Di (2-ethylhexyl) phthalate impairs steroidogenesis in ovarian follicular cells of prepuberal mice

Potential Shared Mitochondrial-Related Gene Signatures and Molecular Mechanisms Between Polycystic Ovary Syndrome (PCOS) and Major Depressive Disorder (MDD): Evidence from Transcriptome Data and Machine Learning

Polycystic ovary syndrome (PCOS) is strongly associated with major depressive disorder (MDD), but the shared pathophysiological mechanisms between them are ambiguous, and the aim of this study was to explore the shared genetic features and associated pathways between these two disorders. MDD-related genes and mitochondrial function genes were downloaded from the GeneCards database. Weighted gene co-expression network analysis of Merge Cohort (GSE80432 and GSE34526) was performed to identify PCOS-related genes. Overlaps between PCOS-related genes, MDD-related genes, and mitochondrial function genes were defined as mitochondrial function-related shared genes. Functional enrichment analysis and protein-protein interaction (PPI) network analysis were performed on the shared genes. Functional genes were then identified using Last Absolute Shrinkage and Selection Operator Regression (LASSO), and a support vector machine (SVM-RFE) was constructed to measure the accuracy of the calculations. Finally, the results were tested using the whole blood datasets GSE54250 (for PCOS) and GSE98793 (for MDD) as external validation sets. A total of 498 PCOS-related genes, 5909 MDD-related genes, and 7232 mitochondrial function genes were acquired, and totally, 40 shared genes were obtained from the overlap of the above three. The shared mitochondrial function genes were enriched for biological processes mainly involving cholesterol biosynthetic process, lipid metabolic process, triglyceride biosynthetic process, response to drug phosphatidic acid biosynthetic process, and endoplasmic reticulum membrane. Based on LASSO regression and SVM-RFE model, NPAS2 and NTS were identified as characteristic genes shared by two disorders. According to two external validation sets for PCOS and MDD, NPAS2 was finally identified as a key shared gene. Our analysis identified a mitochondrial functional gene-NPAS2-as the most critical candidate for linking PCOS and MDD. The present findings may provide new insights into the diagnosis and treatment of PCOS and MDD comorbidities.

Recent advances in toxicological research of di-(2-ethylhexyl)-phthalate: Focus on endoplasmic reticulum stress pathway

The plasticizer di-(2-ethylhexyl)-phthalate (DEHP) is the most significant phthalate in production, usage, and environmental occurrence. DEHP is found in products such as personal care products, furniture materials, cosmetics, and medical devices. DEHP is noncovalently bind with plastic therefore, repeated uses lead to leaching out of it. Exposure to DEHP plasticizers leads to toxicity in essential organs of the body through various mechanisms. The main objective of this review article is to focus on the DEHP-induced endoplasmic reticulum (ER) stress pathway implicated in the testis, brain, lungs, kidney, heart, liver, and other organs. Not only ER stress, PPAR-related pathways, oxidative stress and inflammation, Ca2+ homeostasis disturbances in mitochondria are also identified as the relative mechanisms. ER is involved in various critical functions of the cell such as Protein synthesis, protein folding, calcium homeostasis, and lipid peroxidation but, DEHP exposure leads to augmentation of misfolded/unfolded protein. This review complies with various recently reported DEHP-induced toxicity studies and some pharmacological interventions that have been shown to be effective through ER stress pathway. DEHP exposure does assess health risks and vulnerability to populations across the globe. This study offers possible targets and approaches for addressing various DEHP-induced toxicity.

Follicular fluid exosomes inhibit expression of BTG2 and promote glucose uptake in granulosa cells by delivering miR-21-5p

Glucose metabolism in granulosa cells (GCs) is essential for follicle development and oocyte maturation. Porcine follicular fluid exosomes promote the proliferation of porcine GCs and the synthesis of steroid hormones. However, their role in regulating glucose uptake in GCs is unclear. The objective of this study was to elucidate the effects of porcine follicular fluid exosomes on glucose uptake in porcine GCs and the intrinsic mechanisms involved. First, transcriptome sequencing revealed that glucose metabolism-related pathways were altered in GCs treated with follicular fluid exosomes. Next, in vitro culture experiments showed that glucose uptake was increased and the IRS1/AKT signaling pathway was activated in GCs after treatment with follicular fluid exosomes. Finally, miRNA sequencing of follicular fluid exosomes revealed that miR-21-5p was the most abundant miRNA. Subsequent investigations indicated that miR-21-5p promoted glucose uptake in GCs by targeting BTG2, which activated the IRS1/AKT signaling pathway. In conclusion, the findings of this study indicate that porcine follicular fluid exosomes promote glucose uptake in porcine GCs by delivering miR-21-5p, which inhibits the expression of BTG2, activating the IRS1/AKT signaling pathway.

N-Acetylcysteine Alleviates D-Galactose-Induced Injury of Ovarian Granulosa Cells in Female Rabbits by Regulating the PI3K/Akt/mTOR Signaling Pathway

The ovary plays a crucial role in the reproductive system of female animals. Ovarian problems such as ovarian insufficiency, premature aging, polycystic ovary syndrome, and ovarian cysts may lead to ovulation disorders, abnormal hormone secretion, or luteal dysfunction, thereby increasing the risk of infertility and abortion. Only when the ovarian function and other organs in the reproductive system remain healthy and work normally can female animals be ensured to carry out reproductive activities regularly, improve the pregnancy rate and litter size, promote the healthy development of the fetus, and then improve their economic value. The follicle, as the functional unit of the ovary, is composed of theca cells, granulosa cells (GCs), and oocytes. GCs are the largest cell population and main functional unit in follicles and provide the necessary nutrients for the growth and development of follicles. N-acetylcysteine (NAC) is a prevalent and cell-permeable antioxidant molecule that effectively prevents apoptosis and promotes cellular survival. Over the past few years, its function in boosting reproductive performance in animals at the cellular level has been widely acknowledged. However, its specific role and mechanism in influencing GCs is yet to be fully understood. The objective of this study was to examine the effects of NAC on ovarian damage in female rabbits. For this purpose, D-galactose (D-gal) was first used to establish a model of damaged GCs, with exposure to 1.5 mg/mL of D-gal leading to substantial damage. Subsequently, varying concentrations of NAC were introduced to determine the precise mechanism through which it influences cell damage. Based on the results of the Cell Counting Kit-8 assay, flow cytometry, and Western blotting, it was found that 0.5 mg/mL of NAC could significantly suppress cell apoptosis and promote proliferation. In particular, it decreased the expression levels of Bax, p53, and Caspase-9 genes, while concurrently upregulating the expression of the BCL-2 gene. Moreover, NAC was found to alleviate intracellular oxidative stress, suppress the discharge of mitochondrial Cytochrome c, and boost the enzymatic activities of CAT (Catalase), GSH (Glutathione), and SOD (Superoxide dismutase). RNA sequencing analysis subsequently underscored the critical role of the PI3K/Akt/mTOR pathway in governing proliferation and apoptosis within GCs. These findings demonstrated that NAC could significantly influence gene expression within this pathway, thereby clarifying the exact relationship between the PI3K/Akt/mTOR signaling cascade and the underlying cellular processes controlling proliferation and apoptosis. In conclusion, NAC can reduce the expression of Bax, p53, and Caspase-9 genes, inhibit the apoptosis of GCs, improve cell viability, and resist D-gal-induced oxidative stress by increasing the activity of CAT, GSH, and SOD. The molecular mechanism of NAC in alleviating D-gal-induced ovarian GC injury in female rabbits by regulating the PI3K/Akt/mTOR signaling pathway provides experimental evidence for the effect of NAC on animal reproductive function at the cellular level.

Phthalates (PAEs) and reproductive toxicity: Hypothalamic-pituitary-gonadal (HPG) axis aspects

Phthalates (PAEs) are widely used for their excellent ability to improve plastic products. As an essential endocrine axis that regulates the reproductive system, whether dysfunction of the hypothalamic-pituitary-gonadal (HPG) axis is involved in reproductive toxicity mediated by environmental endocrine disruptors PAEs has become a hot topic of widespread concern. This study systematically reviewed the adverse effects of multiple PAEs on the HPG axis in different models and objectively discussed the possible underlying mechanisms. The abnormal release of gonadotropin-releasing hormone and gonadotropin, dysfunction of sex hormone receptors and steroid hormone synthesis, and general damage, including cell proliferation, oxidative stress, apoptosis, and autophagy have been confirmed to be involved in this process. Although it is widely established that PAEs induce HPG axis dysfunction, the specific mechanisms involved remain unclear. From a systematic review of relevant publications, it appears that the abnormal expression of peroxisome proliferator-activated, aryl hydrocarbon, and insulin receptors mediated by PAEs is key upstream event that induces these adverse outcomes; however, this inference needs to be further verified. Overall, this study aimed to provide reliable potential biomarkers for future environmental risk assessment and epidemiological investigation of PAEs.

Toxicity of microplastics and nanoplastics: invisible killers of female fertility and offspring health

Microplastics (MPs) and nanoplastics (NPs) are emergent pollutants, which have sparked widespread concern. They can infiltrate the body via ingestion, inhalation, and cutaneous contact. As such, there is a general worry that MPs/NPs may have an impact on human health in addition to the environmental issues they engender. The threat of MPs/NPs to the liver, gastrointestinal system, and inflammatory levels have been thoroughly documented in the previous research. With the detection of MPs/NPs in fetal compartment and the prevalence of infertility, an increasing number of studies have put an emphasis on their reproductive toxicity in female. Moreover, MPs/NPs have the potential to interact with other contaminants, thus enhancing or diminishing the combined toxicity. This review summarizes the deleterious effects of MPs/NPs and co-exposure with other pollutants on female throughout the reproduction period of various species, spanning from reproductive failure to cross-generational developmental disorders in progenies. Although these impacts may not be directly extrapolated to humans, they do provide a framework for evaluating the potential mechanisms underlying the reproductive toxicity of MPs/NPs.

The role of endocrine disruptors in female infertility

INTRODUCTION

 According to the World Health Organization, infertility is a public health problem that affects around 48 million couples and 186 million individuals worldwide. Endocrine disruptors are one of the causes that raise more concern, given that it is a problem that has evolved with the progress of society. Many chemicals are used by food industry, entering food chain, and directly affecting human health. Endocrine disruptors have the capacity of interfering with the normal hormonal action, metabolism, and biosynthesis, which can lead to a variation of the normal hormonal homeostasis. Some of these endocrine disruptors are highly associated with diseases that are positively correlated with female infertility, such as polycystic ovary syndrome, endometriosis, irregular menstrual cycle and also disturbances on processes as steroidogenesis and development of the ovarian follicles.

RESULTS

The present literature review covers various aspects of the possible relationship between endocrine disruptors and female infertility. Bisphenol A and its metabolites, phthalates, dioxins, organochlorine, and organophosphate compounds are groups of chemicals considered to have the capacity to disrupt endocrine activity and herein addressed. The results reported in in vivo studies and in clinical trials addressing endocrine disruptors and female infertility were discussed as well as their possible mechanism of action.

CONCLUSIONS

Large, double-blind, placebo-controlled randomized clinical trials are needed to better understand the mechanisms of action of endocrine disruptors in female infertility, as well as the doses and frequency of exposure responsible for it.

Paternal genetic effects of cadmium exposure during pregnancy on hormone synthesis disorders in ovarian granulosa cells of offspring

The aim of this study was to investigate the paternal genetic intergenerational and transgenerational genetic effects of cadmium (Cd) exposure during pregnancy on estradiol (E₂) and progesterone (Pg) synthesis in the ovarian granulosa cells (GCs) of offspring. Pregnant SD rats were intragastrically exposed to CdCl₂ (0, 0.5, 2.0, 8.0 mg/kg) from days 1 to 20 to produce the F1 generation, F1 males were mated with newly purchased females to produce the F2 generation, and the F3 generation was obtained in the same way. Using this model, Cd-induced hormone synthesis disorders in GCs of F1 have been observed [8]. In this study, altered serum E₂ and Pg levels in both F2 and F3 generations showed a nonmonotonic dose‒response relationship. In addition, hormone synthesis-related genes (Star, Cyp11a1, Cyp17a1, Cyp19a1, Sf-1) and miRNAs were observed to be altered in both F2 and F3. No differential changes in DNA methylation modifications of hormone synthesis-related genes were observed, and only the Adcy7 was hypomethylated. In summary, paternal genetic intergenerational and transgenerational effects exist in ovarian GCs E₂ and Pg synthesis disorders induced by Cd during pregnancy. In F2, the upregulation of StAR and CYP11A1, and changes in the miR-27a-3p, miR-27b-3p, and miR-146 families may be important, while changes in the miR-10b-5p and miR-146 families in F3 may be important.

Mitocytosis Is Critical for Phthalate-Induced Injury to the Ovarian Granulosa Cell Layer in Quail (Coturnix japonica)

Phthalates are widely used synthetic chemicals that determine endocrine disruption effects on female reproductivity and oviposition. Our study demonstrated that the mitochondrial quality in ovarian granulosa cells (GCs) is associated with a poor prognosis in female reproduction. However, the molecular mechanism of di-(2-ethylhexyl) phthalate (DEHP) exposure on the quail ovarian GC layer is still unknown. To validate the effects of DEHP on the GC layer, 8 days' old 150 female Japanese quail were treated orally with DEHP (250, 500, and 750 mg/kg BW/day) for 45 days to explore the toxic effects of DEHP on the ovarian GC layer. Histopathological assessment and ultrastructure observation found that DEHP decreased the thickness of the GC layer, resulted in mitochondrial damage, and activated mitocytosis. Additionally, the results further suggested that DEHP impacted the secretion of steroid hormones (reduced FSH, E2, and T levels and boosted Prog, PRL, and LH levels) by triggering mitocytosis (enhanced transcription of MYO19 and protein of KIF5B levels), mitochondrial dynamics (increasing mRNA and protein levels of OPA1, DRP1, MFN1, and MFN2), mitophagy (increasing mRNA and protein levels of Parkin, LC3B, and P62), and inducing GC function disorder. In conclusion, our research provided a new idea to explain the mechanism of DEHP toxicity of the ovarian GC layer in quail and presented insights into the role of mitocytosis in DEHP-induced ovarian GC layer injury.

DEHP Decreases Steroidogenesis through the cAMP and ERK1/2 Signaling Pathways in FSH-Stimulated Human Granulosa Cells

DEHP is an endocrine disruptor that interferes with the function of the female reproductive system. Several studies suggested that DEHP affects steroidogenesis in human and rodent granulosa cells (GC). Some studies have shown that DEHP can also affect the FSH-stimulated steroidogenesis in GC; however, the mechanism by which DEHP affects hormone-challenged steroidogenesis in human GC is not understood. Here, we analyzed the mechanism by which DEHP affects steroidogenesis in the primary culture of human cumulus granulosa cells (hCGC) stimulated with FSH. Cells were exposed to DEHP and FSH for 48 h, and steroidogenesis and the activation of cAMP and ERK1/2 were analyzed. The results show that DEHP decreases FSH-stimulated STAR and CYP19A1 expression, which is accompanied by a decrease in progesterone and estradiol production. DEHP lowers cAMP production and CREB phosphorylation in FSH but not cholera toxin- and forskolin-challenged hCGC. DEHP was not able to decrease steroidogenesis in cholera toxin- and forskolin-stimulated hCGC. Furthermore, DEHP decreases FSH-induced ERK1/2 phosphorylation. The addition of EGF rescued ERK1/2 phosphorylation in FSH- and DEHP-treated hCGC and prevented a decrease in steroidogenesis in the FSH- and DEHP-treated hCGC. These results suggest that DEHP inhibits the cAMP and ERK1/2 signaling pathways, leading to the inhibition of steroidogenesis in the FSH-stimulated hCGC.

Kisspeptin regulates the proliferation and apoptosis of ovary granulosa cells in polycystic ovary syndrome by modulating the PI3K/AKT/ERK signalling pathway

BACKGROUND

The development of polycystic ovary syndrome (PCOS) is closely correlated with apoptosis and oxidative stress in ovarian granulosa cells. Kisspeptin plays an important role in reproductive organ function. This study aimed to explore the role of kisspeptin in PCOS and oxidative stress-triggered apoptosis of ovarian granular cells.

METHODS

A PCOS rat model was established by injecting dehydroepiandrosterone (DHEA) and feeding the rats a high-fat diet. The RNA and protein levels of kisspeptin were analysed by quantitative PCR, western blotting, and histological staining. Tissue damage was evaluated using haematoxylin and eosin (H&E) staining. The viability and proliferation of human granulosa cell KGN were measured using the cell counting kit-8 (CCK-8) and 5-ethynyl-2'-deoxyuridine (EdU) assays. Cell cycle and apoptosis were analysed by flow cytometry. Oxidative stress was analysed by measuring reactive oxygen species (ROS), malondialdehyde (MDA), glutathione (GSH), superoxide dismutase (SOD), and catalase (CAT) levels.

RESULTS

Kisspeptin was downregulated in the ovarian granulosa cells of PCOS rats compared to those of control rats. Kisspeptin overexpression enhanced KGN cell proliferation and inhibited apoptosis. ROS generation was suppressed by kisspeptin, along with decreased levels of MDA and increased levels of the antioxidants GSH, SOD, and CAT. Kisspeptin activates PI3K/AKT and ERK signalling, and inactivation of ERK1/2 suppresses the protective role of kisspeptin in ovarian granulosa cells.

CONCLUSION

Kisspeptin improves proliferation and alleviates apoptosis and oxidative stress in ovarian granulosa cells by activating PI3K/AKT and ERK signalling.

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.

Multi-omics profiling and biochemical assays reveal the acute toxicity of environmental related concentrations of Di-(2-ethylhexyl) phthalate (DEHP) on the gill of crucian carp (Carassius auratus)

Di-(2-ethylhexyl) phthalate (DEHP) is one of the most extensively utilized plasticizers in the plastic manufacturing process. It is widely used in various fields due to its low cost and excellent effect. Although there is evidence that DEHP is harmful to animal and human health, DEHP-induced gill toxicity in aquatic organisms is inconclusive, and its mechanism has not been fully elucidated. Here, we investigated the effects of DEHP acute exposure on crucian carp gills at environmentally relevant concentrations of 20, 100, and 500 μg/L. Multi-omics profiling and biochemical assays were employed to characterize the potential toxicological mechanisms. The results showed that acute exposure to 100 and 500 μg/L of DEHP leads to oxidative stress in gills, as evidenced by overproduction of reactive oxygen species (ROS), increased antioxidant enzyme activity, and the transformation of glutathione from reduced to oxidized form, resulting in lipid peroxidation. Integrative analysis of transcriptomics and metabolomics indicated that increased purine metabolism was the potential source of increased ROS. Moreover, lipid metabolism disorder, including arachidonic acid metabolism, induces inflammation. Further, DEHP causes the imbalance of the CYP enzyme system in the gill, and DEHP-induced gill toxicity in crucian carp was associated with interference with CYP450 homeostasis. Taken together, this study broadens the molecular understanding of the DEHP-induced gill toxicity in aquatic organisms and provides novel perspectives for assessing the effects of DEHP on target and non-target aquatic organisms in the environment.

Impact of In Vitro Long-Term Low-Level DEHP Exposure on Gene Expression Profile in Human Granulosa Cells

Here, we applied a model of long-term exposure of human granulosa cells to low environmentally relevant levels of di(2-ethylhexyl) phthalate (DEHP). This approach provides more relevant data regarding the impact of DEHP on the function of human granulosa cells. The immortalized human granulosa cells HGrC1 were exposed to 50 nM and 250 nM DEHP for four weeks. The cells were collected every week to analyze the basal granulosa cells’ functions. A portion of the DEHP-exposed cells was stimulated with forskolin (FOR) for 48 h. Steroidogenesis was investigated using ELISA, whereas DNBQ sequencing and RT-qPCR were used to analyze gene expression. The results show that steroidogenesis was not affected by DEHP exposure. RNAsequencing shows that DEHP caused week- and concentration-specific changes in various genes and functions in HGrC1. Sulfotransferase family 1A member 3 (SULT1A3) and 4 (SULT1A4), which are involved in catecholamine metabolism, were the most prominent genes affected by DEHP under both the basal and FOR-stimulated conditions in all four weeks of exposure. This study showed, for the first time, that SULT1A3 and SULT1A4 are expressed in human granulosa cells, are regulated by FOR, and are affected by low-level DEHP exposure. These data provide new insight into the relationship between DEHP, SULT1A3, and SULT1A4 in human granulosa cells.

Mapping DEHP to the adverse outcome pathway network for human female reproductive toxicity

Adverse outcome pathways (AOPs) and AOP networks are tools for mechanistic presentation of toxicological effects across different levels of biological organization. These tools are used to better understand how chemicals impact human health. In this study, a four-step workflow was used to derive the AOP network of human female reproductive toxicity (HFRT-AOP) from five AOPs available in the AOP-Wiki and ten AOPs obtained from the literature. Standard network analysis identified key events (KEs) that are point of convergence and divergence, upstream and downstream KEs, and bottlenecks across the network. To map di-(2-ethylhexyl) phthalate (DEHP) to the HFRT-AOP network, we extracted DEHP target genes and proteins from the Comparative Toxicogenomic and the CompTox Chemicals Dashboard databases. Enriched GO terms analysis was used to identify relevant biological processes in the ovary that are DEHP targets, whereas screening of scientific literature was performed manually and automatically using AOP-helpFinder. We combined this information to map DEHP to HFRT-AOP network to provide insight on the KEs and system-level perturbations caused by this endocrine disruptor and the emergent paths. This approach can enable better understanding of the toxic mechanism of DEHP-induced human female reproductive toxicity and reveal potential novel DEHP female reproductive targets for experimental studies.

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

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

Maternal Zearalenone exposure impacted ovarian follicle formation and development of suckled offspring

Zearalenone (ZEN) is a secondary metabolite, which is mainly produced by Fusarium fungi and exists in various feeds and agricultural products. Recently, an increasing amount of data has shown that ZEN, as an estrogen-like hormone, can have harmful effects on the female reproductive system, especially on oogenesis and folliculogenesis. Breast milk is considered to be the ideal form of nutrition for infants; however, there are some records of contaminants in food, such as mycotoxins, which may be transferred from maternal blood to milk. In this study, we investigated the toxic effects of breast milk on folliculogenesis in offspring following maternal ZEN exposure. Our results showed that maternal ZEN exposure significantly inhibited the process of primordial follicle (PF) assembly and reduced the number of PFs in suckled offspring's ovaries. In addition, RNA-seq analysis showed that RIG-I-like receptor (RLRs) signaling pathways were activated after exposed to ZEN, which increased the expression levels of DNA damage (γ-H2AX, RAD51, and PARP1) and apoptosis related protein (BAX/BCL2 and Caspase-3). Finally, ZEN exposure interfered with follicular development, as evidenced by the reduced percentages of oocyte maturation and embryonic development when the offspring grew to adolescence. It is worth noting that maternal ZEN exposure disrupted the tri-methylation levels of H3K4, H3K9, and H3K27 in the offspring's oocytes. Our results indicated that maternal ZEN exposure affected ovarian development in offspring through the breast milk, which may be detrimental to their reproductive capability in adult life.

Nanoplastics impair in vitro swine granulosa cell functions

Soil, water, and air pollution by plastic represents an issue of great concern since the particles produced by degradation of plastic materials can be ingested by animals and humans, with still uncertain health consequences. As a contribution on this crucial subject, the present work reports an investigation on the in vitro effects of different concentrations of polystyrene nanoplastics (5, 25, and 75 µg/mL) on swine granulosa cells, a model of endocrine reproductive cells. In particular, cell growth (BrDU incorporation and ATP production), steroidogenesis (17-β estradiol and progesterone secretion) and redox status (superoxide and nitric oxide production, enzymatic and non-enzymatic scavenging activity) were studied. Nanoplastics, at the highest concentration, stimulated cell proliferation (P < 0.05), while cell viability resulted unaffected. Steroidogenesis was disrupted (P < 0.05). Both enzymatic and non-enzymatic scavenging activity were increased after exposure at the highest nanoplastic dose (P < 0.05, P < 0.001). Nitric oxide secretion was increased by 25 and 75 µg/mL (P < 0.05) while superoxide generation was stimulated (P < 0.001) only by the highest concentration tested. Taken together, main features of cultured swine granulosa cells resulted affected by exposure to nanoplastics. These results raise concerns since environment nanoplastic contamination can represents a serious threat to animal and human health.

Inflammatory cytokines as key players of apoptosis induced by environmental estrogens in the ovary

Natural and synthetic environmental estrogens (EEs), interfering with the physiological functions of the body's estrogens, are widespread and are rising much concern for their possible deleterious effects on human and animal health, in particular on reproduction. In fact, increasing evidence indicate that EEs can be responsible for a variety of disfunctions of the reproductive system especially in females such as premature ovarian insufficiency (POI). Because of their great structural diversity, the modes of action of EEs are controversial. One important way through which EEs exert their effects on reproduction is the induction of apoptosis in the ovary. In general, EEs can exert pro-and anti-apoptotic effects by agonizing or antagonizing numerous estrogen-dependent signaling pathways. In the present work, results concerning apoptotic pathways and diseases induced by representative EEs (such as zearalenone, bisphenol A and di-2-ethylhexyl phthalate), in ovaries throughout development are presented into an integrated network. By reviewing and elaborating these studies, we propose inflammatory factors, centered on the production of tumor necrosis factor (TNF), as a major cause of the induction of apoptosis by EEs in the mammalian ovary. As a consequence, potential strategies to prevent such EE effect are suggested.

Di-(2-ethylhexyl) phthalate exposure induces female reproductive toxicity and alters the intestinal microbiota community structure and fecal metabolite profile in mice

Di-(2-ethylhexyl) phthalate (DEHP) is one of the most commonly used plasticizers, and it is widely applied in various plastic products. DEHP is an endocrine-disrupting chemical (EDC) that has been shown to disrupt the function of reproductive system in females. Although many studies have shown that DEHP potentially causes female reproductive toxicity, including depletion of the primordial follicle and decreased sex hormone production, the specific mechanisms by which DEHP affects female reproduction remain unknown. In recent years, research focused on the intestinal flora has provided an idea to eliminate our confusion, and gut bacterial dysbiosis may contribute to female reproductive toxicity. In the present study, the feces of DEHP-exposed mice were collected and analyzed using 16S rRNA amplicon sequencing and untargeted global metabolite profiling of metabolomics. DEHP obviously causes reproductive toxicity, including the ovarian organ coefficient, estradiol level, histological features of the ovary and estrus. Furthermore, DEHP exposure alters the structure of the intestinal microbiota community and fecal metabolite profile in mice, suggesting that the reproductive toxicity may be caused by gut bacterial dysbiosis and altered metabolites, such as changes in the levels of short-chain fatty acid (SCFA). Additionally, it is well known that changes in gut microbiota and fecal metabolites cause inflammation and tissue oxidative stress, expectedly, we found oxidative stress in the ovary and systemic inflammation in DEHP exposed mice. Thus, based on our findings, DEHP exposure may cause gut bacterial dysbiosis and altered metabolite profiles, particularly SCFA profiles, leading to oxidative stress in the ovary and systemic inflammation to ultimately induce female reproductive toxicity.

Intermittent fasting ameliorates di-(2-ethylhexyl) phthalate-induced precocious puberty in female rats: A study of the hypothalamic-pituitary-gonadal axis

Di-(2-ethylhexyl) phthalate has been reported to interfere with the development and function of animal reproductive systems. However, hardly any studies provide methods to minimize or prevent the adverse effects of DEHP on reproduction. The energy balance state of mammals is closely related to reproductive activities, and the reproductive axis can regulate reproductive activities according to changes in the body's energy balance state. In this study, the effects of every other day fasting (EODF), as a way of intermittent fasting, on preventing the precocious puberty induced by DEHP in female rats was studied. EODF significantly improved the advancement of vaginal opening age (as the markers of puberty onset) and elevated serum levels of luteinizing hormone and estradiol (detected by ELISA) induced by 5 mg kg^-1 DEHP exposure (D5). The mRNA and western blot results showed that the EODF could minimized the increase of gonadotropin-releasing hormone expression induced by DEHP exposure. The administration of DEHP could elevate the levels of kisspeptin protein and the number of kisspeptin-immunoreactive neurons in anteroventral periventricular nucleu, and this increase was diminished considerably by EODF treatment. In contrast, the D5 and D0 groups showed no remarkable difference in the level of Kiss1 expression in arcuate nucleus, whereas the D5 + EODF group had a remarkable decrease in kisspeptin expression as compared with the other two groups. Our results indicated that EODF might inhibit the acceleration of puberty onset induced by DEHP exposure via HPG axis.

Ovarian Toxicity and Epigenetic Mechanisms of Phthalates and Their Metabolites

Ovary plays an important role in the female reproductive system. The maintenance and regulation of ovarian function are affected by various physical and chemical factors. With the development of industrialization, environmental pollutants have caused great harm to public health. Phthalates, as a class of endocrine-disrupting chemicals (EDCs), are synthesized and used in large quantities as plasticizers due to their chemical properties. They are easily released into environment because of their noncovalent interactions with substances, causing human exposure and possibly impairing ovary. In recent years, more and more attention has been paid to the role of epigenetics in the occurrence and development of diseases. And it is urgent to study the role of methylation, gene imprinting, miRNA, and other epigenetic mechanisms in reproductive toxicology.

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.

Di (2-ethylhexyl) phthalate impairs primordial follicle assembly by increasing PDE3A expression in oocytes

It is known that Di (2-ethylhexyl) phthalate (DEHP) may impact mammalian reproduction and that in females one target of the drug's action is follicle assembly. Here we revisited the phthalate's action on the ovary and from bioinformatics analyses of the transcriptome performed on newborn mouse ovaries exposed in vitro to DEHP, up-regulation of PDE3A, as one of the most important alterations caused by DEHP on early folliculogenesis, was identified. We obtained some evidence suggesting that the decrease of cAMP level in oocytes and the parallel decrease of PKA expression, consequent on the PDE3A increase, were a major cause of the reduction of follicle assembly in the DEHP-exposed ovaries. In fact, Pde3a RNAi on cultured ovaries reducing cAMP and PKA decrease counteracted the primordial follicle assembly impairment caused by the compound. Moreover, RNAi normalized the level of Kit, Nobox, Figla mRNA and GDF9, BMP15, CX37, γH2AX proteins in oocytes, and KitL transcripts in granulosa cells as well as their proliferation rate altered by DEHP exposure. Taken together, these results identify PDE3A as a new critical target of the deleterious effects of DEHP on early oogenesis in mammals and highlight cAMP-dependent pathways as major regulators of oocyte and granulosa cell activities crucial for follicle assembly. Moreover, we suggest that the level of intracellular cAMP in the oocytes may be an important determinant for their capability to repair DNA lesions caused by DNA damaging compounds including DEHP.

Di-(2-ethylhexyl) phthalate-induced hepatotoxicity exacerbated type 2 diabetes mellitus (T2DM) in female pubertal T2DM mice

Di-(2-ethylhexyl) phthalate (DEHP), one of the most common plasticizers, is closely associated with a high prevalence of pubertal type 2 diabetes mellitus (T2DM). Numerous studies have indicated that DEHP-induced metabolic toxicity exhibits sex differences. In this study, the sex differences in the effect of DEHP on pubertal T2DM (P-T2DM) mice, the susceptibility of female P-T2DM mice to DEHP-induced metabolic toxicity, and the underlying mechanisms were investigated. DEHP exposure exacerbated metabolic disorders in female P-T2DM mice. Factorial analysis showed that female P-T2DM mice were more sensitive to DEHP exposure than female normal mice and male P-T2DM mice. It was determined by integrated biomarker response results that female P-T2DM mice had higher risks of developing T2DM, metabolic disorders, cardiovascular events and hepatotoxicity than male P-T2DM mice. Moreover, hepatic transcriptome analysis emphasized the effects of DEHP on the expression of oxidative injury- and metabolic function-related genes. Western blotting indicated that DEHP activated Jun-N-terminal kinase (JNK) and impaired insulin sensitivity in the liver, which were the main causes of DEHP-exacerbated metabolic abnormalities in P-T2DM mice. Our study revealed that compared with normal mice and male P-T2DM mice, female P-T2DM mice tend to suffer from increased DEHP-induced metabolic toxicity, which was primarily attributed to hepatotoxicity.

Opposite effects of high- and low-dose di-(2-ethylhexyl) phthalate (DEHP) exposure on puberty onset, oestrous cycle regularity and hypothalamic kisspeptin expression in female rats

Di-(2-ethylhexyl) phthalate (DEHP) is ubiquitous in the environment and has been proposed to lead to reproductive disruption. In this study, we systematically investigated the effects of different doses of DEHP exposure on female hypothalamic-pituitary-gonadal axis development. Female Sprague-Dawley rats were gavaged with vehicle (corn oil) or DEHP (5 or 500mgkg-1 day-1) during postnatal Days (PNDs) 22-28 or PNDs 22-70. Results demonstrated that the low and high doses of DEHP exerted opposite effects on puberty onset, circulating luteinising hormone, serum oestradiol and progesterone levels, with the low dose (5mgkg-1) promoting and the high dose (500mgkg-1) inhibiting these parameters. Significant dose-related differences were also found in the D500 group with longer oestrous cycle duration, lower ovarian/bodyweight ratio, fewer corpus lutea and more abnormal ovarian stromal tissue in comparison with the oil or D5 groups. Molecular data showed that the hypothalamic Kiss1 mRNA expression in the anteroventral periventricular but not in the arcuate nucleus significantly decreased in the D500 rats and increased in the D5 rats relative to the rats in the oil group. These findings suggested that the kisspeptin system is a potential target for DEHP to disrupt reproductive development and function.

Growth hormone activates PI3K/Akt signaling and inhibits ROS accumulation and apoptosis in granulosa cells of patients with polycystic ovary syndrome

BACKGROUND

It is reported that growth hormone (GH) can alleviate oxidative stress (OS) induced apoptosis in some types of cells by activating the PI3K/Akt signaling pathway. This study investigated the role and underlying mechanism of GH in OS and apoptosis in granulosa cells (GCs) of patients with polycystic ovary syndrome (PCOS).

METHODS

Primary GCs were collected from patients with and without PCOS (controls, n = 32) during oocyte retrieval. The patients with PCOS were randomly assigned to take GH treatment (PCOS-GH, n = 30) or without GH treatment (PCOS-C, n = 31). Reactive oxygen species (ROS) level was determined by spectrophotometry and fluorescence microscopy. GC apoptosis and mitochondrial membrane potential (MMP) were detected by Annexin V-FITC/PI double-staining and JC-1 staining, respectively (flow cytometry). The expression of apoptosis-related genes and proteins involved in PI3K/Akt signaling was determined by quantitative reverse-transcription polymerase chain reaction and western blotting, while active caspase-9 and caspase-3 levels of GCs were determined by enzyme-linked immunosorbent assay.

RESULTS

Our study found that in GCs of the PCOS-GH group, the ROS levels and apoptotic rates were significantly decreased, whereas MMP was significantly increased when compared to those in the PCOS-C group (P < 0.05). The mRNA levels of FOXO1, Bax, caspase-9, and caspase-3 were significantly decreased, whereas Bcl-2 was increased in GCs of the PCOS-GH group than those in the PCOS-C group (P < 0.05). The protein levels of FOXO1, Bax, cleaved caspase-9/caspase-9 and cleaved caspase-3/caspase-3 were decreased, whereas p-PI3K/PI3K, p-Akt/Akt, p-FOXO1 and Bcl-2 were increased in GCs of the PCOS-GH group, compared with those in the PCOS-C group (P < 0.05).

CONCLUSION

OS induced apoptosis and downregulated the PI3K/Akt signaling pathway in patients with PCOS. GH could alleviate apoptosis and activate the PI3K/Akt signaling pathway.

CLINICAL TRIAL REGISTRATION NUMBER

Chinese Clinical Trial Registry. ChiCTR1800019437 . Prospectively registered on October 20, 2018.

Effects of nonylphenol induced oxidative stress on apoptosis and autophagy in rat ovarian granulosa cells

Nonylphenol (NP) is a kind of environmental endocrine disruptors which is generally recognized to cause female reproductive toxicity, but its basic mechanism has not been fully elucidated. In this study, granulosa cells (GCs) were treated with 0-70 μM NP for 24 h, the cell viability of GCs was reduced significantly, as well as increased cell apoptosis with G2/M arrest. Furthermore, NP significantly induced autophagy and the production of reactive oxygen species (ROS). However, these phenomenons were inhibited by blocking the production of ROS with N-Acetyl-l-cysteine (NAC) administration. Intriguingly, the inhibition of autophagy with 3-Methyladenine (3-MA) could enhance the apoptosis induced by NP. Moreover, the down regulating of p-Akt/Akt, p-mTOR/mTOR and subsequent up-regulation of p-AMPK/AMPK induced by NP can be rescued by pretreatment of NAC. Our findings suggested that NP promotes rat ovarian GCs apoptosis and autophagy simultaneously, which may involve the activation of ROS-dependent Akt/AMPK/mTOR pathway. Whatever, the activation of autophagy is likely to develop a protective mechanism to improve the apoptosis of rat ovarian GCs induced by NP.

Di-(2-ethylhexyl) phthalate induced developmental abnormalities of the ovary in quail (Coturnix japonica) via disruption of the hypothalamic-pituitary-ovarian axis

An increasing number of epidemiologic studies show that women have a special exposure profile to phthalates, and the exposures have attracted attention regarding their potential health hazards. Here, we developed a model for studying the ovarian action of di-(2-ethylhexyl) phthalate (DEHP) and its major metabolite monoethylhexyl phthalate (MEHP). In vivo, treatment with DEHP (250, 500, and 1000 mg kg^-1) induced decreased thickness of ovarian granulosa cell layer and mitochondrial damage in quail, caused oxidative stress, interfered with the transcription of hypothalamic-pituitary-ovarian axis (HPOA) steroid hormone-related factors (increased transcription of StAR, 3β-HSD, P450scc, and LH and decreased transcription of 17β-HSD, P450arom, FSH, and ERβ), and blocked the secretion of steroid hormones (decreased FSH, E₂, and T levels and increased LH, P, and PRL levels). In vitro, granulosa cells were cultured with MEHP (50, 100, and 200 μM), activator of PPARγ (rosiglitazone, 50 μM), or antagonist of PPARγ (GW9662, 10 μM) for 24 h and gene and protein expression were analyzed by real time RT-PCR and western blot. Rosiglitazone, like MEHP, significantly decreased mRNA and protein levels of P450arom. Antagonist GW9662 partially blocked the suppression of P450arom by MEHP, suggesting that MEHP acts through PPARγ, but not exclusively. Our model shows that MEHP acts on granulosa cells in quail by stimulating PPARs, which leads to decreased gene and protein expression of P450arom. Therefore, the environmental endocrine disruptor DEHP and its major metabolite MEHP act through a receptor-mediated signaling pathway to inhibit the production of estradiol, interfere with the modulation of HPOA, suppress the synthesis of sex hormones, and cause sex hormone secretion disorders, resulting in severe toxicity in the female reproductive system. A framework for an adverse outcome pathway of DEHP/MEHP-induced ovarian toxicity was constructed, which can facilitate an improved understanding of the mechanism of female reproductive toxicity.

Role of the 17β-hydroxysteroid dehydrogenase signalling pathway in di-(2-ethylhexyl) phthalate-induced ovarian dysfunction: An in vivo study

Plasticiser di-(2-ethylhexyl) phthalate (DEHP) is associated with female reproductive endocrine toxicity. Our previous study found that mono-(2-ethylhexyl) phthalate (MEHP), the metabolite of DEHP, can interfere with ovarian function via dysregulation of 17β-hydroxysteroid dehydrogenase (17β-HSD) in vitro. The aim of this study was to verify this hypothesis in vivo. The present study tested the hypothesis that subacute exposure to DEHP induced ovarian dysfunction by dysregulating 17β-HSD signalling. 48 adult female Wistar rats were divided into 4 groups randomly: control group, low-dose group, medium-dose group, and high-dose group. DEHP was intragastrically administrated at the dosage of 0, 300, 1000 and 3000 mg/kg/d (body weight) for 4 weeks. Rats were executed, and the detection of the pathological changes of ovaries, steroid hormone levels, steroid receptor expression, and steroidogenic enzyme expression in sex hormone synthesis pathway and the apoptosis of GCs were performed. This study showed that DEHP could prolong the estrous cycle, increase follicular atresia, inhibit sex hormone secretion, reduce the expression of steroidogenic enzymes, and promote GCs apoptosis associating with ovarian dysfunction. In conclusion, these results indicate that DEHP can disturb ovarian function through the 17β-HSD signalling pathway.

Endocrine Disruptors in Water and Their Effects on the Reproductive System

Anthropogenic contaminants in water can impose risks to reproductive health. Most of these compounds are known to be endocrine disrupting chemicals (EDCs). EDCs can impact the endocrine system and subsequently impair the development and fertility of non-human animals and humans. The source of chemical contamination in water is diverse, originating from byproducts formed during water disinfection processes, release from industry and livestock activity, or therapeutic drugs released into sewage. This review discusses the occurrence of EDCs in water such as disinfection byproducts, fluorinated compounds, bisphenol A, phthalates, pesticides, and estrogens, and it outlines their adverse reproductive effects in non-human animals and humans.

Exposure to di(2-ethylhexyl) phthalate and diisononyl phthalate during adulthood disrupts hormones and ovarian folliculogenesis throughout the prime reproductive life of the mouse

Di(2-ethylhexyl) phthalate (DEHP) is a phthalate commonly used for its plasticizing capabilities. Because of the wide production and use of DEHP, humans are exposed to DEHP on a daily basis. Diisononyl phthalate (DiNP) is often used as a DEHP replacement chemical, and because of the increased use of DiNP, humans are increasingly exposed to DiNP over time. Of concern is that DEHP and DiNP both exhibit endocrine disrupting capabilities, and little is known about how short-term exposure to either of these phthalates affects aspects of female reproduction. Thus, this study tested the hypothesis that short-term exposure to DEHP or DiNP during adulthood has long-lasting consequences on ovarian follicles and hormones in female mice. Female CD-1 mice aged 39-40 days were orally dosed with either vehicle control (corn oil), DEHP (20 μg/kg/day-200 mg/kg/day), or DiNP (20 μg/kg/day-200 mg/kg/day) for 10 days. Ovarian follicle populations, estradiol, testosterone, progesterone, follicle stimulating hormone (FSH), and inhibin B were analyzed at time points immediately post-dosing and 3, 6, and 9 months post-dosing. The results indicate that 10 days of exposure to DEHP and DiNP changed the distribution of ovarian follicle populations and sex steroid hormones at multiple time points, including the last time point, 9 months post-dosing. Further, FSH was increased at multiple doses up to 6 months post-dosing. Inhibin B was not affected by treatment. These data show that short-term exposure to either DEHP or DiNP has long-term consequences that persist long after cessation of exposure.

The effects of a phthalate metabolite mixture on antral follicle growth and sex steroid synthesis in mice

Phthalates are used as solvents and plasticizers in a wide variety of consumer products. Most people are exposed to phthalates as parent compounds through ingestion, inhalation, and dermal contact. However, these parent compounds are quickly metabolized to more active compounds in several tissues. Although studies indicate that phthalate metabolites reach the ovary, little is known about whether they are ovarian toxicants. Thus, this study tested the hypothesis that phthalate metabolites influence the expression of genes involved in sex steroid synthesis, cell cycle regulation, cell death, oxidative stress, and key receptors, as well as production of sex steroid hormones by mouse antral follicles. The selected metabolite mixture consisted of 36.7% monoethyl phthalate (MEP), 19.4% mono(2-ethylhexyl) phthalate (MEHP), 15.3% monobutyl phthalate (MBP), 10.2% monoisobutyl phthalate (MiBP), 10.2% monoisononyl phthalate (MiNP), and 8.2% monobenzyl phthalate (MBzP). Antral follicles from adult CD-1 mice were cultured for 96 h with vehicle control (DMSO) or metabolite mixture (0.065-325 μg/mL). Growth of follicles in culture was monitored every 24 h. Total RNA was isolated after 24 and 96 h and used for gene expression analysis. Media were collected and subjected to hormone analysis. Exposure to the phthalate mixture inhibited follicle growth, decreased expression of steroidogenic enzymes, and altered the levels of sex steroids relative to control. The mixture, primarily at the two highest doses, also altered expression of cell cycle regulators, apoptotic factors, oxidative stress genes, and some receptors. Collectively, these data suggest that mixtures of phthalate metabolites can directly impact follicle health.

Melatonin alleviates meiotic defects in fetal mouse oocytes induced by Di (2-ethylhexyl) phthalate in vitro

Di (2-ethylhexyl) phthalate (DEHP), an estrogen-like compound that is a ubiquitous environmental contaminant, has been reported to adversely affect human and mammalian reproduction. Many studies have found that exposure to DEHP during pregnancy perturbs female germ cell meiosis and is detrimental to oogenesis. Previous studies have demonstrated that melatonin (MLT) is beneficial to reproductive endocrinology, oogenesis, and embryonic development as the ability to antioxidative and antiapoptotic. However, whether the meiotic defect of germ cells exposed to DEHP could be rescued by MLT is not clear. Here, we cultured 12.5 days post coitum (dpc) fetal mouse ovaries for 6 days, exposed them to 100 μM DEHP with or without 1 μM MLT in vitro.. The results showed that DEHP exposure induced the abnormal formation of DNA double-strand breaks (DSBs), and inhibited the repair of DSBs during meiotic recombination. In addition, we found defective oocytes were prone to undergo apoptosis. Notably, this defect could be remarkably ameliorated by the addition of MLT via a reduction of the levels of reactive oxygen species and an inhibition of apoptosis. In conclusion, our data revealed that MLT had a protective action against the meiotic deterioration of fetal oocytes induced by DEHP in the mouse in vitro.

Zearalenone Exposure Induces the Apoptosis of Porcine Granulosa Cells and Changes Long Noncoding RNA Expression To Promote Antiapoptosis by Activating the JAK2-STAT3 Pathway

Zearalenone (ZEA), a pathogenic toxin produced by Fusarium, is widely detected in moldy feed materials. Previous studies have reported that ZEA exerts a harmful influence on animal reproductive systems; however, its effects on the changes of long noncoding RNAs (lncRNAs) remain unclear. Here, tackling this question, we performed RNA sequencing on porcine granulosa cells (GCs) after being exposed to 10 and 30 μM ZEA in vitro. The results showed that ZEA exposure observably changed the expression of lncRNAs in porcine GCs and increased the rate of apoptosis. Furthermore, Gene Ontology analysis showed that ZEA exposure induced variation of the Janus kinase 2 (JAK2)-signal transducer and activator of transcription 3 (STAT3) signaling pathway in porcine GCs. To verify our bioinformatics analysis, western blotting and immunofluorescence analysis were performed and the results demonstrated that porcine GCs after ZEA exposure increased the expression of key proteins in the JAK2-STAT3 signaling pathway. Further bioinformatics analysis found that MSTRG.22680 and MSTRG.23882 played a pivotal role in activating the JAK2-STAT3 signaling pathway. To summarize, our results throw light on the fact that ZEA exposure dramatically increases the apoptosis of porcine GCs and alters the expression of lncRNAs that play an antiapoptotic role in porcine GCs via activating the JAK2-STAT3 signaling pathway.

In Situ Fluorescence Tracking Toxic Metabolite Mono-2-ethylhexyl phthalate (MEHP) of Di-(2-ethylhexyl) phthalate (DEHP) in HeLa Cells

In this study, we synthesized a small molecule fluorescent probe for detecting mono-2-ethylhexyl phthalate (MEHP) named MEHP-AF, which formed by MEHP cross-linked with 5-aminofluorescein (5-AF) through amide bond. MEHP-AF had been purified based on the different physicochemical properties of 5-AF with MEHP. MEHP-AF showed fluorescence characteristics coming from 5-AF and liposoluble property coming from MEHP. After physicochemical characterization, a series of biological studies of its action in cells were carried out. The results indicated that MEHP-AF was a fluorescent probe with strong specificity and high sensitivity. It can visibly track the location of MEHP in HeLa cell or subcellular levels under confocal laser scanning microscopy in situ. This novel fluorescent probe is expected to use for studying its intracellular behavior at the cell level, especially for investigating the interaction between MEHP and cellular molecules.

Identification of oxidative stress-related Xdh gene as a di(2-ethylhexyl)phthalate (DEHP) target and the use of melatonin to alleviate the DEHP-induced impairments in newborn mouse ovaries

This study, using an in vitro ovary culture model, investigates the mechanisms through which di(2-ethylhexyl)phthalate (DEHP) impairs germ cell cyst breakdown and primordial follicle assembly. The results indicate the latter effects exerted by 10 or 100 µmol/L DEHP in cultured newborn ovaries were associated with increased levels of reactive oxygen species (ROS) and apoptosis. Based on a transcriptome analysis, we found the expression of the oxidative stress-related gene Xdh (xanthine dehydrogenase) was significantly upregulated in DEHP-cultured ovaries. Two treatments, namely Xdh RNAi or the addition of melatonin to the ovary culture, inhibited the increase in Xdh expression and ROS levels caused by DEHP and, at the same time, reduced apoptosis and the impairment of primordial follicle assembly in the treated ovaries. Together, the results identify Xdh gene as one of the major targets of DEHP in newborn ovaries and that the consequent increased level of ROS is possibly responsible for the increment of apoptosis and primordial follicle assembly impairment. At the same time, they highlight that melatonin alleviates the effects of DEHP as with other endocrine-disrupting compounds on the ovary.

Di-(2-ethylhexyl) phthalate (DEHP)-induced hepatotoxicity in quail (Coturnix japonica) via suppression of the heat shock response

Di-(2-ethylhexyl) phthalate (DEHP) is a widespread environmental toxicant that severely impacts agricultural production and animal and human health. Nevertheless, DEHP-induced hepatotoxicity at the molecular level in quail remains unexplored. The heat shock response (HSR), involving heat shock proteins (HSPs) and heat shock transcription factors (HSFs), is a highly conserved molecular response that is triggered by stressors, especially exposure to toxicants. To explore the DEHP-induced hepatotoxicity that occurs via regulation of HSR in birds, female quail were dosed with DEHP by oral gavage (0, 250, 500 and 1000 mg/kg) for 45 days. Based on histopathological analysis, the livers of the DEHP-treated groups exhibited structural alterations of hepatocytes, including mitochondrial swelling, derangement of hepatic plates, inflammatory cell infiltration and adipose degeneration. Ultrastructural evaluation of the livers of DEHP-treated quail revealed swollen mitochondria, partial disappearance of mitochondrial membranes and cristae, nuclear chromatin margination and nuclear condensation. The expression of HSF1 and HSF3 significantly decreased after DEHP exposure. The levels of HSPs (HSP10, HSP25, HSP27, HSP40, HSP47, HSP60, HSP70 and HSP90) were significantly downregulated in the livers of DEHP-treated quail. In this study, we concluded that DEHP exposure resulted in liver function damage and hepatotoxicity by reducing the expression of HSFs and HSPs in quail liver, which inhibited the protective effect of the HSR signaling pathway.

Prenatal and ancestral exposure to di(2-ethylhexyl) phthalate alters gene expression and DNA methylation in mouse ovaries

Di(2-ethylhexyl) phthalate (DEHP) is a commonly used plasticizer and known endocrine disrupting chemical, which causes transgenerational reproductive toxicity in female rodents. However, the mechanisms of action underlying the transgenerational toxicity of DEHP are not understood. Therefore, this study determined the effects of prenatal and ancestral DEHP exposure on various ovarian pathways in the F1, F2, and F3 generations of mice. Pregnant CD-1 dams were orally exposed to corn oil (vehicle control) or DEHP (20 μg/kg/day-750 mg/kg/day) from gestation day 10.5 until birth. At postnatal day 21 for all generations, ovaries were removed for gene expression analysis of various ovarian pathways and for 5-methyl cytosine (5-mC) quantification. In the F1 generation, prenatal DEHP exposure disrupted the expression of cell cycle regulators, the expression of peroxisome-proliferator activating receptors, and the percentage of 5-mC compared to control. In the F2 generation, exposure to DEHP decreased the expression of steroidogenic enzymes, apoptosis factors, and ten-eleven translocation compared to controls. It also dysregulated the expression of phosphoinositide 3-kinase (PI3K) factors. In the F3 generation, ancestral DEHP exposure decreased the expression of steroidogenic enzymes, PI3K factors, cell cycle regulators, apoptosis factors, Esr2, DNA methylation mediators, and the percentage of 5-mC compared to controls. Overall, the data show that prenatal and ancestral DEHP exposure greatly suppress gene expression of pathways required for folliculogenesis and steroidogenesis in the ovary in a transgenerational manner and that gene expression may be influenced by DNA methylation. These results provide insight into some of the mechanisms of DEHP-mediated toxicity in the ovary across generations.

Prenatal exposure to di(2-ethylhexyl) phthalate disrupts ovarian function in a transgenerational manner in female mice

Di(2-ethylhexyl) phthalate (DEHP) is a plasticizer found in polyvinyl chloride products such as vinyl flooring, plastic food containers, medical devices, and children's toys. DEHP is a ubiquitous environmental contaminant and is a known endocrine disrupting chemical. Little is known about the effects of prenatal DEHP exposure on the ovary and whether effects occur in subsequent generations. Thus, we tested the hypothesis that prenatal exposure to DEHP disrupts ovarian functions in the F1, F2, and F3 generations of female mice. To test this hypothesis, pregnant CD-1 mice were orally dosed with corn oil (vehicle control) or DEHP (20 and 200 μg/kg/day and 200, 500, and 750 mg/kg/day) daily from gestation day 10.5 until birth (7-28 dams/treatment group). F1 females were mated with untreated males to obtain the F2 generation, and F2 females were mated with untreated males to produce the F3 generation. On postnatal days 1, 8, 21, and 60, ovaries were collected and used for histological evaluation of follicle numbers and sera were used to measure progesterone, testosterone, 17β-estradiol, luteinizing hormone, and follicle stimulating hormone levels. In the F1 generation, prenatal exposure to DEHP disrupted body and organ weights, decreased folliculogenesis, and increased serum 17β-estradiol levels. In the F2 generation, exposure to DEHP decreased body and organ weights, dysregulated folliculogenesis, and disrupted serum progesterone levels. In the F3 generation, DEHP exposure accelerated folliculogenesis. These data suggest that prenatal exposure to DEHP leads to adverse multigenerational and transgenerational effects on ovarian function.

Ochratoxin A Exposure Impairs Porcine Granulosa Cell Growth via the PI3K/AKT Signaling Pathway

The mycotoxin ochratoxin A (OTA), a naturally occurring food contaminant, has a toxic effect on the growth and development of follicles in pigs. However, little is known regarding the specific toxic effects of OTA exposure on oocytes and granulosa cells (GCs). In this study, we cultured porcine ovarian GCs and exposed them to OTA in vitro in order to explore the mechanism causing the negative effects. Initially, it was found that OTA exposure inhibited cell viability in a time and dose dependent manner. We also showed that OTA exposure increased oxidative stress, decreased proliferation ratio, and increased apoptosis ratio in GCs. We revealed an important role for the PI3K/AKT signal pathway in GC proliferation and apoptosis by RNA-seq analysis. The results not only showed that OTA treatment significantly affected the expression of genes within the PI3K/AKT pathway but also demonstrated a concrete relationship between the PI3K/AKT pathway and GC cell proliferation and apoptosis. In conclusion, the results demonstrated that OTA exposure impaired porcine GC growth via the PI3K/AKT signaling pathway.

The potential reproductive toxicity of tannery effluent to the estrous cycle and ovarian follicular dynamics of female Swiss mice

Although the toxic effects of tannery effluent (TE) on tanning-industry workers have been reported in many studies, its effects on females' reproductive system are unknown. We aimed at evaluating the effects of direct contact with TE on the "emotional" status, estrous cycle (during 15 consecutive exposure days), and ovarian follicular dynamics of female Swiss mice at the end of the experiment to broaden the knowledge about the toxicity of this pollutant. The herein adopted exposure protocol simulated tanning-industry workers' exposure to TE. The test animals were subjected to 45 exposure days, for 1 h a day, 5 days a week (from Monday to Friday). Based on the collected data, female mice exposed to TE recorded high anxiety index in the elevated plus maze test, although we did not observe changes in their estrous cycle. The smaller total and specific number of ovarian follicles (types 1 to 6) and the higher frequency of degenerating follicles (atresic) in female mice exposed to TE marked the folliculogenesis reduction in them. Therefore, our study was the first to provide evidences that the exposure to TE can cause reproduction issues in female mice, as well as the first experimental insight about the impact of unhealthy work activities in tanning industries on women's reproductive system.

Foetal-neonatal exposure of Di (2-ethylhexyl) phthalate disrupts ovarian development in mice by inducing autophagy

The female reproductive lifespan is largely determined by the size of the primordial follicle pool, which is established early in life. We previously reported that Di (2-ethylhexyl) phthalate (DEHP), an environmental endocrine disruptor and a widely-spreading plasticizer, impairs primordial folliculogenesis. In the present study, we found DEHP significantly altered the number and sex ratio of the offspring of neonatal-exposed mice. Furthermore, by a neonatal exposure model and an ovary culture model, it showed that DEHP activated autophagy in the ovary, with increased autophagy-related gene expression and recognizable autophagosomes, while inhibition of autophagy by 3-MA attenuated the adverse impact of DEHP on primordial folliculogenesis. Moreover, key components of AMPK-SKP2-CARM1 signalling were up-regulated by DEHP in the ovary, and AMPK inhibitor Compound C reduced autophagy-related gene expression and partially recovered primordial follicle assembly. Collectively, this study demonstrates that DEHP induces autophagy by activating AMPK-SKP2-CARM1 signalling in mice perinatal ovaries, which results in disrupted primordial folliculogenesis and reduced female fertility.

Starvation during pregnancy impairs fetal oogenesis and folliculogenesis in offspring in the mouse

Although it is becoming increasingly evident that maternal starvation during pregnancy can have permanent effects on a range of physiological processes in the offspring, scant information is available about the consequence of such condition for oogenesis and hence for lifetime reproductive success of progeny in mammals. In the present study, we address this topic by starving pregnant mice at the time of ovarian differentiation (12.5 days post coitum (dpc)) for three consecutive days and analyzed the consequence first on the survival of the fetal oocytes and their capability to progress throughout the stages of meiotic prophase I (MPI) and then on the postnatal folliculogenesis of the offspring. The results showed that maternal starvation increased apoptosis in the fetal ovaries, resulting in reduction of the oocyte number. Moreover, MPI progression was slowed down in the surviving oocytes and the expression of DNA repair players in the starved ovaries increased. Transcriptome analysis identified 61 differentially expressed genes between control and starved ovaries, the most part of these being involved in metabolic processes. A significant decrease in the percentage of oocytes enclosed in primordial follicles and the expression of oocyte genes critically involved in folliculogenesis such as Nobox, Lhx8 and Sohlh2 in the 3 days post partum (dpp) starved ovaries were found. Finally, at the time of juvenile period (21 dpp), the number of oocytes and antral follicles resulted significantly lower in the ovaries of the offspring from starved mothers in comparison to controls. Our findings support the notion that maternal starvation can affect ovary development in the offspring that could adversely affect their reproductive success in the adult life.

Di(2-ethylhexyl) phthalate (DEHP) influences follicular development in mice between the weaning period and maturity by interfering with ovarian development factors and microRNAs

Although studies have shown that di(2-ethylhexyl) phthalate (DEHP) can disrupt ovarian function, few reports have focused on follicular development in mice between the weaning period and maturity, especially with respect to microRNA (miRNA) expression. In this study, 21-day-old ICR mice were administered DEHP at doses of 0, 100, 400, and 1600 mg/(kg d) for 6 weeks by gavage. After DEHP administration, a significant decrease in the expression of follicle development-related factors (including c-kit, kitl, gdf9, and atm) was observed by quantitative real-time PCR (RT-PCR), but no significant difference in the proteins encoded by these genes was observed by Western blot. Bisulfite sequencing suggested that the total methylation percentages of promoter regions of these genes were not notably altered after DEHP exposure. However, RT-PCR revealed a significantly increased expression of ovarian miRNAs (let-7b, miR-17-5p miR-181a, and miR-151), which inhibit follicular granulosa cell proliferation. Overall, this study showed that DEHP administration from weaning to maturity could suppress the mRNA expression of follicular development factors, and this effect was not achieved through changes in the methylation of DNA in CpG islands of development factors. In addition, DEHP was shown to induce miRNAs to inhibit the proliferation of follicular granulosa cells and the anti-apoptosis function of KITL and GDF9 while increasing bax/bcl₂ expression to further promote the apoptosis of granulosa cells.

Di (2-ethylhexyl) phthalate exposure impairs meiotic progression and DNA damage repair in fetal mouse oocytes in vitro

Di (2-ethylhexyl) phthalate (DEHP), is the most common member of the class of phthalates that are used as plasticizers and have become common environmental contaminants. A number of studies have shown that DEHP exposure impacts reproductive health in both male and female mammals by acting as an estrogen analog. Here, we investigated the effects of DEHP on meiotic progression of fetal mouse oocytes by using an in vitro model of ovarian tissue culture. The results showed that 10 or 100 μM DEHP exposure inhibited the progression of oocytes throughout meiotic prophase I, specifically from the pachytene to diplotene stages. DEHP possibly impairs the ability to repair DNA double-strand breaks induced by meiotic recombination and as a consequence activates a pachytene check point. At later stages, such defects led to an increased number of oocytes showing apoptotic markers (TUNEL staining, expression of pro-apoptotic genes), resulting in reduced oocyte survival, gap junctions, and follicle assembly in the ovarian tissues. Microarray analysis of ovarian tissues exposed to DEHP showed altered expression of several genes including some involved in apoptosis and gonad development. The expression changes of some genes clustered in cell-cell communication and signal transduction, along with plasma membrane, extracellular matrix and ion channel function classes, were dependent on the DEHP concentration. Together, these results bring new support to the notion that exposure to DEHP during gestation might exert deleterious effects on ovary development, perturbing germ cell meiosis and the expression of genes involved in a wide range of biological processes including ovary development.

Gestational Hyperandrogenism in Developmental Programming

Androgen excess (hyperandrogenism) is a common endocrine disorder affecting women of reproductive age. The potential causes of androgen excess in women include polycystic ovary syndrome, congenital adrenal hyperplasia (CAH), adrenal tumors, and racial disparity among many others. During pregnancy, luteoma, placental aromatase deficiency, and fetal CAH are additional causes of gestational hyperandrogenism. The present report reviews the various phenotypes of hyperandrogenism during pregnancy and its origin, pathophysiology, and the effect of hyperandrogenism on the fetal developmental trajectory and offspring consequences.

Prenatal exposure to an environmentally relevant phthalate mixture disrupts reproduction in F1 female mice

Phthalates are used in a large variety of products, such as building materials, medical devices, and personal care products. Most previous studies on the toxicity of phthalates have focused on single phthalates, but it is also important to study the effects of phthalate mixtures because humans are exposed to phthalate mixtures. Thus, we tested the hypothesis that prenatal exposure to an environmentally relevant phthalate mixture adversely affects female reproduction in mice. To test this hypothesis, pregnant CD-1 dams were orally dosed with vehicle (tocopherol-stripped corn oil) or a phthalate mixture (20 and 200μg/kg/day, 200 and 500mg/kg/day) daily from gestational day 10 to birth. The mixture was based on the composition of phthalates detected in urine samples from pregnant women in Illinois. The mixture included 35% diethyl phthalate, 21% di(2-ethylhexyl) phthalate, 15% dibutyl phthalate, 15% diisononyl phthalate, 8% diisobutyl phthalate, and 5% benzylbutyl phthalate. Female mice born to the exposed dams were subjected to tissue collections and fertility tests at different ages. Our results indicate that prenatal exposure to the phthalate mixture significantly increased uterine weight and decreased anogenital distance on postnatal days 8 and 60, induced cystic ovaries at 13months, disrupted estrous cyclicity, reduced fertility-related indices, and caused some breeding complications at 3, 6, and 9months of age. Collectively, our data suggest that prenatal exposure to an environmentally relevant phthalate mixture disrupts aspects of female reproduction in mice.