Di(2-ethylhexyl) Phthalate Treatment Research Articles

Effect of di(2-ethylhexyl) phthalate on Nrf2-regulated glutathione homeostasis in mouse kidney.

Environmental toxicants such as phthalate have been involved in multiple health disorders including renal diseases. Oxidative damage is implicated in many alterations caused by phthalate especially the di(2-ethylhexyl) phthalate (DEHP), which is the most useful phthalate. However, information regarding its mechanism of renal damage is lacking. The transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) regulates gene expression implicated in free radical scavenging and cytoprotection including the antioxidant glutathione (GSH) pathway. The aim of this study was to assess whether DEHP affects the Nrf2 pathway and the GSH concentration. Mice were divided into four groups: a control group and three groups treated with DEHP at different concentrations (5, 50, and 200 mg/kg body weight) for 30 days. Our results showed that DEHP altered the normal levels of serum biochemical parameters creatinine (CREA), urea, and lactate dehydrogenase (LDH). This phthalate caused oxidative damage through the induction of lipid peroxidation and protein oxidation as marked by increase of protein carbonyl (PC) and loss of protein-bound sulfhydryls (PSH). Simultaneously, DEHP treatment decreased the protein level of Nrf-2, HO-1, and GCLC (responsible of GSH synthesis) and decreased the GSH level. Inhibition of the Nrf2 pathway is related to the activation of the mitochondrial pathway of apoptosis. This apoptotic process is evidenced by an upregulation of p53 and Bax protein levels in addition to a downregulation of Bcl-2. Collectively, our data demonstrated that depletion of Nrf2 and GSH was associated with the elevation of oxidative stress and the activation of intrinsic apoptosis in mouse kidney treated with DEHP.

Di-(2-ethylhexyl) phthalate inhibits expression and internalization of transthyretin in human placental trophoblastic cells

During pregnancy, fetal thyroid hormones (THs) are dependent on maternal placental transport and their physiological level is crucial for normal fetal neurodevelopment. Earlier research has shown that Di-(2-ethylhexyl) phthalate (DEHP) disrupts thyroid function and THs homeostasis in pregnant women and fetuses, and affects placental THs transport. However, the underlying mechanisms are poorly understood. The present study, therefore, aimed to systematically investigate the potential mechanisms of DEHP-induced disruption in the placental THs transport using two human placental trophoblastic cells, HTR-8/SVneo cells and JEG-3 cells. While the exposure of DEHP at the doses of 0–400 μM for 24 h did not affect cell viability, we found reduced consumption of T3 and T4 in the culture medium of HTR-8/Svneo cells treated with DEHP at 400 μM. DEHP treatment did not affect T3 uptake and the expression of monocarboxylate transporters 8 (MCT8) and organic anion transporters 1C1 (OATP1C1). However, DEHP significantly inhibited transthyretin (TTR) internalization, down-regulated TTR, deiodinase 2 (DIO2), and thyroid hormone receptors mRNA expression and protein levels, and up-regulated deiodinase 3 (DIO3) protein levels in a dose-dependent manner. These results indicate that DEHP acts on placental trophoblast cells, inhibits its TTR internalization, down-regulates TTR expression and affects the expression of DIO2, DIO3, and thyroid hormone receptor. These may be the mechanisms by which PAEs affects THs transport through placental.

Di (2-ethylhexyl) phthalate induces cytotoxicity in HEK-293 cell line, implication of the Nrf-2/HO-1 antioxidant pathway.

The di (2-ethylhexyl) phthalate (DEHP) is a plasticizer used in the polyvinyl chloride industry. Human exposure to this plasticizer is inevitable and contributes to several side effects. In this study, we examined whether DEHP induces apoptosis and oxidative stress in embryonic kidney cells (HEK-293) and whether the nuclear factor E2-related factor 2 (Nrf-2)/heme oxygenase-1 (HO-1) antioxidant pathway is involved in the pathogenesis of this process. We demonstrated that DEHP is cytotoxic to HEK-293 cells. It causes oxidative damage through the generation of free radicals, induces lipid peroxidation, and alters superoxide dismutase and catalase activities. Simultaneously, DEHP treatment decreases the expression and the protein level of Nrf-2 and HO-1. Inhibition of the Nrf-2/HO-1 pathway is related to the mitochondrial pathway of apoptosis. This apoptotic process is characterized by a loss of mitochondrial transmembrane potential (ΔΨm) and upregulation of the expression of caspase-3 mRNA as well as its protein level.

Endoplasmic reticulum stress, a novel significant mechanism responsible for DEHP-induced increased distance between seminiferous tubule of mouse testis.

Di(2-ethylhexyl) phthalate (DEHP), a widely existed endocrine disruptor, has been concerned for many years owing to its toxicity in male reproductive development. In this study, we investigated the reproductive effects and the mechanism of mouse testis after in uterus exposure to the plasticizer DEHP. We found that the UPR signaling pathway could be fully activated after DEHP treatment. In uterus DEHP exposure significantly increased abnormal morphology seminiferous tubules, expanded the distance between the tubules as well as caused abnormal endoplasmic reticulum (ER) ultrastructure, which could be reversed by 4-phenylbutyrate (4-PBA), an ER stress inhibitor. In addition, DEHP-induced ER stress pathway promoted a decline in protein expression, including cadherin protein N-cadherin in testis, which could also be reversed by 4-PBA. Taken together, our results provide compelling evidence that the ER stress would be a novel significant mechanism responsible for DEHP-induced the increased the distance between seminiferous tubule by reducing the N-cadherin expression.

Neural mechanisms underlying the deficit of learning and memory by exposure to Di(2-ethylhexyl) phthalate in rats

Di(2-ethylhexyl) phthalate (DEHP), as one of the most broadly representative phthalic acid esters, is used as a plasticizer in Polyvinyl chloride production. The exact neurotoxicologically effects of DEHP to human have not been adequately researched. In order to investigate the effects and mechanisms of DEHP exposure on neural circuit, the spatial learning and memory of Sprague Dawley (SD) rats was measured, and the cellular mechanisms underlying synaptic plasticity, cellular excitability and ion channels were detected. Our data showed that the spatial learning and memory was changed by DEHP (100 and 300 mg) treatment. Meanwhile, the frequency of mini Excitatory Postsynaptic Current (mEPSC) from CA3 pyramidal cells were significantly decreased by DEHP exposure (0.1 and 0.3 M); the firing threshold, membrane potential threshold, number, amplitude and latency of Action Potentials (Aps) of CA1 pyramidal cells were altered with the application of DEHP (0.1 and 0.3 M); furthermore, DEHP, both in 0.1 and 0.3 M could inhibit the voltage-gated potassium channel of CA1 pyramidal cells. Our results indicated that DEHP could impair the spatial learning and memory, and this impairment might due to the DEHP-induced suppression of the neuronal excitability and synaptic plasticity by inhibiting the voltage-gated potassium channel, supporting the hypothesis that DEHP could cause the disruption of neural function.

Di-(2-ethylhexyl) phthalate induced the growth inhibition and oxidative damage in the microalga Chlorella vulgaris

di-2-ethylhexyl phthalate (DEHP) poses a great threat to aquatic ecosystems, with known hazards to aquatic species. The ecotoxicological mechanism of DEHP in ocean microalgae is not yet known. In this study, we investigated growth inhibition, oxidative damage and antioxidant enzyme activities in Chlorella vulgaris under DEHP treatment. After 5-d exposure to DEHP ranging from 2 to 10 mg/L, the growth of C. vulgaris was significantly inhibited. The 96-h median effective concentration values (96h-EC50) of DEHP for C. vulgaris were 6.02 mg/L. This growth inhibition was associated with DEHP-induced oxidative stress, as evidenced by elevated levels of intracellular malondialdehyde (MDA) and hydrogen peroxide. The results showed that DEHP reduced superoxide dismutase and glutathione peroxidise activities, increased hydrogen peroxide level and MDA content in a concentration-dependent way. These results indicated that DEHP could have biochemical and physiological toxic effects in C. vulgaris. These findings will help to understand the toxicity mechanisms of DEHP and the environmental risk assessment of primary producers of aquatic ecosystems

Construction of 3β-HSD gene silencing cell line and its effects on apoptosis induced by DEHP

Objective: To construct 3β-HSD gene shRNA lentivirus interference vecto, then transfect into human MCF-7 cells, and construct cell line with 3β-HSD gene silencing, finally to study the effects of 3β-HSD on apoptosis induced by di- (2-ethylhexyl) phthalate (DEHP) . Methods: According to the mRNA sequence of 3β-HSD gene provided by GenBank, three interference sequences were designed and connected to PLVX-shRNA2-puro after annealing. The recombinant lentivirus vector was transfected into 293FT cells, the virus supernatants were collected and infected with MCF-7 cells. After puromycin screening, MCF-7 cells with 3β-HSD gene silencing were constructed. The cells with 3β-HSD gene silencing were identified by real-time quantitative PCR and western blot. Then the 3β-HSD gene silencing cells and MCF-7 cells were treated at various doses of DEHP for 24 hours to detect the gene expression and protein expression of apoptosis genes including Bax, Caspase-3 and Caspase-8. Results: The interference sequence of 3β-HSD gene inserted into lentivirus vector PLVX-shRNA2-puro is consistent with the designed sequence. 3β-HSD gene expression level in MCF-7 cells with 3β-HSD gene silencing was 77% lower than than that of control MCF-7 cells. 3β-HSD protein level in MCF-7 cells with 3β-HSD gene silencing was 74% lower than that of control MCF-7 cells. After DEHP treatment in MCF-7 cells with 3β-HSD gene silencing and control MCF-7 cells, qRT-PCR results showed that Bax gene expression levels increased by 28%-54%, Caspase-3 gene increased by 13%-49%, Caspase-8 gene increased by 21%-70% in MCF-7 cells when compared with the control group. Additionally, in the 3β-HSD gene silencing cells, Bax gene expression level decreased by 11%-28%, Caspase-3 gene expression decreased by 12%-23%, Caspase-8 gene expression decreased by 11%-34%, compared with the same treatment group of MCF-7 cells. Western blot results showed that Bax protein expression level increased by 28%-61%, Caspase-3 protein expression level increased by 40%-48%, Caspase-8 protein increased by 31%-84% in MCF-7 cells when compared with the control group. In 3β-HSD gene silencing cells, Bax protein expression level increased by 11%-27%, Caspase-3 protein increased by 21%-40%, Caspase-8 protein increased by 12%-25%, compared with the same treatment group of MCF-7 cells. Conclusion: The stable 3β-HSD gene silencing cell line are successfully constructed in this study. DEHP can induce increased expression of apoptotic gene and protein. Silencing of 3β-HSD gene can inhibit the activation of apoptotic gene by DEHP in a certain degree.

Di(2-ethylhexyl) phthalate promotes lung cancer cell line A549 progression via Wnt/β-catenin signaling.

Di(2-ethylhexyl) phthalate (DEHP) is widely used in polyvinylchloride-based materials and remains intact in the environment. Lungs are one route of entry of DEHP into the body; however, there is limited information on the effects and mechanism of action of DEHP on non-small cell lung cancer (NSCLC). Here, we addressed this by examining the effect of DEHP on the proliferation of A549 human lung adenocarcinoma cells by MTS assay. The induction of inflammation and epithelial-to-mesenchymal transition (EMT), as well as activation of the mitogen-activated protein kinase (MAPK) and Wnt/β-catenin signaling pathways, were assessed by western blot and real-time polymerase chain reaction. Although there were discrepancies in the concentration, DEHP treatment enhanced A549 cell viability accompanied by increased mRNA and protein levels of inflammation-related factors, such as matrix metalloproteinase-9 and nuclear factor-κB. Additionally, EMT was activated in cells according to decreased E-cadherin and increased vimentin expression. Furthermore, MAPK pathway components, including phosphorylated p38 and c-Jun N-terminal kinase, and Wnt/β-catenin pathway components, including phosphorylated glycogen synthase kinase 3β and β-catenin, as well as their downstream genes c-Myc and cyclin D1, were upregulated in the presence of DEHP. These results suggest that DEHP promotes NSCLC progression by promoting cell proliferation, inflammation, and EMT via activation of Wnt/β-catenin signaling.

Effects of DEHP on post-embryonic development, nuclear receptor expression, metabolite and ecdysteroid concentrations of the moth Spodoptera littoralis

Di (2-ethylhexyl) phthalate (DEHP) is recognized in vertebrates as an Endocrine Disrupting Chemical (EDC). DEHP can alter steroid hormones production, development, reproduction and behavior in vertebrates. Only few studies investigated DEHP effects on insects. However, some recent studies on aquatic insects showed that DEHP could also act as an EDC by interfering with the signaling pathways of ecdysteroids, the main hormones involved in the control of insect post-embryonic development and physiology. The aim of the study was to investigate (1) the fate of DEHP within a terrestrial insect species by exposing larvae to food containing a wide range of DEHP concentrations and (2) the effects of this chemical on their post-embryonic development and metamorphosis, by using a multi-level approach. DEHP was shown to be present both in larvae and resulting stages, with higher concentrations in chrysalises and adults than in larvae. DEHP concentrations also decreased at the end of the last larval instar, suggesting the metabolic transformation or excretion of this chemical during this time. Only the two highest DEHP doses induced higher insect mortality, whereas low and intermediate concentrations increased larval food consumption without affecting body weight. Metabolic profiles showed that in control insects, the last three days before metamorphosis correspond to a metabolic transition, but with time-dependent changes in treated insects. Interestingly, DEHP treatments also alter both hemolymphatic ecdysteroid titers and expression levels of ecdysteroid response genes. These results confirm that DEHP can alter insect post-embryonic development and metamorphosis, by interfering with ecdysteroid pathways.

Modulation of heat-shock response is associated with Di (2-ethylhexyl) phthalate (DEHP)-induced cardiotoxicity in quail (Coturnix japonica)

Di(2-ethylhexyl) phthalate (DEHP) is an omnipresent environmental pollutant with endocrine disrupting properties. As a plasticizer, DEHP can be leach from the plastic to transfer the external environment and thus enters the animal food chain, causing serious damage to the animal organs. The heat-shock response (HSR) comprising heat-shock protein (HSPs) and heat-shock transcription factor (HSFs) plays a pivotal role in various toxic stress conditions. For the sake of investigating the effects of DEHP exposure on cardiac toxicity and the regulation of HSR, male quail were fed the diet with 0, 250, 500 and 750 mg/kg DEHP by gavage administration for 45 days. Histopathological changes including cardiomyocyte swelling and muscle fiber dilatation were observed in the hearts exposed to DEHP. During the DEHP treatment, the mRNA expression of HSP60 and HSP70 were universally reduced, while the expression of other HSPs (HSP10, HSP25, HSP27, HSP40, HSP47, HSP90, HSP110) had different degrees of growth. In addition, the levels of HSF1, HSF2, and HSF3 were significantly increased. Given the facts above, DEHP exposure induced the toxic effects of quail heart. DEHP exposure did great harm to HSR via affecting the synthesis of HSFs to mediate the transcription of the HSPs. Ultimately, this study provided new evidence that DEHP-induced cardiotoxicity in quail was related to activation of HSR and playing a protective role.

Cell Motility Facilitated by Mono(2-ethylhexyl) Phthalate via Activation of the AKT-β-Catenin-IL-8 Axis in Colorectal Cancer.

Di(2-ethylhexyl) phthalate (DEHP) is a common plasticizer that is widely used in many consumer products and medical devices. Humans can be exposed to DEHP through ingestion, inhalation, or dermal absorption. Previous studies on DEHP have focused on its role as an endocrine-disrupting chemical leading to endocrine-related diseases. However, the correlation between DEHP exposure and the progression of colorectal cancer (CRC) is largely unknown. The aim of this study was to investigate the effects of mono(2-ethylhexyl) phthalate (MEHP), an active metabolite of DEHP, on the progression of CRC. Our results showed that treatment with MEHP enriched the population of cancer-stem-cell (CSC)-like cells and upregulated IL-8 expression by inducing the AKT-β-catenin-TCF4 signaling pathway. Blocking β-catenin-TCF4-mediated IL-8 expression reversed the MEHP-induced migration and enrichment of CSC-like cells. Consistent with the in vitro data, DEHP treatment increased the levels of nuclear β-catenin, polyp formation, and invasive adenocarcinoma in a mouse model. Our results suggest that MEHP facilitates the progression of CRC through AKT-β-catenin signaling.

Variations in microbial community and di-(2-ethylhexyl) phthalate (DEHP) dissipation in different rhizospheric compartments between low- and high-DEHP accumulating cultivars of rice (Oryza sativa L.)

Di-(2-ethylhexyl) phthalate (DEHP) is a typical endocrine disrupting chemical with relatively high concentrations in agricultural soils of China. Here, a rhizobox experiment was conducted to investigate the variations in microbial community and DEHP dissipation among different soil rhizospheric compartments between low (Fengyousimiao) and high (Peizataifeng) DEHP-accumulating cultivars of rice (Oryza sativa L.) grown in DEHP spiked soil (0, 20, 100 mg/kg). The dissipation rates of DEHP in rhizospheric soils of Peizataifeng were generally significantly higher than those of Fengyousimiao, with the highest removal rate in 0–2 mm rhizosphere. The results of Illumina-HiSeq high-throughput sequencing revealed that both bacterial and fungal diversity and community structure were significantly different in rhizospheric soils of the two cultivars. DEHP dissipation rates in 0–2 mm rhizosphere of Peizataifeng were positively correlated with bacterial and fungal diversity. The relative abundance of DEHP-degrading bacterial genera Acinetobacter, Pseudomonas and Bacillus of Peizataifeng was generally higher than those in the same rhizospheric compartment of Fengyousimiao in DEHP treatments, resulting in different rhizospheric DEHP dissipation. Cultivation of Peizataifeng in agricultural soil is promising to facilitate DEHP dissipation and ensure safety of agricultural products.

Exposure to Di-(2-ethylhexyl) Phthalate During Perinatal Period Gender-Specifically Impairs the Dendritic Growth of Pyramidal Neurons in Rat Offspring.

Di-(2-ethylhexyl) phthalate (DEHP), as a prevalent xenoestrogen endocrine disrupter, is omnipresent in the environment and commonly used in polyethylene plastic products. Although DEHP has potential adverse effects on multisystem organs, damage to the central nervous system is more significant. However, the consequences and mechanisms of DEHP exposure remain to be explored. The aim of this study was to investigate the effects and related mechanisms of maternal DEHP exposure on dendritic development of hippocampal pyramidal neurons in a rat model. Pregnant Wistar rats were intragastrically administrated either vehicle or DEHP (30, 300, and 750 mg/kg/d) from gestation day 0 to postnatal day (PN) 21. The dendritic length and complexity of dendritic arbors’ pattern in pyramidal neurons of the hippocampus were measured using Golgi–Cox staining and Sholl analysis. The expression of dendritic development-related proteins was detected using western blot and immunofluorescence staining. DEHP-treated male but not female pups showed an obvious decrease in the total length and branching numbers of basal dendrites on PN7, PN14, and PN21. The phosphorylation of MAP2c, stathmin, and JNK1 in the male pup hippocampus was significantly decreased in DEHP treatment groups compared to controls. However, protein expression alteration in the hippocampus of female offspring was not observed. In summary, our study indicated that DEHP has a gender-specific negative impact on the dendritic growth of CA1 pyramidal neurons in male offspring of a rat model of DEHP exposure. The adverse impact may be related to the dysregulation of phosphorylated and total MAP2c and stathmin mediated by JNK1.

Di (2-ethyl hexyl) phthalate (DEHP)-induced kidney injury in quail (Coturnix japonica) via inhibiting HSF1/HSF3-dependent heat shock response

Di (2-ethyl hexyl) phthalate (DEHP) as a plasticizer can leach away from the plastic and hence entrances into the animal food chain which caused serious hazard in organs of animals, but there are few studies on DEHP kidney toxicity. The heat-shock response (HSR) consisting of the HSPs and HSFs plays an important role in various toxicity stress conditions. To investigate the influence on kidney toxicity and the modulation of HSR during DEHP exposure, female quail were fed the diet with 0, 250, 500 and 750 mg/kg DEHP by gavage administration for 45 days. The shrinkages of glomeruli and dilation of kidney tubule epithelia cells were observed in the kidney of DEHP-exposed quail. DEHP treatment could significantly decrease the expressions of HSP25, HSP27, HSP47, HSP60, while the expressions of HSP10, HSP40, HSP70, HSP90, HSP110 were upregulated in the kidney. In addition, the expression levels of HSF1 and HSF3 were significantly increased under DEHP. This is the first study to demonstrate quail exposure to DEHP is in fact detrimental to bird kidney. Besides, DEHP could attack HSR by affecting the synthesis of HSFs to mediate the transcription of the HSPs resulting in kidney damage.

DEHP exposure destroys blood-testis barrier (BTB) integrity of immature testes through excessive ROS-mediated autophagy

Di-(2-ethylhexyl) phthalate (DEHP), is known to impair testicular functions and reproduction. However, its effects on immature testis Blood-testis barrier (BTB) and the underlying mechanisms remain obscure. We constructed a rat model to investigate the roles of autophagy in BTB toxicity induced by DEHP. Sprague–Dawley rats were developmentally exposed to 0, 250 and 500 mg/kg DEHP via intragastric administration from postnatal day (PND) 1 to PND 35. Testicular morphology, expressions of BTB junction proteins and autophagy related proteins were detected. In addition, expressions of oxidative stress markers were also analyzed. Our results demonstrated that developmental DEHP exposure induced decreasing organ coefficients of immature testes and severe testicular damage in histomorphology. The expressions of junctional proteins were down-regulated significantly after DEHP treatment. Intriguingly, DEHP simultaneously increased the number of autophagosomes and the levels of autophagy marker LC3-II and p62, suggesting that the accumulated autophagosomes resulted from impaired autophagy degradation. Moreover, the expressions of HO-1 and SOD levels remarkably decreased after DEHP exposure. Vitamins E and C could alleviate the DEHP-induced oxidative stress, reverse the autophagy defect and restore the BTB impairment. Taken together, DEHP exposure destroys immature testis blood-testis barrier (BTB) integrity through excessive ROS-mediated autophagy.

Photosynthetic and antioxidant response of wheat to di(2-ethylhexyl) phthalate (DEHP) contamination in the soil

Di(2-ethylhexyl) phthalate (DEHP) is a commonly used, artificially-synthesized, industrial chemical that can be released into the soil. However, to date, there is no comprehensive study on the effects of DEHP on photosynthesis, induction of reactive oxygen species, and response of the antioxidant defense system in wheat plants growing in DEHP contaminated soil. This study was conducted to address this gap in knowledge. Our results showed that after application of 10, 20, and 40 mg/kg DEHP, photosynthetic parameters, fluorescence parameters, and chlorophyll content of wheat leaves at seedling, jointing, and booting stages decreased, while the intercellular carbon dioxide concentration increased. This indicates that the observed decrease in net photosynthetic rate in wheat leaves was due to a non-stomatal limitation, wherein DEHP seems to have hindered the photoelectron transfer process. Both superoxide anion (O2-) and hydrogen peroxide (H2O2) content increased in the roots, stems, and leaves in plant under DEHP treatment compared with those in the control plants. Antioxidant enzyme activity increased with increasing DEHP stress, except under the 40 mg/kg treatment at the seedling stage. The antioxidant system had a certain protective effect on wheat, but DEHP still caused peroxidation of cell membrane lipids. The extent of DEHP damage to the roots, stems, and leaves was concentration dependent. Furthermore, enzymatic activity tolerance increased with metabolism, and long-term effects of DEHP gradually decreased with plant growth. Finally, the toxic effects of DEHP on root tissues were more serious at the seedling and jointing stages.

Inhibition of di(2-ethylhexyl) phthalate (DEHP)-induced endocrine disruption by co-treatment of vitamins C and E and their mechanism of action

ABSTRACTThe endocrine disrupting actions of di(2-ethylhexyl) phthalate (DEHP) on testicular functions are postulated to involve excess free radical generation. Thus the aim of this study was to examine the ability of antioxidant vitamins C and E to prevent DEHP-induced testicular disruption in male Sprague-Dawley (SD) rats. SD male rats were administered DEHP alone or DEHP with vitamin C and/or vitamin E for 30 days. DEHP alone increased the levels of testosterone (T) and reduced estradiol (E2) concentrations. Supplementation with antioxidant vitamins diminished or restored serum T levels noted in DEHP-treated rats to control values. In contrast vitamins C and E increased E2 levels to control in rats administered DEHP. Antioxidants significantly improved the decreased testicular levels of reduced glutathione and activity of superoxide dismutase compared to DEHP-treatment alone. Co-treatment of vitamins C and E also markedly improved the reduced epididymal sperm head counts and elevated levels of malondialdehyde (MDA) or 8-hydroxydeoxyguanosine (8-OHdG) induced by DEHP treatment. These results support the concept that the adverse actions of DEHP may be related to increased free radical generation while co-treatment with vitamins C and E significantly blocked the actions of DEHP on male testicular functions.

Systematic reviews and meta-analyses of human and animal evidence of prenatal diethylhexyl phthalate exposure and changes in male anogenital distance

ABSTRACTMale reproductive alterations found in animals and humans following in utero phthalate exposure include decreased anogenital distance (AGD) and other reproductive-tract malformations. The aim of this investigation was to conduct systematic reviews of human and animal evidence of the effect of in utero exposure to diethylhexyl phthalate (DEHP) on anogenital distance (AGD) in males. PubMed, Embase, and Toxline were searched for relevant human and experimental animal studies on August 15, 2016. Search results were screened for relevance, and studies that met the inclusion criteria were evaluated for quality and data extracted for analysis. Confidence in the human and animal bodies of evidence was assessed and hazard conclusions reached by integrating evidence streams. The search yielded 6 relevant human studies and 19 animal studies. Meta-analysis of 5 human observational prospective cohort studies showed that increased maternal urinary concentrations of DEHP metabolites were associated with decreased AGD in boys (−4.07 [CI, −6.49 to −1.66] % decrease per log10 rise in DEHP metabolites). Meta-analysis and meta-regression of the 19 experimental animal studies found reduced AGD with DEHP treatment, with a dose-response gradient, and with heterogeneity explained by species and strain. There is a moderate level of evidence from human investigations and a high level of data from animal studies that in utero exposure to DEHP decreases AGD. Based upon the available human and animal evidence, and consideration of mechanistic data, DEHP is presumed to be a reproductive hazard to humans on the basis of effects on AGD.

Analysis of the in vitro effects of di-(2-ethylhexyl) phthalate exposure on human uterine leiomyoma cells.

Uterine leiomyoma is the most common benign tumor type of the female reproductive tract. Despite its high prevalence, the exact pathogenesis of the benign tumor remains unknown. In the present study, the effects of di-(2-ethylhexyl) phthalate (DEHP) on the proliferation and apoptosis rates and expression of inflammatory proteins in human leiomyoma cells were evaluated. The effects of DEHP on cell viability were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The effects on apoptosis were evaluated by western blotting, TUNEL assay and Annexin V staining. Western blotting was also performed to evaluate the expression of inflammatory proteins. It was observed that DEHP-treated leiomyoma cells had higher viability, as well as proliferating cell nuclear antigen and B-cell lymphoma 2 protein expression, and lower apoptosis rates compared with the untreated controls. Additionally, hypoxia inducible factor 1α (HIF-1α) and cyclooxygenase-2 (COX-2) expression increased in human leiomyoma cells following DEHP treatment. In conclusion, DEHP promoted cell viability and anti-apoptotic protein expression and induced HIF-1α and COX-2 expression in human leiomyoma cells. These results suggested that DEHP may disrupt mechanisms underlying various processes in human leiomyoma cells. Furthermore, the current study revealed a basic mechanism of action of DEHP in human leiomyoma cells. Further research on the effects of various endocrine disruptors on the pathogenesis of uterine leiomyoma during early development may reveal strategies to prevent this disease.

Intervention effect of gamma aminobutyric acid on anxiety behavior induced by phthalate (2-ethylhexyl ester) in rats

ABSTRACTBackground: Di(2-ethylhexyl) phthalate (DEHP) is one of the most widely used phthalate esters. The application of DEHP has caused serious environmental pollution and posed a threat to human health.Methods: A total of 30 male Sprague-Dawley rats were randomly divided into control group, DEHP group (500 mg/kg DEHP), low GABA (Gama-aminobutyric acid) group (500 mg/kg DEHP and 1 mg/kg GABA), medium GABA group (500 mg/kg DEHP and 2 mg/kg GABA) and high GABA group (500 mg/kg DEHP and 4 mg/kg GABA). The interventions continued for 30 consecutive days. Open-field test and elevated plus-maze test were used to detect behavioral changes of rats before and after interventions.Results: The levels of nitric oxide and nitric oxide synthase in prefrontal cortex of rats were measured using enzyme-linked immunosorbent assay. DEHP and GABA treatment had no significant effects on the body weight of rats. GABA restored food utilization rate of rats impaired by DEHP to the level of healthy rats. According to open-field test and elevated plus-maze test, GABA alleviated the effects of DEHP on rat behaviors. Enzyme-linked immunosorbent assay showed that GABA was effective in reducing the levels of nitric oxide and nitric oxide synthase in rats treated with DEHP.Conclusion: DEHP exposure induced anxiety in rats, which may be achieved through elevating nitric oxide and nitric oxide synthase levels in prefrontal cortex of rats. However, the effects caused by DEHP could be alleviated by GABA.