Xenobiotica最新文献

This investigation was planned to evaluate the mechanistic interactions of Imidacloprid (IM) and Chlorothalonil (CL), inducing toxicity after 28 days of oral administration. Male Wistar rats were divided into a control (CR) and three treatment groups, receiving IM (45 mg/kg), CL (300 mg/kg), and mixture of IM+CL.IM and CL,individually or in combination induced a hypothyroidstate with a sharp decline in insulin levels. Additionally, high plasma alanine transferase (ALT/SGPT) and aspartate transferase (AST/SGOT) levels, as well as alkaline phosphatase (Alk-P) and creatinine were recorded in all treated groups. Both IM and CL significantly compromised the antioxidant defense system by increasing the MDA level, and inhibiting the activity of CAT and SOD.A significant binding affinity of IM and CL to enzymes integral to the blood transport and receptor binding of THs like MCT8 and TSHR was observed. The MD simulations revealed the strong and stable interactions between IM, CL, MCT8, and TSH-R. MMGBSA energies showed that both pesticides compete with hormones at active sites, indicating their potential to modulate key enzymes involved in thyroid hormone transport and action.Therefore, it is anticipated that these resultswill provide beneficial knowledge for future therapeutic endeavors.

Silver diamine fluoride (SDF) is commonly used in clinical settings to manage dental caries in young children. A major drawback of SDF is its tendency to darken carious lesions, turning them brown or black, which has drawn criticism. This study investigates the cytotoxic effects of SDF on human gingival fibroblasts (hGF).hGF cells were exposed to varying concentrations of SDF (0.0001%, 0.001%, and 0.005%) for a 24-hour period. We analysed cytotoxicity, the potential for reactive oxygen species (ROS) production, mitochondrial function, morphological indicators of apoptosis, and key molecular markers of apoptosis.The findings revealed that SDF exposure led to significant, dose-dependent cytotoxicity and ROS generation in hGF. Morphological changes consistent with apoptosis were observed. Furthermore, SDF disrupted the balance of Bax and Bcl-2 proteins and reduced the expression of proliferating cell nuclear antigen in these cells. In animal studies, single SDF application for 3 h resulted in mild structural alterations of gingival tissue and basilar hyperplasia in rats.Overall, the findings demonstrate that SDF exhibits cytotoxicity towards hGF, primarily through intracellular ROS production and subsequent apoptosis. Additionally, the in vivo experiments validate the mild toxic effects of SDF on rat gingival tissues. Developing controlled drug delivery approaches could help mitigate SDF's toxicity in clinical applications.

The mutagenicity and bioactivation potential of N-nitrosoparoxetine, a N-nitrosamine drug substance related impurity (NDSRI) of the marketed antidepressant paroxetine, was characterised in vitro.N-Nitrosoparoxetine was not mutagenic in an OECD 471-compliant bacterial reverse mutation assay even under experimental conditions that supported oxidative metabolism by CYP enzymes. The major biotransformation pathways of N-nitrosoparoxetine paralleled the ones previously noted with paroxetine. Virtually all stable metabolites of N-nitrosoparoxetine in human, rat, and hamster liver tissue were derived from phase 2 conjugations on an unstable catechol intermediate, generated from the oxidative 1,3-benzodioxole ring scission by CYP enzymes. The piperidine ring in N-nitrosoparoxetine was resistant to the α-carbon oxidation step leading to piperidine ring scission, and to the eventual formation of a DNA-reactive electrophilic species.CYP reaction phenotyping studies demonstrated that paroxetine was exclusively metabolised by human CYP2D6, whereas N-nitrosoparoxetine was subject to metabolism by multiple human CYP isoforms including CYP2C19, CYP2D6, and CYP3A4.Whether most NDSRIs derived from parent amine precursors that are resistant to α-carbon oxidation by CYPs will also be devoid of a mutagenic response in vitro needs to be scrutinised further with additional examples to bolster structure-genotoxicity relationships of complex NDSRIs.

Aflatoxin B₁ (AFB₁) is a potent hepatocarcinogen. It is activated by cytochrome P450 3A4 (CYP3A4) into a DNA-reactive epoxide linked to liver cancer.Six scopoletin metabolites were predicted using SmartCYP. Their lipophilicity was assessed via BioTransformer 3.0; molecular docking was performed with CBDock 2 using CYP3A4 (PDB ID: 1TQN).Phase I Metabolite 2 showed the highest binding affinity (Vina score: -7.4 kcal/mol) and was selected for a 100 ns molecular dynamics (MD) simulation using Desmond with the OPLS3e force field.The metabolite maintained stable binding (RMSD < 1.0 Å), showed >80% hydrophobic interaction occupancy with Phe215, Phe108, and Leu210, and formed transient hydrogen bonds with Ser119; MM-GBSA predicted a binding free energy of -75 kcal/mol.Scopoletin metabolites may competitively inhibit AFB₁ activation by binding CYP3A4, indicating potential for chemoprevention pending experimental confirmation.

Xevinapant, a drug previously under development for head and neck cancer, was investigated to determine its intrinsic clearance (CL_int) in vitro and assess the involvement of CYP enzymes in its metabolism. Extensive in vitro studies showed very low turnover, necessitating advanced methodologies to accurately measure CL_int values.Two novel in vitro assays, using a modified suspension hepatocyte protocol or 3D hepatocyte spheroid cultures, allowed measuring hepatic turnover of xevinapant with very low CL_int values of 1.3 or 0.3 µL/min/10⁶ cells, respectively. Reaction phenotyping using specific inhibitors, enabled by enhanced detection capabilities in spheroids, identified primarily CYP3A (> 50%) as contributor to the hepatic metabolism of xevinapant.In vitro-in vivo extrapolation, in combination with data from the human mass balance study, revealed that hepatic metabolism, primarily mediated by CYP3A, accounts for approximately 30% of the overall clearance. The remaining clearance is renal (∼20%) and metabolic, but potentially extrahepatic (∼50%).This research highlights the importance and benefits of utilising advanced in vitro techniques, such as human hepatocyte spheroids, to accurately characterise drug metabolism, providing valuable insights for pharmacokinetic evaluations and, ultimately, supporting the development of a PBPK model and understanding the DDI risk of xevinapant.

This study aimed to develop a targeted metabolomics workflow using low-resolution tandem mass spectrometry (MS/MS) to identify metabolic alterations in zebrafish (Danio rerio) embryos exposed to environmentally relevant concentrations of the antibiotic's amoxicillin and clarithromycin.Zebrafish embryos were exposed to the lowest concentrations (1 µg/L) and the highest concentration (1 mg/L) of amoxicillin and clarithromycin. A library-assisted multiple reaction monitoring-enhanced product ion (MRM-EPI) approach was applied using a QTRAP LC-MS/MS system, enabling the detection and structural confirmation of 108 endogenous metabolites. A targeted MRM-EPI method was subsequently optimised for sensitivity, reproducibility, and specificity. Multivariate statistical analyses, including principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA), were performed to assess metabolic differences between exposed and control groups.Exposure to both antibiotics resulted in significant alterations in amino acid, purine, lipid, and energy metabolism, indicating that even sub-lethal concentrations can disrupt vital physiological processes in zebrafish embryos. These findings highlight the sensitivity of metabolomics for detecting early biochemical perturbations and support the use of zebrafish embryos as a practical and ethically suitable model for environmental toxicity assessment. The developed MRM-driven workflow provides a reproducible platform for predictive toxicology and ecological risk evaluation.

This study aimed to apply a machine learning workflow to identify the most relevant biological parameters for predicting both the dose and the route of crack cocaine administration.Seventeen variables were evaluated in rats exposed to different doses of crack cocaine, either intraperitoneally (18 or 36 mg/kg, i.p.) or via passive inhalation (25, 50, or 100 mg). Random forest (RF) analysis was used to build predictive models, feature importance analysis to identify key variables, and interaction dependence analysis to explore relationships among variables.Eighty percent of the data was used for training and 20% for testing. The model achieved 85% accuracy in the training phase and 100% in the test phase. During training, the highest accuracy was observed for the 100 mg inhaled group, while the lowest was for the 50 mg inhaled group. Notably, 20% of the 50 mg i.p. cases were misclassified as 36 mg i.p. Feature importance analysis highlighted four key predictors: liver karyolysis, kidney Ki-67 expression, liver binucleation, and escape behaviour.These findings demonstrate that machine learning (ML) can accurately predict both dose and route of crack cocaine exposure, and can highlight biologically relevant parameters involved in the drug's systemic and behavioural effects.

Objective: This study evaluated the effects of Serfurosterone A (SSA) from Achyranthes bidentata Bl. on dexamethasone (DEX)-induced osteoblast dysfunction and its intestinal permeability.

Methods: The anti-osteoporotic effects of SSA were assessed by MTT assay, flow cytometry, osteogenic differentiation induction, and western blotting. Intestinal permeability and transport mechanisms were investigated using Caco-2 cell models and single-pass intestinal perfusion (SPIP) in rats.

Results: SSA (5-50 µM) increased the viability and proliferation of DEX-injured MC3T3-E1 cells, enhanced alkaline phosphatase (ALP) activity, and promoted mineralized nodule formation. Western blot analysis suggested that SSA's effects may involve activation of the Wnt/β-catenin signaling pathway, characterized by upregulation of β-catenin and downregulation of GSK3β. In the Caco-2 assays, SSA showed moderate absorption (Papp 1.551-2.443 × 10^-6cm/s; ER 0.751-0.898) via passive transcellular transport. SPIP experiments further indicated efficient absorption across all intestinal segments (Peff > 2 × 10^-5cm/s), with the duodenum as the main absorption site.

Conclusions: SSA mitigates DEX-induced osteogenic inhibition and exhibits favorable intestinal absorption, suggesting its potential as a promising oral candidate for glucocorticoid-induced osteoporosis (GIOP). These results underscore the therapeutic promise of Achyranthes-derived phytosterols for future drug development.

Considering the important role of mitochondria in mammalian cells and the close correlation between mitochondrial dysfunction and various diseases, this study evaluated the potential toxicity of glyphosate on mitochondrial function in swine heart mitochondria.The results indicated that glyphosate did not have a significant effect on mitochondrial respiration, mitochondrial swelling, and F₁F_O-ATPase activity under the experimental conditions tested.These findings suggest that, in this model, glyphosate alone may not exert a direct cardiotoxic effect on mitochondrial bioenergetics.Caution is warranted when extrapolating these results to human health, as differences in species, exposure levels, and experimental conditions may influence outcomes.The toxicity observed in glyphosate-based herbicides could involve adjuvants or synergistic interactions between glyphosate and other formulation components, as proposed by other studies.

Black American Ginseng (Panax quinquefolium L.) is a traditional Chinese medicine taken orally. While saponins from American Ginseng are known to enhance memory, the effects and mechanisms of Black American Ginseng saponins remain unclear.This study investigates their potential in alleviating memory impairment in ageing mice. UPLC-Q-Orbitrap-MS/MS was used to identify compounds in Black American Ginseng, and network pharmacology predicted potential targets. The Morris water maze test assessed cognitive function, while Western blot and ELISA measured BDNF, TrkB, inflammatory markers (IL-1β, TNF-α, IL-6), and the activation of the PI3K/AKT/CREB signalling pathway. Networking pharmacology and PPI analysis identified PIK3CA, EGFR, and PIK3R1 as key targets, with KEGG enrichment highlighting the PI3K/AKT pathway. Behavioural tests confirmed that Black American Ginseng saponins significantly improved memory in ageing mice. Molecular analyses revealed upregulation of BDNF and TrkB and suppression of IL-1β and IL-6. Additionally, Western blot confirmed activation of the PI3K/AKT/CREB pathway, supporting its neuroprotective role.Black American Ginseng saponins enhance cognitive function by modulating neurotrophic signalling and reducing neuroinflammation.These findings provide new insights into their potential therapeutic application for age-related cognitive decline.