Chronic exposure to low dose of bisphenol A impacts on the first round of spermatogenesis via SIRT1 modulation

Application of the Key Characteristics of Carcinogens to Bisphenol A

The ten key characteristics (KCs) of carcinogens are based on characteristics of known human carcinogens and encompass many types of endpoints. We propose that an objective review of the large amount of cancer mechanistic evidence for the chemical bisphenol A (BPA) can be achieved through use of these KCs. A search on metabolic and mechanistic data relevant to the carcinogenicity of BPA was conducted and web-based software tools were used to screen and organize the results. We applied the KCs to systematically identify, organize, and summarize mechanistic information for BPA, and to bring relevant carcinogenic mechanisms into focus. For some KCs with very large data sets, we utilized reviews focused on specific endpoints. Over 3000 studies for BPA from various data streams (exposed humans, animals, in vitro and cell-free systems) were identified. Mechanistic data relevant to each of the ten KCs were identified, with receptor-mediated effects, epigenetic alterations, oxidative stress, and cell proliferation being especially data rich. Reactive and bioactive metabolites are also associated with a number of KCs. This review demonstrates how the KCs can be applied to evaluate mechanistic data, especially for data-rich chemicals. While individual entities may have different approaches for the incorporation of mechanistic data in cancer hazard identification, the KCs provide a practical framework for conducting an objective examination of the available mechanistic data without a priori assumptions on mode of action. This analysis of the mechanistic data available for BPA suggests multiple and inter-connected mechanisms through which this chemical can act.

Molecular characterization of SPATA6 and association of its SNPs with testicular size in sheep

The testis is an important organ for maintaining fertility in males, and testis size is positively correlated with ejaculate volume, sperm motility, thus fertility. Spermatogenesis-associated 6 (SPATA6) is an evolutionarily conserved testis-specific gene reported in many species. However, the effect of SPATA6 expression levels on testicular development and the effect of single nucleotide polymorphisms (SNPs) on testis and epididymis phenotype in sheep have not been studied. The purpose of the research was to investigate the expression profile of SPATA6 and its effect on testicular development and to confirm the effect of SNPs on the testis and epididymis phenotype. In this study, we detected a 1245bp coding sequence (CDS) of SPATA6 and encoded 414 amino acids. The expression levels of SPATA6 were significantly higher in the testis than in other tissues and gradually increased with testis development. Moreover, the expression level in the large testis was significantly higher than that in the small testis at six months. A total of 11 SNPs were detected in the coding region of SPATA6 by cDNA-pooling sequencing and improved multiplex ligation detection reaction (iMLDR) methods. Correlation analysis showed that SNP2 (c. 3631C > G) significantly affected left epididymis weight (LEW) and right epididymis weight (REW), and SNP10 (c. 937 A > G) significantly affected REW. And the combined genotype of SNP1 (c. 4245 G > A) and SNP2 significantly affected REW. The current study concluded that SPATA6 plays an important role in testicular development and the SNPs significantly associated with the epididymis phenotype can provide molecular markers for the early selection of high-fertility Hu sheep.

Bisphenol A accelerates the vascular complications in patients with Type 2 diabetes mellitus through vascular calcification-a molecular approach

PURPOSE

Environmental pollutant Bisphenol A (BPA) strongly interacts with insulin resistance, which leads to type 2 diabetes mellitus (T2DM). Uncontrolled glucose levels in both blood and urine develops vascular complications in T2DM patients. However, glucose-controlled diabetic patients are also affected by vascular complications due to vascular calcification, and there is a lack of clinically relevant data on BPA levels available in patients with T2DM-associated vascular complications due to vascular calcification. Therefore, we measured BPA levels in T2DM-associated vascular complications and correlated systemic BPA levels with vascular calcification-related gene expression.

METHODS

This study included 120 participants with T2DM and its associated vascular complications. Serum and urinary BPA were estimated using an ELISA kit, and gene expression of the study participants in peripheral blood mononuclear cells (PBMCs) was studied with quantitative real-time PCR.

RESULTS

Serum and urinary BPA levels were higher in T2DM and its associated vascular complications with CVD and DN patients compared to control. Both Serum and urinary BPA had higher significance with Sirt1 (p < 0.001, p < 0.001), Runx2 (p < 0.01, p < 0.001) and IL-1beta (p < 0.001, p < 0.02) gene expression in the study groups, but, TNF-alpha significant with Serum BPA (p < 0.04), not urinary BPA (p < 0.31).

CONCLUSION

BPA levels were positively correlated with lower Sirt1 and increased Runx2 in T2DM-associated vascular complications patients. Also, higher expression of IL-1beta and TNF-alpha was observed in T2DM-associated vascular complications patients. Our study is the first to associate BPA levels with vascular calcification in patients with T2DM and its associated vascular complications.

Bisphenol S dysregulates thyroid hormone homeostasis; Testicular survival, redox and metabolic status: Ameliorative actions of melatonin

Bisphenol S (BPS) is an incipient threat for reproductive health augmenting societal burden of infertility worldwide. In the present study, we investigated the mechanism of BPS induced testicular dysfunctions and protective actions of melatonin in mice. BPS (150 mg/kg BW) treatment reduced serum T3/T4, testosterone and elevated insulin levels along with adverse effect on thyroid and testicular histoarchitecture. Further, BPS treatment compromised sperm quality, reduced mRNA expression of steroidogenic (StAR/CYP11A1) markers, elevated oxidative load and disrupts metabolic status. However, melatonin (5 mg/kg BW) administration to BPS treated mice showed improved hormonal/histological parameters, enhanced thyroid hormone (TR-α/Dio-2)/melatonin (MT-1) receptor expressions. Further, melatonin treatment modulated the expression of testicular survival/redox (SIRT1/PGC-1α/FOXO-1, Nrf2/HO-1, p-JAK2/p-STAT3), proliferative (PCNA) and metabolic (IR/pAKT/GLUT-1) markers. Furthermore, melatonin treatment enhanced testicular antioxidant status and reduced caspase-3 expression. In conclusion, our results showed that BPS induces endocrine/oxidative and metabolic anomalies while melatonin improved male reproductive health.

Low-dose Bisphenol A exposure alters the functionality and cellular environment in a human cardiomyocyte model

Early embryonic development represents a sensitive time-window during which the foetus might be vulnerable to the exposure of environmental contaminants, potentially leading to heart diseases also later in life. Bisphenol A (BPA), a synthetic chemical widely used in plastics manufacturing, has been associated with heart developmental defects, even in low concentrations. This study aims to investigate the effects of environmentally relevant doses of BPA on developing cardiomyocytes using a human induced pluripotent stem cell (hiPSC)-derived model. Firstly, a 2D in vitro differentiation system to obtain cardiomyocytes from hiPSCs (hiPSC-CMs) have been established and characterised to provide a suitable model for the early stages of cardiac development. Then, the effects of a repeated BPA exposure, starting from the undifferentiated stage throughout the differentiation process, were evaluated. The chemical significantly decreased the beat rate of hiPSC-CMs, extending the contraction and relaxation time in a dose-dependent manner. Quantitative proteomics analysis revealed a high abundance of basement membrane (BM) components (e.g., COL4A1, COL4A2, LAMC1, NID2) and a significant increase in TNNC1 and SERBP1 proteins in hiPSC-CMs treated with BPA. Network analysis of proteomics data supported altered extracellular matrix remodelling and provided a disease-gene association with well-known pathological conditions of the heart. Furthermore, upon hypoxia-reoxygenation challenge, hiPSC-CMs treated with BPA showed higher rate of apoptotic events. Taken together, our results revealed that a long-term treatment, even with low doses of BPA, interferes with hiPSC-CMs functionality and alters the surrounding cellular environment, providing new insights about diseases that might arise upon the toxin exposure. Our study contributes to the current understanding of BPA effects on developing human foetal cardiomyocytes, in correlation with human clinical observations and animal studies, and it provides a suitable model for New Approach Methodologies (NAMs) for environmental chemical hazard and risk assessment.

The interplay between kisspeptin and endocannabinoid systems modulates male hypothalamic and gonadic control of reproduction in vivo

Introduction

Male reproduction is under the control of the hypothalamus-pituitary-gonadal (HPG) axis. The endocannabinoid system (ECS) and the kisspeptin system (KS) are two major signaling systems in the central and peripheral control of reproduction, but their possible interaction has been poorly investigated in mammals. This manuscript analyzes their possible reciprocal modulation in the control of the HPG axis.

Materials and methods

Adolescent male rats were treated with kisspeptin-10 (Kp10) and endocannabinoid anandamide (AEA), the latter alone or in combination with the type 1 cannabinoid receptor (CB1) antagonist rimonabant (SR141716A). The hypothalamic KS system and GnRH expression, circulating sex steroids and kisspeptin (Kiss1) levels, and intratesticular KS and ECS were evaluated by immunohistochemical and molecular methods. Non-coding RNAs (i.e., miR145-5p, miR-132-3p, let7a-5p, let7b-5p) were also considered.

Results

Circulating hormonal values were not significantly affected by Kp10 or AEA; in the hypothalamus, Kp10 significantly increased GnRH mRNA and aromatase Cyp19, Kiss1, and Kiss1 receptor (Kiss1R) proteins. By contrast, AEA treatment affected the hypothalamic KS at the protein levels, with opposite effects on the ligand and receptor, and SR141716A was capable of attenuating the AEA effects. Among the considered non-coding RNA, only the expression of miR145-5p was positively affected by AEA but not by Kp10 treatment. Localization of Kiss1+/Kiss1R+ neurons in the arcuate nucleus revealed an increase of Kiss1R-expressing neurons in Kp10- and AEA-treated animals associated with enlargement of the lateral ventricles in Kp10-treated animals. In the brain and testis, the selected non-coding RNA was differently modulated by Kp10 or AEA. Lastly, in the testis, AEA treatment affected the KS at the protein levels, whereas Kp10 affected the intragonadal levels of CB1 and FAAH, the main modulator of the AEA tone. Changes in pubertal transition-related miRNAs and the intratesticular distribution of Kiss1, Kiss1R, CB1, and CB2 following KP and AEA treatment corroborate the KS-ECS crosstalk also showing that the CB1 receptor is involved in this interplay.

Conclusion

For the first time in mammals, we report the modulation of the KS in both the hypothalamus and testis by AEA and revealed the KP-dependent modulation of CB1 and FAAH in the testis. KP involvement in the progression of spermatogenesis is also suggested.

The Bacterial Gq Signal Transduction Inhibitor FR900359 Impairs Soil-Associated Nematodes

The cyclic depsipeptide FR900359 (FR) is derived from the soil bacterium Chromobacterium vaccinii and known to bind Gq proteins of mammals and insects, thereby abolishing the signal transduction of their Gq protein-coupled receptors, a process that leads to severe physiological consequences. Due to their highly conserved structure, Gq family of proteins are a superior ecological target for FR producing organisms, resulting in a defense towards a broad range of harmful organisms. Here, we focus on the question whether bacteria like C. vaccinii are important factors in soil in that their secondary metabolites impair, e.g., plant harming organisms like nematodes. We prove that the Gq inhibitor FR is produced under soil-like conditions. Furthermore, FR inhibits heterologously expressed Gαq proteins of the nematodes Caenorhabditis elegans and Heterodera schachtii in the micromolar range. Additionally, in vivo experiments with C. elegans and the plant parasitic cyst nematode H. schachtii demonstrated that FR reduces locomotion of C. elegans and H. schachtii. Finally, egg-laying of C. elegans and hatching of juvenile stage 2 of H. schachtii from its cysts is inhibited by FR, suggesting that FR might reduce nematode dispersion and proliferation. This study supports the idea that C. vaccinii and its excreted metabolome in the soil might contribute to an ecological equilibrium, maintaining and establishing the successful growth of plants.

Bisphenols as promoters of the dysregulation of cellular junction proteins of the blood-testis barrier in experimental animals: A systematic review of the literature

Daily, people are exposed to chemicals and environmental compounds such as bisphenols (BPs). These substances are present in more than 80% of human fluids. Human exposure to BPs is associated with male reproductive health disorders. Some of the main targets of BPs are intercellular junction proteins of the blood-testis barrier (BTB) in Sertoli cells because BPs alter the expression or induce aberrant localization of these proteins. In this systematic review, we explore the effects of BP exposure on the expression of BTB junction proteins and the characteristics of in vivo studies to identify potential gaps and priorities for future research. To this end, we conducted a systematic review of articles. Thirteen studies met our inclusion criteria. In most studies, animals treated with bisphenol-A (BPA) showed decreased occludin expression at all tested doses. However, bisphenol-AF treatment did not alter occludin expression. Cx43, ZO-1, β-catenin, nectin-3, cortactin, paladin, and claudin-11 expression also decreased in some tested doses of BP, while N-cadherin and FAK expression increased. BP treatment did not alter the expression of α and γ catenin, E-cadherin, JAM-A, and Arp 3. However, the expression of all these proteins was altered when BPA was administered to neonatal rodents in microgram doses. The results show significant heterogeneity between studies. Thus, it is necessary to perform more research to characterize the changes in BTB protein expression induced by BPs in animals to highlight future research directions that can inform the evaluation of risk of toxicity in humans.

GGA1 participates in spermatogenesis in mice under stress

BACKGROUND

Infertility is recognized as a common and worrisome problem of human reproduction worldwide. Based on previous studies, male factors account for about half of all infertility cases. Exposure to environmental toxicants is an important contributor to male infertility. Bisphenol A (BPA) is the most prominent toxic environmental contaminant worldwide affecting the male reproductive system. BPA can impair the function of the Golgi apparatus which is important in spermatogenesis. GGA1 is known as Golgi-localized, gamma adaptin ear-containing, ARF-binding protein 1. Previously, it has been shown that GGA1 is associated with spermatogenesis in Drosophila, however, its function in mammalian spermatogenesis remains unclear.

METHODS

Gga1 knockout mice were generated using the CRISPR/Cas9 system. Gga1-/- male mice and wild-type littermates received intraperitoneal (i.p.) injections of BPA (40 µg/kg) once daily for 2 weeks. Histological and immunofluorescence staining were performed to analyze the phenotypes of these mice.

RESULTS

Male mice lacking Gga1 had normal fertility without any obvious defects in spermatogenesis, sperm count and sperm morphology. Gga1 ablation led to infertility in male mice exposed to BPA, along with a significant reduction in sperm count, sperm motility and the percentage of normal sperm. Histological analysis of the seminiferous epithelium showed that spermatogenesis was severely disorganized, while apoptotic germ cells were significantly increased in the Gga1 null mice exposed to BPA. Our findings suggest that Gga1 protects spermatogenesis against damage induced by environmental pollutants.

Comparative study of the effect of oleuropein and hydroxytyrosol rich extracts on the reproductive toxicity induced by bisphenol A in male rats: biochemical, histopathological, and molecular analyses

Bisphenol A, or BPA, goes into the composition of a large number of products including sunglasses, infant's feeding bottles, receipts, or food packaging. Nowadays, there is a growing evidence that BPA may be at the origin of several physiological malignancies. Oleuropein and hydroxytyrosol extracted from olive leaves are highly investigated for numerous health benefits. The present work investigates the potential protective proprieties of olive leaf extracts against BPA-induced testicular damage in Wistar rats. Thirty-two animals were randomly divided into 4 groups: control, BPA-treated (10 mg/kg), BPA and oleuropein rich extract (16 mg/kg) treatment, and the last group treated with BPA and hydroxytyrosol rich extract (16 mg/kg). Biochemical parameters and histological and molecular analyses were evaluated. Our data demonstrated that BPA treatment caused significant alteration in biochemical parameters, disorganization of germinal epithelium, an up-regulation of p53 and Bax, and a reduction of Bcl-2 protein levels. The ingestion of oleuropein- and hydroxytyrosol-rich extracts attenuated BPA-induced biochemical and histological changes. In fact, olive leaf extracts enhanced the enzymatic antioxidant system and the level of Bcl-2, and reduced the expression of p53 and Bax. Fairly, our findings propose that olive leaf extracts may compete with BPA-induced reprotoxicity in vivo.

Re-evaluation of the risks to public health related to the presence of bisphenol A (BPA) in foodstuffs

In 2015, EFSA established a temporary tolerable daily intake (t-TDI) for BPA of 4 μg/kg body weight (bw) per day. In 2016, the European Commission mandated EFSA to re-evaluate the risks to public health from the presence of BPA in foodstuffs and to establish a tolerable daily intake (TDI). For this re-evaluation, a pre-established protocol was used that had undergone public consultation. The CEP Panel concluded that it is Unlikely to Very Unlikely that BPA presents a genotoxic hazard through a direct mechanism. Taking into consideration the evidence from animal data and support from human observational studies, the immune system was identified as most sensitive to BPA exposure. An effect on Th17 cells in mice was identified as the critical effect; these cells are pivotal in cellular immune mechanisms and involved in the development of inflammatory conditions, including autoimmunity and lung inflammation. A reference point (RP) of 8.2 ng/kg bw per day, expressed as human equivalent dose, was identified for the critical effect. Uncertainty analysis assessed a probability of 57-73% that the lowest estimated Benchmark Dose (BMD) for other health effects was below the RP based on Th17 cells. In view of this, the CEP Panel judged that an additional uncertainty factor (UF) of 2 was needed for establishing the TDI. Applying an overall UF of 50 to the RP, a TDI of 0.2 ng BPA/kg bw per day was established. Comparison of this TDI with the dietary exposure estimates from the 2015 EFSA opinion showed that both the mean and the 95th percentile dietary exposures in all age groups exceeded the TDI by two to three orders of magnitude. Even considering the uncertainty in the exposure assessment, the exceedance being so large, the CEP Panel concluded that there is a health concern from dietary BPA exposure.

Fetal Exposure to Endocrine Disrupting-Bisphenol A (BPA) Alters Testicular Fatty Acid Metabolism in the Adult Offspring: Relevance to Sperm Maturation and Quality

Daily exposure to bisphenols can affect reproductive functions due to their pseudo-estrogenic and/or anti-androgenic effects. Testicular lipids contain high levels of polyunsaturated fatty acids necessary for sperm maturity, motility, and spermatogenesis. Whether prenatal exposure to bisphenols alters testicular fatty acid metabolism in adult offspring is unknown. Pregnant Wistar rats were gavaged from gestational day 4 to 21 with BPA and BPS (0.0, 0.4, 4.0, 40.0 μg/kg bw/day). Despite increased body and testis weight, the total testicular cholesterol, triglyceride, and plasma fatty acids were unaffected in the offspring. Lipogenesis was upregulated by increased SCD-1, SCD-2, and expression of lipid storage (ADRP) and trafficking protein (FABP4). The arachidonic acid, 20:4 n-6 (ARA) and docosapentaenoic acid, 22:5 n-6 (DPA) levels were decreased in the BPA-exposed testis, while BPS exposure had no effects. The expression of PPARα, PPARγ proteins, and CATSPER2 mRNA were decreased, which are important for energy dissipation and the motility of the sperm in the testis. The endogenous conversion of linoleic acid,18:2 n-6 (LA), to ARA was impaired by a reduced ARA/LA ratio and decreased FADS1 expression in BPA-exposed testis. Collectively, fetal BPA exposure affected endogenous long-chain fatty acid metabolism and steroidogenesis in the adult testis, which might dysregulate sperm maturation and quality.

The antioxidant effects of coenzyme Q10 on albino rat testicular toxicity and apoptosis triggered by bisphenol A

Polycarbonate plastics for packaging and epoxy resins are both made with the industrial chemical bisphenol A (BPA). This investigation looked at the histological structure, antioxidant enzymes, and albino rats' testis to determine how coenzyme Q10 (CoQ10) impacts BPA toxicity. For the experiments, three sets of 18 male adult rats were created: group 1 received no therapy, group 2 acquired BPA, and group 3 got the daily BPA treatment accompanied by coenzyme Q10, 1 h apart. The experimental period ran for 14 days. The biochemical biomarkers catalase (CAT), superoxide dismutase (SOD), and malondialdehyde (MDA) were altered as a result of BPA exposure. The testicular histological architecture, which is made up of apoptosis, was also exaggerated. Furthermore, rats given BPA and CoQ10 treatment may experience a diminution in these negative BPA effects. These protective properties of CoQ10 may be correlated with the ability to eliminate oxidizing substances that can harm living species. The outcomes might support the hypothesis that CoQ10 prevented oxidative damage and boosted rats' stress responses when BPA was introduced. Thus, by shielding mammals from oxidative stress, CoQ10 aids in the growth and development of the animals. BPA is extremely hazardous to humans and can persist in tissues. Human reproductive functions are a worry due to human exposure to BPA, especially for occupational workers who are typically exposed to higher doses of BPA. As a result, in order to reduce the health risks, BPA usage must be minimized across a diverse range of industries, and improper plastic container handling must be prohibited. By giving CoQ10 to patients, BPA's harmful effects on reproductive structures and functions may be avoided.

The Anti-Oxidant Effects of Coenzyme Q10 on Albino Rat Testicular Toxicity and Apoptosis Triggered by Bisphenol A.. [DOI: 10.21203/rs.3.rs-2073923/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Polycarbonate plastics for packaging and epoxy resins are both made with the industrial chemical bisphenol A (BPA). This investigation looked at the histological structure, antioxidant enzymes, and albino rats' testis to determine how Coenzyme Q10 (CoQ10) impacts BPA toxicity. For the experiments, 18 adult male rats were broken into three groups: group 1 received no therapy, group 2 acquired BPA, and group 3 got daily BPA treatment accompanied by coenzyme Q10, one hour apart. All experiment done for 14 days. The biochemical biomarkers catalase (CAT), superoxide dismutase (SOD), and malondialdehyde (MDA) were altered as a result of BPA exposure. The testicular histological architecture, which is made up of apoptosis, was also exaggerated. Furthermore, rats given BPA and CoQ10 treatment may experience a diminution in these negative BPA effects. These protective properties of CoQ10 may be correlated with the ability to eliminate oxidizing substances that can harm living species.The outcomes might support the hypothesis that CoQ10 prevented oxidative damage and boosted rats' stress responses when BPA was introduced. Thus, by shielding mammals from oxidative stress, CoQ10 aids in the growth and development of the animals.BPA is extremely hazardous to humans and can persist in tissues. Human reproductive functions are a worry due to human exposure to BPA, especially for occupational workers who are typically exposed to higher doses of BPA. As a result, in order to reduce the health risks, BPA usage must be minimized across a diverse range of industries, and improper plastic container handling must be prohibited. By giving CoQ10 to patients, BPA's harmful effects on reproductive structures and functions may be avoided.

Dietary zinc deficient condition increases the Bisphenol A toxicity in diabetic rat testes

Bisphenol A (BPA) is a widely used endocrine disrupter that causes male reproductive dysfunction in humans and rodents. Diabetes-induced hyperglycemia alters spermatogenesis and antioxidant status, which negatively impacts male fertility in adults. Zinc (Zn) deficiency is a global health concern maintaining the testicular structure and functions in developing gonads. The present experiment was designed to investigate the role of Zn deficiency on BPA-induced germ cell and male gonadal toxicity in diabetic conditions. Rats were randomly divided into eight different groups - control (normal feed and water), BPA (10 mg/kg/day), ZDD (fed with a Zn-deficient diet), DIA (diabetic), BPA+ZDD, BPA+DIA, ZDD+DIA and BPA+ZDD+DIA for four weeks. Animals' body and organ weight, sperm count, motility and sperm morphology were examined; testes and epididymis histopathology were investigated. Testicular DNA damage and sperm apoptosis were evaluated by halo and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assays respectively. Testicular catalase and octamer-binding transcription factor 4 (OCT4) expressions were evaluated by western blot analysis. The present results demonstrated that dietary Zn-deficient condition significantly increased the BPA-induced testicular, epididymal and sperm toxicity in diabetic rats due to hypogonadism, increased sperm abnormalities, epididymis, testicular structure and DNA damages, sperm apoptosis as well as decreased testicular catalase and OCT4 expressions. The present results revealed that dietary Zn-deficient condition exacerbated the BPA-induced testicular and epididymal toxicity as well as perturbed the general male reproductive health in diabetic rats.

Investigation of the effect of hesperidin on some reproductive parameters in testicular toxicity induced by Bisphenol A

Bisphenol A (BPA) is one of the chemicals that cause dysfunction and infertility in testicles. Therefore, it is crucial to develop effective treatments against this damage. In this study, the effects of Hesperidin (HESP), a flavonoid in testicular toxicity induced by BPA in rats, on oxidative stress, inflammation, apoptosis, histological damage, spermatogenesis, steroidogenic enzymes and reproductive hormones were investigated. Our study used 52 Sprague Dawley male rats weighing 250-300 g, and four experimental groups were formed. From the experimental groups, 1 ml of olive oil was administered to the control group, HESP at a dose of 50 mg/kg to the HESP group, BPA at a dose of 100 mg/kg to the BPA group, HESP at a dose of 50 mg/kg to the BPA + HESP group and 100 mg/kg BPA was administered intragastrically (ig) for 14 days. We determined that BPA administration causes apoptosis, histological damage, inflammation, oxidative stress and toxic effects on spermatogenesis and steroidogenic enzymes in testicles. We observed that the administration of HESP with BPA attenuated oxidative stress, inflammation and apoptosis resulting in therapeutic effects on both steroidogenic enzymes and spermatogenesis and reproductive hormones (FSH, LH and testosterone). Our findings from this study clearly showed that while HESP treatment alleviates oxidative damage, inflammation and apoptosis in testicles of rats treated with BPA, it has regulatory effects on steroidogenic enzymes, spermatogenesis and serum reproductive hormones.

Genotoxic potential of bisphenol A: A review

Bisphenol A (BPA), as a major component of some plastic products, is abundant environmental pollutant. Due to its ability to bind to several types of estrogen receptors, it can trigger multiple cellular responses, which can contribute to various manifestations at the organism level. The most studied effect of BPA is endocrine disruption, but recently its prooxidative potential has been confirmed. BPA ability to induce oxidative stress through increased ROS production, altered activity of antioxidant enzymes, or accumulation of oxidation products of biomacromolecules is observed in a wide range of organisms - estrogen receptor-positive and -negative. Subsequently, increased intracellular oxidation can lead to DNA damage induction, represented by oxidative damage, single- and double-strand DNA breaks. Importantly, BPA shows several mechanisms of action and can trigger adverse effects on all organisms inhabiting a wide variety of ecosystem types. Therefore, the main aim of this review is to summarize the genotoxic effects of BPA on organisms across all taxa.

Impact of bisphenol-A on the spliceosome and meiosis of sperm in the testis of adolescent mice

BACKGROUND

Bisphenol-A (BPA) has estrogenic activity and adversely affects humans and animals' reproductive systems and functions. There has been a disagreement with the safety of BPA exposure at Tolerable daily intake (TDI) (0.05 mg/kg/d) value and non-observed adverse effect level (5 mg/kg/d). The current study investigated the effects of BPA exposure at various doses starting from Tolerable daily intake (0.05 mg/kg/d) to the lowest observed adverse effect level (50 mg/kg/d) on the testis development in male mice offspring. The BPA exposure lasted for 63 days from pregnancy day 0 of the dams to post-natal day (PND) 45 of the offspring.

RESULTS

The results showed that BPA exposure significantly increased testis (BPA ≥ 20 mg/kg/d) and serum (BPA ≥ 10 mg/kg/d) BPA contents of PND 45 mice. The spermatogenic cells became loose, and the lumen of seminiferous tubules enlarged when BPA exposure at 0.05 mg/kg/d TDI. BPA exposure at a low dose (0.05 mg/kg/d) significantly reduced the expression of Scp3 proteins and elevated sperm abnormality. The significant decrease in Scp3 suggested that BPA inhibits the transformation of spermatogonia into spermatozoa in the testis. The RNA-seq proved that the spliceosome was significantly inhibited in the testes of mice exposed to BPA. According to the RT-qPCR, BPA exposure significantly reduced the expression of Snrpc (BPA ≥ 20 mg/kg/d) and Hnrnpu (BPA ≥ 0.5 mg/kg/d).

CONCLUSIONS

This study indicated that long-term BPA exposure at Tolerable daily intake (0.05 mg/kg/d) is not safe because low-dose long-term exposure to BPA inhibits spermatogonial meiosis in mice testis impairs reproductive function in male offspring.

Prenatal exposure to bisphenol S and bisphenol A differentially affects male reproductive system in the adult offspring

Early exposure to bisphenol may result in adverse reproductive health in later life. The use of bisphenol S (BPS) has increased considerably after bisphenol A (BPA) is regulated worldwide. However, little is known about the fetal exposure to BPS compared with BPA and its effects on the reproductive system in the adult male offspring. Here, we investigated the effects of orally administered BPS and BPA (0.4, 4.0, 40.0 μg/kg bw/d) during gestation (gD4-21) on testicular development by evaluating the sperm DNA damage & methylation and testicular functions in the 90 d Wistar rats. Male offspring prenatally exposed to BPS (0.4 μg/kg) had higher plasma testosterone than BPA and control. The testis histology reveals thickened membrane by producing a wide interstitial gap between seminiferous tubules, increased testicular inflammation, oxidative stress, TIMP-1 expression, and decreased VCAM-1 expression. BPS promotes apoptosis by up-regulating IL-6, cleaved caspases, and a spike in sperm DNA fragmentation. Prenatal BPS exposure reduces sperm motility mediated via impaired PI3K-AKT signaling and increases testicular TEX11 expression in the offspring. Exposure of the fetus to BPS interferes developmental programming of the male reproductive system in the offspring. BPS could be an equally potent endocrine disruptor affecting male reproductive functions.

Bisphenol A damages testicular junctional proteins transgenerationally in mice

Testicular junctions are pivotal to male fertility and regulated by constituent proteins. Increasing evidence suggests that environmental chemicals, including bisphenol A (BPA), may impact these proteins, but whether the impacts persist for generations is not yet known. Here, we investigate the effect of BPA (a ubiquitous endocrine-disrupting chemical) on testis and sperm functions and whether the effects are transferred to subsequent generations. Male mice (F0) were exposed to corn oil (Control) or 5 or 50 mg BPA/kg body weight/day from 6 to 12 weeks of age. The F0 were mated with wild-type females to produce the first filial (F1) generation. F2 and F3 were produced using similar procedures. Our results showed that BPA doses decreased the levels of some junctional proteins partly via binding with estrogen receptors (ERα and Erβ), upregulation of p-ERK1/2, P85, p-JNK and activation of p38 mitogen-activated protein kinase signaling. Consequently, testicular histological abnormalities, disrupted spermatogenesis, decreased sperm count, and inability to fertilize eggs were observed in mice exposed to BPA. These effects were transferred to successive generations (F2), partly through DNA methylation, but mostly alleviated in F3 males. Our findings suggest that paternal exposure to chemicals promoting alteration of testicular junctional proteins and its transgenerational inheritance is a key component of the origin of male reproductive health problems.

A critical review of presence, removal and potential impacts of endocrine disruptors bisphenol A

Bisphenol A (BPA) is a synthetic organic compound that is mainly used in the production of polymer materials polycarbonate and epoxy resin. Widespread use and irregular processing methods have led to BPA being detected globally, raising concerns about its environmental and health effects. This review outlines an overview of the presence and removal of BPA in the environment and consumer products. We also summarized the endocrine-disrupting toxicity of BPA, and the relatively less summarized neurotoxicity, cytotoxicity, reproductive toxicity, genotoxicity, and carcinogenicity. Human exposure data show that humans have been exposed to low concentrations of BPA for a long time, future research should focus on the long-term exposure and the migration of BPA from consumer products to humans and the possible health risks associated with human exposure to BPA. Exploring economical and effective methods to reduce and remove BPA from the environment is imperative. The development of safe, functional and reproducible BPA analogs and the study of its degradation products can be the focus of subsequent research.

SIRT1: A Key Player in Male Reproduction

Reproduction is the way to immortality for an individual, and it is essential to the continuation of the species. Sirtuins are involved in cellular homeostasis, energy metabolism, apoptosis, age-related problems, and sexual reproduction. Sirtuin 1 (SIRT1) belongs to the sirtuin family of deacetylases, and it is a nicotinamide adenine dinucleotide (NAD)-dependent deacetylase. It removes the acetyl group from a variety of substrates. SIRT1 regulates endocrine/metabolic, reproductive, and placental development by deacetylating histone, different transcription factors, and signal transduction molecules in a variety of cellular processes. It also plays a very important role in the synthesis and secretion of sex hormones via regulating the hypothalamus-pituitary-gonadal (HPG) axis. Moreover, SIRT1 participates in several key stages of spermatogenesis and sperm maturation. The current review will give a thorough overview of SIRT1’s functions in male reproductive processes, thus paving the way for more research on restorative techniques and their uses in reproductive medicine.

Dietary high-fructose reduces barrier proteins and activates mitogenic signalling in the testis of a rat model: Regulatory effects of kefir supplementation

There are limited data on the influence of fructose rich diet on the male reproductive system. Kefir may have health beneficial effects, but its mechanism of action remains mostly unclear. Herein, we investigated the impact of dietary high fructose on tight junction proteins and mitogenic pathways in rat testis as well as their modulation by kefir supplementation. Twenty-two male Wistar rats (4 weeks old) were divided into the following three groups: Control; Fructose; Fructose + Kefir. Fructose was added to drinking water at concentration of 20% and administered to the rats for 15 weeks and kefir was supplemented by gavage once a day during final 6 weeks. Dietary fructose-induced testicular degeneration was associated with the downregulation of the blood-testis barrier proteins, claudin-11 and N-cadherin as well as SIRT1 expression in testicular tissue of rats. However, p38MAPK, p-p38MAPK and p-ERK1/2 levels were increased in testis of fructose-fed rats. Interestingly, JNK1 and p-JNK1 protein levels were decreased following this dietary intervention. Raf1, ERK1/2, and caspase 3 and TUNEL staining of the testis reveal the activation of apoptosis due to fructose intake. Kefir supplementation markedly promoted the expression of claudin-11, SIRT1, JNK1 and p-JNK1 but suppressed testicular mitogenic and apoptotic factors in fructose-fed rats.

Maternal exposure of mice to sodium p-perfluorous nonenoxybenzene sulfonate causes endocrine disruption in both dams and offspring

The toxicity of certain novel perfluoroalkyl substances (PFCs) has attracted increasing attention. However, the toxic effects of sodium p-perfluorous nonenoxybenzene sulfonate (OBS) on the endocrine system have not been elucidated. In this study, OBS was added to the drinking water during the pregnancy and lactation of the healthy female mice at dietary levels of 0.0 mg/L (CON), 0.5 mg/L (OBS-L), and 5.0 mg/L (OBS-H). OBS exposure during the pregnancy and lactation resulted in the presence of OBS residues in the placenta and fetus. We also analyzed physiological and biochemical parameters and gene expression levels in mice of the F0 and F1 generations after maternal OBS exposure. The total serum cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) levels were significantly increased in female mice of the F0 generation. The androgen levels in the serum and the ovarian mRNA levels of androgen receptor (AR) also tended to increase after maternal OBS exposure in the F0 generation mice. Moreover, maternal OBS exposure altered the mRNA expression of endocrine-related genes in male mice of F1 generation. Notably, the serum TC and LDL-C levels were significantly increased in 8-weeks-old male mice of the F1 generation, and the serum high-density lipoprotein cholesterol (HDL-C) levels were decreased in 24-week-old male mice of the F1 generation. These results indicated that maternal OBS exposure can interfere with endocrine homeostasis in the F0 and F1 generations. Therefore, exposure to OBS during pregnancy and lactation has the potential toxic effects on the dams and male offspring, which cannot be overlooked.

Effects of bisphenol A exposure during cardiac cell differentiation

Heart development requires a precise temporal regulation of gene expression in cardiomyoblasts. Therefore, the transcriptional changes in differentiating cells can lead to congenital heart diseases. Although the genetic mutations underlie most of these alterations, exposure to environmental contaminants, such as bisphenol A (BPA), has been recently considered as a risk factor as well. In this study we investigated the genotoxic and epigenotoxic effects of BPA throughout cardiomyocyte differentiation. H9c2 cells (rat myoblasts) were exposed to 10 and 30 μM BPA before and during the last two days of cardiac-driven differentiation. Then, we have analysed the phenotypic and molecular modifications (at transcriptional, genetic and epigenetic level). The results showed that treated myoblasts developed a skeletal muscle cell-like phenotype. The transcriptional changes induced by BPA in genes codifying proteins involved in heart differentiation and function depend on the window of exposure to BPA. The exposure before differentiation repressed the expression of heart transcription factors (Hand2 and Gata4), whereas exposure during differentiation reduced the expression of cardiac-specific genes (Tnnt2, Myom2, Sln, and Atp2a1). Additionally, significant effects were observed regarding DNA damage and histone acetylation levels after the two periods of BPA exposure: in cells exposed to the toxicant the percentage of DNA repair foci (formed by the co-localization of γH2AX and 53BP1) increased in a dose-dependent manner, whereas the treatment with the toxicant triggered a decrease in the epigenetic marks H3K9ac and H3K27ac. Our in vitro results reveal that BPA seriously interferes with the process of cardiomyocyte differentiation, which could be related to the reported in vivo effects of this toxicant on cardiogenesis.

Multi-Systemic Alterations by Chronic Exposure to a Low Dose of Bisphenol A in Drinking Water: Effects on Inflammation and NAD+-Dependent Deacetylase Sirtuin1 in Lactating and Weaned Rats

Bisphenol A (BPA) is largely used as a monomer in some types of plastics. It accumulates in tissues and fluids and is able to bypass the placental barrier, affecting various organs and systems. Due to huge developmental processes, children, foetuses, and neonates could be more sensitive to BPA-induced toxicity. To investigate the multi-systemic effects of chronic exposure to a low BPA dose (100 μg/L), pregnant Wistar rats were exposed to BPA in drinking water during gestation and lactation. At weaning, newborn rats received the same treatments as dams until sex maturation. Free and conjugated BPA levels were measured in plasma and adipose tissue; the size of cerebral ventricles was analysed in the brain; morpho-functional and molecular analyses were carried out in the liver with a focus on the expression of inflammatory cytokines and Sirtuin 1 (Sirt1). Higher BPA levels were found in plasma and adipose tissue from BPA treated pups (17 PND) but not in weaned animals. Lateral cerebral ventricles were significantly enlarged in lactating and weaned BPA-exposed animals. In addition, apart from microvesicular steatosis, liver morphology did not exhibit any statistically significant difference for morphological signs of inflammation, hypertrophy, or macrovesicular steatosis, but the expression of inflammatory cytokines, Sirt1, its natural antisense long non-coding RNA (Sirt1-AS LncRNA) and histone deacetylase 1 (Hdac1) were affected in exposed animals. In conclusion, chronic exposure to a low BPA dose could increase the risk for disease in adult life as a consequence of higher BPA circulating levels and accumulation in adipose tissue during the neonatal period.

Bisphenol A and genistein have opposite effects on adult chicken ovary by acting on ERα/Nrf2-Keap1-signaling pathway

The reproductive toxicity of endocrine-disrupting chemicals has become a matter of great concern. However, the potential toxicological mechanism of typical environmental estrogens, bisphenol A (BPA) and genistein (GEN), on adult ovary remains ambiguous. In this study, we used laying hens as the experimental model and aimed to clarify the effect of long-term exposure to safe reference doses of BPA and GEN on adult ovary. Results demonstrated that 1/10 no-observable-adverse effect-level dose (1/10 NOAEL, 500 μg/kg body weight [bw]/day) of BPA significantly reduced the production performance and caused the degeneration of follicles and stromal cells and the increase of atretic follicles. Moreover, 1/10 NOAEL dose of BPA undermined the redox homeostasis of the ovary through activating Keap1 and suppressing the Nrf2-signaling pathway (Nrf2, NQO1, and HO-1). On the contrary, GEN (20, 40 mg/kg bw/day) dramatically improved the antioxidant capacity of the ovary by regulating the Nrf2-Keap1 pathway, enhancing the activities of antioxidant-related enzymes (CAT, GSH-Px, and T-SOD), and inhibiting the excessive accumulation of lipid peroxidation products (MDA). Parallel in vitro studies confirmed that the differential role of BPA and GEN on ovarian redox balance was directly mediated by Nrf2-Keap1 antioxidant system. And GEN could ameliorate BPA-induced oxidative stress. Importantly, our research found that exposure to BPA and GEN altered estrogen receptor alpha (ERα) expression in the ovary. And the use of specific ERα agonist/antagonist confirmed that BPA and GEN have opposite regulatory effects on the Nrf2-Keap1 pathway by targeting ERα.

Bisphenol-A inhibits mitochondrial biogenesis via impairment of GFER mediated mitochondrial protein import in the rat brain hippocampus

Mitochondrial biogenesis relies on different protein import machinery, as mitochondrial proteins are imported from the cytosol. The mitochondrial intermembrane space assembly (MIA) pathway consists of GFER/ALR and CHCHD4/Mia40, responsible for importing proteins and their oxidative folding inside the mitochondria. The MIA pathway plays an essential role in complex IV (COX IV) biogenesis via importing copper chaperone COX17, associated with the respiratory chain. BPA, an environmental toxicant, found in consumable plastics, causes neurotoxicity via impairment in mitochondrial dynamics, neurogenesis, and cognitive functions. We studied the levels of key regulatory proteins of mitochondrial import pathways and mitochondrial biogenesis after BPA exposure in the rat hippocampus. BPA caused a significant reduction in the levels of mitochondrial biogenesis proteins (PGC1α, and TFAM) and mitochondrial import protein (GFER). Immunohistochemical analysis showed reduced co-localization of NeuN with GFER, PGC-1α, and TFAM suggesting impaired mitochondrial biogenesis and protein import. BPA exposure resulted in damaged mitochondria with distorted cristae in neurons and caused a significant reduction in GFER localization inside IMS as depicted by immunogold electron microscopy. The reduced levels of GFER resulted in defective COX17 import. The translocation of cytochrome c into the cytosol and increased cleaved caspase-3 levels triggered apoptosis due to BPA toxicity. Overall, our study implicates GFER as a potential target for impaired mitochondrial protein machinery, biogenesis, and apoptosis against BPA neurotoxicity in the rat hippocampus.

Bisphenol F Exposure in Adolescent Heterogeneous Stock Rats Affects Growth and Adiposity

Bisphenol F (BPF) is increasingly substituting bisphenol A in manufacturing polycarbonates and consumer products. The cardiometabolic effects of BPF in either humans or model organisms are not clear, and no studies to date have investigated the role of genetic background on susceptibility to BPF-induced cardiometabolic traits. The primary goal of this project was to determine if BPF exposure influences growth and adiposity in male N:NIH heterogeneous stock (HS) rats, a genetically heterogeneous population. Littermate pairs of male HS rats were randomly exposed to either vehicle (0.1% ethanol) or 1.125 µg/ml BPF in 0.1% ethanol for 5 weeks in drinking water starting at 3 weeks-of-age. Water consumption and body weight was measured weekly, body composition was determined using nuclear magnetic resonance, urine and feces were collected in metabolic cages, and blood and tissues were collected at the end of the study. BPF-exposed rats showed significantly increased body growth and abdominal adiposity, risk factors for cardiometabolic disease. Urine output was increased in BPF-exposed rats, driving a trend in increased creatinine clearance. We also report the first relationship between a bisphenol metabolizing enzyme and a bisphenol-induced phenotype. Preliminary heritability estimates of significant phenotypes suggest that BPF exposure may alter trait variation. These findings support BPF exposure as a cardiometabolic disease risk factor and indicate that the HS rat will be a useful model for dissecting gene by BPF interactions on metabolic health.

Hepatoprotective effects of oridonin against bisphenol A induced liver injury in rats via inhibiting the activity of xanthione oxidase

Bisphenol A (BPA) is widely used to manufacture packaging materials for various daily necessities and causes harmful effects in organs, especially liver injury, by generating oxidative stress. Oridonin, an active diterpenoid isolated from Rabdosia rubescens (Hemsl.) Hara, has been reported to possess a wide range of pharmacological activities including anti-inflammatory, antioxidative and antiapoptotic effects. However, the role of oridonin in BPA--induced liver injury and its potential protective mechanism have not been well characterized. In this research, we explored the metabolic alterations in the liver tissue of rats after exposure to BPA with or without pretreatment with oridonin for 14 days by metabolomics analysis based on UPLC-MS/MS. Rats were randomly divided into groups as follows: Control, Vehicle, Oridonin (10 mg/kg), Bisphenol A (500 mg/kg), bisphenol A + Oridonin (500 + 10 mg/kg), Bisphenol A + Diammonium glycyrrhizinate (500 + 40 mg/kg). The biochemical results showed that oridonin significantly reduced the levels of AST and ALT (P < 0.05), ameliorated the abnormal histopathological changes and reduced hepatic apoptosis compared with the BPA group. Furthermore, metabolomics results revealed that purine metabolism, phenylalanine, tyrosine and tryptophan biosynthesis and phenylalanine metabolism were reprogrammed, based on 28 identified significant differential metabolites among the Vehicle, BPA and BPA + oridonin groups. In-depth studies demonstrated that pretreatment with oridonin may play a protective role by restoring BPA-induced changes in oxidative stress and the activity of oxidase (XOD) (P < 0.05). Additionally, oridonin could inhibit the activity of XOD by binding to it, therefore decreasing the reactive oxygen species (ROS) level, upregulating the content of hypoxanthine and xanthine, and reducing the level of uric acid in the liver (P < 0.05). This research presents the potential protective mechanisms of oridonin on BPA-induced liver injury at the metabolic level, which might be used to identify new protective agents that prevent BPA-induced liver injury.

Bisphenol A as a Factor in the Mosaic of Autoimmunity

The population worldwide is largely exposed to bisphenol A (BPA), a commonly used plasticizer, that has a similar molecular structure to endogenous estrogens. Therefore, it is able to influence physiological processes in human body, taking part in the pathophysiology of various endocrinopathies, as well as, cardiovascular, neurological and oncological diseases. BPA has been found to affect the immune system, leading to the development of autoimmunity and allergies, too. In the last few decades, the prevalence of autoimmune diseases has significantly increased, that could be explained by a rising exposure of the population to environmental factors, such as BPA. BPA has been found to play a role in the pathogenesis of systemic autoimmune diseases and also organ-specific autoimmunity (thyroid autoimmunity, diabetes mellitus type 1, myocarditis, inflammatory bowel disease, multiple sclerosis, encephalomyelitis etc), but the results of some studies remain still controversial, so further research is needed.

Bisphenol A decreases expression of Insulin-like factor 3 and induces histopathological changes in the Testes of Rats

Bisphenol A (BPA) is a chemical agent known to have detrimental reproductive and developmental effects. The tissue-specific impacts of BPA exposures and target tissues sensitiveness to BPA are still unclear. The aim of this study was to determine the short- and long-term dose-dependent toxic effects of BPA on rat testes. Forty-eight Wistar albino male rats were divided into four groups each containing 12 rats. To induce toxicity, BPA was administered orally at three different dosages (50, 100, and 200 mg/kg) for 14 and 28 days, respectively. Testis tissues were examined using light and electron microscopy, immunohistochemistry, and biochemical methods. Serum testosterone (T) and luteinizing hormone (LH) levels were measured. Additionally, insulin-like factor 3 (INSL3) as a marker of Leydig cell function was evaluated immunohistochemically. Groups administered high doses of BPA showed severe degenerations such as testicular atrophy, spermatogenic arrest, and interstitial edema in testis. Also, a significant decrease in INSL3 immunoreactivity and serum LH and T levels was found. The results indicated that both increased exposure time and dosage of BPA caused more serious detrimental effects on testes in the rat. Decreased INSL3 and T levels was evidence of Leydig cell function impairment due to BPA.

SIRT1 Expression and Regulation in the Primate Testis

The epigenetic mechanisms controlling germ cell development and differentiation are still not well understood. Sirtuin-1 (SIRT1) is a nicotinamide adenosine dinucleotide (NAD)-dependent histone deacetylase and belongs to the sirtuin family of deacetylases. It catalyzes the removal of acetyl groups from a number of protein substrates. Some studies reported a role of SIRT1 in the central and peripheral regulation of reproduction in various non-primate species. However, testicular SIRT1 expression and its possible role in the testis have not been analyzed in primates. Here, we document expression of SIRT1 in testes of different primates and some non-primate species. SIRT1 is expressed mainly in the cells of seminiferous tubules, particularly in germ cells. The majority of SIRT1-positive germ cells were in the meiotic and postmeiotic phase of differentiation. However, SIRT1 expression was also observed in selected premeiotic germ cells, i.e., spermatogonia. SIRT1 co-localized in spermatogonia with irisin, an endocrine factor specifically expressed in primate spermatogonia. In marmoset testicular explant cultures, SIRT1 transcript levels are upregulated by the addition of irisin as compared to untreated controls explants. Rhesus macaques are seasonal breeders with high testicular activity in winter and low testicular activity in summer. Of note, SIRT1 mRNA and SIRT1 protein expression are changed between nonbreeding (low spermatogenesis) and breeding (high spermatogenesis) season. Our data suggest that SIRT1 is a relevant factor for the regulation of spermatogenesis in primates. Further mechanistic studies are required to better understand the role of SIRT1 during spermatogenesis.

The possible role of sirtuins in male reproduction

Global influence of male infertility is increasing in recent decades. Proper understanding of genetics, anatomy, physiology and the intricate interrelation of male reproductive system are much needed for explaining the etiology of male infertility; and a detailed study on the epigenetics, indeed, will reveal the molecular mechanism behind its etiology. Sirtuins, the molecular sensors, are NAD⁺ dependent histone deacetylases and ADP- ribosyl transferases, participate in the chief events of epigenetics. In mammals, sirtuin family comprises seven members (SIRT1-SIRT7), and they all possess a conserved NAD⁺ binding catalytic domain, termed the sirtuin core domain which is imperative for their activity. Sirtuins exert a pivotal role in cellular homeostasis, energy metabolism, apoptosis, age-related disorders and male reproductive system. However, their exact role in male reproduction is still obscure. This article specifically reviews the role of mammalian sirtuins in male reproductive function, thereby, prompting further research to discover the restorative methods and its implementation in reproductive medicine.

Low Doses of Glyphosate/Roundup Alter Blood-Testis Barrier Integrity in Juvenile Rats

It has been postulated that glyphosate (G) or its commercial formulation Roundup (R) might lead to male fertility impairment. In this study, we investigated the possible effects of G or R treatment of juvenile male rats on blood-testis barrier function and on adult male sperm production. Pups were randomly assigned to the following groups: control group (C), receiving water; G2 and G50 groups, receiving 2 and 50 mg/kg/day G respectively; and R2 and R50 groups receiving 2 and 50 mg/kg/day R respectively. Treatments were performed orally from postnatal day (PND) 14 to 30, period of life that is essential to complete a functional blood-testis barrier. Evaluation was done on PND 31. No differences in body and testis weight were observed between groups. Testis histological analysis showed disorganized seminiferous epithelium, with apparent low cellular adhesion in treated animals. Blood-testis barrier permeability to a biotin tracer was examined. A significant increase in permeable tubules was observed in treated groups. To evaluate possible mechanisms that could explain the effects on blood-testis barrier permeability, intratesticular testosterone levels, androgen receptor expression, thiobarbituric acid reactive substances (TBARS) and the expression of intercellular junction proteins (claudin11, occludin, ZO-1, connexin43, 46, and 50 which are components of the blood-testis barrier) were examined. No modifications in the above-mentioned parameters were detected. To evaluate whether juvenile exposure to G and R could have consequences during adulthood, a set of animals of the R50 group was allowed to grow up until PND 90. Histological analysis showed that control and R50 groups had normal cellular associations and complete spermatogenesis. Also, blood-testis barrier function was recovered and testicular weight, daily sperm production, and epididymal sperm motility and morphology did not seem to be modified by juvenile treatment. In conclusion, the results presented herein show that continuous exposure to low doses of G or R alters blood-testis barrier permeability in juvenile rats. However, considering that adult animals treated during the juvenile stage showed no differences in daily sperm production compared with control animals, it is feasible to think that blood-testis barrier impairment is a reversible phenomenon. More studies are needed to determine possible damage in the reproductive function of human juvenile populations exposed to low doses of G or R.

Melatonin ameliorates Bisphenol S induced testicular damages by modulating Nrf-2/HO-1 and SIRT-1/FOXO-1 expressions

BPS has detrimental effects on human reproductive health and emerged as an environmental contaminant for global health concern. This study deals with the adverse impact of BPS exposure on testicular oxidative stress, inflammation and apoptosis in adult male golden hamster, Mesocricetus auratus and its amelioration by melatonin. BPS (75 mg/kg BW/day) exposure caused testicular impairment as evident by histological degenerative changes, declined sperm quality (viability and motility), serum levels of testosterone and melatonin with a concomitant decrease in testicular androgen receptor (AR) and melatonin receptor (MT1) expression. The BPS exposure caused marked increase in testicular oxidative load, inflammation (NF-kB/COX-2) and apoptosis (caspase-3). Melatonin (10 mg/kg BW/alternate day) pretreatment to BPS exposed hamsters resumed normal testicular histoarchitecture, sperm quality and decreased testicular oxidative load as evident by enhanced antioxidant enzymes (SOD and catalase) activities and decreased lipid peroxidation (LPO) level. Further, melatonin also stimulated the testicular antioxidant proteins Nrf-2/HO-1, SIRT-1/FOXO-1 and reduced inflammatory proteins NF-kB/COX-2 expression to counteract BPS induced testicular damages. Melatonin administration to the BPS treated hamsters resulted in increased testicular cell proliferation (PCNA), survival (Bcl-2), gap junction (connexin-43) and decreased apoptosis (caspase-3). In conclusion, our study documented the detrimental effects of BPS on testes that compromises male fertility. Further, melatonin was found as a potent molecule that rescued the BPS induced testicular damages in male golden hamster Mesocricetus auratus.

Microplastics: A Threat for Male Fertility

Much of the planet is swimming in discarded plastic, which is harming animal and possibly human health. Once at sea, sunlight, wind, and wave action break down plastic waste into small particles: the microplastics (MPs). Currently, particular attention has been drawn to their effects on aquatic environments but the health risks, especially in mammals, are poorly known. These non-biodegradable materials can act as a vector for environmental pollutants, can be ingested by humans in food and water, and can enter and accumulate in human tissues with a possible risk for heath. Recent studies revealed the deleterious effects of MPs exposure in male reproduction and sperm quality, making them a potential hazard to reproductive success. This manuscript summarizes the main changes in sperm quality along the lifespan and the upcoming studies on the effects of MPs in male fertility in mammals.

Sirt1 Activity in the Brain: Simultaneous Effects on Energy Homeostasis and Reproduction

Diet deeply impacts brain functions like synaptic plasticity and cognitive processes, neuroendocrine functions, reproduction and behaviour, with detrimental or protective effects on neuronal physiology and therefore consequences for health. In this respect, the activity of metabolic sensors within the brain is critical for the maintenance of health status and represents a possible therapeutic target for some diseases. This review summarizes the main activity of Sirtuin1 (Sirt1), a metabolic sensor within the brain with a focus on the link between the central control of energy homeostasis and reproduction. The possible modulation of Sirt1 by natural phytochemical compounds like polyphenols is also discussed.

The Complex Interplay between Endocannabinoid System and the Estrogen System in Central Nervous System and Periphery

The endocannabinoid system (ECS) is a lipid cell signaling system involved in the physiology and homeostasis of the brain and peripheral tissues. Synaptic plasticity, neuroendocrine functions, reproduction, and immune response among others all require the activity of functional ECS, with the onset of disease in case of ECS impairment. Estrogens, classically considered as female steroid hormones, regulate growth, differentiation, and many other functions in a broad range of target tissues and both sexes through the activation of nuclear and membrane estrogen receptors (ERs), which leads to genomic and non-genomic cell responses. Since ECS function overlaps or integrates with many other cell signaling systems, this review aims at updating the knowledge about the possible crosstalk between ECS and estrogen system (ES) at both central and peripheral level, with focuses on the central nervous system, reproduction, and cancer.

Mitochondrial Reactive Oxygen Species (ROS) Production Alters Sperm Quality

Besides ATP production, mitochondria are key organelles in several cellular functions, such as steroid hormone biosynthesis, calcium homoeostasis, intrinsic apoptotic pathway, and the generation of reactive oxygen species (ROS). Despite the loss of the majority of the cytoplasm occurring during spermiogenesis, mammalian sperm preserves a number of mitochondria that rearrange in a tubular structure at the level of the sperm flagellum midpiece. Although sperm mitochondria are destroyed inside the zygote, the integrity and the functionality of these organelles seem to be critical for fertilization and embryo development. The aim of this review was to discuss the impact of mitochondria-produced ROS at multiple levels in sperm: the genome, proteome, lipidome, epigenome. How diet, aging and environmental pollution may affect sperm quality and offspring health—by exacerbating oxidative stress—will be also described.

Evaluation of Oxidative stress, antioxidant enzymes and genotoxic potential of bisphenol A in fresh water bighead carp (Aristichthys nobils) fish at low concentrations

Bisphenol A (BPA) is one of the emerging contaminants associated with deleterious health effects on both public and wildlife and is extensively incorporated into different industrial products. Therefore, the current trial was conducted to determine the oxidative stress, status of different antioxidant enzymes and genotoxic potential of bisphenol A in fresh water fish at low concentrations. For this purpose, a total of 80 fresh water bighead carp (Aristicthys nobilis) received from commercial fish center were randomly divided and kept in four groups (A-D). Fish in groups (B-D) were exposed to different levels of BPA for a period of 60 days while fish of group A served as control group. Treated fish exhibited different physical and behavioral ailments in a time and treatment manners. Results showed significantly (p < 0.05) increased quantity of different oxidative stress biomarkers such as thiobarbituric acid reactive substance (TBARS), reduced glutathione (GSH) and the contents of reactive oxygen species (ROS) in gills, liver, kidneys and brain of exposed fish. Concentration of different antioxidant enzymes like catalase, superoxide dismutase, peroxidase and total proteins was significantly (p < 0.05) decreased in gills, liver, kidneys and brain of exposed fish. Results showed significantly (p < 0.05) increased frequency of morphological alterations, nuclear changes in red blood cells and increased DNA damage potential of bisphenol A in gills, liver, kidneys and brain tissues. The current trial concludes that even at very low concentrations bisphenol A causes toxic effects via turbulences in physiological and biochemical parameters in multiple tissues of fish.

Bisphenol A-associated alterations in DNA and histone methylation affects semen quality in rare minnow Gobiocypris rarus

Bisphenol A (BPA), a well-known estrogenic endocrine disruptor, is ubiquitously present in the environment, possessing the potential to interfere with the reproductive endocrine system in male mammals. However, there are limited studies on the reproductive toxicity in male aquatic animals associated with epigenetic modifications. In order to evaluate the potential effects of BPA on reproduction and better understand the underlying mechanism, adult male rare minnow (Gobiocypris rarus) were exposed to 15 μg L^-1 BPA over a period of 63 d. Results showed that BPA induced congestion of blood vessels and infiltration of inflammatory cells after 21 d exposure, and decreased sperm fertilization after 63 d exposure. The genome DNA methylation levels were significantly increased throughout the treatment, and a strong positive stain were found in the spermatocyte, spermatid and sperm. The H3K4me3 level in all types of germ cell were increased by 21 d exposure while decreased following 63 d exposure. The positive stain of H3K9me3 was decreased in sperms while increased in spermatids by 21 d exposure. In addition, the H3K9me3 level was significantly increased after 63 d exposure, and a strong positive stain were found in spermatocytes, spermatids, and sperms. Our result also revealed that the transcripts of DNA methyltransferase genes (dnmt1 and dnmt3-8) and histone methyltransferase genes (mll2-5, setdb1-2 and ezh2) were also markedly changed under BPA exposure for 21-63 d. These findings indicated that BPA had toxicity in male reproductive, and DNA/histone methylation might play a vital role in the regulation of BPA-triggered the decreased of sperm quality.

Bisphenol A induces DNA damage in cells exerting immune surveillance functions at peripheral and central level

Bisphenol A (BPA) is a synthetic xenoestrogen diffused worldwide. Humans are chronically exposed to low doses of BPA from food and drinks, thus BPA accumulates in tissues posing human health risk. In this study, we investigated the effects of BPA on peripheral blood mononuclear cells (PBMC) from human healthy donors, and in glia and microglia of rat offspring at postnatal day 17 (17PND) from pregnant females who received BPA soon after coupling and during lactation and weaning. Results indicated that BPA affected Phytoemagglutinin (PHA) stimulated PBMC proliferation causing an S-phase cell cycle accumulation at nanomolar concentrations while BPA was almost ineffective in resting PBMC. Furthermore, BPA induced chromosome aberrations and the appearance of shattered cells characterized by high number of fragmented and pulverized chromosomes, suggesting that the compound could cause a massive genomic rearrangement by inducing catastrophic events. The BPA-induced DNA damage was observed mainly in TCD4+ and TCD8+ subsets of T lymphocytes and was mediated by the increase of ERK1/2 phosphorylation, p21/Waf1 and PARP1 protein expression. Intriguingly, we observed for the first time that BPA-induced effects were associated to a sex specific modulation of ERα and ERβ in human PBMC. Immunofluorescence analysis of rat hippocampus corroborated in vitro findings showing that BPA induced ɣH2AX phosphorylation in microglia and astrocytosis by decreasing ERα expression within the dentate gyrus. Overall these results suggest that BPA can alter immune surveillance functions at both peripheral and central level with a potential risk for cancer, neuroinflammation and neurodegeneration.

Environmental Impact on Male (In)Fertility via Epigenetic Route

In the last 40 years, male reproductive health-which is very sensitive to both environmental exposure and metabolic status-has deteriorated and the poor sperm quality observed has been suggested to affect offspring development and its health in adult life. In this scenario, evidence now suggests that epigenetics shapes endocrine functions, linking genetics and environment. During fertilization, spermatozoa share with the oocyte their epigenome, along with their haploid genome, in order to orchestrate embryo development. The epigenetic signature of spermatozoa is the result of a dynamic modulation of the epigenetic marks occurring, firstly, in the testis-during germ cell progression-then, along the epididymis, where spermatozoa still receive molecules, conveyed by epididymosomes. Paternal lifestyle, including nutrition and exposure to hazardous substances, alters the phenotype of the next generations, through the remodeling of a sperm epigenetic blueprint that dynamically reacts to a wide range of environmental and lifestyle stressors. With that in mind, this review will summarize and discuss insights into germline epigenetic plasticity caused by environmental stimuli and diet and how spermatozoa may be carriers of induced epimutations across generations through a mechanism known as paternal transgenerational epigenetic inheritance.

Environmental contaminants and male infertility: Effects and mechanisms

The escalating prevalence of male infertility and decreasing trend in sperm quality have been correlated with rapid industrialisation and the associated discharge of an excess of synthetic substances into the environment. Humans are inevitably exposed to these ubiquitously distributed environmental contaminants, which possess the ability to intervene with the growth and function of male reproductive organs. Several epidemiological reports have correlated the blood and seminal levels of environmental contaminants with poor sperm quality. Numerous in vivo and in vitro studies have been conducted to investigate the effect of various environmental contaminants on spermatogenesis, steroidogenesis, Sertoli cells, blood-testis barrier, epididymis and sperm functions. The reported reprotoxic effects include alterations in the spermatogenic cycle, increased germ cell apoptosis, inhibition of steroidogenesis, decreased Leydig cell viability, impairment of Sertoli cell structure and function, altered expression of steroid receptors, increased permeability of blood-testis barrier, induction of peroxidative and epigenetic alterations in spermatozoa resulting in poor sperm quality and function. In light of recent scientific reports, this review discusses the effects of environmental contaminants on the male reproductive function and the possible mechanisms of action.

Oxidative Stress and BPA Toxicity: An Antioxidant Approach for Male and Female Reproductive Dysfunction

Bisphenol A (BPA) is a non-persistent anthropic and environmentally ubiquitous compound widely employed and detected in many consumer products and food items; thus, human exposure is prolonged. Over the last ten years, many studies have examined the underlying molecular mechanisms of BPA toxicity and revealed links among BPA-induced oxidative stress, male and female reproductive defects, and human disease. Because of its hormone-like feature, BPA shows tissue effects on specific hormone receptors in target cells, triggering noxious cellular responses associated with oxidative stress and inflammation. As a metabolic and endocrine disruptor, BPA impairs redox homeostasis via the increase of oxidative mediators and the reduction of antioxidant enzymes, causing mitochondrial dysfunction, alteration in cell signaling pathways, and induction of apoptosis. This review aims to examine the scenery of the current BPA literature on understanding how the induction of oxidative stress can be considered the "fil rouge" of BPA's toxic mechanisms of action with pleiotropic outcomes on reproduction. Here, we focus on the protective effects of five classes of antioxidants-vitamins and co-factors, natural products (herbals and phytochemicals), melatonin, selenium, and methyl donors (used alone or in combination)-that have been found useful to counteract BPA toxicity in male and female reproductive functions.

The effects of maternal exposure to BPA during pregnancy on the male reproductive system and the testicular microRNA expression profile

The effect of prenatal bisphenol A (BPA) exposure is increasingly concerned. We investigated the effect of maternal BPA exposure during pregnancy on male offspring and its potential mechanism. Thirty pregnant Sprague Dawley (SD) rats were randomly divided into exposed and control groups. At PND56, the number of sperm, luteinizing hormone, and testosterone in the BPA-exposed group decreased, and testicular tissue structure was damaged in offsprings. At GD20, the miRNA profile in the testis of male offspring was examined and the expression levels of 28 deregulated miRNAs were validated by qRT-PCR. We found that miR-361-5p, miR-203a-3p, and miR-19b-2-5p had significantly different expression levels in the testis. These results suggest that maternal exposure to BPA can lead to differential changes in progeny miRNAs, which will provide direction for future in-depth mechanisms of reproductive injury.

Neuro-toxic and Reproductive Effects of BPA

Background:

Bisphenol A (BPA) is one of the highest volume chemicals produced worldwide. It has recognized activity as an endocrine-disrupting chemical and has suspected roles as a neurological and reproductive toxicant. It interferes in steroid signaling, induces oxidative stress, and affects gene expression epigenetically. Gestational, perinatal and neonatal exposures to BPA affect developmental processes, including brain development and gametogenesis, with consequences on brain functions, behavior, and fertility.

Methods:

This review critically analyzes recent findings on the neuro-toxic and reproductive effects of BPA (and its ana-logues), with focus on neuronal differentiation, synaptic plasticity, glia and microglia activity, cognitive functions, and the central and local control of reproduction.

Results:

BPA has potential human health hazard associated with gestational, peri- and neonatal exposure. Beginning with BPA’s disposition, this review summarizes recent findings on the neurotoxicity of BPA and its analogues, on neuronal dif-ferentiation, synaptic plasticity, neuro-inflammation, neuro-degeneration, and impairment of cognitive abilities. Furthermore, it reports the recent findings on the activity of BPA along the HPG axis, effects on the hypothalamic Gonadotropin Releas-ing Hormone (GnRH), and the associated effects on reproduction in both sexes and successful pregnancy.

Conclusion:

BPA and its analogues impair neuronal activity, HPG axis function, reproduction, and fertility. Contrasting re-sults have emerged in animal models and human. Thus, further studies are needed to better define their safety levels. This re-view offers new insights on these issues with the aim to find the “fil rouge”, if any, that characterize BPA’s mechanism of action with outcomes on neuronal function and reproduction.