Dibutyl phthalate-mediated oxidative stress induces splenic injury in mice and the attenuating effects of vitamin E and curcumin

In vivo, in vitro, and in silico approaches in the detailed study of di-butyl phthalate (DBP), a plasticizer-induced lung fibrosis via Nrf-2/Keap-1/HO-1 pathway and its regulation

The alveolar epithelium is a crucial barrier against external threats, yet it becomes a key player in initiating pulmonary fibrosis when compromised. Despite its importance, the intricate relationship between, DBP exposure and alveolar epithelial cell injury ensuing pro-fibrotic effects remains poorly understood. Phthalates, ubiquitous in nature, pose a significant risk to lung health upon inhalation, acting as immune triggers that cause airway inflammation and epithelial damage. We aimed to investigate the impact of intranasal administration ofDi-butyl Phthalate (DBP) inhalation, and its probable effects on normal and asthmatic lungs. DBP was administered via intranasal route in normal and OVA-induced asthmatic mice. DBP exposure enhanced oxidative stress and inflammatory parameters, leading to exacerbated asthmatic response and oxidative lung damage. Enhanced accumulation of immune cells, bronchial thickening, and collagen deposition was noted in histopathological investigations of DBP-exposed lung sections. Curcumin, a plant-derived molecule, significantly mitigated DBP-exposed asthma exacerbations by suppressing NF-κB expression and enhancing NRF2 levels via the Nrf-2/Keap-1/HO-1 signaling pathway. FACS analysis revealed increased CD11b+ cells (32 %) in asthmatic mice which were reduced in the curcumin pre-treatment group (10.5 %). Enhanced epithelial to mesenchymal transition (EMT) was noted in mice lungs and A549 cells where E-cadherin expression was reduced as compared to Vimentin, and α-SMA. Apart from aggravated airway inflammation, DBP exposure damages healthy lungs also. MMP-9/TIMP-1 ratios and collagen-1 levels were restored which were enhanced after DBP exposure. Moreover, antioxidant enzyme levels such as NQO-1, HO-1, and Catalase were significantly enhanced (p < 0.01) and comparable to dexamethasone, a conventional corticosteroid. Notably, both dexamethasone and curcumin treatments effectively regulated the stimulation and accumulation of Nrf-2 in the nucleus, promoting antioxidant production and offering potential therapeutic benefits in mitigating pulmonary fibrosis. OVA and DBP alone caused DNA damage in the lung cells where increasedpercentage of damaged DNA movement in thetail, tail length, tail moment, and olive tail moment indicated severe damage in theDBP and OVA combined exposure strategies. Dexamethasone and Curcumin treatments reduced theextent of the DNA damage indicating anti-inflammatory and ant-oxidative potentials. Moreover, in silico studies are supportive of therapeutic potential of Curcumin and Dexamethasone in DBP-induced lung inflammation and fibrosis.

Female rat liver after sub-acute dibutyl phthalate treatment: Histological, stereological, biochemical, and global gene expression study

Although it has been recognized that females are more susceptible to chemical-induced liver injury, the effects of dibutyl phthalate (DBP), a widely used synthetic chemical, on female liver structure and function are under-researched. Here, we sought to investigate the effects of DBP on histological, stereological, and biochemical parameters, as well as global gene expression in female rat liver. Female Wistar rats were exposed to 100, 500, and 5000 mg DBP/kg diet for 28 days, corresponding to 8.6, 41.43, and 447.33 mg DBP/kg body weight (B.W.)/day, respectively. The highest dose (447.33 mg DBP/kg B.W./day) was between the no-observed-adverse-effect level (NOAEL) and the lowest-observed-adverse-effect level for liver toxicity, whereas two lower doses (8.6 and 41.43 mg DBP/kg B.W./day) were below the NOAEL. Analysis of hematoxylin and eosin-stained sections revealed an increased volume of hepatocytes, their nuclei and cytoplasm, while the volume of sinusoids decreased in DBP-exposed groups compared to the control. Examination of Periodic acid-Schiff-stained sections showed reduced glycogen content, which was the most prominent in the highest dose group. Increased glutathione S-transferase and catalase activities, and decreased GSH content and superoxide dismutase activity were observed in DBP-exposed groups. The mRNA sequencing revealed DBP-induced dose-specific changes in various genes and biological functions in female rat liver. The highest number of deregulated genes was observed in the 500 mg DBP/kg diet group. In summary, exposure to DBP caused significant liver microstructural changes, decreased glycogen content, disturbed the redox status, and affected global gene expression in female rat liver.

Antioxidant vitamins' modification of the adverse health effects induced by phthalate exposure: A scoping review of epidemiological and experimental studies

The exposure to and health hazards of phthalates have received abundant attention. However, reducing phthalate exposure and further decreasing the associated health risks are difficult. Nonetheless, it is important to actively seek relevant measures. Recently, antioxidant vitamins have been frequently mentioned to improve phthalate-related issues. This scoping review summarizes the existing epidemiological and experimental studies on the interaction of phthalates with antioxidant vitamins. Through a systematic search, sparse epidemiological studies explored the effects of interaction between phthalates and vitamins on reproduction, the endocrine, respiratory, and nervous system and human aging. Four prospective studies were conducted in China, the United States, Canada and Netherlands. Only one study from Netherlands focused on the female reproductive system.The other three studies focused on neurological damage to fetuses caused by phthalate exposure, and its mitigation by vitamin supplementation during pregnancy. Four cross-sectional studies were conducted based on the United States National Health and Nutrition Examination Survey database. These studies involved hazards in different systems and interactions with different vitamins. Overall, epidemiological evidence suggests that antioxidant vitamins such as vitamin A, B, D, and folic acid probably may alter the health hazards induced by phthalate exposure. Current animal studies often focus on three phthalates, DBP, DEHP and DIDP,2 and most commonly, the first two phthalates. These chemicals cause reproductive, urinary, digestive and neurodevelopmental damage; the antioxidant vitamin C, E and B could mitigate the harm caused by phthalates. Possible mechanisms involve reducing oxidative stress, removing methylation,etc. Determining whether these mechanisms are similar to those in humans requires a rigorous experimental study.

Environmental Chemical-Induced Reactive Oxygen Species Generation and Immunotoxicity: A Comprehensive Review

Significance: Reactive oxygen species (ROS), the reactive oxygen-carrying chemicals moieties, act as pleiotropic signal transducers to maintain various biological processes/functions, including immune response. Increased ROS production leads to oxidative stress, which is implicated in xenobiotic-induced adverse effects. Understanding the immunoregulatory mechanisms and immunotoxicity is of interest to developing therapeutics against xenobiotic insults. Recent Advances: While developmental studies have established the essential roles of ROS in the establishment and proper functioning of the immune system, toxicological studies have demonstrated high ROS generation as one of the potential mechanisms of immunotoxicity induced by environmental chemicals, including heavy metals, pesticides, aromatic hydrocarbons (benzene and derivatives), plastics, and nanoparticles. Mitochondrial electron transport and various signaling components, including NADH oxidase, toll-like receptors (TLRs), NF-κB, JNK, NRF2, p53, and STAT3, are involved in xenobiotic-induced ROS generation and immunotoxicity. Critical Issues: With many studies demonstrating the role of ROS and oxidative stress in xenobiotic-induced immunotoxicity, rigorous and orthogonal approaches are needed to achieve in-depth and precise understanding. The association of xenobiotic-induced immunotoxicity with disease susceptibility and progression needs more data acquisition. Furthermore, the general methodology needs to be possibly replaced with high-throughput precise techniques. Future Directions: The progression of xenobiotic-induced immunotoxicity into disease manifestation is not well documented. Immunotoxicological studies about the combination of xenobiotics, age-related sensitivity, and their involvement in human disease incidence and pathogenesis are warranted. Antioxid. Redox Signal. 40, 691-714.

Integrated transcriptomic and biochemical characterization of the mechanisms governing stress responses in soil-dwelling invertebrate (Folsomia candida) upon exposure to dibutyl phthalate

Dibutyl phthalate (DBP) is one of the most commonly utilized plasticizers and a frequently detected phthalic acid ester (PAE) compound in soil samples. However, the toxicological effects of DBP on soil-dwelling organisms remain poorly understood. This study employed a multi-biomarker approach to investigate the impact of DBP exposure on Folsomia candida's survival, reproduction, enzyme activity levels, and transcriptional profiles. Analyses of antioxidant biomarkers, including catalase (CAT) and glutathione S-transferase (GST), as well as detoxifying enzymes such as acetylcholinesterase (AChE), Cytochrome P450 (CYP450), and lipid peroxidation (LPO), revealed significant increases in CAT activity, GST levels, and CYP450 expression following treatment with various doses of DBP for 2, 4, 7, or 14 days. Additionally, LPO induction was observed along with significant AChE inhibition. In total, 3175 differentially expressed genes (DEGs) were identified following DBP treatment that were enriched in six Gene Ontology (GO) terms and 144 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, including 85 upregulated and 59 downregulated primarily associated with lipid metabolism, signal transduction, DNA repair, and cell growth and death. Overall these results provide foundational insights for further research into the molecular mechanisms underlying responses of soil invertebrates to DBP exposure.

Effects of Dibutylphthalate and Steroid Hormone Mixture on Human Prostate Cells

Phthalates are a family of aromatic chemical compounds mainly used as plasticizers. Among phthalates, di-n-butyl phthalate (DBP) is a low-molecular-weight phthalate used as a component of many cosmetic products, such as nail polish, and other perfumed personal care products. DBP has toxic effects on reproductive health, inducing testicular damage and developmental malformations. Inside the male reproductive system, the prostate gland reacts to both male and female sex steroids. For this reason, it represents an important target of endocrine-disrupting chemicals (EDCs), compounds that are able to affect the estrogen and androgen signaling pathways, thus interfering with prostate homeostasis and inducing several prostate pathologies. The aim of this project was to investigate the effects of DBP, alone and in combination with testosterone (T), 17β-estradiol (E2), and both, on the normal PNT1A human prostate cell-derived cell line, to mimic environmental contamination. We showed that DBP and all of the tested mixtures increase cell viability through activation of both estrogen receptor α (ERα) and androgen receptor (AR). DBP modulated steroid receptor levels in a nonmonotonic way, and differently to endogenous hormones. In addition, DBP translocated ERα to the nucleus over different durations and for a more prolonged time than E2, altering the normal responsiveness of prostate cells. However, DBP alone seemed not to influence AR localization, but AR was continuously and persistently activated when DBP was used in combination. Our results show that DBP alone, and in mixture, alters redox homeostasis in prostate cells, leading to a greater increase in cell oxidative susceptibility. In addition, we also demonstrate that DBP increases the migratory potential of PNT1A cells. In conclusion, our findings demonstrate that DBP, alone and in mixtures with endogenous steroid hormones, acts as an EDC, resulting in an altered prostate cell physiology and making these cells more prone to cancer transformation.

In silico, in vitro and in vivo studies: Dibutyl phthalate promotes prostate cancer cell proliferation by activating Forkhead Box M1 and remission after Natura-α pretreatment

Dibutyl phthalate (DBP) is widely used in perfumes, cosmetics, shampoos and medical devices. It is ubiquitous in the environment and greatly endangers people's health. Several studies have reported that being exposed to it can promote the development of lung cancer, breast cancer, hepatoma, and multiple myeloma. However, there are still few studies on the specific molecular mechanism and prevention methods of DBP promoting the progression of prostate cancer. This study, in silico, in vitro and in vivo, aims to explore the promoting effect of DBP on prostate cancer cell proliferation. In silico analysis, we obtained a set of DBP interactive genes by utilizing TCGA, CTD and GEO database. These genes are mainly enriched in cell cycle regulatory pathways and they have high degree of homogeneity. We found that these genes shared one transcription factor - Forkhead Box M1 (FOXM1) by performing Chip-X Enrichment Analysis (Version 3.0). FOXM1, once called the 2010 Molecule of the Year, aberrantly expressed in up to 20 kinds of tumors. In vitro experiments, we used DBP at concentrations of 10^-8 M and 5 * 10^-7 M to treat C4-2 and PC3 cells for 6 days, respectively. Cell viability was promoted significantly. When Natura-α was added in the background of above-mentioned concentration of DBP, this effect was significantly inhibited. In addition, we also found that DBP can interfering with the efficacy of enzalutamide therapy. The introduction of Natura-α can also reverse this phenomenon. In vivo, subcutaneous tumor formation experiments in nude mice, 800 mg/kg/day DBP can promote the growth of prostate cancer. This phenomenon was suppressed when Natura-α (100 mg/kg/day) was added. Based on the results of the above three levels, we confirmed that DBP can target FOXM1 to promote prostate cancer cell proliferation. Natura-α can reverse its cancer-promoting effect. This study provides new insights into the impact of DBP on prostate cancer.

Probiotic cultures as a potential protective strategy against the toxicity of environmentally relevant chemicals: State-of-the-art knowledge

Environmentally relevant toxic substances may affect human health, provoking numerous harmful effects on central nervous, respiratory, cardiovascular, endocrine and reproductive system, and even cause various types of carcinoma. These substances, to which general population is constantly and simultaneously exposed, enter human body via food and water, but also by inhalation and dermal contact, while accumulating evidence suggests that probiotic cultures are able to efficiently adsorb and/or degrade them. Cell wall of probiotic bacteria/fungi, which contains structures such as exopolysaccharide, teichoic acid, protein and peptidoglycan components, is considered the main place of toxic substances adsorption. Moreover, probiotics are able to induce metabolism and degradation of various toxic substances, making them less toxic and more suitable for elimination. Other probable in vivo protective effects have also been suggested, including decreased intestinal absorption and increased excretion of toxic substances, prevented gut microbial dysbiosis, increase in the intestinal mucus secretion, decreased production of reactive oxygen species, reduction of inflammation, etc. Having all of this in mind, this review aims to summarize the state-of-the-art knowledge regarding the potential protective effects of different probiotic strains against environmentally relevant toxic substances (mycotoxins, polycyclic aromatic hydrocarbons, pesticides, perfluoroalkyl and polyfluoroalkyl substances, phthalates, bisphenol A and toxic metals).

DBP and BaP co-exposure induces kidney injury via promoting pyroptosis of renal tubular epithelial cells in rats

Dibutyl phthalate (DBP) and benzo(a)pyrene (BaP) are widespread environmental and foodborne contaminants that have detrimental effects on human health. Although people are often simultaneously exposed to DBP and BaP via the intake of polluted food and water, the combined effects on the kidney and potential mechanisms remain unclear. Hence, we treated rats with DBP and BaP for 90 days to investigate their effects on kidney histopathology and function. We also investigated the levels of paramount proteins and genes involved in pyroptosis and TLR4/NF-κB p65 signaling in the kidney. Our research showed that combined exposure to DBP and BaP triggered more severe histopathological and renal function abnormalities than in those exposed to DBP or BaP alone. Simultaneously, combined exposure to DBP and BaP enhanced the excretion of IL-1β and IL-18, along with the release of LDH in rat renal tubular epithelial cells (RTECs). Moreover, combined exposure to DBP and BaP increased the expression of pyroptosis marker molecules, including NLRP3, ASC, cleaved-Caspase-1, and GSDMD. Meanwhile, the combination of DBP and BaP activated TLR4/NF-κB signaling in the kidney. Taken together, the combined exposure to DBP and BaP causes more severe kidney injury than that caused by DBP or BaP exposure separately. In addition, pyroptosis of RTECs regulated by TLR4/NF-κB signaling may add to the kidney damage triggered by combined exposure to DBP and BaP.

Isolated Mitochondrial Preparations and In organello Assays: A Powerful and Relevant Ex vivo Tool for Assessment of Brain (Patho)physiology

Mitochondria regulate multiple aspects of neuronal development, physiology, plasticity, and pathology through their regulatory roles in bioenergetic, calcium, redox, and cell survival/death signalling. While several reviews have addressed these different aspects, a comprehensive discussion focussing on the relevance of isolated brain mitochondria and their utilities in neuroscience research has been lacking. This is relevant because the employment of isolated mitochondria rather than their in situ functional evaluation, offers definitive evidence of organelle-specificity, negating the interference from extra mitochondrial cellular factors/signals. This mini-review was designed primarily to explore the commonly employed in organello analytical assays for the assessment of mitochondrial physiology and its dysfunction, with a particular focus on neuroscience research. The authors briefly discuss the methodologies for biochemical isolation of mitochondria, their quality assessment, and cryopreservation. Further, the review attempts to accumulate the key biochemical protocols for in organello assessment of a multitude of mitochondrial functions critical for neurophysiology, including assays for bioenergetic activity, calcium and redox homeostasis, and mitochondrial protein translation. The purpose of this review is not to examine each and every method or study related to the functional assessment of isolated brain mitochondria, but rather to assemble the commonly used protocols of in organello mitochondrial research in a single publication. The hope is that this review will provide a suitable platform aiding neuroscientists to choose and apply the required protocols and tools to address their particular mechanistic, diagnostic, or therapeutic question dealing within the confines of the research area of mitochondrial patho-physiology in the neuronal perspective.

Trehalose-Carnosine Prevents the Effects of Spinal Cord Injury Through Regulating Acute Inflammation and Zinc(II) Ion Homeostasis

Spinal cord injury (SCI) leads to long-term and permanent motor dysfunctions, and nervous system abnormalities. Injury to the spinal cord triggers a signaling cascade that results in activation of the inflammatory cascade, apoptosis, and Zn(II) ion homeostasis. Trehalose (Tre), a nonreducing disaccharide, and L-carnosine (Car), (β-alanyl-L-histidine), one of the endogenous histidine dipeptides have been recognized to suppress early inflammatory effects, oxidative stress and to possess neuroprotective effects. We report on the effects of the conjugation of Tre with Car (Tre-car) in reducing inflammation in in vitro and in vivo models. The in vitro study was performed using rat pheochromocytoma cells (PC12 cell line). After 24 h, Tre-car, Car, Tre, and Tre + Car mixture treatments, cells were collected and used to investigate Zn²⁺ homeostasis. The in vivo model of SCI was induced by extradural compression of the spinal cord at the T6-T8 levels. After treatments with Tre, Car and Tre-Car conjugate 1 and 6 h after SCI, spinal cord tissue was collected for analysis. In vitro results demonstrated the ionophore effect and chelating features of L-carnosine and its conjugate. In vivo, the Tre-car conjugate treatment counteracted the activation of the early inflammatory cascade, oxidative stress and apoptosis after SCI. The Tre-car conjugate stimulated neurotrophic factors release, and influenced Zn²⁺ homeostasis. We demonstrated that Tre-car, Tre and Car treatments improved tissue recovery after SCI. Tre-car decreased proinflammatory, oxidative stress mediators release, upregulated neurotrophic factors and restored Zn²⁺ homeostasis, suggesting that Tre-car may represent a promising therapeutic agent for counteracting the consequences of SCI.

Dibutyl phthalate-induced oxidative stress and apoptosis in swine testis cells and therapy of naringenin via PTEN/PI3K/AKT signaling pathway

Dibutyl phthalate (DBP) is a phthalic acid ester (PAE) that has posed a health hazard to the organisms. Naringenin (NRG) is a flavanone compound that has shown protection against several environmental chemicals through suppression of oxidative stress and activation of phosphatidylinositol 3-kinase/threonine kinase (PI3K/AKT) signaling pathway. Herein, swine testis (ST) cells were treated with 1.8 μM of DBP or/and 25.39 nM of NRG for 24 h, we described the discovery path of NRG inhibition on apoptosis in DBP-exposed ST cells through targeting phosphatase and tensin homologue deleted on chromosome 10 (PTEN). We first found that the anti-apoptosis effect of NRG is dependent on mitochondrial pathway through flow cytometry and related gene/protein expression, and then we detected PI3K/AKT pathway-related gene/protein expression, and established a computational docking assay between NRG and PTEN. We found that NRG specifically binds to three basic residues (His93, Lys125, Lys128) of P loop in PTEN, as well as phosphatase domains (Asp92, His93, Cys124, Lys125, Ala126, Lys128, and Arg130) in active dephosphorylation pockets, thereby reducing PTEN level and activating PI3K/AKT signaling pathway, and further inhibiting oxidative stress and mitochondrial pathway apoptosis. Taken together, our results push forward that NRG deserves further attention as a potential antagonistic therapy against DBP through targeting PTEN to inhibit oxidative stress and activate PI3K/AKT signaling pathway.

Plasticizers: negative impacts on the thyroid hormone system

This review aims to understand the impacts of plasticizers on the thyroid system of animals and humans. The thyroid gland is one of the earliest endocrine glands that appear during embryogenesis. The thyroid gland synthesizes thyroid hormones (TH), triiodothyronine (T3), and thyroxine (T4) that are important in the regulation of body homeostasis. TH plays critical roles in regulating different physiological functions, including metabolism, cell growth, circadian rhythm, and nervous system development. Alteration in thyroid function can lead to different medical problems. In recent years, thyroid-related medical problems have increased and this could be due to rising environmental pollutants. Plasticizers are one such group of a pollutant that impacts thyroid function. Plasticizers are man-made chemicals used in a wide range of products, such as children's toys, food packaging items, building materials, medical devices, cosmetics, and ink. The increased use of plasticizers has resulted in their detection in the environment, animals, and humans. Studies indicated that plasticizers could alter thyroid function in both animals and humans at different levels. Several studies demonstrated a positive and/or negative correlation between plasticizers and serum T4 and T3 levels. Plasticizers could also change the expression of various TH-related genes and proteins, including thyroid-stimulating hormone (TSH), thyrotropin-releasing hormone (TRH), and transporters. Histological analyses demonstrated thyroid follicular cell hypertrophy and hyperplasia in response to several plasticizers. In conclusion, plasticizers could disrupt TH homeostasis and the mechanisms of toxicity could be diverse.

Exposure to a combination of MWCNTs and DBP causes splenic toxicity in mice

The large conjugated π bond in the molecular structure of carbon nanotubes (CNTs) interacts with the benzene ring structure in di (n-butyl) phthalates (DBP) through a π - π bond. Compounds of CNTs and DBP form easily, becoming another environmental pollutant of concern. We explore whether CNTs entering animals slow down the degradation of the DBP adsorbed in the CNT cavity, thereby prolonging the "hormonal activity" of DBP. In our study, male BALb/c mice were used as experimental subjects divided into four groups: the control group; the multi-walled carbon nanotubes (MWCNTs) exposure group (10mg/kg/d); the DBP exposure group (2.15 mg/kg/d); and the compound exposure group (MWCNTs + DBP). After 30 days of exposure, the mice were sacrificed and their spleens used for immunotoxicology study. The results showed that the exposure groups exhibited splenomegaly and suffered severe oxidative damage to the spleen. In the compound exposure group: levels of IgA and IgG in the serum of the mice changed, and were significantly different from levels in both the MWCNTs and DBP exposure groups (p <0.05); the pathological sections of the spleen showed that the boundary between the white pulp area (WP) and the red pulp area (RP) was blurred, that the cell arrangement was loose, and that more red blood cells were retained in the spleen. Proteomics mass spectrometry analysis showed that compared with the control group, 70 proteins were up-regulated and 27 proteins were down-regulated in the MWCNTs group, 36 proteins were up-regulated and 23 proteins were down-regulated in the DBP group, 87 proteins were up-regulated and 21 proteins were down-regulated in the compound exposure group. The results of GO enrichment analysis and KEGG enrichment analysis of the differentially expressed proteins showed that the compound exposure harmed the spleen antigen recognition, processing, and presentation, inhibited the activation and proliferation of B cells and T cells, and hindered the adaptive immune responses. Our results showed that MWCNTs and DBP compounds can damage the spleen, and impair the innate and adaptive immune functions of the body.

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.

The aggravation of allergic airway inflammation with dibutyl phthalate involved in Nrf2-mediated activation of the mast cells

Dibutyl phthalate (DBP)-an organic pollutant-is ubiquitous in the environment. DBP as an immune adjuvant is related to the development of multiple allergic diseases. However, the current research involving DBP-induced pulmonary toxicity remains poorly understood. Therefore, this research aimed to explore the adverse effect and potential mechanism of DBP exposure on the lungs in rats. In our study, ovalbumin was used to build a rat model of allergic airway inflammation to study any harmful effect of DBP exposure on lung tissues. Rats were treated by intragastric administration of DBP (500 mg kg^-1 or 750 mg kg^-1) and/or subcutaneous injection of SFN (4 mg kg^-1). The results of histopathological analysis, cell count, and myeloperoxidase showed that DBP promoted the inflammatory damage of lungs. In the lung tissues, the detection of terminal deoxynucleotidyl transferase dUNT nick end labeling and oxidative stress indices showed that DBP significantly increased the level of apoptosis and oxidative stress. Western blot analysis indicated that DBP raised the expression level of thymic stromal lymphopoietin and reduced the nuclear expression level of nuclear factor-erythroid-2-related factor 2 (Nrf2), which was further verified by quantitative real-time PCR. Meanwhile, DBP treatment markedly up-regulated the inflammatory cytokines such as IL-4 and IL-13, and rat mast cell protease-2, a marker secreted by mast cells (MCs). Conversely, sulforaphane, a Nrf2 inducer, ameliorated the pulmonary damage induced by DBP in the above. Altogether, our data provides a new insight into the impacts of the activation of MCs on the DBP-induced pulmonary toxicity as well as the safety evaluation of DBP.

Mechanistic insight into toxicity of phthalates, the involved receptors, and the role of Nrf2, NF-κB, and PI3K/AKT signaling pathways

The wide use of phthalates, as phthalates are used in the manufacturing of not only plastics but also many others goods, has become a main concern in the current century because of their potency to induce deleterious effects on organism health. The toxic effects of phthalates such as reproductive toxicity, cardiotoxicity, hepatotoxicity, nephrotoxicity, teratogenicity, and tumor development have been widely indicated by previous experimental studies. Some of the important mechanisms of toxicity by phthalates are the induction and promotion of inflammation, oxidative stress, and apoptosis. Awareness of the involved molecular pathways of these mechanisms will permit the detection of exact molecular targets of phthalates to protect or treat their toxicity. Up to now, various transcription factors and signaling pathways have been associated with phthalate-induced toxicity which by influencing on nuclear surface and the expression of different genes can alter cell hemostasis. In different studies, the role of nuclear factor erythroid 2-related factor 2 (Nrf2), nuclear factor-κB (NF-κB), and phosphatidylinositol-3-kinase (PI3K)/AKT signaling pathways in processes of oxidative stress, inflammation, apoptosis, and cancer has been shown following exposure to phthalates. In the present review, we aim to survey experimental studies (in vitro and in vivo) in order to show firstly the most involved receptors and also the importance and the role of the mentioned signaling pathways in phthalate-induced toxicity, and with considering this point, the future studies can focus on these molecular targets as a strategic method to reduce environmental chemicals-induced toxicity especially phthalates toxic effects.

Nimodipine attenuates dibutyl phthalate-induced learning and memory impairment in kun ming mice: An in vivo study based on bioinformatics analysis

Dibutyl phthalate (DBP), a typical representative of phthalate esters (PAEs), is used as a plasticizer in various industrial applications and has been reported to be responsible for neurobehavioral changes. Despite mounting evidence showing that nimodipine (Nim) palys a neuropharmacological and psychopharmacological role in neurons, the attenuating effects of Nim on learning and memory impairment induced by DBP exposure remain unknown. Based on bioinformatics analysis we found that the biological processes affected by both DBP and Nim may involve the calcium signaling pathway, the MAPK signaling pathway and the apoptosis pathway. The results of an in vivo study confirmed that DBP affects the levels of Ca²⁺ -related proteins, up-regulates phosphorylated -ERK1/2 expression and results in hippocampal neuronal damage and apoptosis, whereas Nim as a Ca²⁺ antagonist, has a certain neuroprotective role to avoid these adverse effects. Our data suggest that Nim could be used to attenuate the learning and memory impairment in DBP-exposed mice, to down-regulate intracellular Ca²⁺ levels, subordinate the ERK1/2 pathway and attenuate apoptosis in hippocampal tissue.

Dibutyl phthalate-induced oxidative stress, inflammation and apoptosis in grass carp hepatocytes and the therapeutic use of taxifolin

The widespread use of plastic products has led to the widespread presence of plasticizers in the environment. As a common environmental pollutant, research on plasticizer toxicity is insufficient in fish cells. In particular, research on the toxicity of dibutyl phthalate (DBP) in grass carp hepatocyte lines is insufficient. To further explore these mechanisms, we treated grass carp hepatocytes with 300 μM DBP, a common plasticizer, for 24 h, and hepatocytes were also treated with 1 μM taxifolin (TAX), an antioxidant, for 24 h to study its antagonistic effect on DBP. After DBP exposure, oxidative stress levels and inflammation in hepatocytes increased, and the mRNA and protein expression of apoptosis-related markers increased significantly, leading to hepatocyte apoptosis. Moreover, AO/EB staining, Hoechst staining and flow cytometry also showed that the level of apoptotic cells increased after DBP exposure. Notably, both TAX pretreatment and TAX simultaneous treatment alleviated oxidative stress, increased inflammatory factor levels and apoptosis induced by DBP. In comparison, the effect of simultaneous TAX treatment was better than that of TAX pretreatment. Our results showed that TAX alleviates DBP-induced apoptosis in grass carp hepatocytes through oxidative stress and inflammation, and TAX pretreatment and simultaneous treatment exhibited specific effects. Specifically, simultaneous treatment had a better effect. Our study assessed the toxicity of DBP in grass carp hepatocytes and provided a theoretical and research basis for the in vivo study of animal models in the future. The innovation of this study involves the exploration of the interaction between DBP and TAX for the first time. This study may enrich knowledge regarding the theoretical mechanism of DBP toxicity in fish hepatocytes and propose methods address DBP toxicity.

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.

Effects of dibutyl phthalate on lipid metabolism in liver and hepatocytes based on PPARα/SREBP-1c/FAS/GPAT/AMPK signal pathway

Phateacid esters (PAEs), such as dibutyl phthalate (DBP), have been widely used and human exposure results into serious toxic effects; such as the development of fatty liver disease. In the present study, SD rat models for in vivo study (normal and fatty liver model group) and hepatocytes for in vitro study (normal and abnormal lipid metabolism model group) were established to determine the effects of DBP on liver function and discover the possible mechanisms. Meanwhile, the peroxisome proliferator activated receptor (PPARα) blocker, GW6471, with the Adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) activator, AICAR, were applied in vitro study to clarify the role of PPARα/SREBP-1c/FAS/GPAT/AMPK signal pathway in the process. Results suggested that DBP could activate PPARα signaling pathway and affected the protein expression of SREBP, FAS and GPAT to cause hyperlipidemia and abnormal liver function. DBP also could inhibit the phosphorylation and activation of AMPK to inhibit the decomposition and metabolism of lipids. Interestingly, the effects of DBP could be alleviated by GW6471 and AICAR. Our experimental results provide reliable evidence that DBP exposure could further induce liver lipid metabolism disorder and other hepatic toxicity through PPARα/SREBP-1c/FAS/GPAT/AMPK signal pathway.

Overexpression of miR-506-3p Aggravates DBP-Induced Testicular Oxidative Stress in Rats by Downregulating ANXA5 via Nrf2/HO-1 Signaling Pathway

Background

Di-N-butylphthalate (DBP) is a kind of unique endocrine toxicity linked to hormonal disruptions that affects the male reproductive system and has given rise to more and more attention. However, the mechanism of DBP-induced testicular injury remains unclear. Here, the objective of this study was to investigate the potential molecular mechanism of miR-506-3p in DBP-induced rat testicular oxidative stress injury via ANXA5 (Annexin A5)/Nrf2/HO-1 signaling pathway.

Methods

In vivo, a total of 40 adolescent male rats were treated from 2 weeks with 800 mg/kg/day of DBP in 1 mL/kg corn oil administered daily by oral gavage. Among them, some rats were also injected subcutaneously with 2 nmol agomir-506-3p and/or 10 nmol recombinant rat ANXA5. The pathomorphological changes of testicular tissue were assessed by histological examination, and the antioxidant factors were evaluated. Subsequently, ANXA5, Nrf2, and its dependent antioxidant enzymes, such as HO-1, NQO1, and GST, were detected by Western blotting or immunohistochemical staining. In vitro, TM3 cells (Leydig cells) were used to detect the cell activity by CCK-8 and the transfection in the DBP-treated group.

Results

Differentially expressed miRNAs between the DBP-treated and normal rats were analyzed, and qRT-PCR showed miR-506-3p was highly expressed in testicular tissues of the DBP-treated rats. DBP-treated rats presented severe inflammatory infiltration, increased abnormal germ cells, and missed cell layers frequently existed in seminiferous tubules, resulted in oxidative stress and decreased testicular function. Meanwhile, upregulation of miR-506-3p aggravated the above changes. In addition, miR-506-3p directly bound to ANXA5, and overexpression of miR-506-3p could reduce the ANXA5 expression and also decrease the protein levels of Nrf2/HO-1 signaling pathway. Additionally, we found that recombinant rat ANXA5 reversed the DBP-treated testicular oxidative stress promoting injury of miR-506-3p in rats. In vivo results were reproduced in in vitro experiments.

Conclusions

This study provided evidence that miR-506-3p could aggravate the DBP-treated testicular oxidative stress injury in vivo and in vitro by inhibiting ANXA5 expression and downregulating Nrf2/HO-1 signaling pathway, which might provide novel understanding in DBP-induced testicular injury therapy.