Mono-(2-ethyl-5-hydroxyhexyl) phthalate promotes uterine leiomyoma cell survival through tryptophan-kynurenine-AHR pathway activation.

Uterine leiomyoma is the most common tumor in women and causes severe morbidity in 15 to 30% of reproductive-age women. Epidemiological studies consistently indicate a correlation between leiomyoma development and exposure to endocrine-disrupting chemical phthalates, especially di-(2-ethylhexyl) phthalate (DEHP); however, the underlying mechanisms are unknown. Here, among the most commonly encountered phthalate metabolites, we found the strongest association between the urine levels of mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), the principal DEHP metabolite, and the risk of uterine leiomyoma diagnosis (n = 712 patients). The treatment of primary leiomyoma and smooth muscle cells (n = 29) with various mixtures of phthalate metabolites, at concentrations equivalent to those detected in urine samples, significantly increased cell viability and decreased apoptosis. MEHHP had the strongest effects on both cell viability and apoptosis. MEHHP increased cellular tryptophan and kynurenine levels strikingly and induced the expression of the tryptophan transporters SLC7A5 and SLC7A8, as well as, tryptophan 2,3-dioxygenase (TDO2), the key enzyme catalyzing the conversion of tryptophan to kynurenine that is the endogenous ligand of aryl hydrocarbon receptor (AHR). MEHHP stimulated nuclear localization of AHR and up-regulated the expression of CYP1A1 and CYP1B1, two prototype targets of AHR. siRNA knockdown or pharmacological inhibition of SLC7A5/SLC7A8, TDO2, or AHR abolished MEHHP-mediated effects on leiomyoma cell survival. These findings indicate that MEHHP promotes leiomyoma cell survival by activating the tryptophan-kynurenine-AHR pathway. This study pinpoints MEHHP exposure as a high-risk factor for leiomyoma growth, uncovers a mechanism by which exposure to environmental phthalate impacts leiomyoma pathogenesis, and may lead to the development of novel druggable targets.

The effects of short-term and long-term phthalate exposures on ovarian follicle growth dynamics and hormone levels in female mice†.

Di(2-ethylhexyl) phthalate and diisononyl phthalate are widely used as plasticizers in polyvinyl chloride products. Short-term exposures to phthalates affect hormone levels, ovarian follicle populations, and ovarian gene expression. However, limited data exist regarding the effects of long-term exposure to phthalates on reproductive functions. Thus, this study tested the hypothesis that short-term and long-term exposure to di(2-ethylhexyl) phthalate or diisononyl phthalate disrupts follicle dynamics, ovarian and pituitary gene expression, and hormone levels in female mice. Adult CD-1 female mice were exposed to vehicle, di(2-ethylhexyl) phthalate, or diisononyl phthalate (0.15 ppm, 1.5 ppm, or 1500 ppm) via the chow for 1 or 6 months. Short-term exposure to di(2-ethylhexyl) phthalate (0.15 ppm) and diisononyl phthalate (1.5 ppm) decreased serum follicle-stimulating hormone levels compared to control. Long-term exposure to di(2-ethylhexyl) phthalate and diisononyl phthalate (1500 ppm) increased the percentage of primordial follicles and decreased the percentages of preantral and antral follicles compared to control. Both phthalates increased follicle-stimulating hormone levels (di(2-ethylhexyl) phthalate at 1500 ppm; diisononyl phthalate at 1.5 ppm) and decreased luteinizing hormone levels (di(2-ethylhexyl) phthalate at 0.15 and 1.5 ppm; diisononyl phthalate at 1.5 ppm and 1500 ppm) compared to control. Furthermore, both phthalates altered the expression of pituitary gonadotropin subunit genes (Cga, Fshb, and Lhb) and a transcription factor (Nr5a1) that regulates gonadotropin synthesis. These data indicate that long-term exposure to di(2-ethylhexyl) phthalate and diisononyl phthalate alters follicle growth dynamics in the ovary and the expression of gonadotropin subunit genes in the pituitary and consequently luteinizing hormone and follicle-stimulating hormone synthesis.

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

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

Prenatal exposure to Di(2-ethylhexyl) phthalate and high-fat diet synergistically disrupts gonadal function in male mice†.

Prenatal exposure to Di (2-ethylhexyl) phthalate (DEHP) impairs the reproductive system and causes fertility defects in male offspring. Additionally, high-fat (HF) diet is a risk factor for reproductive disorders in males. In this study, we tested the hypothesis that prenatal exposure to a physiologically relevant dose of DEHP in conjunction with HF diet synergistically impacts reproductive function and fertility in male offspring. Female mice were fed a control or HF diet 7 days prior to mating and until their litters were weaned on postnatal day 21. Pregnant dams were exposed to DEHP or vehicle from gestational day 10.5 until birth. The male offspring's gross phenotype, sperm quality, serum hormonal levels, testicular histopathology, and testicular gene expression pattern were analyzed. Male mice born to dams exposed to DEHP + HF had smaller testes, epididymides, and shorter anogenital distance compared with those exposed to HF or DEHP alone. DEHP + HF mice had lower sperm concentration and motility compared with DEHP mice. Moreover, DEHP + HF mice had more apoptotic germ cells, fewer Leydig cells, and lower serum testosterone levels than DEHP mice. Furthermore, testicular mRNA expression of Dnmt1 and Dnmt3a was two to eight-fold higher than in DEHP mice by qPCR, suggesting that maternal HF diet and prenatal DEHP exposure additively impact gonadal function by altering the degree of DNA methylation in the testis. These results suggest that the combined exposure to DEHP and high-fat synergistically impairs reproductive function in male offspring, greater than exposure to DEHP or HF diet alone.

Inhibitory effects of phthalate esters (PAEs) and phthalate monoesters towards human carboxylesterases (CESs).

Phthalate esters (PAEs), accompanied by phthalate monoesters as hydrolysis metabolites in humans, have been widely used as plasticizers and exhibited disruptive effects on the endocrine and metabolic systems. The present study aims to investigate the inhibition behavior of PAEs and phthalate monoesters on the activity of the important hydrolytic enzymes, carboxylesterases (CESs), to elucidate the toxicity mechanism from a new perspective. The results showed significant inhibition on CES1 and CES2 by most PAEs, but not by phthalate monoesters, above which the activity of CES1 was strongly inhibited by DCHP, DEHP, DiOP, DiPP, DNP, DPP and BBZP, with inhibition ratios exceeding 80%. Kinetic analyses and in vitro-in vivo extrapolation were conducted, revealing that PAEs have the potential to disrupt the metabolism of endogenous substances catalyzed by CES1 in vivo. Molecular docking results revealed that hydrogen bonds and hydrophobic contacts formed by ester bonds contributed to the interaction of PAEs towards CES1. These findings will be beneficial for understanding the adverse effect of PAEs and phthalate monoesters.

Long-term exposure to the mixture of phthalates induced male reproductive toxicity in rats and the alleviative effects of quercetin.

Phthalates (PEs), such as di(2-ethylhexyl) phthalate (DEHP), dibutyl phthalate (DBP) and butyl benzyl phthalate (BBP) could cause reproductive and developmental toxicities, while human beings are increasingly exposed to them at low-doses. Phytochemical quercetin (Que) is a flavonoid that has estrogenic effect, anti-inflammatory and anti-oxidant effects. This study was conducted to assess the alleviative effect of Que. on male reproductive toxicity induced by the mixture of three commonly used PEs (MPEs) at low-dose in rats, and explore the underlying mechanism. Male rats were treated with MPEs (16 mg/kg/day) and/or Que. (50 mg/kg/d) for 91 days. The results showed that MPEs exposure caused male reproductive injuries, such as decreased serum sex hormones levels, abnormal testicular pathological structure, increased abnormal sperm rate and changed expressions of PIWIL1 and PIWIL2. Furthermore, MPEs also changed the expression of steroidogenic proteins in steroid hormone metabolism, including StAR, CYP11A1, CYP17A1, 17ß-HSD, CYP19A1. However, the alterations of these parameters were reversed by Que. MPEs caused male reproductive injuries in rats; Que. inhibited MPEs' male reproductive toxicity, which might relate to the improvement of testosterone biosynthesis.

Increased di-(2-ethylhexyl) phthalate exposure poses a differential risk for adult asthma clusters.

BACKGROUND: DEHP, a common plasticizer known for its hormone-disrupting properties, has been associated with asthma. However, a significant proportion of adult asthma cases are "non-atopic", lacking a clear etiology. METHODS: In a case-control study conducted between 2011 and 2015, 365 individuals with current asthma and 235 healthy controls from Kaohsiung City were enrolled. The control group comprised individuals without asthma, Type 2 Diabetes Mellitus (T2DM), hypertension, or other respiratory/allergic conditions. The study leveraged asthma clusters (Clusters A to F) established in a prior investigation. Analysis involved the examination of urinary DEHP metabolites (MEHP and MEHHP), along with the assessment of oxidative stress, sphingolipid metabolites, and inflammatory biomarkers. Statistical analyses encompassed Spearman's rank correlation coefficients, multiple logistic regression, and multinomial logistic regression. RESULTS: Asthma clusters (E, D, C, F, A) exhibited significantly higher ORs of MEHHP exposures compared to the control group. When considering asthma-related comorbidities (T2DM, hypertension, or both), patients without comorbidities demonstrated significantly higher ORs of the sum of primary and secondary metabolites (MEHP + MEHHP) and MEHHP compared to those with asthma comorbidities. A consistent positive correlation between urinary HEL and DEHP metabolites was observed, but a consistent negative correlation between DEHP metabolites and selected cytokines was identified. CONCLUSION: The current study reveals a heightened risk of MEHHP and MEHP + MEHHP exposure in specific asthma subgroups, emphasizing its complex relationship with asthma. The observed negative correlation with cytokines suggests a new avenue for research, warranting robust evidence from epidemiological and animal studies.

Green Tea Polyphenols Alleviate Kidney Injury Induced by Di(2-Ethylhexyl) Phthalate in Mice.

INTRODUCTION: Di(2-ethylhexyl) phthalate (DEHP) is a common plasticizer. Studies have revealed that DEHP exposure can cause kidney damage. Green tea is among the most popular beverages in China. Green tea polyphenols (GTPs) have been proven to have therapeutic effects on organ damage induced by heavy metal exposure. However, few studies have reported on GTP-relieving DEHP-induced kidney damage. METHODS: C57BL/6J male mice aged 6-8 weeks were treated with distilled water (control group), 1,500 mg/kg/d DEHP + corn oil (model group), 1,500 mg/kg/d DEHP + corn oil + 70 mg/kg GTP (treatment group), corn oil (oil group), and 70 mg/kg GTP (GTP group) by gavage for 8 weeks, respectively. The renal function of mice and renal tissue histopathology of each group were evaluated. The renal tissues of mice in the model, treatment, and control groups were analyzed using high-throughput sequencing. We calculated the differentially expressed microRNAs (miRNAs) and messenger RNAs (mRNAs) using the limma R package, the CIBERSORT algorithm was used to predict immune infiltration, the starBase database was used to screen the miRNA-mRNA regulatory axis, and immunohistochemical analyses were performed to verify protein expression. RESULTS: GTP alleviated the deterioration of renal function, renal inflammation and fibrosis, and mitochondrial and endoplasmic reticulum lesions induced by DEHP in mice. Differential immune infiltrations of plasma, dendritic, T, and B cells were noted between the model and treatment groups. We found that three differentially expressed miRNAs (mmu-miR-383-5p, mmu-miR-152-3p, and mmu-miR-144-3p), three differentially expressed mRNAs (Ddit4, Dusp1, and Snx18), and three differentially expressed proteins (Ddit4, Dusp1, and Snx18) played crucial roles in the miRNA-mRNA-protein regulatory axes when GTPs mitigate DEHP-induced kidney damage in mice. CONCLUSION: GTP can alleviate DEHP-induced kidney damage and regulate immune cell infiltration. We screened four important miRNA-mRNA-protein regulatory axes of GTP, mitigating DEHP-induced kidney damage in mice.

Regulation of BTB (POZ) Structural Domain 6b by MicroRNA-222b in Zebrafish Embryos after Exposure to Di(2-ethylhexyl)phthalate at Low Concentrations.

Di-(2-ethylhexyl) phthalate (DEHP) is a sort of endocrine disruptor that induces abnormal physiological and biochemical activities such as epigenetic alterations, apoptosis, and oxidative stress. MicroRNAs (miRNAs) are a class of short noncoding RNAs that may regulate the expression of many protein-coding genes when organisms are exposed to environmental chemicals. miR-222b is a differentially expressed miRNA after DEHP exposure. miRNA-mRNA prediction suggested that BTB (POZ) structural domain 6b (BTBD6B) might be a target mRNA of miR-222b, and DEHP exposure altered its expression. However, the correlation between miR-222b and BTBD6B has not been experimentally confirmed. The aim of this study was to investigate the regulation of BTBD6B by miR-222b in zebrafish embryos under the effect of low concentration of DEHP. Dual fluorescent protein assays and dual luciferase reporter gene assays confirmed the interaction between miR-222b and the 3'-untranslated region (3'-UTR) of BTBD6B. Ectopic expression assays showed that miR-222b could negatively regulate BTBD6B in ZF4 cells. However, the relative expression of miR-222b and BTBD6B was significantly higher at both transcriptional and post-transcriptional levels in zebrafish embryos exposed to low concentrations of DEHP. The results of this study improved our understanding of the molecular mechanism of DEHP exposure toxicity. It identified that the aberrant expression of miR-222b/BTBD6B may be one of the mechanisms of DEHP toxicity, which can provide a theoretical reference and scientific basis for environmental management and biological health risk assessment.

Phthalate Exposure and Coronary Heart Disease: Possible Implications of Oxidative Stress and Altered miRNA Expression.

The relationship between phthalate exposure and coronary heart disease (CHD) is still unclear. This study aimed to investigate the association between phthalate exposure and CHD and determine the possible atherogenic mechanisms of phthalates by assessing oxidative stress and altering miRNA expression. This case-control study included 110 participants (55 CHD patients and 55 healthy controls). The levels of oxidative stress markers, malondialdehyde (MDA), and superoxide dismutase (SOD), and the expression of miRNA-155 (miR-155) and miRNA-208a (miR-208a), were measured and correlated with the urinary mono-2-ethylhexyl phthalate (MEHP). Highly significant differences were detected between the CHD cases and the control group regarding MEHP, MDA, SOD, miR-155, and miR-208a (p-value < 0.001). Spearman correlations revealed a significant positive correlation between MDA and MEHP in urine (P = 0.001 and rs = 0.316) and a significant negative correlation between SOD and MEHP in urine (P < 0.001 and rs = -0.345). Furthermore, significant positive correlations were observed between miR-155 and urinary MEHP (P = 0.001 and rs = 0.318) and miR-208a and urinary MEHP (P < 0.001 and rs = -0.352). This study revealed an association between phthalate exposure, as indicated by urinary MEHP and CHD; altered expression of miR-155 and miR-208a and oxidative stress could be the fundamental mechanisms.

Exposure to MEHP during Pregnancy and Lactation Impairs Offspring Growth and Development by Disrupting Thyroid Hormone Homeostasis.

Mono(2-ethylhexyl) phthalate (MEHP), as a highly toxic and biologically active phthalate metabolite, poses considerable risks to the environment and humans. Despite the existence of in vitro studies, there is a lack of in vivo experiments assessing its toxicity, particularly thyroid toxicity. Herein, we investigated the thyroid-disrupting effects of MEHP and the effects on growth and development of maternal exposure to MEHP during pregnancy and lactation on the offspring modeled by SD rats. We found that thyroid hormone (TH) homeostasis was disrupted in the offspring, showing a decrease in total TH levels, combined with an increase in free TH levels. Nonhomeostasis ultimately leads to weight loss in female offspring, longer anogenital distance in male offspring, prolonged eye-opening times, and fewer offspring. Our findings indicate that maternal exposure to MEHP during pregnancy and lactation indirectly influences the synthesis, transport, transformation, and metabolism of THs in the offspring. Meanwhile, MEHP disrupted the morphology and ultrastructure of the thyroid gland, leading to TH disruption. This hormonal disruption might ultimately affect the growth and development of the offspring. This study provides a novel perspective on the thyroid toxicity mechanisms of phthalate metabolites, emphasizing the health risks to newborns indirectly exposed to phthalates and their metabolites.

First Insight into Fetal Exposure to Legacy and Emerging Plasticizers Revealed by Infant Hair and Meconium: Occurrence, Biotransformation, and Accumulation.

Epidemiological studies have demonstrated the embryonic and developmental toxicity of plasticizers. Thus, understanding the in utero biotransformation and accumulation of plasticizers is essential to assessing their fate and potential toxicity in early life. In the present study, 311 infant hair samples and 271 paired meconium samples were collected at birth in Guangzhou, China, to characterize fetal exposure to legacy and emerging plasticizers and their metabolites. Results showed that most of the target plasticizers were detected in infant hair, with medians of 9.30, 27.6, and 0.145 ng/g for phthalate esters (PAEs), organic phosphate ester (OPEs), and alternative plasticizers (APs), and 1.44, 0.313, and 0.066 ng/g for the metabolites of PAEs, OPEs, and APs, respectively. Positive correlations between plasticizers and their corresponding primary metabolites, as well as correlations among the oxidative metabolites of bis(2-ethylhexyl) phthalate (DEHP) and 1,2-cyclohexane dicarboxylic acid diisononyl ester (DINCH), were observed, indicating that infant hair retained the major phase-I metabolism of the target plasticizers. While no positive correlations were found in parent compounds or their primary metabolites between paired infant hair and meconium, significant positive correlations were observed among secondary oxidative metabolites of DEHP and DINCH in hair and meconium, suggesting that the primary metabolites in meconium come from hydrolysis of plasticizers in the fetus but most of the oxidative metabolites come from maternal-fetal transmission. The parent compound/metabolite ratios in infant hair showed a decreasing trend across pregnancy, suggesting in utero accumulation and deposition of plasticizers. To the best of our knowledge, this study is the first to report in utero exposure to both parent compounds and metabolites of plasticizers by using paired infant hair and meconium as noninvasive biomonitoring matrices and provides novel insights into the fetal biotransformation and accumulation of plasticizers across pregnancy.

Developmental exposure to environmentally relevant doses of phthalates alters the neural control of male and female reproduction in mice.

The present study aims to analyze the effects of developmental exposure to phthalates at environmentally relevant doses on the neural control of male and female reproduction. For this purpose, C57Bl/6J mice were exposed to di-(2-ethylexyl) phthalate (DEHP) alone (5 or 50 µg/kg/d), or DEHP (5 µg/kg/d) in a phthalate mixture. Exposure through diet started 6 weeks before the first mating and lasted until weaning of litters from the second gestation (multiparous dams). Analyses of offspring born from multiparous dams exposed to DEHP alone or in a phthalate mixture showed that females experienced a delayed pubertal onset, and as adults they had prolonged estrous cyclicity and reduced Kiss1 expression in the preoptic area and mediobasal hypothalamus. Male littermates showed a reduced anogenital distance and delayed pubertal onset compared with controls. However, in adulthood the weight of androgen-sensitive organs and hypothalamic Kiss1 expression were unaffected, suggesting normal functioning of the male gonadotropic axis. Developmental exposure to DEHP alone or in a phthalate mixture reduced the ability of intact males and ovariectomized and hormonally primed females to attract a sexual partner and to express copulatory behaviors. In addition, females were unable to discriminate between male and female stimuli in the olfactory preference test. Social interaction was also impaired in females, while locomotor activity and anxiety-like behavior in both sexes were unaffected by the treatment. The sexual deficiencies were associated with reduced expression of the androgen receptor in the preoptic area and progesterone receptor in the mediobasal hypothalamus, the key regions involved in male and female sexual behavior, respectively. Thus, the neural structures controlling reproduction are vulnerable to developmental exposure to phthalates at environmentally relevant doses in male and female mice. Adult females had an impaired gonadotropic axis and showed more affected behaviors than adult males.

Exposure to di-2-ethylhexyl phthalate (DEHP) increases the risk of cancer.

Cancer is a major socioeconomic burden that seriously affects the life and spirit of patients. However, little is known about the role of environmental toxicant exposure in diseases, especially ubiquitous di-(2-ethylhexyl) phthalate (DEHP) which is one of the most widely used plasticizers. Hence, the objective of this study was to assess the potential association between cancer and DEHP. The data were collected using the 2011-2018 National Health and Nutrition Examination Survey (NHANES) data (n = 6147), and multiple logistic regression was conducted to evaluate the association. The concentrations of DEHP were calculated by each metabolite and split into quartiles for analysis. After adjusting for confounding factors, DEHP was significantly associated with an increased risk of cancer prevalence, and the metabolites of DEHP showed similar results (OR > 1.0, p < 0.05). Simultaneously, the association remained when the analyses were stratified by age and sex, and the risk of cancer appeared to be higher in male patients. In addition, further analysis suggested that DEHP exposure obviously increased the risk of female reproductive system cancer, male reproductive system cancer, and other cancers (OR > 1.0, p < 0.05) but not skin and soft tissue cancer. DEHP exposure is associated with the risk of cancer, especially female reproductive system cancer, male reproductive system cancer and other cancers.

Novel Insights into Ethanol-Soluble Oyster Peptide-Zinc-Chelating Agents: Structural Characterization, Chelation Mechanism, and Potential Protection on MEHP-Induced Leydig Cells.

Numerous studies have reported that mono-(2-ethylhexyl) phthalate (MEHP) (bioactive metabolite of Di(2-ethylhexyl) phthalate) has inhibitory effects on Leydig cells. This study aims to prepare an oyster peptide-zinc complex (PEP-Zn) to alleviate MEHP-induced damage in Leydig cells. Zinc-binding peptides were obtained through the following processes: zinc-immobilized affinity chromatography (IMAC-Zn2+), liquid chromatography-mass spectrometry technology (LC-MS/MS) analysis, molecular docking, molecular dynamic simulation, and structural characterization. Then, the Zn-binding peptide (PEP) named Glu-His-Ala-Pro-Asn-His-Asp-Asn-Pro-Gly-Asp-Leu (EHAPNHDNPGDL) was identified. EHAPNHDNPGDL showed the highest zinc-chelating ability of 49.74 ± 1.44%, which was higher than that of the ethanol-soluble oyster peptides (27.50 ± 0.41%). In the EHAPNHDNPGDL-Zn complex, Asn-5, Asp-7, Asn-8, His-2, and Asp-11 played an important role in binding to the zinc ion. Additionally, EHAPNHDNPGDL-Zn was found to increase the cell viability, significantly increase the relative activity of antioxidant enzymes and testosterone content, and decrease malondialdehyde (MDA) content in MEHP-induced TM3 cells. The results also indicated that EHAPNHDNPGDL-Zn could alleviate MEHP-induced apoptosis by reducing the protein level of p53, p21, and Bax, and increasing the protein level of Bcl-2. These results indicate that the zinc-chelating peptides derived from oyster peptides could be used as a potential dietary zinc supplement.

Prenatal to peripubertal exposure to Di(2-ethylhexyl) phthalate induced endometrial atrophy and fibrosis in female mice.

Di(2-ethylhexy) phthalate (DEHP) is a widely used plasticizer that is ubiquitously found in the environment. Using a mouse model, we investigated the impact of early life DEHP exposure ranging from the prenatal to peripubertal developmental period of the female reproductive system. Pregnant female mice were allocated to three groups as follows: control, 100 mg/kg/day, and 500 mg/kg/day DEHP treatment. DEHP exposure was introduced through feeding during pregnancy (3 weeks) and lactation (3 weeks). After weaning, the offspring were also exposed to DEHP through feeding for another 2 weeks. Observations were conducted on female offspring at 10 and 24 weeks. The number of live offspring per dam was significantly lower in the high-DEHP-exposed group (500 mg/kg/day) compared to the control group (7.67 ± 1.24 vs. 14.17 ± 0.31; p < 0.05) despite no difference in pregnancy rates across the groups. Low-DEHP exposure (100 mg/kg/day) resulted to a decreased body weight (36.07 ± 3.78 vs. 50.11 ± 2.11 g; p < 0.05) and decreased left uterine length (10.60 ± 1.34 vs. 14.77 ± 0.82 mm; p < 0.05) in 24-week- old female mice. As early as 10 weeks, endometrial atrophy and fibrosis were observed, and endometrial cystic hyperplasia was noted in female mice at 24 weeks. Our study is the first to demonstrate that female mice exposed to DEHP in the early life developed endometrial fibrosis in the female offspring. Further studies on the consequences of these observations in fecundity and other reproductive functions are warranted.

Effect of aging on the release of di-(2-ethylhexyl) phthalate from biodegradable and petroleum-based microplastics into soil.

Due to microplastics (MPs) being widely distributed in soil, the use of advanced oxidation to remediate organic-contaminated soils may accelerate the aging of MPs in soil and impact the release of di-(2-ethylhexyl) phthalate (DEHP), a potential carcinogen used as a plasticizer in plastics, from MPs. In this study, persulfate oxidation (PO) and temperature treatment (TT) were used to treat biodegradable and petroleum-based MPs, including polylactic acid (PLA), polyvinyl chloride (PVC), and polystyrene (PS). The methods used for evaluating the characteristics changes of MP were X-ray diffraction (XRD) analysis and water contact angle measurement. The effects of aging on DEHP release from MPs were investigated via soil incubation. The results showed PO and TT led to increased surface roughness, oxygen-containing functional group content, and hydrophilicity of the MPs with prolonged aging, consequently accelerating the release of DEHP from the MPs. Interestingly, PLA aged faster than PVC and PS under similar conditions. After 30 days of PO treatment, DEHP release from PLA into the soil increased 0.789-fold, exceeding the increase from PVC (0.454-fold) and PS (0.287-fold). This suggests that aged PLA poses a higher ecological risk than aged PVC or PS. Furthermore, PO treatment resulted in the oxidation and degradation of DEHP on the MP surface. After 30 days of PO treatment, the DEHP content in PLA, PVC, and PS decreased by 19.1%, 25.8%, and 23.5%, respectively. Specifying the types of MPs studied and the environmental conditions would provide a more precise context for the results. These findings provide novel insights into the fate of biodegradable and petroleum-based MPs and the potential ecotoxicity arising from advanced oxidation remediation in contaminated soils.

Di-(2-ethylhexyl) phthalate (DEHP) contamination suppressed soil microbial biomass carbon and mitigated CO2 emissions against the background of alfalfa from different soils.

Plastic mulching and organic amendments are prevalent agricultural practices worldwide. Plastic mulching has long been suspected as a significant source of DEHP contamination in terrestrial ecosystems. However, effects of DEHP contamination on greenhouse gas emissions and microbial biomass carbon (MBC) remain unclear. Here, a microcosm experiment was set up to assess the impact of DEHP exposure on MBC and carbon dioxide (CO2) emission in two different soils (acidic and alkaline) with the inclusion of alfalfa straw. The treatment includes: (i) control with no amendment (T1); (ii) alfalfa straw addition (20 g kg-1) (T2); (iii) DEHP (10 mg kg-1) + alfalfa straw (T3); and (iv) DEHP (100 mg kg-1) + alfalfa straw (T4). Against the background of alfalfa inclusion, DEHP exposure led to a potential reduction in cumulative CO2 emissions by 16.35 % and 6.91 % in alkaline soil and 12.27 % and 13.65 % in acidic soil for T3 and T4, respectively. The addition of DEHP triggered CO2 emissions and manifested a detrimental negative priming effect in both soil types. In both soils, average CO2 emission fluxes were highest for the T2 treatment. The MBC fluctuated at around 80 mg kg-1 for the control group, alfalfa straw alone (T2) treatment considerably enhanced MBC contents, whereas DEHP contamination in T3 and T4 treatments suppressed the stimulatory effect of alfalfa on MBC in both alkaline and acidic soils. Furthermore, a positive relationship was observed between soil CO2 emissions and MBC in both soils. Overall, these findings highlight the toxic impact of DEHP on MBC and its role in mitigating CO2 emissions in diverse soils. DEHP exposure counters the CO2 emissions induced by alfalfa straw. In addition, the inhibitory effect of DEHP on CO2 fluxes in alkaline soil is less pronounced than in acidic soil. Therefore, further cutting-edge research is crucial since DEHP contamination poses serious ecological threats to agroecosystems.

Prenatal exposure to low-dose di-(2-ethylhexyl) phthalate (DEHP) induces potentially hepatic lipid accumulation and fibrotic changes in rat offspring.

Di(2-ethylhexyl) phthalate (DEHP) is a plasticizer that is widely used to enhance the flexibility and durability of various products. As an endocrine disruptor, DEHP can interfere with normal hormonal functions, posing substantial health risks to organisms. Given the critical role of the liver in DEHP metabolism, we investigated potential liver damage in offspring induced by prenatal exposure to low doses of DEHP in Sprague Dawley rats. Pregnant rats were divided into three groups and administered 20 or 200 µg/kg/day of DEHP or corn oil vehicle control via oral gavage from gestation days 0-20. Male rat offspring were euthanized on postnatal day 84, and blood and liver specimens were collected for analysis. We observed fibrotic changes in the livers of the exposed groups, accompanied by the proliferation and activation of hepatic stellate cells and upregulated expression of TGF-B and collagen 1A1. Additionally, an inflammatory response, characterized by increased macrophage infiltration and elevated levels of pro-inflammatory cytokines, was evident. Third, hepatic and serum triglyceride and serum cholesterol were notably increased, along with upregulated expression of lipid metabolism-related proteins, such as sterol regulatory element-binding protein-1c, acetyl-CoA carboxylase, fatty acid synthase, and diacylglycerol O-acyltransferase 1, particularly in the low-dose group. These results suggest that prenatal exposure to DEHP can disrupt lipid metabolism, resulting in hepatic lipid accumulation in the offspring. This exposure may also induce an inflammatory response that contributes to the development of liver fibrosis. Thus, even at relatively low doses, such exposure can precipitate latent liver damage in offspring.

Maternal exposure to di-(2-ethylhexyl) phthalate impaired the social interaction via activating microglia in male pups.

Di-(2-ethylhexyl) phthalate (DEHP), a common endocrine-disrupting chemical (EDC), is widely used in daily articles, early exposure to DEHP is associated with many behavioral changes in pups. This study aimed to investigate the effects and underlying mechanisms of maternal exposure to DEHP on the impaired social interaction in pups. Pregnant rats were administered 0, 30, 300, or 750 mg/kg/d DEHP daily by oral gavage. Highly aggressive proliferating immortalized (HAPI) cells were treated with mono-(2-ethylhexyl) phthalate (MEHP) and tyrosine phosphorylation inhibitor (AG490). Our results showed that DEHP exposure induced the activation of microglias (MGs) via activating the janus kinase 2 / signal transducer and activator of transcription 3 (JAK2/STAT3) signaling pathway, and increased the level of pro-inflammatory factors, then impaired the social behavior in male pups, but not female pups. Moreover, MEHP exposure could also activate HAPI via activating this signaling pathway, and AG490 could inhibit the activation of this signaling pathway caused by MEHP. Therefore, we indicated that maternal exposure to DEHP could cause the gender-specific impaired social interaction in pups that might be related to the activation of MGs.