Diethylstilbestrol at environmental levels affects the development of early life stage and target gene expression in Japanese Medaka (Oryzias latipes)

Differences in MCF-7 response to endocrine disruptors in waste, superficial, and treated water from Southern Brazil

The aim of this study was to evaluate the effect of possible endocrine disruptors in surface and wastewater using a cell proliferation assay in an estrogen-responsive cell line (MCF-7). This study was conducted in the Sinos River (Brazil). The residual water was collected from a Pilot Treatment Plant (using Typha domingensis) and surface waters of the Luis Rau stream, the Sinos River, and the Water Treatment Station (WTS). After exposures (24-120 h), a Sulforhodamine B assay was performed to determine the proliferation rate. The higher increase in proliferation rate was observed with the Luiz Rau stream and the sewage treated by macrophytes in a flotation filter. The results from WTS water remained with a proliferation rate similar to the negative control at all times, suggesting that the conventional treatment is partially effective for the withdrawal of endocrine-disrupting agents. The study demonstrated the efficiency of the MCF-7 line in assessing endocrine disruption caused by wastewater and surface water samples. Our results indicate that conventional water treatment can partially remove the polluting load of endocrine disruptors, minimizing their environmental and public health impacts. Besides, it demonstrates the need to expand sanitary services to improve the population's quality of life.

A systematic review of the evaluation of endocrine-disrupting chemicals in the Japanese medaka (Oryzias latipes) fish

Japanese medaka (Oryzias latipes) is an acceptable small laboratory fish model for the evaluation and assessment of endocrine-disrupting chemicals (EDCs) found in the environment. In this research, we used this fish as a potential tool for the identification of EDCs that have a significant impact on human health. We conducted an electronic search in PubMed (http://www.ncbi.nlm.nih.gov/pubmed) and Google Scholar (https://scholar.google.com/) using the search terms, Japanese medaka, Oryzias latipes, and endocrine disruptions, and sorted 205 articles consisting of 128 chemicals that showed potential effects on estrogen-androgen-thyroid-steroidogenesis (EATS) pathways of Japanese medaka. From these chemicals, 14 compounds, namely, 17β-estradiol (E2), ethinylestradiol (EE2), tamoxifen (TAM), 11-ketotestosterone (11-KT), 17β-trenbolone (TRB), flutamide (FLU), vinclozolin (VIN), triiodothyronine (T3), perfluorooctanoic acid (PFOA), tetrabromobisphenol A (TBBPA), terephthalic acid (TPA), trifloxystrobin (TRF), ketoconazole (KTC), and prochloraz (PCZ), were selected as references and used for the identification of apical endpoints within the EATS modalities. Among these endpoints, during classification, priorities are given to sex reversal (masculinization of females and feminization of males), gonad histology (testis-ova or ovotestis), secondary sex characteristics (anal fin papillae of males), plasma and liver vitellogenin (VTG) contents in males, swim bladder inflation during larval development, hepatic vitellogenin (vtg) and choriogenin (chg) genes in the liver of males, and several genes, including estrogen-androgen-thyroid receptors in the hypothalamus-pituitary-gonad/thyroid axis (HPG/T). After reviewing 205 articles, we identified 108 (52.68%), 46 (22.43%), 19 (9.26%), 22 (17.18%), and 26 (12.68%) papers that represented studies on estrogen endocrine disruptors (EEDs), androgen endocrine disruptors (AEDs), thyroid endocrine disruptors (TEDs), and/or steroidogenesis modulators (MOS), respectively. Most importantly, among 128 EDCs, 32 (25%), 22 (17.18%), 15 (11.8%), and 14 (10.93%) chemicals were classified as EEDs, AEDs, TEDs, and MOS, respectively. We also identified 43 (33.59%) chemicals as high-priority candidates for tier 2 tests, and 13 chemicals (10.15%) show enough potential to be considered EDCs without any further tier-based studies. Although our literature search was unable to identify the EATS targets of 45 chemicals (35%) studied in 60 (29.26%) of the 205 articles, our approach has sufficient potential to further move the laboratory-based research data on Japanese medaka for applications in regulatory risk assessments in humans.

Endocrine disrupting effect and reproductive toxicity of the separate exposure and co-exposure of nano-polystyrene and diethylstilbestrol to zebrafish

The co-occurrence of nanoplastics and other pollutants in the environment has gotten a lot of attention, but information on the biological toxicity of their co-exposure was limited. This study aims to reveal the endocrine disrupting effect and reproductive toxicity of nano-polystyrene (NPS) and diethylstilbestrol (DES) to zebrafish under separate and combined exposure. Results indicated that NPS and DES exposure in isolation reduced the hepatosomatic index and gonadosomatic index, and altered the cell maturity in gonads in both cases. Even worse, the co-exposure of NPS and DES exacerbated the damage to the liver and gonads of fish. The two pollutants individually inhibited the secretion of sex hormones and vitellogenin. The inhibition effect of DES was especially dose-dependent, while NPS had weaker effect than DES. Their combined action on the secretion of sex hormones and vitellogenin exhibited additive effect. However, NPS did not affect the content of thyroid hormones in fish, and also had no significant effect on the reduction of thyroid hormone caused by DES exposure. Furthermore, their co-exposure decreased the cumulative eggs from 1031 to 306, and the spawning number from 12 to 8. The fertilization rate and hatchability rete of eggs were reduced by 30.9% and 40.4%, respectively. The abnormality rate of embryos was 65.0%, significantly higher than in separate DES and NPS groups (55.7% and 30.8% respectively). The abnormal development of offspring was mainly pericardial cyst, spinal curvature, and growth retardation.

Effects of Diethylstilbestrol on Zebrafish Gonad Development and Endocrine Disruption Mechanism

Environmental estrogen is a substance that functions as an endocrine hormone in organisms and can cause endocrine system disruption. A typical environmental estrogen, diethylstilbestrol (DES), can affect normal sexual function and organism development. However, even though the effects of different exposure stages of DES on the endocrine system and gonadal development of zebrafish juveniles are unknown, sex determination is strongly influenced by endocrine-disrupting chemicals (EDCs). From 10–90 days post fertilization (dpf), juvenile zebrafish were exposed to DES (100 and 1000 ng/L) in three different stages (initial development stage (IDS), 10–25 dpf; gonadal differentiation stage (GDS), 25–45 dpf and gonadal maturity stage (GMS), 45–60 dpf). Compared with that of IDS and GMS, the growth indicators (body length, body weight, and others) decreased significantly at GDS, and the proportion of zebrafish females exposed to 100 ng/L DES was significantly higher (by 59.65%) than that of the control; in addition, the zebrafish were biased towards female differentiation. The GDS is a critical period for sex differentiation. Our results show that exposure to environmental estrogen during the critical gonadal differentiation period not only affects the development of zebrafish, but also affects the population development.

Endocrine disrupting chemicals (EDCs) and sex steroid receptors

Sex-steroid receptors (SSRs) are essential mediators of estrogen, progestin, and androgen signaling that are critical in vast aspects of human development and multi-organ homeostasis. Dysregulation of SSR function has been implicated in numerous pathologies including cancers, obesity, Type II diabetes mellitus, neuroendocrine disorders, cardiovascular disease, hyperlipidemia, male and female infertility, and other reproductive disorders. Endocrine disrupting chemicals (EDCs) modulate SSR function in a wide variety of cell and tissues. There exists strong experimental, clinical, and epidemiological evidence that engagement of EDCs with SSRs may disrupt endogenous hormone signaling leading to physiological abnormalities that may manifest in disease. In this chapter, we discuss the molecular mechanisms by which EDCs interact with estrogen, progestin, and androgen receptors and alter SSR functions in target cells. In addition, the pathological consequences of disruption of SSR action in reproductive and other organs by EDCs is described with an emphasis on underlying mechanisms of receptors dysfunction.

Diethylstilbestrol exposure disrupts mouse oocyte meiotic maturation in vitro through affecting spindle assembly and chromosome alignment

An adverse tendency induced by the environmental estrogens in female reproductive health is one serious problem worldwide. Diethylstilbestrol (DES), as a synthetic estrogen, is still used as an animal growth stimulant in terrestrial livestock and aquaculture illegally. It has been reported to negatively affect ovarian function and oogenesis. Nevertheless, the mechanism and toxicity of DES on oocyte meiotic maturation are largely unknown. Herein, we found that DES (40 μM) intervened in mouse oocyte maturation and first polar body extrusion (PBE) was decreased in vitro. Cell cycle analysis showed meiotic process was disturbed with oocytes arrested at metaphase I (MI) stage after DES exposure. Further study showed that DES exposure disrupted the spindle assembly and chromosome alignment, which then continuously provoke the spindle assemble checkpoint (SAC). We also observed that the acetylation levels of α-tubulin were dramatically increased in DES-treated oocytes. In addition, the dynamics of actin were also affected. Moreover, the distribution patterns of estrogen receptor α (ERα) were altered in DES-treated oocyte, as indicated by the significant signals accumulation in the spindle area. However, ERα inhibitor failed to rescue the defects of oocyte maturation caused by DES. Of note, the same phenomenon was observed in estrogen-treated oocytes. Collectively, we showed that DES exposure lead to the oocyte meiotic failure via impairing the spindle assembly and chromosome alignment. Our research is helpful to understand how environmental estrogen affects female germ cells and contribute to design the potential therapies to preserve fertility especially for occupational exposure.

Overview of the analysis, occurrence and ecological effects of hormones in lake waters in Asia

Hormones are natural and synthetic compounds that are now being detected in the aquatic environment. Many lakes in Asia are important water sources that may be affected by these emerging contaminants. Lakes are drains and reservoirs of watersheds that are altered by changing land use and environmental conditions. While there are several studies on the detection of hormones in lakes, these studies were mostly done in China. Limited information is available on the presence of these contaminants in the lakes in other Asian countries. Hormones in the lake water come from discharge waters in urban areas, farm runoffs, and effluents of wastewater and sewage treatment plants. Hormones contamination in water has been shown to affect the reproduction and growth of certain aquatic organisms. In this review, a background on the chemical nature and physiological functions of hormones is provided and the existing knowledge on the occurrence and ecological impacts of hormones in lakes is described. The available analytical methods for sampling, analyte extraction and instrumental analysis are outlined. This overview provides insights on the current conditions of lakes that may be impacted by hormones contamination. Understanding the levels and possible ecological consequences will address the issues on these emerging contaminants especially in the Asian environment. This will elicit discussions on improving guidelines on wastewater discharges and will drive future research directions.

Perturbation of Nuclear Hormone Receptors by Endocrine Disrupting Chemicals: Mechanisms and Pathological Consequences of Exposure

Much of the early work on Nuclear Hormone Receptors (NHRs) focused on their essential roles as mediators of sex steroid hormone signaling in reproductive development and function, and thyroid hormone-dependent formation of the central nervous system. However, as NHRs display tissue-specific distributions and activities, it is not surprising that they are involved and vital in numerous aspects of human development and essential for homeostasis of all organ systems. Much attention has recently been focused on the role of NHRs in energy balance, metabolism, and lipid homeostasis. Dysregulation of NHR function has been implicated in numerous pathologies including cancers, metabolic obesity and syndrome, Type II diabetes mellitus, cardiovascular disease, hyperlipidemia, male and female infertility and other reproductive disorders. This review will discuss the dysregulation of NHR function by environmental endocrine disrupting chemicals (EDCs), and the associated pathological consequences of exposure in numerous tissues and organ systems, as revealed by experimental, clinical, and epidemiological studies.

Isolation and Characterization of a Novel Diethylstilbestrol-Degrading Bacillus subtilis JF and Biochemical Degradation Metabolite Analysis

Diethylstilbestrol (DES) can adversely affect the immune system of developing fetuses or even elicit toxic responses such as nerve toxicity and genotoxicity in human beings, thereby warranting methods to remove DES from the environments. The present study characterized a novel DES-degrading Bacillus subtilis JF and analyzed the degradation metabolites. The strain was collected at the China General Microbiological Culture Collection Center (Collection number: CGMCC 7950). The environmental effects, such as DES concentrations, pH levels, and temperature, on the strain's degradation ability were tested. Degradation metabolites of DES by strain JF were analyzed via high performance liquid chromatography (HPLC) and liquid-chromatography time of flight mass spectrometry (LC-TOF-MS). Results indicated that B. subtilis JF can effectively degrade DES within a concentration of 25-200 mg/L. Increasing pH levels (pH > 7) are reported to increase the degradation rate of DES by the strain. The optimal temperature for strain JF to degrade DES was identified as 45°C. In this study, 4, 4'-hexene estrogen quinones (DESQ) and DES-4-semiquinone were speculated as two degradation metabolites of DES, and both can be completely degraded by strain JF. A slight reduction of DES in the blank system [DES cultured in Luria-Bertani (LB) medium without strain JF] was observed in this study. The reduction trend in the blank system only occurred during the first few days (about 4 days) and was considerably lesser than the decomposition and transformation effect of DES via strain JF. Furthermore, the metabolite DESQ could not be further decomposed in blank LB medium without strain JF. All the results demonstrate that complete degradation of DES in the fermentation broth occurs due to the function of strain JF rather than organic decomposition. In conclusion, the high efficiency of degradation and the potential to degrade DES completely indicates that strain JF has potential for the bioremediation of DES-contaminated environments (soil, river, and so on) and fermented foods.

Long-term exposure of xenoestrogens with environmental relevant concentrations disrupted spermatogenesis of zebrafish through altering sex hormone balance, stimulating germ cell proliferation, meiosis and enhancing apoptosis

Environmental estrogens are capable of interfering with the spermatogenesis and fertility of fish. However in natural waters, these chemicals are more likely to occur as a combination rather than a single stressor. Whether and how the mixture of xenoestrogens with environmental relevant concentrations may affect fish spermatogenesis remains largely unknown. In this study, male zebrafish adults were administered to 17alpha-ethinylestradiol (EE2) and a mixture of xenoestrogens (Mix (E2, EE2, DES, 4-t-OP, 4-NP and BPA)), with the estrogenic potency equivalent to EE2. After a 60-day exposures, elevated mRNA levels of vitellogenin 1 (vtg1) and estrogen receptor 1 (esr1) in the liver of fish in both treated groups were observed. Moreover, the plasma level of E2 declined significantly in the Mix group and the ratio of 11-KT/E2 was significantly elevated in both treated groups. Consistently, the mRNA level of P450 side-chain cleavage (scc) in the EE2 group and ovarian type aromatase (cyp19a1a) in the Mix group was significantly suppressed. In addition, decreased gonadosomatic index and sperm count in the fish of Mix group were present. Furthermore, increased number of the proliferating germ cells (such as spermatogonia and spermatocytes) was observed in the fish of both groups, suggesting a stimulated germ cell proliferation and meiosis. Accordingly, both exposures significantly up-regulated the mRNA levels of genes in mitosis (cyclinb1) and meiosis (cyp26a1 in EE2 group, aldh1a2, cyp26a1, sycp3 and spo11 in Mix). In addition, decreased number of spermatozoa and increased number of TUNEL-positive signals were present in the testis of fish in the Mix group, indicating an enhanced apoptosis. Further analyses demonstrated the significant elevated expressions of tnfrsf1a and the ratio of tnfrsf1a/tnfrsf1b in the Mix group, suggesting an elevated apoptosis in the testis of fish in the Mix group via extrinsic pathway. The present study greatly extends our understanding of the underlying mechanisms of the reproductive toxicity of xenoestrogens on fish.

Diethylstilbestrol arrested spermatogenesis and somatic growth in the juveniles of yellow catfish (Pelteobagrus fulvidraco), a fish with sexual dimorphic growth

In fish, spermatogenesis and somatic growth are mainly regulated by hypothalamic-pituitary-gonadal (HPG) and hypothalamic-pituitary-somatic (HPS) axes, respectively. Xenoestrogens have been reported to impair spermatogenesis in some fishes, and arrest somatic growth in some others, whereas, whether xenoestrogens are capable of disrupting spermatogenesis and somatic growth simultaneously in fish that exhibits sexual dimorphic growth is little known, and the underlying mechanisms remain poorly understood. In this study, male juveniles of yellow catfish (Pelteobagrus fulvidraco), which exhibits a sexual dimorphic growth that favors males, were exposed to diethylstilbestrol (DES) for 28 days. After exposure, DES significantly disrupted the spermatogenesis (decreased gonadal-somatic index (GSI) and germ cell number) and arrested the somatic growth (declined body weight) of the catfish juveniles. Gene expression and plasma steroid analyses demonstrated the suppressed mRNA levels of genes in HPG axis (gnrh-II, fshβ, and lhβ in the brain and dmrt1, sf1, fshr, cyp17a1, cyp19a1a, and cyp11b2 in the testis) and decreased 17β-estrodial (E2) and 11-ketotestosterone (11-KT) levels in plasma. Further analysis revealed the arrested germ cell proliferation (cyclin d1), meiosis (dmc1, sycp3), and enhanced apoptosis (decreased bcl-2 and elevated bax/bcl-2 ratio) in the testis. Besides, DES also suppressed the mRNA levels of genes in HPS axis (ghrh, gh, and prl in the brain and ghr, igf1, igf2a, and igf2b in the liver). The suppressed HPG and HPS axes were thus supposed to disturb spermatogenesis and arrest somatic growth in yellow catfish. The present study greatly extended our understanding on the mechanisms underlying the toxicity of DES on spermatogenesis and somatic growth of fish.

Removal and Biodegradation of 17β-Estradiol and Diethylstilbestrol by the Freshwater Microalgae Raphidocelis subcapitata

Natural steroidal and synthetic non-steroidal estrogens such as 17β-estradiol (E2) and diethylstilbestrol (DES) have been found in natural water, which can potentially endanger public health and aquatic ecosystems. The removal and biodegradation of E2 and DES by Raphidocelis subcapitata were studied in bacteria-free cultures exposed to single and mixture treatments at different concentrations for 96 h. The results showed that R. subcapitata exhibited a rapid and strong ability to remove E2 and DES in both single and mixture treatments by biodegradation. At the end of 96 h, the removal percentage of single E2 and DES achieved 82.0%, 80.4%, 74.6% and 89.9%, 73.4%, 54.1% in 0.1, 0.5, and 1.5 mg·L^-1, respectively. With the exception of the 0.1 mg·L^-1 treatment at 96 h, the removal capacity of E2 was more efficient than that of DES by R. subcapitata. Furthermore, the removal percentage of mixture E2 and DES achieved 88.5%, 82.9%, 84.3% and 87.2%, 71.8%, 51.1% in 0.1, 0.5, and 1.5 mg·L^-1, respectively. The removal percentage of mixed E2 was significantly higher than that of the single E2. The presence of DES could accelerate the removal of E2 from the mixture treatments in equal concentrations. In addition, the removal was mainly attributed to the biodegradation or biotransformation process by the microalgae cells rather than simple sorption and accumulation in the cells. The microalgae R. subcapitata demonstrated a high capability for the removal of the E2 and DES indicating future prospects for its application.

Diethylstilbestrol impaired oogenesis of yellow catfish juveniles through disrupting hypothalamic-pituitary-gonadal axis and germ cell development

Diethylstilbestrol (DES), a non-steroidal estrogen, has been found to cause altered germ cell development and disordered ovarian development in fish females. However, the mechanisms that might be involved are poorly understood. In this study, female juveniles of yellow catfish (Pelteobagrus fulvidraco) (120 days post-hatching) were exposed to two doses (10 and 100 ng l^-1 ) of DES for 28 days. After the endpoint of exposure, decreased ovary weight and gonadosomatic index, as well as various ovarian impairments were observed in response to DES. Besides, DES elevated the mRNA levels of vitellogenin 1 (vtg 1) and estrogen receptor 1 (esr 1) in liver and decreased 17β-estradiol level in plasma. Correspondingly, suppressed mRNA levels of the key genes in the hypothalamic-pituitary-gonadal axis (such as cyp19a1b, gnrh-II, fshβ and lhβ in brain and fshr, lhr and cyp19a1a in ovary) after DES exposure were also observed. The declined level of plasma 17β-estradiol and altered gene expressions of genes in the hypothalamic-pituitary-gonadal axis were thus supposed to be closely related to the disrupted oogenesis in DES-treated fish. Analyses further demonstrated that, higher concentration of DES elevated the expression ratio of bax/bcl-2, indicating the enhanced apoptosis occurred in ovary. Moreover, DES upregulated the expressions of genes involved in proliferation (cyclin d1 and pcna), meiotic entry (cyp26a1 and scp3) and meiotic maintenance (dmc1), resulting in arrested oogenesis in catfish. The present study greatly extended our understanding on the mechanisms underlying of reproductive toxicity of DES on fish oogenesis.

Diethylstilbestrol, flutamide and their combination impaired the spermatogenesis of male adult zebrafish through disrupting HPG axis, meiosis and apoptosis

Both diethylstilbestrol (DES, an environmental estrogen) and flutamide (FLU, an anti-androgen) are found to impair spermatogenesis by disrupting hypothalamic-pituitary-gonadal (HPG) axis and altering androgen levels through different mechanisms/modes of action in fish with poorly understood underlying mechanisms. Furthermore, it is not known whether and how a combined exposure of DES and FLU has a stronger effect than the compounds alone. In this study, male zebrafish adults were exposed to DES, FLU and their combination (DES+FLU) for 30days, and their effects on histological structure and sperm count in testis, androgen level in plasma, as well as the mRNA levels of genes involved in HPG axis, meiotic regulation and apoptosis were analyzed. After exposure, DES and FLU disrupted spermatogenesis in zebrafish, and their combination resulted in even more severe impairment, indicating the inhibitory roles of these chemicals on spermatogenesis and their additive effects on zebrafish. The different regulation of vtg1 expression in the liver in response to DES and FLU further confirmed the different modes of action of these drugs. Gene expression and plasma steroid level analyses demonstrated the suppressed mRNA levels of the key genes (such as gnrh3, fshβ and lhβ in brain and dmrt1, sf1, cyp17a1 and cyp11b2 in testis) in HPG axis and decreased 11-ketotestosterone (11-KT) levels in plasma. The declined level of 11-KT was thus supposed to be closely related to the down-regulation of cyp26a1 (encoding the catabolic enzyme of retinoic acid) and suppression of genes involved in meiotic regulation (nanos1, dmc1 and sycp3). In fish exposed to DES and DES+FLU, enhanced apoptosis (elevated bax/bcl-2 expression ratio) was also observed. The suppression of meiotic regulation in response to all the exposures and enhanced apoptosis in response to DES were thus supposed to result in the spermatogenic impairment in zebrafish. The present study greatly extends our understanding on the mechanisms underlying of reproductive toxicity of environment estrogens and anti-androgens in fish.

Diethylstilbestrol activates CatSper and disturbs progesterone actions in human spermatozoa

STUDY QUESTION

Is diethylstilbestrol (DES), a prototypical endocrine-disrupting chemical (EDC), able to induce physiological changes in human spermatozoa and affect progesterone actions?

SUMMARY ANSWER

DES promoted Ca²⁺ flux into human spermatozoa by activating the cation channel of sperm (CatSper) and suppressed progesterone-induced Ca²⁺ signaling, tyrosine phosphorylation and sperm functions.

WHAT IS KNOWN ALREADY

DES significantly impairs the male reproductive system both in fetal and postnatal exposure. Although various EDCs affect human spermatozoa in a non-genomic manner, the effect of DES on human spermatozoa remains unknown.

STUDY DESIGN, SIZE, DURATION

Sperm samples from normozoospermic donors were exposed in vitro to a range of DES concentrations with or without progesterone at 37°C in a 5% CO₂ incubator to mimic the putative exposure to this toxicant in seminal plasma and the female reproductive tract fluids. The incubation time varied according to the experimental protocols. All experiments were repeated at least five times using different individual sperm samples.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Human sperm intracellular calcium concentrations ([Ca²⁺]_i) were monitored with a multimode plate reader following sperm loading with Ca²⁺ indicator Fluo-4 AM, and the whole-cell patch-clamp technique was performed to record CatSper and alkalinization-activated sperm K⁺ channel (KSper) currents. Sperm viability and motility parameters were assessed by an eosin-nigrosin staining kit and a computer-assisted semen analysis system, respectively. The ability of sperm to penetrate into viscous media was examined by penetration into 1% methylcellulose. The sperm acrosome reaction was measured using chlortetracycline staining. The level of tyrosine phosphorylation was determined by western blot assay.

MAIN RESULTS AND THE ROLE OF CHANCE

DES exposure rapidly increased human sperm [Ca²⁺]_i dose dependently and even at an environmentally relevant concentration (100 pM). The elevation of [Ca²⁺]_i was derived from extracellular Ca²⁺ influx and mainly mediated by CatSper. Although DES did not affect sperm viability, motility, penetration into viscous media, tyrosine phosphorylation or the acrosome reaction, it suppressed progesterone-stimulated Ca²⁺ signaling and tyrosine phosphorylation. Consequently, DES (1-100 μM) significantly inhibited progesterone-induced human sperm penetration into viscous media and acrosome reaction.

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

Although DES has been shown to disturb progesterone actions on human spermatozoa, this study was performed in vitro, and caution must be taken when extrapolating the results in practical applications.

WIDER IMPLICATIONS OF THE FINDINGS

The present study revealed that DES interfered with progesterone-stimulated Ca²⁺ signaling and tyrosine phosphorylation, ultimately inhibited progesterone-induced human sperm functions and, thereby, might impair sperm fertility. The non-genomic manner in which DES disturbs progesterone actions may be a potential mechanism for some estrogenic endocrine disruptors to affect human sperm function.

STUDY FUNDING/COMPETING INTERESTS

National Natural Science Foundation of China (No. 31400996); Natural Science Foundation of Jiangxi, China (No. 20161BAB204167 and No. 20142BAB215050); open project of National Population and Family Planning Key Laboratory of Contraceptives and Devices Research (No. 2016KF07) to T. Luo; National Natural Science Foundation of China (No. 81300539) to L.P. Zheng. The authors have no conflicts of interest to declare.