Bioremediation of petroleum refinery wastewater using Bacillus subtilis IH-1 and assessment of its toxicity.

Environmental contamination from petroleum refinery operations has increased due to the rapid population growth and modernization of society, necessitating urgent repair. Microbial remediation of petroleum wastewater by prominent bacterial cultures holds promise in circumventing the issue of petroleum-related pollution. Herein, the bacterial culture was isolated from petroleum-contaminated sludge samples for the valorization of polyaromatic hydrocarbons and biodegradation of petroleum wastewater samples. The bacterial strain was screened and identified as Bacillus subtilis IH-1. After six days of incubation, the bacteria had degraded 25.9% of phenanthrene and 20.3% of naphthalene. The treatment of wastewater samples was assessed using physico-chemical and Fourier-transform infrared spectroscopy analysis, which revealed that the level of pollutants was elevated and above the allowed limits. Following bacterial degradation, the reduction in pollution parameters viz. EC (82.7%), BOD (87.0%), COD (80.0%), total phenols (96.3%), oil and grease (79.7%), TKN (68.8%), TOC (96.3%) and TPH (52.4%) were observed. The reduction in pH and heavy metals were also observed after bacterial treatment. V. mungo was used in the phytotoxicity test, which revealed at 50% wastewater concentration the reduction in biomass (30.3%), root length (87.7%), shoot length (93.9%), and seed germination (30.0%) was observed in comparison to control. When A. cepa root tips immersed in varying concentrations of wastewater samples, the mitotic index significantly decreased, suggesting the induction of cytotoxicity. However, following the bacterial treatment, there was a noticeable decrease in phytotoxicity and cytotoxicity. The bacterial culture produces lignin peroxidase enzyme and has the potential to degrade the toxic pollutants of petroleum wastewater. Therefore the bacterium may be immobilised or directly used at reactor scale or pilot scale study to benefit the industry and environmental safety.

Proteomic response of Pseudomonas aeruginosa IIPIS-8 during rapid and efficient degradation of naphthalene.

Polycyclic aromatic hydrocarbons (PAHs) are widely distributed in the ecosystem and are of significant concern due to their toxicity and mutagenicity. Bioremediation of PAHs is a popular and benign approach that ameliorates the environment. This study investigated the biodegradation and proteome response of Pseudomonas aeruginosa IIPIS-8 for two-ringed PAH: naphthalene (NAP) to understand proteome alteration during its bioremediation. Rapid biodegradation was observed up to 98 ± 1.26% and 84 ± 1.03%, respectively, for initial concentrations of 100 mg L-1 and 500 mg L-1 of NAP. Degradation followed first-order kinetics with rate constants of 0.12 h-1 and 0.06 h-1 and half-life (t1/2) of 5.7 h and 11.3 h, respectively. Additionally, the occurrence of key ring cleavage and linear chain intermediates, 2,3,4,5,6, -pentamethyl acetophenone, 1-octanol 2-butyl, and hexadecanoic acid supported complete NAP degradation. Proteomics study of IIPIS-8 throws light on the impact of protein expression, in which 415 proteins were quantified in sequential windowed acquisition of all theoretical fragment ion mass spectra (SWATH-MS) analysis, of which 97 were found to be significantly up-regulated and 75 were significantly down-regulated by ≥ 2-fold change (p values ≤ 0.05), during the NAP degradation. The study also listed the up-regulation of several enzymes, including oxido-reductases, hydrolases, and catalases, potentially involved in NAP degradation. Overall, differential protein expression, through proteomics study, demonstrated IIPIS-8's capability to efficiently assimilate NAP in their metabolic pathways even in a high concentration of NAP.

Polychlorinated naphthalene concentrations and temporal trends in serum from the general Chinese adult population and effects of polychlorinated naphthalenes on thyroid function.

Polychlorinated naphthalenes (PCNs) have stopped being produced and used but have been detected in human serum around the world. Investigating temporal trends in PCN concentrations in human serum will improve our understanding of human exposure to PCNs and the risks posed. We determined the PCN concentrations in serum collected from 32 adults in five consecutive years (2012-2016). The total PCN concentrations in the serum samples were 0.00-5443 pg/g lipid weight. We found no significant decreases in the total PCN concentrations in human serum and even found that the concentrations of some PCN congeners (e.g., CN20) increased over time. We found differences in the PCN concentrations in serum from males and females, the CN75 concentration being significantly higher in serum from females than males, meaning CN75 poses more serious risks to females than males. We found, using molecular docking techniques, that CN75 interferes with thyroid hormone transport in vivo and that CN20 affects thyroid hormone binding to receptors. These two effects are synergistic and can cause hypothyroidism-like symptoms.

Proteome-wide effects of naphthalene-derived secondary organic aerosol in BEAS-2B cells are caused by short-lived unsaturated carbonyls.

Exposure to air pollution causes adverse health outcomes, but the toxicity mechanisms remain unclear. Here, we investigated the dynamic toxicities of naphthalene-derived secondary organic aerosol (NSOA) in a human bronchial epithelial cell line (BEAS-2B) and identified the chemical components responsible for toxicities. The chemical composition of NSOA was found to vary with six simulated atmospheric aging conditions (C1-C6), as characterized by high-resolution mass spectrometry and ion mobility mass spectrometry. Global proteome profiling reveals dynamic evolution in toxicity: Stronger proteome-wide impacts were detected in fresh NSOA, but the effects declined along with atmospheric aging. While Nrf2-regulated proteins (e.g., NQO1) were significantly up-regulated, the majority (78 to 97%) of proteins from inflammation and other pathways were down-regulated by NSOA exposure (e.g., Rho GTPases). This pattern is distinct from the reactive oxygen species (ROS)-mediated toxicity pathway, and an alternative cysteine reaction pathway was revealed by the decreased abundance of proteins (e.g., MT1X) prone to posttranslational thiol modification. This pathway was further validated by observing decreased Nrf2 response in reporter cells, after preincubating NSOA with cysteine. Ethynyl-naphthalene probe was employed to confirm the alkylation of cellular proteome thiols on the proteome-wide level by fresh NSOA via in-gel fluorescence imaging. Nontarget analysis identified several unsaturated carbonyls, including naphthoquinones and hydroxylated naphthoquinones, as the toxic components responsible for cysteine reactivity. Our study provides insights into the dynamic toxicities of NSOA during atmospheric aging and identifies short-lived unsaturated carbonyls as the predominant toxic components at the posttranslational level.

Human Astrocyte Spheroids as Suitable In Vitro Screening Model to Evaluate Synthetic Cannabinoid MAM2201-Induced Effects on CNS.

There is growing concern about the consumption of synthetic cannabinoids (SCs), one of the largest groups of new psychoactive substances, its consequence on human health (general population and workers), and the continuous placing of new SCs on the market. Although drug-induced alterations in neuronal function remain an essential component for theories of drug addiction, accumulating evidence indicates the important role of activated astrocytes, whose essential and pleiotropic role in brain physiology and pathology is well recognized. The study aims to clarify the mechanisms of neurotoxicity induced by one of the most potent SCs, named MAM-2201 (a naphthoyl-indole derivative), by applying a novel three-dimensional (3D) cell culture model, mimicking the physiological and biochemical properties of brain tissues better than traditional two-dimensional in vitro systems. Specifically, human astrocyte spheroids, generated from the D384 astrocyte cell line, were treated with different MAM-2201 concentrations (1-30 µM) and exposure times (24-48 h). MAM-2201 affected, in a concentration- and time-dependent manner, the cell growth and viability, size and morphological structure, E-cadherin and extracellular matrix, CB1-receptors, glial fibrillary acidic protein, and caspase-3/7 activity. The findings demonstrate MAM-2201-induced cytotoxicity to astrocyte spheroids, and support the use of this human 3D cell-based model as species-specific in vitro tool suitable for the evaluation of neurotoxicity induced by other SCs.

In vitro airway models from mice, rhesus macaques, and humans maintain species differences in xenobiotic metabolism and cellular responses to naphthalene.

The translational value of high-throughput toxicity testing will depend on pharmacokinetic validation. Yet, popular in vitro airway epithelia models were optimized for structure and mucociliary function without considering the bioactivation or detoxification capabilities of lung-specific enzymes. This study evaluated xenobiotic metabolism maintenance within differentiated air-liquid interface (ALI) airway epithelial cell cultures (human bronchial; human, rhesus, and mouse tracheal), isolated airway epithelial cells (human, rhesus, and mouse tracheal; rhesus bronchial), and ex vivo microdissected airways (rhesus and mouse) by measuring gene expression, glutathione content, and naphthalene metabolism. Glutathione levels and detoxification gene transcripts were measured after 1-h exposure to 80 µM naphthalene (a bioactivated toxicant) or reactive naphthoquinone metabolites. Glutathione and glutathione-related enzyme transcript levels were maintained in ALI cultures from all species relative to source tissues, while cytochrome P450 monooxygenase gene expression declined. Notable species differences among the models included a 40-fold lower total glutathione content for mouse ALI trachea cells relative to human and rhesus; a higher rate of naphthalene metabolism in mouse ALI cultures for naphthalene-glutathione formation (100-fold over rhesus) and naphthalene-dihydrodiol production (10-fold over human); and opposite effects of 1,2-naphthoquinone exposure in some models-glutathione was depleted in rhesus tissue but rose in mouse ALI samples. The responses of an immortalized bronchial cell line to naphthalene and naphthoquinones were inconsistent with those of human ALI cultures. These findings of preserved species differences and the altered balance of phase I and phase II xenobiotic metabolism among the characterized in vitro models should be considered for future pulmonary toxicity testing.

Comprehensive Evaluation of Dietary Exposure and Health Risk of Polychlorinated Naphthalenes.

Intake from food is considered an important route of human exposure to polychlorinated naphthalenes. To our knowledge, several studies have quantified dietary exposure but only in European countries and measuring only a few of the 75 congeners. In addition, the influence of source diversity on human exposure has seldom been assessed. We analyzed 192 composite food samples composed of 17,280 subsamples from 24 provinces in China to measure the concentrations of polychlorinated naphthalenes and estimate their daily intake and potential health risks on a national scale. The estimated cancer risk was in the range of 6.8 × 10-8 to 4.6 × 10-7. We compared our findings for 75 congeners with reports in the literature that quantified only 12 congeners. We estimate that these 12 congeners contribute only approximately 4% to the total mass daily intake of polychlorinated naphthalenes and 70% to the total toxic equivalent quantity, indicating underestimation of dietary exposure. The contributions of combustion-associated congeners to the total concentrations of polychlorinated naphthalenes were in the range of 31-52%, suggesting that the ongoing unintentional release of these compounds from industrial thermal processes is an important factor in polychlorinated naphthalene contamination and human exposure in China.

VEGFR3 tyrosine kinase inhibition aggravates cisplatin nephrotoxicity.

Expansion of renal lymphatic networks, or lymphangiogenesis (LA), is well recognized during development and is now being implicated in kidney diseases. Although LA is associated with multiple pathological conditions, very little is known about its role in acute kidney injury. The purpose of this study was to evaluate the role of LA in a model of cisplatin-induced nephrotoxicity. LA is predominately regulated by vascular endothelial growth factor (VEGF)-C and VEGF-D, ligands that exert their function through their cognate receptor VEGF receptor 3 (VEGFR3). We demonstrated that use of MAZ51, a selective VEGFR3 inhibitor, caused significantly worse structural and functional kidney damage in cisplatin nephrotoxicity. Apoptotic cell death and inflammation were also increased in MAZ51-treated animals compared with vehicle-treated animals following cisplatin administration. Notably, MAZ51 caused significant upregulation of intrarenal phospho-NF-κB, phospho-JNK, and IL-6. Cisplatin nephrotoxicity is associated with vascular congestion due to endothelial dysfunction. Using three-dimensional tissue cytometry, a novel approach to explore lymphatics in the kidney, we detected significant vascular autofluorescence attributed to erythrocytes in cisplatin alone-treated animals. Interestingly, no such congestion was detected in MAZ51-treated animals. We found increased renal vascular damage in MAZ51-treated animals, whereby MAZ51 caused a modest decrease in the endothelial markers endomucin and von Willebrand factor, with a modest increase in VEGFR2. Our findings identify a protective role for de novo LA in cisplatin nephrotoxicity and provide a rationale for the development of therapeutic approaches targeting LA. Our study also suggests off-target effects of MAZ51 on the vasculature in the setting of cisplatin nephrotoxicity.NEW & NOTEWORTHY Little is known about injury-associated LA in the kidney and its role in the pathophysiology of acute kidney injury (AKI). Observed exacerbation of cisplatin-induced AKI after LA inhibition was accompanied by increased medullary damage and cell death in the kidney. LA inhibition also upregulated compensatory expression of LA regulatory proteins, including JNK and NF-κB. These data support the premise that LA is induced during AKI and lymphatic expansion is a protective mechanism in cisplatin nephrotoxicity.

Intestinal Microbiome-Macrophage Crosstalk Contributes to Cholestatic Liver Disease by Promoting Intestinal Permeability in Mice.

BACKGROUND AND AIMS: Mounting evidence supports an association between cholestatic liver disease and changes in the composition of the microbiome. Still, the role of the microbiome in the pathogenesis of this condition remains largely undefined. APPROACH AND RESULTS: To address this, we have used two experimental models, administering alpha-naphtylisocyanate or feeding a 0.1% 3,5-diethoxycarbonyl-1,4-dihydrocollidine diet, to induce cholestatic liver disease in germ-free mice and germ-free mice conventionalized with the microbiome from wild-type, specific pathogen-free animals. Next, we have inhibited macrophage activation by depleting these cells using clodronate liposomes and inhibiting the inflammasome with a specific inhibitor of NOD-, LRR-, and pyrin domain-containing protein 3. Our results demonstrate that cholestasis, the accumulation of bile acids in the liver, fails to promote liver injury in the absence of the microbiome in vivo. Additional in vitro studies supported that endotoxin sensitizes hepatocytes to bile-acid-induced cell death. We also demonstrate that during cholestasis, macrophages contribute to promoting intestinal permeability and to altered microbiome composition through activation of the inflammasome, overall leading to increased endotoxin flux into the cholestatic liver. CONCLUSIONS: We demonstrate that the intestinal microbiome contributes to cholestasis-mediated cell death and inflammation through mechanisms involving activation of the inflammasome in macrophages.

Novel aminoarylcysteine adducts in globin of rats dosed with naphthylamine and nitronaphthalene isomers.

Novel aminonaphthylcysteine (ANC) adducts, formed via naphthylnitrenium ions and/or their metabolic precursors in the biotransformation of naphthylamines (NA) and nitronaphthalenes (NN), were identified and quantified in globin of rats dosed intraperitoneally with 0.16 mmol/kg b.w. of 1-NA, 1-NN, 2-NA and 2-NN. Using HPLC-ESI-MS2 analysis of the globin hydrolysates, S-(1-amino-2-naphthyl)cysteine (1A2NC) together with S-(4-amino-1-naphthyl)cysteine (4A1NC) were found in rats given 1-NA or 1-NN, and S-(2-amino-1-naphthyl)cysteine (2A1NC) in those given 2-NA or 2-NN. The highest level of ANC was produced by the most mutagenic and carcinogenic isomer 2-NA (35.8 ± 5.4 nmol/g globin). The ratio of ANC adduct levels for 1-NA, 1-NN, 2-NA and 2-NN was 1:2:100:3, respectively. Notably, the ratio of 1A2NC:4A1NC in globin of rats dosed with 1-NA and 1-NN differed significantly (2:98 versus 16:84 respectively), indicating differences in mechanism of the adduct formation. Moreover, aminonaphthylmercapturic acids, formed via conjugation of naphthylnitrenium ions and/or their metabolic precursors with glutathione, were identified in the rat urine. Their amounts excreted after dosing rats with 1-NA, 1-NN, 2-NA and 2-NN were in the ratio 1:100:40:2, respectively. For all four compounds tested, haemoglobin binding index for ANC was several-fold higher than that for the sulphinamide adducts, generated via nitrosoarene metabolites. Due to involvement of electrophilic intermediates in their formation, ANC adducts in globin may become toxicologically more relevant biomarkers of cumulative exposure to carcinogenic or non-carcinogenic arylamines and nitroarenes than the currently used sulphinamide adducts.

Grouping of chemicals based on the potential mechanisms of hepatotoxicity of naphthalene and structurally similar chemicals using in vitro testing for read-across and its validation.

Integrated Approaches to Testing and Assessment provides a framework to improve the reliability of read-across for chemical risk assessment of systemic toxicity without animal testing. However, the availability of only a few case studies hinders the use of this concept for regulatory purposes. Thus, we compared the biological similarity of structurally similar chemicals using in vitro testing to demonstrate the validity of this concept for grouping chemicals and to extract key considerations in read-across. We analyzed the hepatotoxicity of naphthalene and three chemicals structurally similar to naphthalene (2,7-naphthalenediol, 1,5-naphthalenediol, and 1-naphthol) for which 90-day repeated dose toxicity data are available. To elucidate and compare their potential mechanisms, we conducted in vitro microarray analysis using rat primary hepatocytes and validated the results using a biomarker and metabolic activation analysis. We observed that 2,7-naphthalenediol, 1,5-naphthalenediol, and 1-naphthol had similar potential mechanisms, namely, induction of oxidative stress by their metabolic activation. Conversely, naphthalene did not show a similar toxicity effect. The existing in vivo data confirmed our grouping of chemicals based on this potential mechanism. Thus, our findings suggest that in vitro toxicogenomics and related biochemical assays are useful for comparing biological similarities and grouping chemicals based on their toxicodynamics for read-across.

A novel study for joint toxicity of typical aromatic compounds in coal pyrolysis wastewater by Tetrahymena thermophile.

The coal pyrolysis wastewater (CPW) contributed to aquatic environment contamination with amount of aromatic pollutants, and the research on joint toxicity of the mixture of aromatic compounds was vital for environmental protection. By using Tetrahymena thermophile as non-target organism, the joint toxicity of typical nonpolar narcotics and polar narcotics in CPW was investigated. The results demonstrated that the nonpolar narcotics exerted chronic and reversible toxicity by hydrophobicity-based membrane perturbation, while polar narcotics performed acute toxicity by irreversible damage of cells. As the most hydrophobic nonpolar narcotics, indole and naphthalene caused the highest joint toxicity in 24 h with the lowest EC50mix (24.93 mg/L). For phenolic compounds, the combination of p-cresol and p-nitrophenol also showed the top toxicity (EC50mix = 10.9 mg/L) with relation to high hydrophobicity, and the joint toxicity was obviously stronger and more acute than that of nonpolar narcotics. Furthermore, by studying the joint toxicity of nonpolar narcotics and polar narcotics, the hydrophobicity-based membrane perturbation was the first step of toxicity effects, and afterwards the acute toxicity induced by electrophilic polar substituents of phenols dominated joint toxicity afterwards. This toxicity investigation was critical for understanding universal and specific effects of CPW to aquatic organisms.

Role of Integrated Biomarker Response Tool for Assessment of Naphthalene Toxicity in Anabas testudineus.

Polyaromatic hydrocarbons are highly stable and can easily permeate through biological membranes due to their lipophilic nature. They are characterized by their ability to act at the site of application and even at sites distant to the zone of application. Any contamination associated with aquatic bodies due to the presence of PAHs can be assessed by investigating biochemical changes. The most common polycyclic aromatic hydrocarbon (PAH) pollutant naphthalene was selected for the bioassay experiment using Indian climbing perch Anabas testudineus. The biochemical response in the muscle tissue was investigated after exposure to varying concentrations of naphthalene by estimating protein, glycogen, Alanine Aminotransaminase, and Aspartate Aminotransaminase. The results showed inhibition of protein and glycogen levels due to naphthalene stress. Similarly, a decrease in the activity of transaminase in muscle tissues was noticed. The results have been computed using star plots for interpretation of integrated biomarker response (IBR). The results clearly support the role of biochemical parameters in assessing the impact of naphthalene stress on fish health. IBR index can be developed as a useful tool in monitoring quantitative as well as the qualitative effect of naphthalene toxicity in fishes and other aquatic animals.

Synthetic cannabinoids enhanced ethanol-induced motor impairments through reduction of central glutamate neurotransmission.

Marijuana or synthetic cannabinoids and alcohol are often used together, with these combinations causing motor impairments that can subsequently lead to motor vehicle accidents. This study investigated the combined use of both synthetic cannabinoids and ethanol and their effect on motor coordination in mice in addition to examining the neurochemical changes in the cerebellum. Ethanol (2 g/kg, i.p.) significantly induced motor impairment in the accelerating rotarod test in mice. Furthermore, ethanol-induced motor impairments were further accentuated when combined with the synthetic cannabinoid, JWH-018 or AB-CHMINACA. The enhancement effects of the synthetic cannabinoids were completely antagonized by pretreatment with the selective CB1 receptor antagonist AM251, but not by the selective CB2 receptor antagonist AM630. Neurochemical study results showed that ethanol caused a reduction in the extracellular glutamate levels in the cerebellum during periods of ethanol-induced motor impairment. In addition to the enhanced motor impairment seen when ethanol was combined with JWH-018, these combinations also enhanced the reduction of the extracellular glutamate levels in the cerebellum. We additionally used microelectrode array recordings to examine the effects of ethanol and/or JWH-018 on the spontaneous network activity in primary cultures from mouse cerebellum. Results showed that ethanol combined with JWH-018 significantly reduced spontaneous neuronal network activity in the primary cerebellar culture. Our findings demonstrate that ethanol-induced motor impairments are enhanced by synthetic cannabinoids, with these effects potentially mediated by CB1 receptors. An accentuated reduction of neurotransmissions in the cerebellum may play an important role in motor impairments caused by ethanol combined with synthetic cannabinoids.

Cannabinoids induce latent sensitization in a preclinical model of medication overuse headache.

AIM: Evaluation of cannabinoid receptor agonists in a preclinical model of medication overuse headache. METHODS: Female Sprague Dawley rats received graded intraperitoneal doses of WIN55,212-2 or Δ-9-tetrahydrocannabinol (Δ-9-THC). Antinociception (tail-flick test), catalepsy and hypomotility (open field test) and impairment of motor function (rotarod test) were assessed to establish effective dosing. Rats were then treated twice daily with equianalgesic doses of WIN55,212-2 or Δ-9-THC, or vehicle, for 7 days and cutaneous tactile sensory thresholds were evaluated during and three weeks following drug discontinuation. Rats then received a one-hour period of bright light stress (BLS) on two consecutive days and tactile sensory thresholds were re-assessed. RESULTS: WIN55,212-2 and Δ-9-THC produced antinociception as well as hypomotility, catalepsy and motor impairment. Repeated administration of WIN55,212-2 and Δ-9-THC induced generalized periorbital and hindpaw allodynia that resolved within 3 weeks after discontinuation of drug. Two episodes of BLS produced delayed and long-lasting periorbital and hindpaw allodynia selectively in rats previously treated with WIN55,212-2, and Δ-9-THC. INTERPRETATION: Cannabinoid receptor agonists including Δ-9-THC produce a state of latent sensitization characterized by increased sensitivity to stress, a presumed migraine trigger. Overuse of cannabinoids including cannabis may increase the risk of medication overuse headache in vulnerable individuals.

Resveratrol delay the cataract formation against naphthalene-induced experimental cataract in the albino rats.

Oxidative stress-induced toxicity plays a major role in ocular diseases such as retinal degeneration, age-related cataract (ARC) formation and macular dystrophy. In this study, we explored the possible role of resveratrol (RSV) at the different dose levels (10, 20 and 40 mg/kg/day, ip) in an experimental model of naphthalene (1 g/kg/day, po)-induced age-related cataracts. Morphological changes in the eyes of the rats in two groups, the RSV and the ARC groups, were monitored weekly, and biochemical parameters in the lenses were assessed after completion of the experimental work. A comparison between the rats in the two groups showed that treatments at RSV doses of 20 and 40 mg/kg/day significantly retarded lenticular opacity, restored antioxidants (CAT, SOD, GPX, GSH), Ca2+ ATPase function, and protein contents, and reduced lipid peroxidation in the lenses of the animals in the RSV group. The treatment with resveratrol at a dose of 10 mg/kg/day did not show any anti-cataractogenic effects. Based on the results of our investigation, we conclude that supplemental doses of resveratrol at 40 mg/kg/day effectively prevent cataract formation associated with the aging via increased soluble protein contents and Ca2+ homeostasis, apart from the antioxidant restoration. The results demonstrate that RSV treatment may be considered as a promising preventive or supplemental measure for delaying and/or preventing the formation of ARCs.

Prenatal cannabinoid exposure alters the ovarian reserve in adult offspring of rats.

In animals, research in the past two decades has demonstrated the strong involvement of the endocannabinoid system (ECS) in numerous steps of the reproductive process, including ovarian physiology. Reproductive lifespan is closely related to the number of nongrowing ovarian follicles, called ovarian reserve (OR), which is definitively established during foetal life. Thus, OR damage may lead to poor reproductive outcomes and a shortened reproductive lifespan. We investigated whether prenatal ECS modulation had an effect on the OR at different ages in the rat offspring. Four groups of gestating female rats (F0) were exposed to the CB1-/CB2-receptor agonist WIN55212 (0.5 mg/kg), the CB1R inverse agonist SR141716 (3 mg/kg) or Δ9THC (5 mg/kg) and were compared to negative control groups. OR was histologically assessed at different postnatal timepoints (F1 individuals): postnatal day (PND) 6, PND40 and PND90. At PND6, prenatal exposure had no effect on OR. In the young adult group (PND90) exposed during gestation to WIN55212, we observed a CB1R-mediated delayed OR decrease, which was reversed by prenatal CB1R blockade by SR141716. Conversely, after prenatal SR141716 exposure, we observed higher OR counts at PND90. RT-PCR experiments also showed that prenatal ECS modulation perturbed the mRNA levels of ECS enzymes and OR regulation genes. Our findings support the role of the ECS in OR regulation during the foetal life of rats and highlight the need for further studies to elucidate its precise role in OR physiology.

Comparison of acute respiratory epithelial toxicity for 4-Methylimidazole and naphthalene administered by oral gavage in B6C3F1 mice.

4-Methylimidazole (4MEI) is a contaminant in food and consumer products. Pulmonary toxicity and carcinogenicity following chronic dietary exposures to 4MEI is a regulatory concern based on previous rodent studies. This study examined acute pulmonary toxicity in B6C3F1 mice from 6 h to 5 days after oral gavage with a single dose of 150 mg/kg 4MEI, a double dose delivered 6 h apart, or vehicle controls. Oral gavage of 150 mg/kg naphthalene, a prototypical Club cell toxicant, was used as a positive control. Intrapulmonary conducting airway cytotoxicity was assessed in fixed-pressure inflated lungs using qualitative histopathology scoring, quantitative morphometric measurement of vacuolated and exfoliating epithelial cells, and immunohistochemistry. 4MEI treatment did not change markers of cytotoxicity including the mass of vacuolated epithelium, the thickness of the epithelium, or the distributions of epithelial proteins: secretoglobin 1A1, proliferating cell nuclear antigen, calcitonin gene-related peptide, and myeloperoxidase. 4MEI and vehicle controls caused slight cytotoxicity with rare vacuolization of the epithelium relative to the severe bronchiolar epithelial cell toxicity found in the naphthalene exposed mice at terminal bronchioles, intrapulmonary airways, or airway bifurcations. In summary, 4MEI caused minimal airway epithelial toxicity without characteristic Club Cell toxicity when compared to naphthalene, a canonical Club Cell toxicant.

Phototoxic risk assessment of dermally-applied chemicals with structural variety based on photoreactivity and skin deposition.

Combined use of photochemical and pharmacokinetic (PK) data for phototoxic risk assessment was previously proposed, and the system provided reliable phototoxic risk predictions of chemicals in same chemical series. This study aimed to verify the feasibility of the screening system for phototoxic risk assessment on dermally-applied chemicals with wide structural diversity, as a first attempt. Photochemical properties of test chemicals, 2-acetonaphthalene, 4'-methylbenzylidene camphor, 6-methylcoumarin, methyl N-methylanthranilate, and sulisobenzone, were evaluated in terms of UV absorption and reactive oxygen species (ROS) generation, and PK profiles of the test chemicals in rat skin were characterized after dermal co-application. All test chemicals showed strong UVA/B absorption with molar extinction coefficients of over 3000 M-1⋅cm-1, and irradiated 2-acetonaphthalene, 6-methylcoumarin, and methyl N-methylanthranilate exhibited significant ROS generation. Dermally-applied 2-acetonaphthalene and 4'-methylbenzylidene camphor indicated high and long-lasting skin deposition compared with the other test chemicals. Based on the photochemical and PK data, 2-acetonaphthalene was predicted to have potent phototoxic risk. The predicted phototoxic risk of the test chemicals by integration of obtained data was mostly consistent with their in vivo phototoxicity observed in rat skin. The screening strategy employing photochemical and PK data would have high prediction capacity and wide applicability for photosafety evaluation of chemicals.

Antagonism or synergism? Responses of Hydrocharis dubia (Bl.) Backer to linear alkylbenzene sulfonate, naphthalene and their joint exposure.

The presence of surfactants may affect the bioavailability of polycyclic aromatic hydrocarbons. A hydroponic experiment was conducted to investigate the response of Hydrocharis dubia (Bl.) Backer to different concentrations of linear alkylbenzene sulfonate (LAS), naphthalene (NAP) and their mixture (0.5, 5, 10, and 20 mg/L) for 14 days and 28 days. The results showed that LAS had a greater toxic effect on H. dubia growth than NAP at treatment concentrations of 0.5-20 mg/L. The combined effect of LAS and NAP was damaging to H. dubia at concentrations of LAS + NAP ≥5 + 5 mg/L. When LAS + NAP ≥10 + 10 mg/L, the underground parts of H. dubia suffered more significant damage than the aboveground parts. Under the treatments with LAS, NAP and their mixture, H. dubia experienced oxidative stress. Soluble proteins and antioxidant enzymes were the main substances protecting H. dubia from LAS stress, and superoxide dismutase (SOD) and peroxidase (POD) were the main protective enzymes. When exposed to NAP, H. dubia growth was stimulated and promoted at the same time. In the short-term treatment (14 d), catalase (CAT) activity was sensitive to NAP stimulation, and soluble proteins and SOD were the main protective substances produced. Soluble sugars, SOD and ascorbate peroxidase (APX) played important protective roles during the longer exposure time (28 d). The physiological response of H. dubia exposed to the combined toxicants was weaker than the response to exposure to individual toxicants. The responses of SOD and CAT activity were positive in the short term (14 d), and these were the main protective enzymes. As the exposure time increased (28 d), the plant antioxidant system responded negatively.