Subchronic Exposure to Di(2-ethylhexyl) Phthalate and Diisononyl Phthalate During Adulthood Has Immediate and Long-Term Reproductive Consequences in Female Mice

Endocrine-disrupting chemicals and female reproductive health: a growing concern

Female fertility and reproductive health depend on a series of developmental steps from embryogenesis through puberty, in addition to the proper functioning of the reproductive system in adulthood. Two important steps are the establishment of the ovarian reserve and development of the hypothalamic-pituitary-ovarian axis. During reproductive years, maintaining an adequate ovarian reserve of follicles as well as balanced neuroendocrine control of reproductive organs is crucial for fertility. Dysregulation of either of these events, during development or in adulthood, can lead to reproductive disorders. Over the past five decades, human fertility rates have declined, whereas the incidence of female reproductive disorders has risen, trends partially linked to environmental factors such as exposure to endocrine-disrupting chemicals (EDCs). Here we outline epidemiological and mechanistic evidence for how EDCs affect the ovarian reserve during early development, its maintenance during adulthood and the establishment of the hypothalamic-pituitary control of puberty and ovulation. Our Review not only reveals strong support for the role of EDC exposure in the development of female reproductive disorders such as abnormal puberty, impaired fertility, premature menopause or polycystic ovarian syndrome, but also highlights knowledge gaps, including the difficulty to prove causality between exposure and human disease manifestation.

Epidemiologically relevant phthalate mixture and mono(2-ethyl-5-hydroxyhexyl) phthalate exposure alter cell energy metabolism in primary mouse granulosa cells

Many products including plastic food containers, medical tubing, and personal care products contain phthalate diesters. Phthalates have been shown to negatively affect the female reproductive system. However, the ovarian cellular impacts of monoester phthalates, the metabolites of phthalate diesters, are largely unknown. This study tested the hypothesis that a monophthalate metabolite mixture or single monophthalate affects cell energy metabolism in granulosa cells. To test this hypothesis, granulosa cells were exposed to vehicle control, the mean urinary level and 100-fold higher monophthalate mixture (2.0 µM and 200.0 µM), or mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) (0.22 µM and 22.0 µM) for 24 or 72 h. Gene expression was assessed for antioxidant enzymes, glycolytic enzymes, and glucose transporters. Cellular metabolism was assessed by Agilent Seahorse assays. MEHHP did not alter expression of the antioxidant enzymes, glycolytic enzymes, or glucose transporters compared to control. However, the monophthalate mixture significantly increased expression of Ldha (200.0 µM, 72-hour exposure) and Glut1 (2.0 µM, 24-hour exposure) compared to control. MEHHP (22.0 µM) increased total ATP production rate at 24 h compared to control, but did not change total ATP production after 72 h. Further, the mixture (2.0 µM and 200.0 µM) altered total ATP production rates compared to control at the 72-hour and 24-hour time points. Short-term phthalate exposure led to significant effects on ATP production rates, making this endpoint a logical indicator of early phthalate toxicity. These data indicate that a monophthalate mixture as well as single monophthalate exposure alter cellular metabolism in granulosa cells.

Phthalates Impair Estrogenic Regulation of HIF2α and Extracellular Vesicle Secretion by Human Endometrial Stromal Cells

High levels of exposure to di(2-ethylhexyl) phthalate (DEHP), a known endocrine disruptor, have been linked to adverse pregnancy outcomes, yet the mechanisms by which it impacts human uterine functions remain unclear. Here we report that exposure of differentiating primary human endometrial stromal cells (HESCs) to an environmentally relevant concentration of DEHP or its primary metabolite, mono(2-ethylhexyl) phthalate, markedly reduces the expression of the estrogen-regulated transcription factor hypoxia-inducible factor 2-α (HIF2α). We also noticed a simultaneous decrease in RAB27B expression, which is crucial for the trafficking and secretion of extracellular vesicles (EVs). EVs enhance communication among various cell types within the pregnant uterus, thereby ensuring reproductive success. We found that estrogen receptor α (ERα) could no longer bind to the HIF2α regulatory region following phthalate treatment, and epigenetic analysis suggested that this may be due to hypermethylation of nearby CpG islands. Further investigation revealed a potential interaction between ERα and the transcription factor specificity protein 1 (Sp1) within the HIF2α regulatory region, which is affected by the inhibition of Sp1 binding to the phthalate-induced hypermethylated DNA. Additionally, our results suggest that the abnormal DNA methylation is likely due to increased expression of the DNA methyltransferase 1 (DNMT1) gene in response to phthalate exposure. Overall, this study provides valuable mechanistic insights into how phthalate-induced differential DNA methylation disrupts estrogenic regulation of the HIF2α gene and, consequently, EV secretion during HESC differentiation. This knowledge is essential for understanding how phthalates may lead to adverse reproductive outcomes by disrupting hormonal regulation of cell-to-cell communication in the uterus.

Morin hydrate treatment minimizes Di(2-ethylhexyl) phthalate-induced uterine fibrosis, oxidative stress, and apoptosis in mice

BACKGROUND

Di (2-ethylhexyl) phthalate (DEHP), a widely used chemical in plastics, has various health hazards when accumulated in the environment. DEHP has been shown to cause toxicity to various organs like the liver, kidney, and reproductive organs. Phytocompounds have been used to mitigate DEHP-mediated organ toxicity. Morin hydrate (MH), a phytocompound, has also been known to protect tissue and organs against various induced toxic conditions. However, the impact of MH treatment on DEHP-induced uterine dysfunction has not yet been still investigated. Therefore, the present study has investigated the impact of MH on uterine physiology and morphology of DEHP-intoxicated mice.

METHODS

Twenty Swiss mice were randomly divided into four groups (n = 5): control (CN), Di (2-ethylhexyl) phthalate (DP) (500 mg/kg), Di (2-ethylhexyl) phthalate (DP) + Morin hydrate (MH) (10 mg/kg), and Di (2-ethylhexyl) phthalate (DP) + Morin hydrate (MH) (100 mg/kg) for 14 days.

RESULTS

Our results showed that the expression of active caspase-3 was up-regulated, and Bcl2 was down-regulated in the uterus of DEHP-treated mice. Furthermore, the uterine histology also showed decreased luminal epithelium height and endometrium thickness in the DEHP-treated mice; however, myometrium layer (outer and inner) thickness was higher in DEHP-treated mice. The uterus of DEHP-treated mice also exhibited elevated oxidative stress and fibrosis, along with decreased estrogen levels and expression of estrogen receptors (ERs). MH treatment at both doses (10 and 100 mg/kg) suppressed DEHP-induced uterine apoptosis (increased Bcl2 and decreased active caspase-3 expression) and fibrosis. MH also increased the circulating estrogen levels at both doses; Further ERα and ERβ expression were elevated in the MH treated in both groups). The levels of oxidative stress malondialdehyde (MDA levels) were higher in the uterus of DEHP alone and DEHP plus MH-treated mice (100 mg/kg). Moreover, the antioxidant enzymes catalase, glutathione peroxidase and superoxide dismutase (Gpx and SOD) did not show a dose-dependent response to MH treatment; rather, MH showed a differential effect on these enzymes. The elevated oxidative stress in 100 mg/kg MH treated uterus, despite elevated Gpx and SOD, remains unclear. Thus, these results suggest that MH ameliorates DEHP-induced uterine fibrosis, apoptosis, and histoarchitecture through ER modulation.

CONCLUSION

These findings suggest that MH improves uterine structure and function in DEHP-treated mice.

Evaluation of the endocrine disrupting potential of Di-isononyl phthalate

Low molecular weight ortho-phthalate compounds have been implicated in disruption of androgen pathways when exposure occurs during the masculinization programming window. Di-isononyl phthalate (DINP) is a high molecular weight phthalate and a high production volume chemical. To understand the potential for DINP and its metabolites to disrupt endocrine pathways, a weight of evidence assessment was conducted according to the European Chemicals Agency (ECHA)/ European Food Safety Authority (EFSA) Endocrine Disruptor Guidance (2018). Toxicological data related to estrogen (E), androgen (A), thyroid (T), or steroidogenesis (S) pathways was assessed. Literature searches returned 110 articles from which data were extracted and assessed in conjunction with 105 high-throughput assays. An in-silico assessment of the EATS activity for DINP metabolites also was conducted. Based on the available evidence, DINP did not elicit thyroid- or estrogen-related apical outcomes in vivo. There were no studies evaluating thyroid hormone levels in vivo which, according to the ECHA/EFSA guidance, constitutes a data gap and prevents a conclusion being drawn on the T-pathway. The E, A, and S-pathways were sufficiently assessed to conclude on the endocrine disrupting potential of DINP. Based on the lack of apical outcomes, DINP did not disrupt the E-pathway. For the A and S-pathways, there was limited evidence to support adverse apical outcomes, so a mode of action assessment using a structured adverse outcome pathway (AOP) framework was performed. No biologically plausible link could be established between the key events in the hypothesized AOP that lead to adverse outcomes. Further, no dose or temporal concordance for A- and S-mediated findings were identified. Therefore, DINP does not meet the ECHA/EFSA criteria to be considered an endocrine disruptor.

Phthalates Impair Estrogenic Regulation of HIF2α and Extracellular Vesicle Secretion by Human Endometrial Stromal Cells

Di(2-ethylhexyl) phthalate (DEHP), a known endocrine-disrupting chemical, is a plasticizer found in many common consumer products. High levels of DEHP exposure have been linked to adverse pregnancy outcomes, yet little is known about how it affects human uterine functions. We previously reported that the estrogen-regulated transcription factor hypoxia-inducible factor 2 alpha (HIF2α) promotes the expression of Rab27b, which controls the trafficking and secretion of extracellular vesicles (EVs). EVs facilitate communication between multiple cell types within the pregnant uterus, ensuring reproductive success. In this study, we report that exposure of differentiating primary human endometrial stromal cells (HESC) to an environmentally relevant concentration (1 μg/mL) of DEHP or its primary metabolite mono(2-ethylhexyl) phthalate (MEHP) markedly reduces the expression of HIF2α . We also observed a concomitant decrease in RAB27B expression, reducing EV secretion from HESC. Interestingly, we found that DEHP or MEHP exposure disrupts estrogenic regulation of the HIF2α/Rab27b signaling pathway. Estrogen receptor alpha (ERα) could no longer bind to the HIF2α regulatory region following phthalate treatment, and epigenetic analysis suggested that this may be due to hypermethylation of nearby CpG islands. Further investigation revealed a potential interaction between ERα and the transcription factor Sp1 within the HIF2α regulatory region, which is affected by the inhibition of Sp1 binding to the phthalate-induced hypermethylated DNA. Additionally, our results suggest that the abnormal DNA methylation is likely due to increased expression of the DNA methyltransferase 1 ( DNMT1 ) gene in response to phthalate exposure. Overall, this study provides valuable mechanistic insights into how phthalate-induced differential DNA methylation disrupts estrogenic regulation of the HIF2α gene and, consequently, EV secretion during HESC differentiation. This knowledge is crucial for our understanding of how phthalates may cause adverse reproductive outcomes by disrupting the hormonal regulation of cell-to-cell communication within the pregnant uterus.

Can Mammalian Reproductive Health Withstand Massive Exposure to Polystyrene Micro- and Nanoplastic Derivatives? A Systematic Review

The widespread use of plastics has increased environmental pollution by micro- and nanoplastics (MNPs), especially polystyrene micro- and nanoplastics (PS-MNPs). These particles are persistent, bioaccumulative, and linked to endocrine-disrupting toxicity, posing risks to reproductive health. This review examines the effects of PS-MNPs on mammalian reproductive systems, focusing on oxidative stress, inflammation, and hormonal imbalances. A comprehensive search in the Web of Science Core Collection, following PRISMA 2020 guidelines, identified studies on the impact of PS-MNPs on mammalian fertility, including oogenesis, spermatogenesis, and folliculogenesis. An analysis of 194 publications revealed significant reproductive harm, such as reduced ovarian size, depleted follicular reserves, increased apoptosis in somatic cells, and disrupted estrous cycles in females, along with impaired sperm quality and hormonal imbalances in males. These effects were linked to endocrine disruption, oxidative stress, and inflammation, leading to cellular and molecular damage. Further research is urgently needed to understand PS-MNPs toxicity mechanisms, develop interventions, and assess long-term reproductive health impacts across generations, highlighting the need to address these challenges given the growing environmental exposure.

Long-term dietary exposure to a mixture of phthalates enhances estrogen and beta-catenin signaling pathways, leading to endometrial hyperplasia in mice

Phthalates, synthetic chemicals widely utilized as plasticizers and stabilizers in various consumer products, present a significant concern due to their persistent presence in daily human life. While past research predominantly focused on individual phthalates, real-life human exposure typically encompasses complex mixtures of these compounds. The cumulative effects of prolonged exposure to phthalate mixtures on uterine health remain poorly understood. To address this knowledge gap, we conducted studies utilizing adult female mice exposed to a phthalate mixture for 6 and 12 months through ad libitum chow consumption. We previously reported that continuous exposure to this phthalate mixture for 6 months led to uterine fibrosis. In this study, we show that the exposure, when continued beyond 6 months to 1 year, caused fibrotic uteri to display hyperplasia with a significant increase in gland to stroma ratio. Endometrial hyperplasia is commonly caused by unopposed estrogen action, which promotes increased expression of pro-inflammatory cytokines and chemokines and proliferation of the endometrial epithelial cells. Indeed, RNA sequencing analysis revealed a marked upregulation of several estrogen-regulated genes, Wnt ligands that are involved in oncogenic pathways, as well as chemokines, in phthalate-exposed uterine tissues. Consequently, the exposed uteri exhibited increased proliferation of endometrial epithelial cells, and a heightened inflammatory response indicated by extensive homing of macrophages. Further studies revealed a marked enhancement of the Wnt/β-Catenin signaling pathway, potentially contributing to the development of endometrial hyperplasia. Collectively, this study underscores the significance of understanding the exposure to environmental factors in the pathogenesis of endometrial disorders.

The impact of follicular fluid phthalate metabolites on the ovarian reserve and ovarian function in Indian women undergoing intracytoplasmic sperm injection

OBJECTIVE

To investigate the adverse effects of phthalate-induced ovarian toxicity on the ovarian reserve and ovarian function. To assess whether the accumulation of higher levels of selected phthalate metabolites in the follicular fluid (FF) of Indian women undergoing intracytoplasmic sperm injection (ICSI) was associated with a decline in their antral follicle count (AFC) and/or serum antimüllerian hormone (AMH) levels, suggesting a negative impact on the ovarian reserve. To evaluate the effects of follicular phthalate metabolites on peak serum estradiol (E2) levels and the total number of oocytes and mature metaphase II (MII) stage oocytes retrieved to assess the impact of phthalate toxicity on ovarian function.

DESIGN

A subanalysis of an ongoing prospective cohort study was conducted to examine the association between the levels of six phthalate metabolites, namely, mono-n-butyl phthalate (MBP), mono-ethyl phthalate (MEP), mono-isononyl phthalate (MiNP), mono-isodecyl phthalate (MiDP), mono(2-ethyl-5-oxohexyl) phthalate, and mono(2-ethyl-5-hydroxyhexyl) phthalate, in the FF of Indian women undergoing ICSI and their ovarian reserve markers (AFC and serum AMH levels). To investigate the association of these follicular phthalate metabolite levels with the peak E2 levels and the total number of oocytes and number of MII stage oocytes retrieved.

SETTING

In vitro fertilization center in a referral hospital in India.

PATIENT(S)

A total of 245 consenting Indian women who had undergone oocyte retrieval between April 2017 and mid-March 2020 were included. Each woman contributed one FF sample to the study. This was screened for six phthalate metabolites. The samples were collected before the coronavirus disease 2019 pandemic.

INTERVENTION(S)

Using liquid chromatography-tandem mass spectrometry, the total levels of six phthalate metabolites were quantified in the FF of 245 women. Using linear regression models that were unadjusted and adjusted for maternal age and body mass index (BMI), we evaluated the association between the follicular metabolites in these women and their AFC, serum AMH levels, peak E2 levels, total number of oocytes, and MII stage oocytes.

MAIN OUTCOME MEASURE(S)

To evaluate the impact of phthalate-induced ovarian toxicity on the ovarian reserve and ovarian function in Indian women undergoing ICSI by studying their accumulated levels in their FF.

RESULT(S)

For MiNP (a metabolite of di-isononyl phthalate), in linear regression models adjusted for age and BMI, we found that with increasing quartiles of follicular MiNP, there was a significant trend in the decrease in mean AFC (P-trend = 0.023) and a suggestive trend in the decrease in mean serum AMH levels (P-trend = 0.077). For MiDP (a metabolite of di-isodecyl phthalate), in the unadjusted regression model, we found that with increasing quartiles of follicular MiDP, there was a significant trend in the decrease in mean serum AMH levels (P-trend = 0.045). For MBP (a metabolite of dibutyl phthalate), in linear regression models adjusted for age and BMI, we found that with increasing quartiles of follicular MBP, there were significant trends in the decrease in the mean number of total oocytes retrieved (P-trend = 0.003), a decrease in the mean number of MII stage oocytes retrieved, (P-trend = 0.003) and a decrease in the mean peak E2 levels (P-trend = 0.016). Although we found that with increasing quartiles of follicular mono(2-ethyl-5-oxohexyl) phthalate there was a decrease in the mean number of total and MII stage oocytes retrieved and higher follicular MEP levels were negatively associated with the mean AFC and serum AMH levels, neither trend was statistically significant. We also found that although follicular MEP levels did not show an adverse impact on ovarian function, follicular mono(2-ethyl-5-hydroxyhexyl) phthalate levels did not show an adverse impact on both the ovarian reserve and function.

CONCLUSION

In this study of 245 Indian women, higher accumulated FF levels of MiNP and MiDP were negatively associated with AFC and serum AMH levels, suggesting an adverse effect on the ovarian reserve. Higher accumulated FF levels of MBP were negatively associated with the total number of oocytes, MII stage oocytes, and peak E2 values, suggesting a negative impact on ovarian function. Although we found that phthalate-induced ovarian toxicity was statistically significant for selected phthalate metabolites, the role of the cumulative effect of multiple phthalates in the ovarian microenvironment cannot be ruled out and needs to be investigated further.

Relationship between phthalates exposure, risk of decreased ovarian reserve, and oxidative stress levels

Phthalates (PAEs), a group of environmental endocrine disruptors, are associated with oxidative stress and have adverse effects on female ovarian reserves. However, this association has been poorly investigated, particularly with respect to clinical evidence. In this study, we provided clinical evidence of a relationship between exposure levels of PAEs, oxidative stress and decreased ovarian reserve (DOR). Firstly, the urinary concentrations of metabolites of PAEs were measured by high performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS). The serum concentrations of follicle-stimulating hormone (FSH), luteinizing hormone (LH), and anti-Mullerian hormone (AMH), and the biomarkers of oxidative stress, malondialdehyde (MDA), superoxide dismutase (SOD), and total antioxidant capacity (T-AOC), were determined. Finally, statistical analyses were conducted to describe the relationship between the PAEs exposure, oxidative stress and DOR. We found that the levels of monomethyl phthalate (MMP), monoisobutyl phthalate (MiBP), mono-(2-ethylhexyl) phthalate (MEHP), and mono-(2-ethyl-5-hydroxypentyl) phthalate (MECPP) in the DOR group were significantly higher than those in the control group. There was a significant negative association between AMH and MMP, MiBP levels. and a significant positive association between FSH and MMP levels. PAEs exposure was also associated with a significant increase in MDA levels and decrease in SOD levels. In conclusion, the exposure of PAEs was closely associated with DOR, potentially mediated by oxidative stress pathways; however, small sample size was a limitation in this study.

Impact of DEHP exposure on female reproductive health: Insights into uterine effects

Several endocrine disrupting compounds released from plastics, including polyfluoroalkyl substances, bisphenols, flame retardants, phthalates and others, are of great concern to human health due to their high toxicity. This review discusses the effects of di-(2-ethylhexyl) phthalate (DEHP), the most common member of the phthalate family, on female reproduction. In vitro and in vivo studies link DEHP exposure to impaired hypothalamic-pituitary-ovarian s (HPO) axis function, alteration of steroid-hormone levels and dysregulation of their receptors, and changes in uterine morphophysiology. In addition, high urinary DEPH levels have been associated with several reproductive disorders in women, including endometriosis, fibromyoma, fetal growth restriction and pregnancy loss. These data suggest that DEHP may be involved in the pathophysiology of various female reproductive diseases. Therefore, exposure to these compounds should be considered a concern in clinician surveillance practices for women at reproductive age and should be regulated to protect their health and that of their progeny.

The role of the aryl hydrocarbon receptor in mediating the effects of mono(2-ethylhexyl) phthalate in mouse ovarian antral follicles†

Di(2-ethylhexyl) phthalate (DEHP) is a pervasive environmental toxicant used in the manufacturing of numerous consumer products, medical supplies, and building materials. DEHP is metabolized to mono(2-ethylhexyl) phthalate (MEHP). MEHP is an endocrine disruptor that adversely affects folliculogenesis and steroidogenesis in the ovary, but its mechanism of action is not fully understood. Thus, we tested the hypothesis that the aryl hydrocarbon receptor (AHR) plays a functional role in MEHP-mediated disruption of folliculogenesis and steroidogenesis. CD-1 mouse antral follicles were isolated and cultured with MEHP (0-400 μM) in the presence or absence of the AHR antagonist CH223191 (1 μM). MEHP treatment reduced follicle growth over a 96-h period, and this effect was partially rescued by co-culture with CH223191. MEHP exposure alone increased expression of known AHR targets, cytochrome P450 (CYP) enzymes Cyp1a1 and Cyp1b1, and this induction was blocked by CH223191. MEHP reduced media concentrations of estrone and estradiol compared to control. This effect was mitigated by co-culture with CH223191. Moreover, MEHP reduced the expression of the estrogen-sensitive genes progesterone receptor (Pgr) and luteinizing hormone/choriogonadotropin receptor (Lhcgr) and co-treatment with CH223191 blocked this effect. Collectively, these data indicate that MEHP activates the AHR to impair follicle growth and reduce estrogen production and signaling in ovarian antral follicles.

Melatonin alleviates the toxic effect of di(2-ethylhexyl) phthalate on oocyte quality resulting from CEBPB suppression during primordial follicle formation

Presently, the exposure of plasticizers to humans and animals occurs daily, which pose a potential threat to reproductive health. In the present study, a pregnant mouse model exposed to di(2-ethylhexyl) phthalate (DEHP, one of the most common plasticizers) and melatonin was established, and the single-cell transcriptome technology was applied to investigate the effects of melatonin in ovarian cells against DEHP. Results showed that DEHP markedly altered the gene expression pattern of ovarian cells, and severely weakened the histone methylation modification of oocytes. The administration of melatonin recovered the expression of LHX8 and SOHLH1 proteins that essential for primordial follicle formation, and increased the expression of CEBPB, as well as key genes of histone methylation modification (such as Smyd3 and Kdm5a). In addition, the ovarian damage caused by DEHP was also relieved after the overexpression of CEBPB, which suggested melatonin could improve primordial follicle formation progress via enhancing CEBPB expression in mice. Besides, the apoptosis of ovarian cells induced by DEHP also was diminished by melatonin. The study provides evidence of melatonin preventing the damage mediated by plasticizers on the reproductive system in females and CEBPB may serve as a downstream target factor of melatonin in the process.

Chronic exposure of mice to phthalates enhances TGF beta signaling and promotes uterine fibrosis

Phthalates are synthetic chemicals widely used as plasticizers and stabilizers in various consumer products. Because of the extensive production and use of phthalates, humans are exposed to these chemicals daily. While most studies focus on a single phthalate, humans are exposed to a mixture of phthalates on a regular basis. The impact of continuous exposure to phthalate mixture on uterus is largely unknown. Thus, we conducted studies in which adult female mice were exposed for 6 months to 0.15 ppm and 1.5 ppm of a mixture of phthalates via chow ad libitum. Our studies revealed that consumption of phthalate mixture at 0.15 ppm and 1.5 ppm for 6 months led to a significant increase in the thickness of the myometrial layer compared to control. Further investigation employing RNA-sequencing revealed an elevated transforming growth factor beta (TGF-β) signaling in the uteri of mice fed with phthalate mixture. TGF-β signaling is associated with the development of fibrosis, a consequence of excessive accumulation of extracellular matrix components, such as collagen fibers in a tissue. Consistent with this observation, we found a higher incidence of collagen deposition in uteri of mice exposed to phthalate mixture compared to unexposed controls. Second Harmonic Generation (SHG) imaging showed disorganized collagen fibers and nanoindentation indicated a local increase in uterine stiffness upon exposure to phthalate mixture. Collectively, our results demonstrate that chronic exposure to phthalate mixture can have adverse effects on uterine homeostasis.

Dietary exposure to an environmentally relevant phthalate mixture alters follicle dynamics, hormone levels, ovarian gene expression, and pituitary gene expression in female mice

Phthalates are chemicals ubiquitously used in industry. Individual phthalates have been found to adversely affect female reproduction; however, humans are exposed to a mixture of phthalates daily, primarily through ingestion. Previous studies show that exposure to an environmentally relevant mixture of phthalates (Mix) can affect female reproduction. Little research, however, has been conducted on the effects of short-term (1 month) and long-term (6 months) exposure to Mix on ovarian functions. Thus, this study tested the hypothesis that short-term and long-term exposure to Mix alters ovarian folliculogenesis, serum hormone concentrations, pituitary gene expression, and ovarian expression of genes involved in steroidogenesis, apoptosis, cell cycle regulation, and oxidative stress. Adult CD-1 female mice were exposed to vehicle control (corn oil) or Mix (0.15-1500 ppm) in the chow for 1 or 6 months. Exposure to Mix for 1 month increased the number of atretic follicles (0.15 ppm), altered ovarian gene expression (0.15 ppm, 1500 ppm), and decreased serum testosterone (1.5 ppm) compared to control. Exposure to Mix for 6 months increased serum follicle-stimulating hormone (FSH) (0.15 ppm), decreased serum luteinizing hormone (LH) (0.15 ppm, 1.5 ppm, and 1500 ppm), decreased serum estradiol (1500 ppm), altered pituitary gene expression (1500 ppm), increased the number (1500 ppm) and percentage (1.5 ppm and 1500 ppm) of primordial follicles, and decreased the percentage of preantral (1500 ppm) and antral (1.5 ppm and 1500 ppm) follicles compared to control. These data indicate that exposure to Mix can alter folliculogenesis, steroidogenesis, and gene expression in female mice.

A two-generational reproductive study to assess the effects of Juglans regia on reproductive developments in the male and female rats

Environmental pollutants and lifestyle severely threaten human and animal health, leading to disturbances of various functions, including infertility. So, exploring a safe treatment that could effectively reverse infertility remains a challenge. The current study was intended to explore the fertility-enhancing effect of Juglans Regia oil in two successive generations of rats; F0 and F1. J. Regia oil was initially tested for in vitro antioxidant assay via ROS and DPPH, followed by in vivo toxicity testing. In the fertility assessment, eighteen pairs of male and female rats (n=36, 1:1, F0 generation) were divided into three groups and dosed with 1 mL/kg and 2 mL/kg daily of J. Regia oil and saline, respectively, up to pre-cohabitation, cohabitation, gestation and lactation periods. The reproductive performance, including body weight, live birth index, fertility index, and litter size, was assessed. Hormonal and antioxidant markers of F1 generations were assessed with the histopathological evaluation of male and female organs. The oil of J. Regia showed great antioxidant potential (P < 0.05) in DPPH (1,1-diphenyl-2-picrylhydrazyl) and ROS (Reactive Oxygen Species) methods (P<0.05). The continued exposure of the F0 and F1 generations to J. Regia oil did not affect body weight, fertility index, litter size, and survival index. We have found pronounced fertility outcomes in both genders of F0 and F1 generations with J. Regia 2 mL/kg/day in comparison to the control. Results showed that J. Regia significantly increased (P < 0.05) luteinizing hormone (LH), plasma testosterone, follicular stimulating hormone (FSH), glutathione peroxidase (GPx) and superoxide dismutase (SOD) activities in both generations. Histology of both generations reveals improved spermatogenesis and folliculogenesis with enhanced architecture. Altogether, the present results suggest that J. Regia improved fertility in both male and female rats by improving hormonal activities and oxidative stress.

Di(2-ethylhexyl) phthalate induces reproductive toxicity and transgenerational reproductive aging in Caenorhabditis elegans

With the large-scale production and use of plastic products, the global plastic pollution problem is becoming more and more serious. The plasticizer di (2-ethylhexyl) phthalate (DEHP), which is widely used in the production of plastics, has caused great concern for the health of the population. Exposure of organisms to DEHP can cause a variety of health damage, of which reproductive system damage is an important part. At present, there are still few studies on DEHP in reproductive aging, and it is of great significance to explore the role of DEHP in promoting reproductive aging and its underlying mechanism. In this study, the model organism Caenorhabditis elegans (C. elegans) was used to preliminarily explore the mechanism of DEHP-induced female reproductive senescence. The results showed that DEHP reduced the number of offspring and gonad area of C. elegans, resulting in shortened reproductive and life span, abnormal phenotypes in somatic gonad structure including the Emo phenotype, the BOW phenotype, a twisted gonad arm, and atrophied oocytes. Biochemical studies showed that DEHP promoted oxidative stress and autophagy in C. elegans. Further, we found the decreased number of offspring, malformed somatic gonad structure, oxidative damage and autophagy induced by DEHP in parental worms can be inheritance to the not directly exposed offspring.

Exposure to di-isononyl phthalate during early pregnancy disrupts decidual angiogenesis and placental development in mice

Di-isononyl phthalate (DiNP), an endocrine-disrupting chemical, is found in numerous consumer products and human exposure to this phthalate is becoming inevitable. The impact of DiNP exposure on the establishment and maintenance of pregnancy remains largely unknown. Thus, we conducted studies in which pregnant mice were exposed to an environmentally relevant dose (20 µg/kg BW/day) of DiNP on days 1-7 of gestation, then analyzed the effects of this exposure on pregnancy outcome. Our studies revealed that exposure to DiNP during this window led to fetal loss towards the end of gestation. Further studies showed that, although embryos were able to attach to the uterus, implantation sites in DiNP-exposed uteri exhibited impaired differentiation of stromal cells to decidual cells and an underdeveloped angiogenic network in the decidual bed. We also found that exposure to this phthalate has a significant effect on trophoblast differentiation and causes disorganization of the placental layers. The labyrinth was significantly reduced, resulting in compromised expression of nutrient transporters in the placentas of mice exposed to DiNP. These placental defects in DiNP-exposed females were the cause of fetal loss during the later stages of gestation.

Chronic exposure to a mixture of phthalates shifts the white and brown adipose tissue phenotypes in female mice

Phthalates are endocrine-disrupting chemicals used in consumer products. Although phthalates are obesogens and affect metabolic function, it is unknown if chronic exposure for 6 months to a phthalate mixture alters adipose tissue phenotype in female mice. After vehicle or mixture exposure, white adipose tissue and brown adipose tissue (WAT and BAT) were analyzed for expression of adipogenesis, proliferation, angiogenesis, apoptosis, oxidative stress, inflammation, and collagen deposition markers. The mixture altered WAT morphology, leading to an increase in hyperplasia, blood vessel number, and expression of BAT markers (Adipoq and Fgf2) in WAT. The mixture increased the expression of the inflammatory markers, Il1β, Ccl2, and Ccl5, in WAT. The mixture also increased expression of the proapoptotic (Bax and Bcl2) and antiapoptotic (Bcl2l10) factors in WAT. The mixture increased expression of the antioxidant Gpx1 in WAT. The mixture changed BAT morphology by increasing adipocyte diameter, whitening area, and blood vessel number and decreased expression of the thermogenic markers Ucp1, Pgargc1a, and Adrb3. Furthermore, the mixture increased the expression of adipogenic markers Plin1 and Cebpa, increased mast cell number, and increased Il1β expression in BAT. The mixture also increased expression of the antioxidant markers Gpx and Nrf2 and the apoptotic marker Casp2 in BAT. Collectively, these data indicate that chronic exposure to a phthalate mixture alters WAT and BAT lipid metabolism phenotypes in female mice, leading to an apparent shift in their normal morphology. Following long-term exposure to a phthalate mixture, WAT presented BAT-like features and BAT presented WAT-like features.

Long-term exposure to di(2-ethylhexyl) phthalate, diisononyl phthalate, and a mixture of phthalates alters estrous cyclicity and/or impairs gestational index and birth rate in mice

Phthalates are found in plastic food containers, medical plastics, and personal care products. However, the effects of long-term phthalate exposure on female reproduction are unknown. Thus, this study investigated the effects of long-term, dietary phthalate exposure on estrous cyclicity and fertility in female mice. Adult female CD-1 mice were fed chow containing vehicle control (corn oil) or 0.15-1500 ppm of di(2-ethylhexyl) phthalate (DEHP), diisononyl phthalate (DiNP), or a mixture of phthalates (Mix) containing DEHP, DiNP, benzyl butyl phthalate, di-n-butyl phthalate, diisobutyl phthalate, and diethyl phthalate. Measurements of urinary phthalate metabolites confirmed effective delivery of phthalates. Phthalate consumption for 11 months did not affect body weight compared to control. DEHP exposure at 0.15 ppm for 3 and 5 months increased the time that the mice spent in estrus and decreased the time the mice spent in metestrus/diestrus compared to control. DiNP exposure (0.15-1500 ppm) did not significantly affect time in estrus or metestrus/diestrus compared to control. Mix exposure at 0.15 and 1500 ppm for 3 months decreased the time the mice spent in metestrus/diestrus and increased the time the mice spent in estrus compared to control. DEHP (0.15-1500 ppm) or Mix (0.15-1500 ppm) exposure did not affect fertility-related indices compared to control. However, long-term DiNP exposure at 1500 ppm significantly reduced gestational index and birth rate compared to control. These data indicate that chronic dietary exposure to phthalates alters estrous cyclicity, and long-term exposure to DiNP reduces gestational index and birth rate in mice.

Effects of phthalates on human chorionic trophoblast cells and mouse embryonic development

Phthalate exposure is associated with reproductive health, but the mechanism is unclear. This study used human chorionic trophoblast epithelial cells (HTR8/Svneo cells) and mouse embryos as objects aims to explore the effects of phthalate plasticizers on germ cells and fertility and the possible signalling pathways. In the present study, high concentrations of MEHP for 24 h significantly inhibited the proliferation and viability of HTR8/SVneo cells. Compared with the negative control (NC) group, the MEHP medium and high concentration groups promoted the apoptosis of HTR8/SVneo cells and inhibited the cell cycle, HTR8/SVneo cells were blocked in G1/G0 phase and could not enter S phase, and cell meiosis was inhibited. Western blot experiments showed that there was no difference in the protein expression of wnt inhibitory factor 1 (WIF1) and β-catenin in HTR8/SVneo cells between the MEHP exposure groups and the NC groups. In vitro embryo culture experiments found that there was no difference in blastocyst formation rate among groups after exposure to DEHP for 2 h. Immunofluorescence showed that the expression of WIF1 decreased in the low concentration group, and there was no difference in the medium and high concentration groups, while the expression of β-catenin was increased in both the low concentration group and the high concentration group. Our data suggest that exposure to phthalate plasticizers can affect the viability, cell cycle and apoptosis of trophoblast cells, resulting in abnormal expression of the embryonic WIF1/β-catenin signalling pathway and impaired fertility.

Exposure to Di-(2-Ethylhexyl) phthalate drives ovarian dysfunction by inducing granulosa cell pyroptosis via the SLC39A5/NF-κB/NLRP3 axis

Endocrine-disrupting chemicals (EDCs) have been reported to affect populations by disrupting the human endocrine system. Di-(2-ethylhexyl) phthalate (DEHP) is an EDC that is present in various consumer products. Exposure to DEHP could contribute to reproductive system dysfunction, with subsequent adverse female reproductive outcomes. Granulosa cells (GCs) play essential roles in ovarian function and fertility. To further reveal the underlying mechanism by which DEHP impairs female fertility and affects the normal function of GCs, in vivo and in vitro experiments were performed. Transcript sequencing was used to identify genes that were differentially expressed in GCs after DEHP treatment. SLC39A5 was shown to be overexpressed in the DEHP group compared to the normal control group. DEHP treatment and overexpression of SLC39A5 activated NF-κB-related factors, followed by an increase in the transcript expression level of NLRP3. NLRP3 inflammasomes play crucial roles in pyroptosis by acting as sensors. Pyroptosis is a type of inflammation-related cell death associated with various diseases, including ovarian cancer and polycystic ovary syndrome. Activation of NF-κB contributed to the upregulation of pyroptosis in GCs, while pyroptosis factors were downregulated after the inhibition of NF-κB with JSH-23. The same phenomenon was also observed in a mouse model in which DEHP-treated mice had higher expression levels of NF-κB and pyroptosis markers in GCs. Moreover, this phenomenon could be partially reversed by the NF-κB inhibitor JSH-23. DEHP treatment also disrupted the normal expression of ovarian function-related genes and inhibited the proliferation of GCs. Reproductive system impairment was observed in mice exposed to DEHP. DEHP-treated mice had a lower body weight, smaller reproductive organs, fewer healthy follicles, and diminished ovarian reserve. Thus, DEHP contributes to ovarian dysfunction by inducing pyroptosis via the SLC39A5/NF-κB/NLRP3 axis in GCs.

H3K4me3 as a target of di(2-ethylhexyl) phthalate (DEHP) impairing primordial follicle assembly

Di (2-ethylhexyl) phthalate (DEHP) is a widely used plastics additive that growing evidence indicates as endocrine disruptor able to negatively affect various reproductive processes both in female and male animals, including humans. However, the precise molecular mechanism of such actions is not completely understood. In the present study, scRNA-seq was performed on the ovaries of offspring from mothers exposed to DEHP from 16.5 days post coitum to 3 days post-partum, when the primordial follicle (PF) stockpile is established. While the histological observations of the offspring ovaries from DEHP exposed mothers confirmed previous data about a distinct reduction of oocytes enclosed in PFs. Focusing on oocytes, scRNA-seq analyses showed that the genes that mostly changed by DEHP were enriched GO terms related to histone H3-K4 methylation. Moreover, we observed H3K4me3 level, an epigenetics modification of H3 that is crucial for chromatin transcription, decreased by 40.28% (P < 0.01) in DEHP-treated group compared with control. When the newborn ovaries were cultured in vitro, the DEHP effects were abolished by tamoxifen (an estrogen receptor antagonist) or overexpression of Smyd3 (one specific methyltransferase of H3K4me3), in particular, the percentage of oocyte enclosed in PF was increased by 15.39% in DEHP plus Smyd3 overexpression group than of DEHP group (P < 0.01), which was accompanied by the upregulation of H3K4me3. Collectively, the present results discover Smyd3-H3K4me3 as a novel target of the deleterious ER-mediated effect of DEHP on PF formation during early folliculogenesis in the mouse and highlight epigenetics changes as prominent targets of endocrine disruptors like DEHP.

Bisphenols, but not phthalate esters, modulate gene expression in activated human MAIT cells in vitro

One route of human exposure to environmental chemicals is oral uptake. This is primarily true for chemicals that may leach from food packaging materials, such as bisphenols and phthalate esters. Upon ingestion, these compounds are transported along the intestinal tract, from where they can be taken up into the blood stream or distributed to mucosal sites. At mucosal sites, mucosal immune cells and in the blood stream peripheral immune cells may be exposed to these chemicals potentially modulating immune cell functions. In the present study, we investigated the impact of three common bisphenols and two phthalate esters on mucosal-associated invariant T (MAIT) cells in vitro, a frequent immune cell type in the intestinal mucosae and peripheral blood of humans. All compounds were non-cytotoxic at the chosen concentrations. MAIT cell activation was only slightly affected as seen by flow cytometric analysis. Phthalate esters did not affect MAIT cell gene expression, while bisphenol-exposure induced significant changes. Transcriptional changes occurred in ∼ 25 % of genes for BPA, ∼ 22 % for BPF and ∼ 8 % for BPS. All bisphenols down-modulated expression of CCND2, CCL20, GZMB and IRF4, indicating an effect on MAIT cell effector function. Further, BPA and BPF showed a high overlap in modulated genes involved in cellular stress response, activation signaling and effector function suggesting that BPF may not be safe substitute for BPA.

Perfluorooctanoic acid exposure in vivo perturbs mitochondrial metabolic during oocyte maturation

Perfluorooctanoic acid (PFOA), a member of a group of polyfluorinated and perfluorinated alkyl substances (PFAS), is associated with adverse pregnancy outcomes in mammals. However, the effects of in vivo exposure to PFOA on the female reproductive system and the underlying mechanisms remain unclear. In our study, we constructed a mouse model to investigate whether low-dose PFOA (1 mg/kg/day) or high-dose PFOA (5 mg/kg/day) affect meiosis maturation of oocytes and the potential mechanisms that may be associated with oocyte maturation disorder. Our results indicate that low-dose and high-dose PFOA can lead to impaired oocyte maturation, which is manifested by decreased rate of embryonic foam rupture and first polar body extrusion. Moreover, PFOA exposure harmed the mitochondrial metabolic, resulting in low levels of ATP contents, high reactive oxygen species, aberrant mitochondrial membrane potential. In addition, the proportion of DNA damage marker γ-H2AX was also significantly increased in PFOA exposure oocytes. These changes lead to abnormal arrangements of the spindle and chromosomes during oocyte maturation. In conclusion, our results for the first time illustrated that exposure to PFOA in vivo in female mice impaired the meiosis maturation of oocytes, which provided a basis for studying the mechanism of PFOA reproductive toxicity in female mammals.

Maternal rodent exposure to di-(2-ethylhexyl) phthalate decreases muscle mass in the offspring by increasing myostatin

BACKGROUND

Di-(2-ethylhexyl) phthalate (DEHP) and its metabolites can cross the placenta and may cause birth defects and developmental disorders. However, whether maternal DEHP exposure affects skeletal muscle development in the offspring and the pathways involved are unknown. This study investigated the effects of maternal DEHP exposure and the contribution of myostatin (MSTN) to skeletal muscle development in the offspring.

METHODS

Pregnant wild-type and muscle-specific myostatin knockout (MSTN KO) C57BL/6 mice were randomized to receive vehicle (corn oil) or 250 mg/kg DEHP by gavage every other day until their pups were weaned (postnatal day 21 [PND21]). Body weights of the offspring mice were measured longitudinally, and their hindleg muscles were harvested at PD21. Also, C2C12 cells were treated with mono-2-ethylhexyl phthalate (MEHP), the primary metabolite of DEHP, and proteolysis, protein synthesis, and myogenesis markers were measured. The contribution of myostatin to maternal DEHP exposure-induced muscle wasting in the offspring was determined.

RESULTS

Maternal DEHP exposure reduced body weight growth, myofibre size, and muscle mass in the offspring compared to controls (Quad: 2.70 ± 0.1 vs. 3.38 ± 0.23, Gastroc: 2.29 ± 0.09 vs. 2.81 ± 0.14, Tibialis: 1.01 ± 0.07 vs. 1.25 ± 0.11, mg/tibial length in mm, all P < 0.01, n = 35). Maternal DEHP exposure significantly increased Myostatin expression (2.45 ± 0.41 vs. 0.03 ± 0.00 DEHP vs. controls, P < 0.01, n = 5), Atrogin-1(2.68 ± 0.65 vs. 0.63 ± 0.01, P < 0.05, n = 5), MuRF1 (1.56 ± 0.51 vs. 0.31 ± 0.01, P < 0.05, n = 5), and Smad2/3 phosphorylation (4.12 ± 0.35 vs. 0.49 ± 0.18, P < 0.05), and decreased MyoD (0.27 ± 0.01 vs. 1.52 ± 0.01, P < 0.05, n = 5), Myogenin (0.25 ± 0.03 vs. 1.95 ± 0.56, P < 0.05, n = 5), and AKT phosphorylation (4.12 ± 0.35 vs. 1.00 ± 0.06, P < 0.05, n = 5), in skeletal muscle of the offspring in MSTNflox/flox , but not in MSTN KO mice. Maternal DEHP exposure resulted in up-regulation of CCAAT/enhancer-binding protein δ (C/EBPδ, 4.12 ± 0.35 vs. 1.00 ± 0.19, P < 0.05, n = 5) in skeletal muscle of the offspring in MSTNflox/flox and MSTN KO mice (4.12 ± 0.35 vs. 4.35 ± 0.28, P > 0.05, n = 5). In vitro, C/EBPδ silencing abrogated the MEHP-induced increases in Myostatin, MuRF-1, and Atrogin-1 and decreases in MyoD and Myogenin expression.

CONCLUSIONS

Maternal DEHP exposure impairs skeletal muscle development in the offspring by enhancing the C/EBPδ-myostatin pathway in mice.

Subchronic exposure to environmentally relevant concentrations of di-(2-ethylhexyl) phthalate differentially affects the colon and ileum in adult female mice

Di(2-ethylhexyl) phthalate (DEHP) is a large-molecular-weight phthalate added to plastics to impart versatile properties. DEHP can be found in medical equipment and devices, food containers, building materials, and children's toys. Although DEHP exposure occurs most commonly by ingesting contaminated foods in the majority of the population, its effects on the gastrointestinal tract have not been well studied. Therefore, we analyzed the effects of subchronic exposure to DEHP on the ileum and colon morphology, gene expression, and immune microenvironment. Adult C57BL/6 female mice were orally dosed with corn oil (control, n = 7) or DEHP (0.02, 0.2, or 30 mg/kg, n = 7/treatment dose) for 30-34 days. Mice were euthanized during diestrus, and colon and ileum tissues were collected for RT-qPCR and immunohistochemistry. Subchronic DEHP exposure in the ileum altered the expression of several immune-mediating factors (Muc1, Lyz1, Cldn1) and cell viability factors (Bcl2 and Aifm1). Similarly, DEHP exposure in the colon impacted the gene expression of factors involved in mediating immune responses (Muc3a, Zo2, Ocln, Il6, and Il17a); and also altered the expression of cell viability factors (Ki67, Bcl2, Cdk4, and Aifm1) as well as a specialized epithelial cell marker (Vil1). Immunohistochemical analysis of the ileum showed DEHP increased expression of VIL1, CLDN1, and TNF and decreased number of T-cells in the villi. Histological analysis of the colon showed DEHP altered morphology and reduced cell proliferation. Moreover, in the colon, DEHP increased the expression of MUC2, MUC1, VIL1, CLDN1, and TNF. DEHP also increased the number of T-cells and Type 2 immune cells in the colon. These data suggest that subchronic DEHP exposure differentially affects the ileum and colon and alters colonic morphology and the intestinal immune microenvironment. These results have important implications for understanding the effects of DEHP on the gastrointestinal system.

The effects of endocrine-disrupting chemicals on ovarian- and ovulation-related fertility outcomes

Exposure to endocrine-disrupting chemicals (EDCs) is unavoidable, which represents a public health concern given the ability of EDCs to target the ovary. However, there is a large gap in the knowledge about the impact of EDCs on ovarian function, including the process of ovulation. Defects in ovulation are the leading cause of infertility in women, and EDC exposures are contributing to the prevalence of infertility. Thus, investigating the effects of EDCs on the ovary and ovulation is an emerging area for research and is the focus of this review. The effects of EDCs on gametogenesis, uterine function, embryonic development, and other aspects of fertility are not addressed to focus on ovarian- and ovulation-related fertility issues. Herein, findings from epidemiological and basic science studies are summarized for several EDCs, including phthalates, bisphenols, per- and poly-fluoroalkyl substances, flame retardants, parabens, and triclosan. Epidemiological literature suggests that exposure is associated with impaired fecundity and in vitro fertilization outcomes (decreased egg yield, pregnancies, and births), while basic science literature reports altered ovarian follicle and corpora lutea numbers, altered hormone levels, and impaired ovulatory processes. Future directions include identification of the mechanisms by which EDCs disrupt ovulation leading to infertility, especially in women.

Endocrine disrupting chemicals impact on ovarian aging: Evidence from epidemiological and experimental evidence

Endocrine-disrupting chemicals (EDCs) are ubiquitous in daily life, but their harmful effects on the human body have not been fully explored. Recent studies have shown that EDCs exposure could lead to infertility, menstrual disorder and menopause, resulting in subsequent effects on female health. Therefore, it is of great significance to clarify and summarize the impacts of EDCs on ovarian aging for explaining the etiology of ovarian aging and maintaining female reproductive health. Here in this review, we focused on the impacts of ten typical environmental contaminants on the progression of ovarian aging during adult exposure, including epidemiological data in humans and experimental models in rodents, with their clinical phenotypes and underlying mechanisms. We found that both persistent (polychlorinated biphenyls, perfluoroalkyl and polyfluoroalkyl substances) and non-persistent (phthalates) EDCs exposure could increase an overall risk of ovarian aging, leading to the diminish of ovarian reserve, decline of fertility or fecundity, irregularity of the menstrual cycle and an earlier age at menopause, and/or premature ovarian insufficiency/failure in epidemiological studies. Among these, the loss of follicles can also be validated in experimental studies of some EDCs, such as BPA, phthalates, parabens and PCBs. The underlying mechanisms may involve the impaired ovarian follicular development by altering receptor-mediated pro-apoptotic pathways, inducing signal transduction and cell cycle arrest and epigenetic modification. However, there were inconsistent results in the impacts on fertility/fecundity, menstrual/estrous cycle and hormone changes response to different EDCs, and differences between human and animal studies. Our review summarizes the current state of knowledge on ovarian disrupters, highlights their risks to ovarian aging and identifies knowledge gaps in humans and animals. We therefore propose that females adopt healthy lifestyle changes to minimize their exposure to both persistent and non-persistent chemicals, that have the potential damage to their reproductive function.

Effects of DEHP, DEHT and DINP Alone or in a Mixture on Cell Viability and Mitochondrial Metabolism of Endothelial Cells In Vitro

Plasticizers are chemicals in high demand, used in a wide range of commercial products. Human are exposed through multiple pathways, from numerous sources, to multiple plasticizers. This is a matter of concern, as it may contribute to adverse health effects. The vascular system carries plasticizers throughout the body and therefore can interact with the endothelium. The aim of the study was to evaluate the in vitro toxicity on endothelial cells by considering the individual and the mixture effects of bis-(2-ethylhexyl) phthalate (DEHP), diisononyl phthalate (DINP) or bis-(2-ethylhexyl) terephthalate (DEHT). In this study, their cytotoxicity on HMEC-1 cells was evaluated on cell function (viability, cell counting, total glutathione and intracellular adenosines) and mitochondrial function (mitochondrial respiration). Results showed cellular physiological perturbations induced with all the condition tested, excepted for DEHT. Plasticizers induced a cytotoxicity by targeting mitochondrial respiration, depleting mitochondrial ATP production and increasing glycolytic metabolism. Additionally, delayed effects were observed between the cellular and the mitochondrial parameters. These results suggest that endothelial cells could go through a metabolic adaptation to face plasticizer-induced cellular stress, to effectively maintain their cellular processes. This study provides additional information on the adverse effects of plasticizers on endothelial cells.

Apigenin ameliorates di(2-ethylhexyl) phthalate-induced ferroptosis: The activation of glutathione peroxidase 4 and suppression of iron intake

Di(2-ethylhexyl) phthalate (DEHP) is a widely artificial persistent organic pollutant, the contamination of which infiltrates daily human life from many aspects, imperceptibly causing damage to multiple organs in the body, including the liver. Apigenin (APG) is widely distributed in vegetables and fruits and can relieve or prevent the injuries caused by exogenous chemicals through various pharmacological effects, such as antioxidant effects. To investigate the mechanism of DEHP-induced liver injury and the antagonistic effects of APG, we treated AML12 cells with 1 mM DEHP and/or APG. Ultrastructural morphology analysis indicated that DEHP induced typical ferroptosis-like damage. In addition, we found that DEHP exposure induced ferroptosis by enhancing reactive oxygen species (ROS) levels, disrupting iron homeostasis and lipid peroxidation, and regulating the expression of ferroptosis-related genes. Notably, supplementation with APG significantly inhibited these abnormal changes, and molecular docking further showed evidence of the activating effects of APG ligand on glutathione peroxidase 4 (GPX4). These results demonstrated that the protective effects of APG on DEHP-induced ferroptosis were achieved by activating GPX4 and suppressing intracellular iron accumulation. This information not only adds to DEHP toxicological data but also provides a basis for the practical application of APG.

A Correlational Analysis of Phthalate Exposure and Thyroid Hormone Levels in Common Bottlenose Dolphins (Tursiops truncatus) from Sarasota Bay, Florida (2010-2019)

Phthalates are chemical esters used to enhance desirable properties of plastics, personal care, and cleaning products. Phthalates have shown ubiquitous environmental contamination due to their abundant use and propensity to leach from products to which they are added. Following exposure, phthalates are rapidly metabolized and excreted through urine. Common bottlenose dolphins (Tursiops truncatus) sampled from Sarasota Bay, Florida, have demonstrated prevalent di(2-ethylhexyl) phthalate (DEHP) exposure indicated by detectable urinary mono(2-ethylhexyl) phthalate (MEHP) concentrations. Widespread exposure is concerning due to evidence of endocrine disruption from human and laboratory studies. To better understand how phthalate exposure may impact dolphin health, correlations between relevant hormone levels and detectable urinary MEHP concentrations were examined. Hormone concentrations measured via blood serum samples included triiodothyronine (T3), total thyroxine (T4), and free thyroxine (FT4). Urinary MEHP concentrations were detected in 56% of sampled individuals (n = 50; mean = 8.13 ng/mL; s.d. = 15.99 ng/mL). Adult female and male FT4 was significantly correlated with urinary MEHP concentrations (adult female Kendall's tau = 0.36, p = 0.04; adult male Kendall's tau = 0.42, p = 0.02). Evidence from this study suggests DEHP exposure may be impacting thyroid hormone homeostasis. Cumulative effects of other stressors and resultant endocrine impacts are unknown. Further research is warranted to understand potential health implications associated with this relationship.

Risk of Abdominal Obesity Associated with Phthalate Exposure of Nurses

Background: Occupational health hazards associated with phthalate exposure among nurses are still not well understood. Methods: We used high-performance liquid chromatography and tandem mass spectrometry to analyze phthalates. Anthropometric measurements and questionnaires were conducted. Results: We observed associations between mono-benzyl phthalate (MBzP) and body mass index (BMI), hip circumference (HC), waist circumference (WC), waist to height ratio (WHtR), and fat mass index (FMI), visceral fat content, BMI risk and hip index risk (HIrisk), adjusted to consumer behavior and consumer practices (r = 0.36−0.61; p ≤ 0.046). In the same model, we detected an association between mono-n-butyl phthalate (MnBP) and waist to hip ratio (WHR; r = 0.36; p = 0.046), mono-carboxy-isononyl phthalate (cx-MiNP) and BMI (r = 0.37; p = 0.043), HC (r = 0.4; p = 0.026) and WHtR (r = 0.38; p = 0.037), between mono-oxo-isononyl phthalate oxo (MiNP) and HC (r = 0.36; p = 0.045), mono-2-ethylhexyl phthalate (MEHP), mono(2-ethyl-5-oxohexyl) phthalate (oxo-MEHP) and HIrisk (r = 0.38−0.41; p ≤ 0.036), between oxo-MEHP and Anthropometric Risk Index (ARI risk; r = 0.4; p = 0.028). We detected a relationship between BMI and MBzP (β = 0.655; p < 0.001) and mono-2-ethylhexyl phthalate (MEHP; β = −0.365; p = 0.003), between hip circumference and MBzP (β = 0.486; p < 0.001), MEHP (β = −0.402; p = 0.001), and sum of secondary metabolites of diisononyl phthalate (∑DiNP; β = 0.307; p = 0.016). We observed a relationship between fat content and MBzP (β = 0.302; p = 0.033), OH-MnBP (β = −0.736; p = 0.006) and MiBP (β = 0.547; p = 0.046), visceral fat content and MBzP (β = 0.307; p = 0.030), HI-risk and MBzP (β = 0.444; p = 0.001), ARI-risk and sum of di-n-butyl phthalate metabolites (∑DnBP; β = 0.337; p = 0.018). We observed an association between the use of protective equipment with cx-MiNP. Conclusions: Occupational exposure to phthalates may induce abdominal obesity and result in obesity-related metabolic disorders.

Isolation of DiNP-Degrading Microbes from the Mouse Colon and the Influence DiNP Exposure Has on the Microbiota, Intestinal Integrity, and Immune Status of the Colon

Di-isononyl phthalate (DiNP) is a plasticizer used to impart flexibility or stability in a variety of products including polyvinyl chloride, cable coatings, artificial leather, and footwear. Previous studies have examined the impact of DiNP on gut integrity and the colonic immune microenvironment, but this study further expands the research by examining whether DiNP exposure alters the colonic microbiota and various immune markers. Previous studies have also revealed that environmental microbes degrade various phthalates, but no studies have examined whether anaerobic gut bacteria can degrade DiNP. Thus, this study tested the hypothesis that DiNP exposure alters the gut microbiota and immune-related factors, and that anaerobic bacteria in the gut can utilize DiNP as the sole carbon source. To test this hypothesis, adult female mice were orally dosed with corn oil or various doses of DiNP for 10–14 consecutive days. After the treatment period, mice were euthanized during diestrus. Colonic contents were collected for full-length 16S rRNA gene sequencing to identify the bacteria in the colon contents. Sanger sequencing of the 16S rRNA gene was used to identify bacteria that were able to grow in Bacteroides minimal media with DiNP as the sole carbon source. Colon tissues were collected for immunohistochemistry of immune(-related) factors. An environmentally relevant dose of DiNP (200 µg/kg) significantly increased a Lachnoclostridium taxon and decreased Blautia compared to the control. Collectively, minimal changes in the colonic microbiota were observed as indicated by non-significant beta-diversities between DiNP treatments and control. Furthermore, three strains of anaerobic bacteria derived from the colon were identified to use DiNP as the sole carbon source. Interestingly, DiNP exposure did not alter protein levels of interleukin-6, tumor necrosis factor alpha, claudin-1, and mucin-1 compared to the control. Collectively, these findings show that DiNP exposure alters the gut microbiota and that the gut contains DiNP-degrading microbes.

The concentration of phthalates in toys and children's care items in Kosovo

In this study, one hundred and twenty-eight toys and children's care items available in the Kosovo market were analyzed to determine the presence of phthalates and evaluate if the analyzed samples meet the national and EU standards. Toys and children's care items were imported from twelve countries, most of them from China. Phthalates were extracted and then analyzed using gas chromatography and mass spectrometry. Nine phthalates were analyzed in total, of them, benzyl butyl phthalate, di-isodecyl phthalate, diisobutyl phthalate and di-isononyl phthalate were the most frequently detected phthalates in the analyzed samples. Phthalates were not detected only in three toys and children's care items, others contained one or more phthalates, while none of them contained all (nine) analyzed phthalates. In total, 22 analyzed toys and children's care items did not fulfill at least one of the EU standards, of these 16 were toys and children's care items intended for children under age three and designed to be placed in the mouth. Overall, our work shows that toys and children's care items that exceed EU standards for phthalates are still present in the Kosovo market.

Prenatal exposure to an environmentally relevant phthalate mixture alters ovarian steroidogenesis and folliculogenesis in the F1 generation of adult female mice

Phthalates are a family of chemicals that can be found in plastic and personal care products used by consumers every day and they are known endocrine disrupting chemicals that can disrupt female reproduction. In previous studies, an environmentally relevant phthalate mixture was shown to affect female reproduction in a transgenerational manner. However, limited information was available on the effect of phthalate mixtures on ovarian steroidogenesis and folliculogenesis. Ovarian steroidogenesis is important for producing hormones needed for reproduction and ovarian regulation, and folliculogenesis is essential for the development of ovarian follicles and successful fertility. Thus, this study tested the hypothesis that prenatal exposure to an environmentally relevant phthalate mixture adversely affects ovarian steroidogenesis and folliculogenesis in the F1 generation of adult female mice. Pregnant dams (F0 generation) were orally dosed with vehicle control or a phthalate mixture (20 μg/kg/day-500 mg/kg/day) daily from gestational day 10 to birth, and the adult F1 females were the offspring of the dosed dams. The ovaries of the F1 generation were collected at postnatal day 60. One ovary was used for histological examination of the numbers and percent of different follicle types. The other ovary was used to measure expression of theca and granulosa cell enzymes. Additionally, sera were collected for measuring hormone levels. The results indicate that prenatal exposure to the phthalate mixture decreases hormone levels and gene expression, alters the transitioning of follicle types, and leads to a higher incidence of atresia in the F1 generation offspring.

Phthalates and Alternative Plasticizers Differentially affect Phenotypic Parameters in Gonadal Somatic and Germ Cell Lines

The developmental and reproductive toxicity associated with exposure to phthalates has motivated a search for alternatives. However, there is limited knowledge regarding the adverse effects of some of these chemicals. We used high-content imaging to compare the effects of mono (2-ethylhexyl) phthalate (MEHP) with six alternative plasticizers: di-2-ethylhexyl terephthalate (DEHTP); diisononyl-phthalate (DINP); di-isononylcyclohexane-1,2-dicarboxylate (DINCH); 2-ethylhexyl adipate (DEHA); 2,2,4-trimethyl 1,3-pentanediol diisobutyrate (TXIB) and di-iso-decyl-adipate (DIDA). A male germ spermatogonial cell line (C18-4), a Sertoli cell line (TM4) and two steroidogenic cell lines (MA-10 Leydig and KGN granulosa) were exposed for 48h to each chemical (0.001-100 μM). Cell images were analyzed to assess cytotoxicity and effects on phenotypic endpoints. Only MEHP (100 μM) was cytotoxic and only in C18-4 cells. However, several plasticizers had distinct phenotypic effects in all four cell lines. DINP increased Calcein intensity in C18-4 cells, whereas DIDA induced oxidative stress. In TM4 cells, MEHP, and DINCH affected lipid droplet numbers, while DEHTP and DINCH increased oxidative stress. In MA-10 cells, MEHP increased lipid droplet areas and oxidative stress; DINP decreased the number of lysosomes, while DINP, DEHA and DIDA altered mitochondrial activity. In KGN cells, MEHP, DINP and DINCH increased the number of lipid droplets, whereas DINP decreased the number of lysosomes, increased oxidative stress and affected mitochondria. The Toxicological Priority Index (ToxPi) provided a visual illustration of the cell line specificity of the effects on phenotypic parameters. The lowest administered equivalent doses were observed for MEHP. We propose that this approach may assist in screening alternative plasticizers.

Urinary phthalate metabolite concentrations and serum hormone levels in pre- and perimenopausal women from the Midlife Women's Health Study

BACKGROUND

Phthalate exposure is associated with altered reproductive function, but little is known about associations between phthalate and hormone levels in midlife women.

METHODS

This cross-sectional analysis includes 45-54-year-old pre- and perimenopausal women from Baltimore, MD and its surrounding counties enrolled in the Midlife Women's Health Study (n = 718). Serum and urine samples were collected from participants once a week for four consecutive weeks to span the menstrual cycle. Serum samples were assayed for estradiol, testosterone, progesterone, sex hormone binding globulin (SHBG), follicle-stimulating hormone (FSH), and anti-Müllerian hormone (AMH), and geometric means were calculated for each hormone across all four weeks. Urine samples were analyzed for nine phthalate metabolites from pools of one-to-four urine samples. Phthalate metabolite concentrations were specific gravity-adjusted and assessed as individual metabolites or as molar sums of metabolites from common parents (di(2-ethylhexyl) phthalate metabolites, ∑DEHP), exposure sources (plastic, ∑Plastics; personal care products, ∑PCP), biological activity (anti-androgenic, ∑AA), and sum of all metabolites (∑Phthalates). We used linear regression models to assess overall associations of phthalate metabolites with hormones, controlling for important demographic, lifestyle, and health factors. We also explored whether associations differed by menopause status, body mass index (BMI), and race/ethnicity.

RESULTS

Most participants were non-Hispanic white (67%) or black (29%), college-educated (65%), employed (80%), and had somewhat higher mean urinary phthalate metabolite concentrations than other U.S. women. Overall, the following positive associations were observed between phthalate metabolites and hormones: ∑DEHP (%Δ: 4.9; 95%CI: 0.5, 9.6), ∑Plastics (%Δ: 5.1; 95%CI: 0.3, 10.0), and ∑AA (%Δ: 7.8; 95%CI: 2.3, 13.6) with estradiol; MiBP (%Δ: 6.6; 95%CI: 1.5, 12.1) with testosterone; ∑DEHP (%Δ: 8.3; 95%CI: 1.5, 15.6), ∑Plastics (%Δ: 9.8; 95%CI: 2.4, 17.7), MEP (%Δ: 4.6; 95%CI: 0.1, 9.2), ∑PCP (%Δ: 6.0; 95%CI: 0.2, 12.2), ∑Phthalates (%Δ: 9.0; 95%CI: 2.1, 16.5), and ∑AA (%Δ: 12.9; 95%CI: 4.4, 22.1) with progesterone; and MBP (%Δ: 8.5; 95%CI: 1.2, 16.3) and ∑AA (%Δ: 9.0; 95%CI: 1.3, 17.4) with AMH. Associations of phthalate metabolites with hormones differed by menopause status (strongest in premenopausal women for estradiol, progesterone, and FSH), BMI (strongest in obese women for progesterone), and race/ethnicity (strongest in non-Hispanic white women for estradiol and AMH).

CONCLUSIONS

We found that phthalate metabolites were positively associated with several hormones in midlife women, and that some demographic and lifestyle characteristics modified these associations. Future longitudinal studies are needed to corroborate these findings in more diverse midlife populations.

Prenatal exposure to a mixture of phthalates accelerates the age-related decline in reproductive capacity but may not affect direct biomarkers of ovarian aging in the F1 generation of female mice

Phthalates are used in many consumer products, leading to daily human exposure. Although many studies focus on single phthalates, humans are exposed to mixtures of phthalates. Our laboratory created a phthalate mixture consisting of six different phthalates and found that it negatively affected female reproduction and accelerated some biomarkers of reproductive aging. However, it was unknown if prenatal exposure to the mixture accelerates the natural decline in reproductive capacity and ovarian aging in mice. Therefore, we tested the hypothesis that prenatal exposure to a phthalate mixture accelerates the age-related decline in reproductive capacity and biomarkers of ovarian aging in the F1 generation of mice. Pregnant CD-1 dams were orally dosed with control or phthalate mixture (20 µg/kg/day-200 mg/kg/day) daily from gestational day 10-birth. The F1 female pups were aged to 11-13 months, and then estrous cyclicity and breeding trials were conducted at 11 and 13 months. Ovaries were collected from the F1 females at 13 months to examine biomarkers of ovarian aging. Prenatal exposure to the phthalate mixture decreased the time the F1 females spent in proestrus and the ability of the F1 females to give birth at 11 and 13 months of age compared to control. In contrast, prenatal exposure to the mixture did not affect biomarkers of direct aging of the ovary in the F1 generation. Collectively, our data show that prenatal phthalate mixture exposure accelerates the natural age-related decline in reproductive capacity but may not affect some biomarkers of ovarian aging in the F1 generation.

Subacute Exposure to an Environmentally Relevant Dose of Di-(2-ethylhexyl) Phthalate during Gestation Alters the Cecal Microbiome, but Not Pregnancy Outcomes in Mice

Di-2-ethylhexyl phthalate (DEHP) is a plasticizer commonly found in polyvinyl chloride, medical equipment, and food packaging. DEHP has been shown to target the reproductive system and alter the gut microbiome in humans and experimental animals. However, very little is known about the impact of DEHP-induced microbiome changes and its effects during pregnancy. Thus, the objective of this study was to investigate the effects of DEHP exposure during pregnancy on the cecal microbiome and pregnancy outcomes. Specifically, this study tested the hypothesis that subacute exposure to DEHP during pregnancy alters the cecal microbiome in pregnant mice, leading to changes in birth outcomes. To test this hypothesis, pregnant dams were orally exposed to corn oil vehicle or 20 µg/kg/day DEHP for 10 days and euthanized 21 days after their last dose. Cecal contents were collected for 16S Illumina and shotgun metagenomic sequencing. Fertility studies were also conducted to examine whether DEHP exposure impacted birth outcomes. Subacute exposure to environmentally relevant doses of DEHP in pregnant dams significantly increased alpha diversity and significantly altered beta diversity. Furthermore, DEHP exposure during pregnancy significantly increased the relative abundance of Bacteroidetes and decreased the relative abundance of Firmicutes and Deferribacteres compared with controls. The affected taxonomic families included Deferribacteraceae, Lachnospiraceae, and Mucisprillum. In addition to changes in the gut microbiota, DEHP exposure significantly altered 14 functional pathways compared with the control. Finally, DEHP exposure did not significantly impact the fertility and birth outcomes compared with the control. Collectively, these data indicate that DEHP exposure during pregnancy shifts the cecal microbiome, but the shifts do not impact fertility and birth outcomes.

COVID-19 discarded disposable gloves as a source and a vector of pollutants in the environment

The appearance of the virus SARS-CoV-2 at the end of 2019 and its spreading all over the world has caused global panic and increase of personal protection equipment usage to protect people against infection. Increased usage of disposable protective gloves, their discarding to random spots and getting to landfills may result in significant environmental pollution. The knowledge concerning possible influence of gloves and potential of gloves debris on the environment (water, soil, etc.), wildlife and humans is crucial to predict future consequences of disposable gloves usage caused by the pandemic. This review focuses on the possibility of chemical release (heavy metals and organic pollutants) from gloves and gloves materials, their adsorptive properties in terms of contaminants accumulation and effects of gloves degradation under environmental conditions.

Exposure to endocrine-disrupting compounds such as phthalates and bisphenol A is associated with an increased risk for obesity

Increasing evidence from epidemiological, animal and in vitro studies suggests that the increased production of synthetic chemicals that interfere with the proper functioning of the hormonal system, so-called endocrine-disrupting compounds (EDCs), might be involved in the development and rapid spread of obesity, coined the obesity epidemic. Recent findings have demonstrated that EDCs may interfere with hormonal receptors that regulate adipogenesis and metabolic pathways. Furthermore, prenatal exposure to EDCs has been shown to influence the metabolism of the developing embryo through epigenetic mechanisms and to promote obesity in subsequent generations. In this Review, we discuss the potential impact of bisphenol A (BPA) and phthalate-based plasticizers on obesity and obesity-related metabolic disorders. Special emphasis is given to the obesogenic effects of prenatal exposure and strategies for identifying, regulating, and replacing EDCs.

Phthalates, ovarian function and fertility in adulthood

Phthalates are a family of high-production volume industrial chemicals used in the manufacture of plastics. Some phthalates are regulated as endocrine disrupting chemicals (EDCs) and reproductive toxicants based on adverse effects in the male. Potential effects in females are less understood although exposure levels can be higher in women compared to men. Here, we review the literature on the effects of phthalate exposures in adulthood on ovarian function and fertility in women. Experimental studies using cell cultures and rodents combined with human evidence from epidemiological studies suggest that phthalates pose a hazard to ovaries. Phthalates can disrupt follicle growth pattern, increase oxidative stress and cause follicle death. These effects could lead to infertility, faster depletion of ovarian reserve, and earlier reproductive senescence. However, more studies using more realistic exposure levels will be needed to properly assess the risks in women.

The Impact of Environmental Chemicals on the Gut Microbiome

Since the surge of microbiome research in the last decade, many studies have provided insight into the causes and consequences of changes in the gut microbiota. Among the multiple factors involved in regulating the microbiome, exogenous factors such as diet and environmental chemicals have been shown to alter the gut microbiome significantly. Although diet substantially contributes to changes in the gut microbiome, environmental chemicals are major contaminants in our food and are often overlooked. Herein, we summarize the current knowledge on major classes of environmental chemicals (bisphenols, phthalates, persistent organic pollutants, heavy metals, and pesticides) and their impact on the gut microbiome, which includes alterations in microbial composition, gene expression, function, and health effects in the host. We then discuss health-related implications of gut microbial changes, which include changes in metabolism, immunity, and neurological function.

Oncogenic Role of miRNA in Environmental Exposure to Plasticizers: A Systematic Review

The daily environmental exposure of humans to plasticizers may adversely affect human health, representing a global issue. The altered expression of microRNAs (miRNAs) plays an important pathogenic role in exposure to plasticizers. This systematic review summarizes recent findings showing the modified expression of miRNAs in cancer due to exposure to plasticizers. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology, we performed a systematic review of the literature published in the past 10 years, focusing on the relationship between plasticizer exposure and the expression of miRNAs related to cancer. Starting with 535 records, 17 articles were included. The results support the hypothesis that exposure to plasticizers causes changes in or the deregulation of a number of oncogenic miRNAs and show that the interaction of plasticizers with several redundant miRNAs, such as let-7f, let-7g, miR-125b, miR-134, miR-146a, miR-22, miR-192, miR-222, miR-26a, miR-26b, miR-27b, miR-296, miR-324, miR-335, miR-122, miR-23b, miR-200, miR-29a, and miR-21, might induce deep alterations. These genotoxic and oncogenic responses can eventually lead to abnormal cell signaling pathways and metabolic changes that participate in many overlapping cellular processes, and the evaluation of miRNA-level changes can be a useful target for the toxicological assessment of environmental pollutants, including plastic additives and plasticizers.

Biodegradation of diisononyl phthalate by a consortium of saline soil bacteria: optimisation and kinetic characterisation

Diisononyl phthalate (DINP) is one of plasticisers most employed in the production of plastic materials and belongs to the most important environmental contaminants. In this work, a consortium of saline soil bacterial (SSB) capable of degrading DINP is presented. The genera of SSB-consortium were Serratia sp., Methylobacillus sp., Achromobacter sp., Pseudomonas sp., Stenotrophomonas sp., Methyloversatilis sp., Delftia sp. and Brevundimonas sp. Response surface methodology (RSM) study was employed to optimise and evaluate the culture conditions to improve the biodegradation of DINP. The optimal conditions were a pH 7.0, 31 °C and an initial DINP concentration of 500 mg L^-1, resulting in almost complete biodegradation (99%) in 168 h. DINP degradation followed a first-order kinetic model, and the half-life was 12.76 h. During the biodegradation of DINP, 4-derived compounds were identified: monoisononyl phthalate, methyl nonyl phthalate, iso-nonanol and dimethyl phthalate. The metabolite profiling indicated that DINP was degraded through simultaneous pathways of de-esterification and β-oxidation. Results suggest that the SSB-consortium could be useful for efficient biodegradation of the DINP-contaminated environments. KEY POINTS: • DINP degradation is mediated by de-esterification and β-oxidation processes. • Temperature and the concentration of the substrate are key factors for DINP biodegradation • The SSB-consortium has the ability to biodegrade 99% of DINP (500 mg L^-1).

Single-cell transcriptome dissection of the toxic impact of Di (2-ethylhexyl) phthalate on primordial follicle assembly

Rationale: Accumulated evidence indicates that environmental plasticizers are a threat to human and animal fertility. Di (2-ethylhexyl) phthalate (DEHP), a plasticizer to which humans are exposed daily, can trigger reproductive toxicity by acting as an endocrine-disrupting chemical. In mammals, the female primordial follicle pool forms the lifetime available ovarian reserve, which does not undergo regeneration once it is established during the fetal and neonatal period. It is therefore critical to examine the toxicity of DEHP regarding the establishment of the ovarian reserve as it has not been well investigated. Methods: The ovarian cells of postnatal pups, following maternal DEHP exposure, were prepared for single cell-RNA sequencing, and the effects of DEHP on primordial follicle formation were revealed using gene differential expression analysis and single-cell developmental trajectory. In addition, further biochemical experiments, including immunohistochemical staining, apoptosis detection, and Western blotting, were performed to verify the dataset results. Results: Using single-cell RNA sequencing, we revealed the gene expression dynamics of female germ cells and granulosa cells following exposure to DEHP in mice. Regarding germ cells: DEHP impeded the progression of follicle assembly and interfered with their developmental status, while key genes such as Lhx8, Figla, and others, strongly evidenced the reduction. As for granulosa cells: DEHP likely inhibited their proliferative activity, and activated the regulation of cell death. Furthermore, the interaction between ovarian cells mediated by transforming growth factor-beta signaling, was disrupted by DEHP exposure, since the expression of GDF9, BMPR1A, and SMAD3 was affected. In addition, DNA damage and apoptosis were elevated in germ cells and/or somatic cells. Conclusion: These findings offer substantial novel insights into the reproductive toxicity of DEHP exposure during murine germ cell cyst breakdown and primordial follicle formation. These results may enhance the understanding of DEHP exposure on reproductive health.

The effects of plasticizers on the ovary

Endocrine disrupting chemicals pose a threat to health and reproduction. Plasticizers such as phthalates and bisphenols are particularly problematic because they are present in many consumer products and exposure can begin in utero and continue throughout the lifetime of the individual. Evidence suggests that these chemicals can have ancestral and transgenerational effects, making them a huge public health concern for the reproductive health of current and future generations. Studies performed in rodents or using rodent- or human-derived tissues have been critical for understanding the toxic effects of plasticizers on the ovary and their mechanisms of action. This review addresses current in vitro and rodent-based in vivo studies investigating the effects of bisphenols and phthalates on ovarian health, female reproduction, and correlations between human exposure and reproductive pathologies.

Endocrine disrupting chemicals and reproductive disorders in women, men, and animal models

This chapter covers the known effects of endocrine disrupting chemicals (EDCs) on reproductive disorders. The EDCs represented are highly studied, including plasticizers (bisphenols and phthalates), chemicals in personal care products (parabens), persistent environmental contaminants (polychlorinated biphenyls), and chemicals in pesticides or herbicides. Both female and male reproductive disorders are reviewed in the chapter. Female disorders include infertility/subfertility, irregular reproductive cycles, early menopause, premature ovarian insufficiency, polycystic ovarian syndrome, endometriosis, and uterine fibroids. Male disorders include infertility/subfertility, cryptorchidism, and hypospadias. Findings from both human and animal studies are represented.