS

In children with cryptorchidism, plasma levels of BPA, BPS and BPF were significantly higher compared to the control subjects. For BPA, it was: median value: 9.95 ng/mL vs. 5.54 ng/mL, p<0.05. For BPS, it was: median value: 3.93 ng/mL vs. 1.45 ng/mL, p<0.001. For BPF, it was: median value: 3.56 ng/mL vs. 1.83 ng/mL, p<0.05. In cryptorchid group, BPA was detected in 61.4% samples, BPS in 19.3% and BPF in 19.3%. All the three bisphenols were detected in plasma samples of both the healthy subjects and the study cohort. In the latter group, we found significant higher levels of BPA in boys from urban areas. We found a weak positive correlation between the levels of BPS and BPF and reduced turgor of the testes. Furthermore, results showed weak positive correlations between BPA and BPS levels and the age of the children as well as between BPS and BPF concentrations and the place of residence.

CONCLUSIONS

Results provide a first characterization of prepubertal boys suffering from cryptorchidism and exposed to different kind of bisphenols. Our study suggests that cryptorchid boys are widely exposed to BPA and, to a lesser extent, also to its alternatives, such as BPS and BPF.

The impact of endocrine-disrupting chemical exposure in the mammalian hypothalamic-pituitary axis

The hypothalamic-pituitary axis (HP axis) plays a critical and integrative role in the endocrine system control to maintain homeostasis. The HP axis is responsible for the hormonal events necessary to regulate the thyroid, adrenal glands, gonads, somatic growth, among other functions. Endocrine-disrupting chemicals (EDCs) are a worldwide public health concern. There is growing evidence that exposure to EDCs such as bisphenol A (BPA), some phthalates, polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and biphenyls (PBBs), dichlorodiphenyltrichloroethane (DDT), tributyltin (TBT), and atrazine (ATR), is associated with HP axis abnormalities. EDCs act on hormone receptors and their downstream signaling pathways and can interfere with hormone synthesis, metabolism, and actions. Because the HP axis function is particularly sensitive to endogenous hormonal changes, disruptions by EDCs can alter HP axis proper function, leading to important endocrine irregularities. Here, we review the evidence that EDCs could directly affect the mammalian HP axis function.