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

Altered mammary gland development and pro-tumorigenic changes in young female mice following prenatal BPAF exposure

Bisphenol A (BPA) is being phased out owing to its endocrine-disrupting effects and is increasingly being replaced by its substitute compounds such as bisphenol AF (BPAF). This study aims to explore the potential adverse outcomes of prenatal BPAF exposure combined with postnatal cross-fostering on the development and long-term health effects of the mammary gland in offspring. The results suggested that prenatal BPAF exposure accelerates the puberty, and induces duct dilatations, angiogenesis, lobular hyperplasia, and enhanced inflammatory cell infiltration in the mammary gland of female offspring. Differentially expressed genes exhibiting time series patterns induced by BPAF exposure were enriched in biological processes related to mammary gland development, epithelial cell proliferation and so on. Notably, 13 breast cancer-related biomarkers including Pgr, Gata3, Egfr and Areg were screened, showing a time-dependent increase in expression. After human homologous gene transformation, TCGA analysis suggested that the human homologues of genes differentially expressed in BPAF-treated mice were associated with increased tumor stages in female patients with breast cancer. Furthermore, postnatal cross-fostering did not completely restore the adverse effects of prenatal BPAF exposure and even showed a reverse tendency. These results imply that prenatal BPAF exposure in utero and postnatally nursing by BPAF exposed dams, have long-term effects on the mammary glands health of female offspring.

Preconception exposure to bisphenol A and its alternatives: Effects on female fecundity mediated by oxidative stress and ovarian reserve

BACKGROUND

Various 'Bisphenol A (BPA)-free' alternatives have emerged in numerous personal products in recent years. However, it remains unclear whether BPA analogs affect female fecundity and possible biological mechanisms.

OBJECTIVES

We aimed to evaluate the relationships of bisphenol analogs with female fecundability and infertility and whether oxidative stress, inflammation, and ovarian reserve may play a mediation role in such associations.

METHODS

This prospective preconception cohort study included 957 couples who attempted pregnancy. BPA and six alternatives were measured in women's urine samples. Bisphenol analogs-outcome associations were estimated using discrete-time Cox hazards and logistic regression models. A quantile g-computation (QGC) methodology was further applied to assess the joint effects of co-exposure to bisphenol analogs on fecundity. We also quantified three biomarkers, including malondialdehyde (MDA), C-reactive protein and Anti-Müllerian hormone (AMH), to explore possible biological pathways.

RESULTS

Using an integrated analytical approach consisting of both single-pollutant and mixture models, we found that BPA and bisphenol AP (BPAP) were significantly associated with decreased fecundability (adjusted fecundability ratio (aFR) = 0.87, 95%CI: 0.81, 0.94 for BPA; aFR = 0.64, 95%CI: 0.48, 0.84 for BPAP) and increased risk of infertility (adjusted odd ratio (aOR) = 1.23, 95%CI: 1.06, 1.44 for BPA; aOR = 2.27, 95%CI: 1.29, 3.99 for BPAP) after controlling for other bisphenol analogs. The link between BPA and prolonged time to pregnancy was more prominent in overweight or obese women and those who had regular menstrual cycles. Bisphenol AF was associated with impaired fecundity in women aged 35 years or older. The mixed effects of bisphenol analogs on fecundity were statistically non-significant. Mediation analysis revealed a significant indirect effect of urinary MDA and serum AMH in bisphenol analogs-induced impaired fecundity, with all average causal mediation effects (ACME) showing statistical significance (PACME < 0.05).

CONCLUSIONS

Our prospective preconception cohort study suggests that BPA and BPAP may be associated with impaired female fecundity. Increased oxidative stress and decreased ovarian reserve may be the underlying pathways.

Bisphenol H exposure disrupts Leydig cell function in adult rats via oxidative stress-mediated m6A modifications: Implications for reproductive toxicity

Bisphenol H (BPH) has emerged as a potential alternative to bisphenol A (BPA), which has been curtailed for use due to concerns over its reproductive and endocrine toxicity. This study investigates whether BPH exerts antiandrogenic effects by impairing Leydig cell function, a critical component in testosterone production. We administered orally BPH to adult male rats at doses of 0, 1, 10, and 100 mg/kg/day for 7 days. Notably, BPH treatment resulted in a dose-dependent reduction in testicular testosterone levels, with significant decreases observed at ≥ 1 mg/kg/day. Additionally, BPH affected the expression of key genes involved in steroidogenesis and cholesterol metabolism, including Nr5a1, Nr3c4, Lhcgr, Scarb1, and Star, at higher doses (10 and/or 100 mg/kg/day). The study also revealed alterations in antioxidant gene expression (Sod2 and Cat) and modulation of m6A-related genes (Ythdf1-3 and Foxo3) and their proteins. Through MeRIP-qPCR analysis, we identified increased m6A modifications in Scarb1 and Star genes following BPH exposure. In vitro experiments with primary Leydig cells confirmed that BPH enhanced oxidative stress and diminished testosterone production, which were partially mitigated by antioxidant vitamin E supplementation and Ythdf3 knockdown. Meanwhile, simultaneous administration of BPH and vitamin E to primary Leydig cells partially counteracted BPH-induced alterations in the Ythdf3 expression. Our findings underscore a novel mechanism by which BPH disrupts Leydig cell function through the oxidative stress-m6A modification-autophagy pathway, raising concerns about its potential reproductive toxicity.

Effect of thyroid disruption on ovarian development following maternal exposure to Bisphenol S

Thyroid hormones play a crucial role in numerous physiological processes, including reproduction. Bisphenol S (BPS) is a structural analog of Bisphenol A known for its toxic effects. Interference of this substitute with normal thyroid function has been described. To investigate the effect of thyroid disruption on ovarian development following maternal exposure to BPS, female rats were exposed, daily, to either AT 1-850 (a thyroid hormone receptor antagonist) (10 nmol/rat) or BPS (0.2 mg/kg) during gestation and lactation. The effects on reproductive outcome, offspring development, histological structures, hormone levels, oxidative status, cytoskeleton proteins expression, and oocyte development gene expression were examined. Our results are in favor of offspring ovarian development disruption due to thyroid disturbance in adult pregnant females. During both fetal and postnatal stages, BPS considerably altered the histological structure of the thyroid tissue as well as oocyte and follicular development, which led to premature ovarian failure and stimulation of oocyte atresia, being accompanied with oxidative stress, hypothalamic-pituitary-ovarian axis disorders, and cytoskeletal dynamic disturbance. Crucially, our study underscores that BPS may induce reproductive toxicity by blocking nuclear thyroid hormone receptors, evidenced by the parallelism and the perfect meshing between the data obtained following exposure to AT 1-850 and those after the treatment by this substitute.

Impacts of Acrylamide on testis and spermatozoa

Acrylamide (ACR) is an industrial chemical used to produce polyacrylamide, a synthetic polymer with a wide range of applications. Depending on the dosage, its presence in occupational and environmental sources poses potential health risks to humans and animals. ACR can be formed in starchy foods cooked at high temperatures. Its effects on human sperm are not well understood. Animal studies indicate that ACR induces toxicity in the male reproductive system through oxidative stress mechanisms. Exposure to ACR alters the normal structure of testicular tubules, leading to congestion, interstitial edema, degeneration of spermatogenic cells, formation of abnormal spermatid giant cells, and necrosis and apoptosis. It also disrupts the balance of important biomarkers such as malondialdehyde, nitric oxide, superoxide dismutase, catalase, and glutathione. ACR has a negative impact on mitochondrial function, antioxidant enzymes, ATP production, and sperm membrane integrity, resulting in decreased sperm quality. Furthermore, it interferes with the expression of steroidogenic genes associated with testosterone biosynthesis. This review explores the detrimental effects of ACR on sperm and testicular function and discusses the potential role of antioxidants in mitigating the adverse effects of ACR on male reproduction.

Reproductive and transgenerational toxicity of bisphenol S exposure in pregnant rats: Insights into hormonal imbalance and steroid biosynthesis pathway disruption

Bisphenol S (BPS) is an alternative chemical to bisphenol A commonly used in food packaging materials. It raises concerns due to potential adverse effects on human health. However, limited evidence exists regarding reproductive toxicity from BPS exposure, and the mechanism of associated transgenerational toxicity remains unclear. In this study, pregnant SD rats were exposed to two different doses of BPS (0.05 or 20 mg/kg) from GD6 to PND21. The objective was to investigate reproductive and transmissible toxicity induced by BPS, explore endocrine effects, and uncover potential underlying mechanisms in rats. Perinatal exposure to BPS in the F0 generation significantly decreased the rate of body weight, ovarian organ coefficient, and growth and development of the F1 generation. Notably, these changes included abnormal increases in body weight and length, estrous cycle disruption, and embryonic dysplasia in F1. 4D-DIA proteomic and PRM analyses revealed that exposure to 20 mg/kg group significantly altered the expression of proteins, such as Lhcgr and Akr1c3, within the steroid biosynthetic pathway. This led to elevated levels of FSH and LH in the blood. The hypothalamic-pituitary-ovarian (HPO) axis, responsible for promoting fertility through the cyclic secretion of gonadotropins and steroid hormones, was affected. RT-qPCR and Western blot results demonstrated that the expression of GnRH in the hypothalamus was decreased, the GnRHR in the pituitary gland was decreased, and the expression of FSHβ and LHβ in the pituitary gland was increased. Overall, BPS exposure disrupts the HPO axis, hormone levels, and steroid biosynthesis in the ovaries, affecting offspring development and fertility. This study provides new insights into the potential effects of BPS exposure on the reproductive function of the body and its relevant mechanisms of action.

Endocrine effect of phthalate metabolites and a butterfly effect of prenatal exposure to androgens on qualitative aspects of female sexual response- an initial survey

There is growing evidence that endocrine disruptive chemicals have deleterious effects on sexual and reproductive function. To examine subjective sexual functions in human females and their relationship to postnatal phthalate exposure and perinatal androgenization, a Sexuality Score (SS) was established from a first-stage survey questionnaire of subjective sexual function filled out by female university students (n = 68; average age 25.23 ± 5.17 years; rural 25.51 ± 6.74 vs. urban 25.85 ± 1.43 years). Seventeen phthalate metabolites in urine samples were analyzed by high-performance liquid chromatography (HPLC) and tandem mass spectrometry (MS/MS). Females were also assessed for the 2D:4D digit ratio as an index of perinatal androgenization. The mean age of menarche was 12.82 ± 1.35 years (rural 12.59 ± 1.39 vs. urban 13.18 ± 1.27; p = 0.01). The mean age at first sexual intercourse was 14.88 ± 6.89 years (rural 14.62 ± 7.20 vs. urban 15.24 ± 6.55), and as the age of first sexual intercourse increases, the SS score tends to increase as well, albeit moderately (r = 0.25, p = 0.037). Mono-iso-butyl phthalate, mono(2-ethyl-5-carboxypentyl) phthalate, mono(hydroxy-n-butyl) phthalate, mono(2-ethyl-5-oxohexyl) phthalate (p ≤ 0.05) and mono(2-carboxymethylhexyl) phthalate (p ≤ 0.01) were negatively associated with SS. A compounding butterfly effect of prenatal exposure to androgens was observed with disruptive effects of mono(2-ethyl-5-oxohexyl) phthalate and mono(2-ethyl-5-carboxypentyl) phthalate on sexual function. Exposure to phthalates in adult females may lead to disruption of subjective sexual function, especially concerning sexual desire and sexual satisfaction, and perinatal androgenization could augment these effects.

Functional role of autophagy in testicular and ovarian steroidogenesis

Autophagy is an evolutionarily conserved cellular recycling process that maintains cellular homeostasis. Despite extensive research in endocrine contexts, the role of autophagy in ovarian and testicular steroidogenesis remains elusive. The significant role of autophagy in testosterone production suggests potential treatments for conditions like oligospermia and azoospermia. Further, influence of autophagy in folliculogenesis, ovulation, and luteal development emphasizes its importance for improved fertility and reproductive health. Thus, investigating autophagy in gonadal cells is clinically significant. Understanding these processes could transform treatments for endocrine disorders, enhancing reproductive health and longevity. Herein, we provide the functional role of autophagy in testicular and ovarian steroidogenesis to date, highlighting its modulation in testicular steroidogenesis and its impact on hormone synthesis, follicle development, and fertility therapies.

Effects of environmentally relevant concentrations of niclosamide on lipid metabolism and steroid hormone synthesis in adult female zebrafish

Niclosamide (NIC) is a commonly used molluscicide that reportedly disrupts the endocrine system and may lead to lipid metabolism disorders. However, few studies have investigated the mechanism by which NIC affects the endocrine system from the perspective of lipid metabolism. Adult female zebrafish were fed either a normal-fat diet (NFD) or a high-fat diet (HFD) and then exposed for 28 days to environmentally relevant concentrations of NIC. NIC accumulated most in the liver followed by the brain and then the gonads in both feeding conditions. Somatic index changes confirmed that HFD promotes fish growth, and NIC administration inhibits it. Lipid metabolites were decreased by NIC, as were levels of pregnenolone, androstenedione, estrogen, testosterone, and estradiol, suggesting that NIC impacted steroidogenesis. In addition, gene transcription changes related to the hypothalamic-pituitary-gonad-liver (HPGL) axis and altered ovarian histology strongly suggest that environmental relevant concentrations of NIC exposure may disrupt endocrine function. These findings highlighted that NIC exposure at environmentally relevant concentrations elicited endocrine-disruption effects may through impairing of steroid hormone synthesis.

Comparison of the Effect of BPA and Related Bisphenols on Membrane Integrity, Mitochondrial Activity, and Steroidogenesis of H295R Cells In Vitro

Bisphenol A (BPA) is an endocrine-disruptive chemical that is widely utilized in the production of polycarbonate plastic and epoxy resin, which are used to make a wide range of consumer products, food and drink containers, and medical equipment. When the potential risk of BPA emerged, it was substituted by allegedly less harmful substitutes such as bisphenols S, F, B, and AF. However, evidence suggests that all bisphenols can have endocrine-disruptive effects, while the extent of these effects is unknown. This study aimed to determine effect of BPA, BPAF, BPB, BPF, and BPS on viability and steroidogenesis in human adrenocortical carcinoma cell line in vitro. The cytotoxicity of bisphenols was shown to be considerable at higher doses. However, at low concentrations, it improved viability as well as steroid hormone secretion, indicating that bisphenols have a biphasic, hormetic effect in biological systems. The results are consistent with the hypothesis that bisphenols selectively inhibit some steroidogenic enzymes. These findings suggest that bisphenols have the potential to disrupt cellular steroidogenesis in humans, but substantially more detailed and systematic research is needed to gain a better understanding of the risks associated with bisphenols and their endocrine-disrupting effect on humans and wildlife.

Analyzing the impact and mechanism of bisphenol A on testicular lipid metabolism in Gobiocypris rarus through integrated lipidomics and transcriptomics

Bisphenol A (BPA) is one of the most common environmental endocrine chemicals, known for its estrogenic effects that can interfere with male spermatogenesis. Lipids play crucial roles in sperm production, capacitation, and motility as important components of the sperm plasma membrane. However, limited research has explored whether BPA affects lipid metabolism in the testes of male fish and subsequently impacts spermatogenesis. In this study, we employed Gobiocypris rarus rare minnow as a research model and exposed them to environmentally relevant concentrations of BPA (15 μg/L) for 5 weeks. We assessed sperm morphology and function and analyzed changes in testicular lipid composition and transcriptomics. The results demonstrated a significant increase in the sperm head membrane damage rate, along with reduced sperm motility and fertilization ability due to BPA exposure. Lipidomics analysis revealed that BPA increased the content of 11 lipids while decreasing the content of 6 lipids in the testes, particularly within glycerophospholipids, glycerolipids, and sphingolipid subclasses. Transcriptomics results indicated significant up-regulation in pathways such as cholesterol metabolism, peroxisome proliferator-activated receptor signaling, and fat digestion and absorption, with significant alterations in key genes related to lipid metabolism, including apolipoprotein A-I, apolipoprotein C-I, and translocator protein. These findings suggest that BPA exposure can induce testicular lipid metabolism disruption in rare minnows, potentially resulting in abnormalities in rare minnow spermatogenesis.