Genotoxicity and cytotoxicity in male reproductive cells caused by sediment pollutants

In recent years, mounting evidence has highlighted a global decline in male semen quality, paralleling an increase in male infertility problems. Such developments in the male reproductive system are likely due to a range of environmental factors, which could negatively affect the outcomes of pregnancy, reproductive health, and the well-being of fetuses. Different environmental contaminants ultimately accumulate in riverbed sediments due to gravity, so these sediments are frequently considered hotspots for pollutants. Therefore, understanding the detrimental effects of river sediment pollution on human reproductive health is crucial. This study indicates male germ cells' high vulnerability to environmental contaminants. There is a strong positive correlation between the concentration of complex accumulated pollutants from human activities and the reproductive toxicity observed in human testicular embryonic cell lines NCCIT and NTERA-2. This toxicity is characterized by increased levels of reactive oxygen species, disruption of critical cellular functions, genotoxic impacts, and the induction of cell apoptosis. This research marks a significant step in providing in vitro evidence of the damaging effects of environmental pollutants on the human male germline.

The mitochondrial link: Phthalate exposure and cardiovascular disease

Phthalates' pervasive presence in everyday life poses concern as they have been revealed to induce perturbing health defects. Utilized as a plasticizer, phthalates are riddled throughout many common consumer products including personal care products, food packaging, home furnishings, and medical supplies. Phthalates permeate into the environment by leaching out of these products which can subsequently be taken up by the human body. It is previously established that a connection exists between phthalate exposure and cardiovascular disease (CVD) development; however, the specific mitochondrial link in this scenario has not yet been described. Prior studies have indicated that one possible mechanism for how phthalates exert their effects is through mitochondrial dysfunction. By disturbing mitochondrial structure, function, and signaling, phthalates can contribute to the development of the foremost cause of death worldwide, CVD. This review will examine the potential link among phthalates and their effects on the mitochondria, permissive of CVD development.

Dibutyl phthalate (DBP) promotes Epithelial-Mesenchymal Transition (EMT) to aggravate liver fibrosis into cirrhosis and portal hypertension (PHT) via ROS/TGF-β1/Snail-1 signalling pathway in adult rats

OBJECTIVE

The primary objective of this study was to investigate the toxicological impact of Dibutyl phthalate (DBP) on the process of liver fibrosis transitioning into cirrhosis and the subsequent development of portal hypertension (PHT) through the mechanism of epithelial-mesenchymal transition (EMT) mediated by the ROS/TGF-β/Snail-1 signaling pathway.

METHOD

Carbon tetrachloride (CCl4) (1 mg/kg) was introduced in adult rats by oral feeding in CCl4 and CCl4+DBP groups twice a week for 8 weeks, and twice for another 8 week in CCl4 group. DBP was introduced by oral feeding in the CCl4+DBP group twice over the following 8 weeks. We subsequently analyzed hemodynamics measurements and liver cirrhosis degree, hepatic inflammation and liver function in the different groups. EMT related genes expression in rats in the groups of Control, DBP, CCl4 and CCl4+DBP were measured by immunohistochemistry (IHC). Enzyme-linked immunosorbent Assay (ELISA), qRT-PCR, western blot were used to detect the EMT related proteins and mRNA gene expression levels in rats and primary hepatocytes (PHCs). Reactive oxygen species (ROS) were examined with a ROS detection kit.

RESULTS

The results showed that the CCl4+DBP group had higher portal pressure (PP) and lower mean arterial pressure (MAP) than the other groups. Elevated collagen deposition, profibrotic factor, inflammation, EMT levels were detected in DBP and CCl4+DBP groups. ROS, TGF-β1 and Snail-1 were highly expressed after DBP exposure in vitro. TGF-β1 had the potential to regulate Snail-1, and both of them were subject to regulation by ROS.

CONCLUSION

DBP could influence the progression of EMT through its toxicological effect by ROS/TGF-β1/Snail-1 signalling pathway, causing cirrhosis and PHT in final. The findings of this research might contribute to a novel comprehension of the underlying toxicological mechanisms and animal model involved in the progression of cirrhosis and PHT, and potentially offered a promising therapeutic target for the treatment of the disease.

Dibutyl phthalate adsorbed on multi-walled carbon nanotubes can aggravate liver injury in mice via the Jak2/STAT3 pathway

Phthalic acid esters (PAEs) and carbon nanotubes (CNTs) are common environmental pollutants and may degrade differently with different resulting biotoxicity, when present together. This study investigated the toxicological effects of singular or combined exposure to dibutyl phthalate (DBP) and multi-walled carbon nanotubes (MWCNTs) in KM mice. Results indicated that combined exposure led to slower weight gain and an increased leukocyte count in the blood, as well as liver tissue lesions and downregulation of organ coefficients. Additionally, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were elevated in the liver, and glucose, pyruvate, triglyceride (TG), and total cholesterol (T-CHO) were significantly reduced, suggesting compromised liver function. Furthermore, mRNA levels of genes related to hepatic glucose and lipid metabolism were significantly altered. These findings suggest that combined exposure to DBP and MWCNTs can have severe impacts on liver function in mice, highlighting the importance of considering interactions between multiple contaminants in environmental risk assessments.

Dibutyl phthalate induces liver fibrosis via p38MAPK/NF-κB/NLRP3-mediated pyroptosis

Dibutyl phthalate (DBP) is one of the most employed plasticizers pervading the environment. DBP is a newly identified global organic pollutant that can activate NLRP3 inflammasomes and induce inflammatory liver injury. However, its hepatotoxicity remains poorly understood. The objective of this investigation was to investigate the probable pathways underlying DBP-induced liver injury. First, C57BL/6N mice were orally administered DBP at 10 and 50 mg/kg B.W. doses for 28 days. The observed results indicated a significant increase in liver collagen deposition and upregulated protein expression of fibrosis markers in mice. In addition, the p38MAPK/NF-κB signaling pathway and pyroptosis-related protein expression were upregulated. To establish a correlation between these changes, we conducted a conditioned medium co-culture of human hepatocellular carcinoma (HepG2) and human hepatic stellate (LX-2) cells. We performed inhibitor interventions to validate the mechanism of DBP-induced liver fibrosis in vitro. After treatment with p38MAPK (SB203580), NF-κB (PDTC), and NLRP3 (MCC950) inhibitors, the activation of LX-2 cells, the p38MAPK/NF-κB signaling pathway and pyroptosis due to DBP were alleviated. Therefore, DBP exposure leads to NLRP3-mediated pyroptosis of hepatocytes via the p38MAPK/NF-κB signaling pathway, activating LX-2 cells and causing liver fibrosis. Our findings offer a conceptual framework to understand the pathological underpinnings of DBP-induced liver injury while proposing novel ideas to prevent and treat DBP hepatotoxicity. Thus, targeting p38MAPK, NF-κB, and NLRP3 may prevent DBP-induced liver fibrosis.

Comprehensive investigation of hepatotoxicity of the mixture containing phthalates and bisphenol A

Connections between the mixture containing bis(2- ethylhexyl) phthalate (DEHP), dibutyl phthalate (DBP) and bisphenol A (BPA) and liver injury were explored through in silico investigation and 2 in vivo models. Comparative Toxicogenomics Database (CTD), ShinyGO, ToppCluster and Cytoscape were used for bioinformatic analysis. In vivo subacute study was performed on rats - five groups (n = 6): (1) Control: corn oil, (2) DEHP: 50 mg/kg b.w./day, (3) DBP: 50 mg/kg b.w./day, (4) BPA: 25 mg/kg b.w./day, (5) MIX: DEHP + DBP + BPA. Zebrafish embryos were exposed to the investigated substances in different doses, singularly and combined (binary and ternary mixtures). Liver injury was linked to 75 DEHP, DBP, and BPA genes, mostly connected to inflammation/oxidative stress. In rats, significant alterations in redox status/bioelements and pathohistology were most notable or exclusively present in MIX (probable additive effects). BPA decreased liver area (LA) index in dose-dependent manner. DEHP (< 2 µg/mL) and DBP (≤ 5 µg/mL) reduced LA values, while their higher doses increased LA index. The effect of DBP in binary mixtures led to a lethal outcome at the two highest concentrations, while the hepatotoxicity of DEHP/DBP/BPA mixture was dictated by BPA (confirmed by the benchmark dose analysis).

Sediment pollutant exposures caused hepatotoxicity and disturbed glycogenesis

Liver metabolic syndrome, which involves impaired hepatic glycogen synthesis, is persistently increased by exposure to environmental pollutants. Most studies have investigated the pathogenesis of liver damage caused by single metal species or pure organics. However, under normal circumstances, the pollutants that we are exposed to are usually chemical mixtures that accumulate over time. Sediments are long-term repositories for environmental pollutants due to their environmental cycles, which make them good samples for evaluating the effect of environmental pollutants on the liver via bioaccumulation. This study aimed to clarify the effects of sediment pollutants on liver damage. Our results indicate that industrial wastewater sediment (downstream) is more cytotoxic than sediments from other zones. Downstream sediment extract (DSE) causes hepatotoxicity, stimulates reactive oxygen species (ROS) generation, triggers mitochondrial dysfunction, induces cell apoptosis, and results in the release of glutamic oxaloacetic transaminase (GOT) and glutamic pyruvic transaminase (GPT) proteins. Additionally, to elucidate the underlying mechanism by which sediment pollutants disturb hepatic glycogen synthesis, we investigated the effects of different sediment samples from different pollution situations on glycogen synthesis in liver cell lines. It was found that DSE induced multiple severe impairments in liver cells, and disturbed glycogen synthesis more than under other conditions. These impairments include decreased hepatic glycogen synthesis via inhibition and insulin receptor substrate 1 (IRS-1) /AKT /glycogen synthase kinase3β (GSK3β)-mediated glycogen synthase (GYS) inactivation. To our knowledge, this study provides the first detailed evidence of in vitro sediment-accumulated toxicity that interferes with liver glycogen synthesis, leading to hepatic cell damage through apoptosis.

The Relationship between Typical Environmental Endocrine Disruptors and Kidney Disease

Endocrine disrupting chemicals (EDCs) are exogenous substances that alter the endocrine function of an organism, to result in adverse effects on growth and development, metabolism, and reproductive function. The kidney is one of the most important organs in the urinary system and an accumulation point. Studies have shown that EDCs can cause proteinuria, affect glomeruli and renal tubules, and even lead to diabetes and renal fibrosis in animal and human studies. In this review, we discuss renal accumulation of select EDCs such as dioxins, per- and polyfluoroalkyl substances (PFAS), bisphenol A (BPA), and phthalates, and delineate how exposures to such EDCs cause renal lesions and diseases, including cancer. The regulation of typical EDCs with specific target genes and the activation of related pathways are summarized.

Health risks of phthalates: A review of immunotoxicity

Phthalates (PAEs) are known environmental endocrine disruptors that have been widely detected in several environments, and many studies have reported the immunotoxic effects of these compounds. Here, we reviewed relevant published studies, summarized the occurrence and major metabolic pathways of six typical PAEs (DMP, DEP, DBP, BBP, DEHP, and DOP) in water, soil, and the atmosphere, degradation and metabolic pathways under aerobic and anaerobic conditions, and explored the molecular mechanisms of the toxic effects of eleven PAEs (DEHP, DPP, DPrP, DHP, DEP, DBP, MBP, MBzP, BBP, DiNP, and DMP) on the immune system of different organisms at the gene, protein, and cellular levels. A comprehensive understanding of the mechanisms by which PAEs affect immune system function through regulation of immune gene expression and enzymes, increased ROS, immune signaling pathways, specific and non-specific immunosuppression, and interference with the complement system. By summarizing the effects of these compounds on typical model organisms, this review provides insights into the mechanisms by which PAEs affect the immune system, thus supplementing human immune experiments. Finally, we discuss the future direction of PAEs immunotoxicity research, thus providing a framework for the analysis of other environmental pollutants, as well as a basis for PAEs management and safe use.

Association of urinary phthalate metabolites with renal function among 9989 US adults

PURPOSE

This study aimed to investigate the relationship between phthalate metabolites and renal function.

METHODS

We analyzed data from 9989 participants who took part in the National Health and Nutrition Examination Survey (NHANES) from 2005 to 2018. Renal function was reflected by estimated glomerular filtration rate (eGFR), urinary albumin-to-creatinine ratio (UACR), and hypertension. We used generalized linear regression to estimate the correlation between covariate-adjusted creatinine-normalized phthalate metabolites and renal function. In addition, subgroup analysis was used to further compare the effect differences between various populations.

RESULTS

In the adjusted model, we found differential associations between phthalates and plasticizers metabolites and renal function. We found that Mono-benzyl phthalate, Mono-(3-carboxypropyl) phthalate, and Mono-(2-ethyl-5-oxohexyl) phthalate were positively associated with lower eGFR with odds ratios (95% confidence intervals) of 1.38 (1.14, 1.67), 1.30 (1.09, 1.57), and 1.27 (1.04, 1.53). While Mono-ethyl phthalate, Mono-(2-ethyl)-hexyl phthalate, Mono-isononyl phthalate and Mono-isobutyl phthalate were negatively associated with lower eGFR with OR values of 0.79 (0.69, 0.90), 0.64 (0.52, 0.78), 0.65 (0.51, 0.82) and 0.80 (0.63, 1.00), respectively. In addition, we found that Mono(carboxyoctyl) phthalate and Mono-isobutyl phthalate were negatively associated with hypertension with ORs of 0.86 (0.78, 0.96) and 0.84 (0.72, 0.98). But phthalates and plasticizers metabolites were not associated with UACR.

CONCLUSION

This study found differences in the effects of phthalates and plasticizers metabolites on kidney function, which may raise concerns about possible changes in kidney function resulting from exposure to current levels of plasticizers.

Effects of dibutyl phthalate and di (2-ethylhexyl) phthalate on hepatic structure and function of adult male mice

The objective of the present research was to determine if dibutyl phthalate (DBP) and di-(2-ethylhexyl) phthalate (DEHP) alone and combined exposure induced pathological alterations in laboratory reared albino mice. Adult male mice were equally divided (n = 10) into Control, corn oil (CO), DBP, DEHP, and DBP+DEHP treated groups. Dibutyl phthalate (250 mg/kg), DEHP (300 mg/kg), and DBP+DEHP (250+300 mg/kg), respectively, were administered by oral gavage mixed in corn oil (0.2 mL) for 28 days. All animals were sacrificed following 28 days of treatment and blood was collected for serum lipid profiles and liver function tests. Liver samples were also collected for observation of histological changes. Microphotographs of hematoxylin and eosin-stained sections were used for computer-based micrometry. CO, DBP, DEHP, and DBP+DEHP treatment resulted in a significant increase in the mean body and liver weights as compared with the Control group. Histological examination of the livers with DBP and/or DEHP treatment showed marked alterations leading to hepatic hypertrophy. In the treated groups, a significant increase in the mean number of mononucleated, binucleated cells, and oval cells per unit area was noticed with disorganized trabecular arrangement as compared with the Control group. Treatment with DBP and/or DEHP resulted in large regeneration zones in the liver and an increased relative nucleo-cytoplasmic index of mononuclear shepatocytes when compared with the Control group. All treatments caused a significant increases in the liver enzymes and proteins as well as altered serum cholesterol, triglycerides, LDL, and VLDL levels. The histopathological and serological findings confirmed the toxic potentials to hepatic tissue of DBP and DEHP either given alone or in combination.

Polystyrene microplastics affect learning and memory in mice by inducing oxidative stress and decreasing the level of acetylcholine

Microplastics pollution has become a growing environmental concern, but its potential neurotoxic effects remain unknown. In this study, we determined the effects of exposure to polystyrene microplastics (micro-PS) on learning and memory, and explored the underlying mechanisms. Kunming mice were orally exposed to 0.01, 0.1, 1 mg/d micro-PS or saline for four weeks. Employing the Morris water maze test, we observed that exposure to micro-PS affected the learning and exploration abilities of mice, and impaired their learning and memory functions. After exposure to micro-PS, the nerve cells in the hippocampus became loose and disordered, and the number of Nissl bodies decreased. Increases in the levels of ROS and MDA, and a decrease in levels of glutathione were found in the brain tissue of the mice exposed to micro-PS. Exposure to micro-PS also induced a reduction in the level of acetylcholine, and inhibited the CREB/BDNF pathway. Importantly, after treatment with the antioxidant, Vitamin E, the learning and memory abilities of the mice were restored, and the release of neurotransmitters rebounded. These results show that micro-PS exposure can affect the learning and memory functions through inducing oxidative stress and decreasing the levels of acetylcholine.

Urban sediment pollutants alternate human cell essential behaviour through promoting oxidative damage

The main objective of this study was to establish a human cell-based platform to assess the effects of sediment toxicity on oxidative damage and cell essential behaviour. Since sediment pollution has increased as a consequence of including but not limited to industrialisation, the contaminants accumulated in sediments have already led to human health concerns. The Hsinchu Science Park is one of the most prominent semiconductor manufacturing centres in the world, and the Ke-Ya River flows through Hsinchu Science Park and the Hsinchu urban district. Because semiconductor wastes potentially contribute to higher-than-normal rates of cancers, birth defects, and serious diseases, the quality assessment of the Ke-Ya River has prompted widespread concerns. While previous studies have shown an association between the degradation of fish populations and sediment pollutants, very little is known about the issues on human health. Herein, the effects of sediment from three sediment sampling sites of the Ke-Ya River on 11 different human cell lines were directly evaluated. The upstream represents the undeveloped zone, the middle-stream represents the household/industrial wastewater zone, and the downstream represents the accumulation zone. Our results indicated that the sediment pollution of the downstream Ke-Ya River was more cytotoxic than that of the middle stream and upstream. Downstream sediment extract (DSE) significantly increased reactive oxygen species (ROS) levels across all cell types. Accordingly, oxidative stress can trigger redox-sensitive pathways and alter essential biological processes such as cell viability, cell adhesion, and cell motility. Importantly, the MTT assay indicated that DSE significantly decreased the viability of brain, oral, lung, breast, liver, pancreatic, cervical, prostate, and colorectal cells. Furthermore, the adhesive ability and wound healing ability of most cells were greatly reduced in the presence of DSE compared to other conditions. Thus, this study shows the results of the first analyses completed on the sediment cytotoxicity in human cells, and stimulated ROS levels are crucial for cellular life. In future research, the detailed cause and effect mechanisms of the abundant ROS generated in DSE will be further investigated. We sincerely hope that our study provides a scientific basis for further investigations with a global perspective on public health challenges.

Exposure to phthalates and environmental phenols in association with chronic kidney disease (CKD) among the general US population participating in multi-cycle NHANES (2005-2016)

Exposure to consumer chemicals has been associated with chronic kidney disease (CKD) among humans, but their associations with estimated glomerular filtration rate (eGFR) are inconsistent. Such observations may be due to potential bias caused by the method of urine dilution adjustment and lack of consideration for multiple chemical exposure in the association models. This study aimed to identify major urinary chemicals associated with CKD by applying an alternative adjustment method of urine dilution ('novel' covariate-adjusted creatinine adjustment vs 'traditional' creatinine adjustment) and with a mixture exposure concept in the association model. For this purpose, the adult participants of US National Health and Nutrition Examination Survey (NHANES) 2005-2016 (n = 9008) were used, and the associations of urinary exposure biomarkers of major consumer chemicals, e.g., phthalates, bisphenol A, benzophenone-3, and parabens, with CKD related parameters of eGFR and albumin-to-creatinine ratio (ACR), were assessed. The use of the novel covariate-adjusted creatinine standardization resulted in significant inverse associations with eGFR for most measured chemicals, unlike the results with the use of the conventional creatinine adjustment. Phthalate metabolites, such as monobutyl phthalate (MBP) and mono-benzyl phthalate (MBzP), were positively associated with ACR. Even in mixture exposure models using weighted quantile sum (WQS) regression, MBzP, metabolites of di-(2-ethylhexyl) phthalate (DEHP), and bisphenol A (BPA) were revealed as major drivers of the association with eGFR or ACR. Results of sensitivity analyses with the subpopulation with normal eGFR range (n = 7041) were generally similar. Our observation suggests that exposure to benzyl butyl phthalate (BBP), DEHP, and BPA may be responsible for declined eGFR and increased ACR even at the exposure levels occurring among general adults.

miR-122-5p regulates hepatocytes damage caused by BaP and DBP co-exposure through SOCS1/STAT3 signaling in vitro

BaP and DBP are ubiquitously and contemporaneously present in the environment. However, Current studies largely concentrate on the effects of a single pollutant (BaP or DBP). The liver is vital for biogenic activities. The effects of BaP and DBP co-exposure on liver remain unclear. Thus, we treated human normal liver cell (L02 cell) with BaP or/and DBP. We found that compared to individual exposure, co-exposure to BaP and DBP induced further increased levels of AST and ALT. BaP and DBP co-exposure caused further increased levels of IL-2, IL-6, and TNF-α, decreased IL-10 level, and a higher percentage of apoptotic cells and S-phase arrest cells. BaP and DBP co-exposure worsen the decrease of miR-122-5p level and chaos of SOCS1/STAT3 signaling. Dual-luciferase reporter gene assays showed that SOCS1 was a validated target of miR-122-5p. miR-122-5p overexpression alleviated the increased SOCS1 expression, decreased phospho-STAT3 expression, decreased IL-10 level, increased TNF-α levels, increased percentage of apoptosis and S-phase arrest, and cytotoxicity induced by BaP and DBP co-exposure in hepatocytes. These results suggested that miR-122-5p negatively regulated the synergistic effects on apoptosis and disorder of inflammatory factor secretion involved in hepatocyte injury caused by BaP and DBP co-exposure through targeting SOCS1/STAT3 signaling.

Phthalates exposure is associated with non-alcoholic fatty liver disease among US adults

PURPOSE

Non-alcoholic fatty liver disease (NAFLD) has become the most common liver disease in the western countries. We aimed to ascertain the relationship of urinary phthalates concentrations with presence of NAFLD among US adults.

METHODS

A cross-sectional analysis of data from National Health and Nutrition Examination Survey (NHANES) during 2003-2016 was performed. NAFLD was predicted by Hepatic Steatosis Index (HSI) and US Fatty Liver Index (US FLI), respectively. The logistic regression models were conducted to evaluate associations of urinary phthalates with NAFLD by adjustment for other covariates.

RESULTS

Of the 4206 participants (mean age 47.99 years old; 50.06% men), risk of suspected NAFLD was increased in those with higher concentrations of urinary phthalates. The results of multivariate models suggested that urinary phthalate metabolites MEOHP (odds ratio [OR] = 1.56, 95% confidence interval [CI] = 1.08-2.24), MEHHP (OR = 1.55, 95% CI = 1.09-2.21), MECPP (OR = 1.44, 95% CI = 1.06-1.95) and the mixtures of nine phthalates (OR = 1.58, 95%CI = 1.18-2.11) were positively related to NAFLD defined by HSI; the similar significant associations were observed for MEHHP (OR = 1.98, 95% CI = 1.32-2.97) when NAFLD was determined based upon US FLI ≥30. In subgroup analyses, the positive associations of urinary phthalates concentrations with NAFLD risk remained robust both in males and females, whereas only in individuals aged <60 years.

CONCLUSIONS

Phthalates exposure was independently associated with NAFLD both in males and females, regardless of being defined using HSI or US FLI.

Curcumin decreases dibutyl phthalate-induced renal dysfunction in Kunming mice via inhibiting oxidative stress and apoptosis

Curcumin (Cur) has been used extensively in dietary supplement with antioxidant and anti-apoptotic properties. Although dibutyl phthalate (DBP) has adverse effects on the kidney, any association between DBP exposure and the role of Cur is unclear. We tested the hypothesis that exposure to DBP has adverse consequences on renal dysfunction in mice and the potential protective role of Cur in decreasing DBP-induced renal dysfunction via inhibiting oxidative stress and apoptosis. Kidney function, oxidative stress biomarkers, and apoptosis factors as well as Bcl-2 and Bax were investigated. The results showed a marked increase of renal dysfunction, oxidative stress and apoptosis level after DBP exposure compared to the control. While administration of Cur to DBP-treated mice may reduce these adverse biochemical changes compared with DBP-alone group. Overall, these results suggest that oxidative stress and apoptosis are involved in DBP-induced renal disorder, whereas Cur plays a protective role in inhibiting these two pathways.

Combining metabolomics with bioanalysis methods to investigate the potential toxicity of dihexyl phthalate

Dihexyl phthalate (DHP) is one of the most commonly used phthalate esters in various plastic and consumer products. Human are inevitably exposed to DHPs. Although several animal and human experiments have revealed that DHP can cause multiple toxicities, few studies have previously assessed the effects of DHP exposure by liquid chromatography mass spectrometry (LC-MS) analysis combine with molecular biology methods on human cells. Therefore, the purpose of our study was to investigate the effect of DHP on human cell metabolism by systems biology methods. In this study, U₂ OS cancer cells were treated with 10 μM DHP for metabolomics analysis and apoptosis analysis at indicate time. Metabolomic study of the metabolic changes caused by DHP in U₂ OS cells was performed for the first time using integrative liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (LC-Q-TOF-MS). To investigate the possible reason of fatty acids level altered by DHP, we measured some key fatty acid synthesis and oxidation-related enzyme expression levels by quantitative real-time PCR (Q-PCR). Apoptotic cells were analyzed by flow cytometry and apoptosis-related gene expressions were measured by Q-PCR. 2',7'-Dichlorofluorescein diacetate (DCFH-DA) staining was used to evaluate ROS content. Partial least squares-discriminate analysis (PLS-DA) clearly showed that significant differences in metabolic profiles were observed in U₂ OS cells exposed to DHP compared with controls. A total of 58 putative metabolites in electrospray ionization source (ESI) + mode and 32 putative metabolites in ESI-mode were detected, the majority of the differential metabolites being lipids and lipid-like molecules. Among them, the altered fatty acids level corresponded to expression levels of genes encoding enzymes related to fatty acids synthesis and oxidation. Moreover, DHP induced reactive oxygen species (ROS) accumulation, promoted cell apoptosis and inflammation, and resulted in a significant increase in apoptosis and inflammation-related gene expression levels compared with controls. In summary, our results suggested that metabolomics combined with molecular bioanalysis methods could be an efficient tool to assess toxic effects, which contribute to explore the possible cytotoxicity mechanisms of DHP, and provide a basis for further research.

Dibutyl phthalate induces allergic airway inflammation in rats via inhibition of the Nrf2/TSLP/JAK1 pathway

Dibutyl phthalate (DBP), an important plastic contaminant in the environment, is known to cause organ toxicity. Although current research has shown that DBP-induced organ toxicity is associated with oxidative stress, the toxic effect of DBP on the lungs have not been fully elucidated. Therefore, we investigated the potential mechanism by which DBP induces pulmonary toxicity using a model of DBP-induced allergic airway inflammation in rats. The results showed that chronic exposure to DBP induced histopathological damage, inflammation, oxidative stress, apoptosis, and increased the protein levels of thymic stromal lymphopoietin (TSLP) and its downstream protein Janus kinase 1 (JAK1) and signal transducer and activator of transcription 6 (STAT6). Moreover, DBP exposure inhibited nuclear factor-erythroid-2-related factor 2 (Nrf2) and levels of its target genes NAD(P)H quinone oxidoreductase 1 (NQO1) and heme oxygenase-1 (HO-1). Additionally, using in vitro experiments, we found that DBP induced oxidative stress, reduced cell viability, and inhibited the Nrf2/HO-1/NQO1 pathway in mouse alveolar type II epithelial cell line. Overall, these data demonstrate that DBP induces allergic airway inflammation in rats via inhibition of the Nrf2/TSLP/JAK1 pathway.

Evaluation of the protective effects of quercetin and gallic acid against oxidative toxicity in rat's kidney and HEK-293 cells

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Gallic acid has better antioxidant protective effect than quercetin in vivo.

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Quercetin has better antioxidant protective effect than gallic acid in vitro.

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The antioxidant effect of quercetin was at the least concentration tested.

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The antioxidant effect of gallic acid was at a higher concentrated tested.

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The in vivo dosage for the antioxidant effects of quercetin in the kidney is low.

Quercetin and gallic acid are phytochemicals with interesting pharmacological properties. We herein investigated the protective effect of quercetin (QUE) in comparison with gallic acid (GAL) against exogenously-induced oxidative damage in rats’ kidney and human embryonic kidney (HEK-293) cell lines. Adult Wistar rats were treated with QUE and GAL (50 mg/kg) separately or in combination with di-n-butylphthalate (DnBP) for 14 days; and HEK-293 cells were treated with different concentrations of GAL (25−294 μM) or QUE (2−17 μM or 28−165.43 μM) singly or in combination with H₂O₂ (200 μM). After treatment, the kidney and cell extracts were processed for biochemical analysis and histopathology. We found that GAL but not QUE prevented DnBP-induced increase in lipid peroxidation (2.603 ± 0.25 vs. 3.65 ± 0.21 μmol/mL). Treatment with QUE but not GAL was associated with increased plasma creatinine (729.09 ± 55.68 vs. 344.25 ± 50.78 μmol/l) and tissue malondialdehyde (3.72 ± 0.62 vs. 1.67 ± 0.47 μmol/mL) concentrations, along with histo-pathological changes such as glomerular and tubular degenerations. However, QUE exhibited wider therapeutic concentration ranges than GAL at which it inhibits lipid peroxidation in HEK-293 cells, and was found to inhibit H₂O₂-induced lipid peroxidation even at the lowest concentration (2 μM) that was tested (0.607 ± 0.074 vs. 0.927 ± 0.106 μmol/l). These suggest that the in vivo dosages required for the antioxidant protective effects of QUE in renal tissues are low.

Human Erythrocytes Exposed to Phthalates and Their Metabolites Alter Antioxidant Enzyme Activity and Hemoglobin Oxidation

Phthalates used as plasticizers have become a part of human life because of their important role in various industries. Human exposure to these compounds is unavoidable, and therefore their mechanisms of toxicity should be investigated. Due to their structure and function, human erythrocytes are increasingly used as a cell model for testing the in vitro toxicity of various xenobiotics. Therefore, the purpose of our study was to assess the effect of selected phthalates on methemoglobin (metHb), reactive oxygen species (ROS) including hydroxyl radical levels, as well as the activity of antioxidative enzymes, such as superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px), in human erythrocytes. Erythrocytes were incubated with di-n-butyl phthalate (DBP), butylbenzyl phthalate (BBP), and their metabolites, i.e., mono-n-butyl phthalate (MBP) and monobenzyl phthalate (MBzP), at concentrations ranging from 0.5 to 100 µg/mL for 6 or 24 h. This study shows that the analyzed phthalates disturbed the redox balance in human erythrocytes. DBP and BBP, at much lower concentrations than their metabolites, caused a statistically significant increase of metHb and ROS, including hydroxyl radical levels, and changed the activity of antioxidant enzymes. The studied phthalates disturbed the redox balance in human erythrocytes, which may contribute to the accelerated removal of these cells from the circulation.

Oxidative damage in the liver and kidney induced by dermal exposure to diisononyl phthalate in Balb/c mice

As a general alternative, diisononyl phthalate (DINP) has gradually replaced di(2-ethylhexyl) phthalate (DEHP) as the main plasticizer used in polyvinyl chloride. Like DEHP, DINP can also be released into the environment, resulting in humans being exposed through skin contact. This study aims to explore whether oxidative damage to hepatic and renal tissues can be induced by dermal exposure to DINP in mice. Forty-two male Balb/c mice were divided into six groups. The five DINP dermal exposure groups were exposed to different doses of DINP (0.02, 0.2, 2, 20, and 200 mg/kg) for 28 consecutive days. The pathological alterations to the skin, liver, and kidney in the mice were examined. Levels of reactive oxygen species (ROS), reduced glutathione (GSH), malondialdehyde (MDA), and DNA-protein cross-links (DPC) in the liver and kidney were also determined to investigate oxidative damage. The experimental results showed that the levels of ROS, MDA, and DPC coefficients increased gradually in a dose-dependent manner, whereas the level of GSH decreased accordingly. When the exposure dose was ≥20 mg/kg, ROS, GSH, MDA content, and the DPC coefficient were significantly different compared to the control group ( p < 0.05). These results suggest that a high dose of DINP can induce oxidative stress and histopathological alterations in the liver and kidney via dermal exposure.