Toxicology Mechanisms and Methods最新文献

{"title":"Sevoflurane pre-treatment attenuates myocardial cell ferroptosis caused by hypoxia and reoxygenation <i>via</i> regulating lncRNA NNT-AS1.","authors":"Zanhui Gong, Yajun Wu, Yongsheng Wang, Zhiwei Huang, Jianxing Chen, Lijuan Pan, Zhijian Chen","doi":"10.1080/15376516.2026.2668535","DOIUrl":"10.1080/15376516.2026.2668535","url":null,"abstract":"<p><p>Myocardial ischemia-reperfusion injury (MIRI) is the primary cause of death for acute myocardial infarction. LncRNA NNT-AS1 was upregulated in the H9c2 hypoxia-reoxygenation (H/R) model. However, the interaction between sevoflurane and NNT-AS1 is unknown in MIRI. The specific aim of this study was to explore the mechanism by which sevoflurane regulates cardiomyocyte injury <i>via</i> the NNT-AS1/miR-23a-3p/USP24 axis. The Caspase-3 level and apoptosis rate were used to assess the cell apoptosis level. Reactive oxygen species (ROS), malondialdehyde (MDA), glutathione (GSH), glutathione disulfide (GSSG), GSH/GSSG ratio, the total iron content, and Glutathione Peroxidase 4 (GPX4) protein content were measured to evaluate the level of ferroptosis. The targeting relationship was detected by the dual-luciferase reporter gene assay. In the H9c2 H/R model, the NNT-AS1 and USP24 levels were increased, but miR-23a-3p was decreased. The cell damage was aggravated, and apoptosis and ferroptosis were promoted. However, the NNT-AS1 and USP24 expression was downregulated, and miR-23a-3p expression was upregulated by sevoflurane pre-treatment. Cell damage, apoptosis, and ferroptosis were also improved. NNT-AS1 functions as a molecular sponge for miR-23a-3p. The NNT-AS1 overexpression further aggravated cell damage, apoptosis, and ferroptosis, while miR-23a-3p overexpression reversed the damaging effect of NNT-AS1. In summary, sevoflurane pretreatment alleviates apoptosis and ferroptosis in H/R-stimulated cardiomyocytes by regulating the NNT-AS1/miR-23a-3p/USP24 signaling axis, which may provide a potential target for MIRI treatment.</p>","PeriodicalId":23177,"journal":{"name":"Toxicology Mechanisms and Methods","volume":" ","pages":"1199-1210"},"PeriodicalIF":2.7,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148151400","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Glycycoumarin ameliorates pyroptosis in autoimmune hepatitis by activating autophagy and reducing NLRP3 inflammasome activation.","authors":"Qian Gao, Yiqun Zhou, Jun Shi, Fang Yuan, Yanping Shen","doi":"10.1080/15376516.2026.2664034","DOIUrl":"10.1080/15376516.2026.2664034","url":null,"abstract":"<p><strong>Objective: </strong>This study explored the protective effect of glycycoumarin (GCM) against autoimmune hepatitis (AIH) and its underlying mechanisms.</p><p><strong>Methods: </strong>An AIH mouse model was established by concanavalin A induction and treated with GCM or methylprednisolone (MP) positive control. Liver index and serum levels of alanine aminotransferase, aspartate aminotransferase, and lactate dehydrogenase (LDH) were measured. Histopathological changes in liver tissues were observed <i>via</i> H&E staining. Pyroptosis-associated proteins and inflammatory cytokines in liver tissues were assessed by Western blot, RT-qPCR, and ELISA. <i>In vitro</i>, AML12 cells were stimulated with lipopolysaccharide and Nigericin to construct an inflammatory pyroptosis model. Cell viability, LDH release, autophagic flux, pyroptosis-related protein expression, Caspase-1 activity, and mitochondrial function were assessed. To assess the autophagy-dependence of GCM's effect, cells were treated with 3-methyladenine, an inhibitor of autophagy.</p><p><strong>Results: </strong>In AIH mice, GCM treatment reduced liver index, serum transaminases, and LDH levels while alleviating hepatic necrosis and inflammatory infiltration. GCM downregulated NLRP3, Caspase-1, and GSDMD mRNA expression, reduced NLRP3, Cleaved Caspase-1, and GSDMD-NT protein expression, and suppressed IL-1β and IL-18 release in liver tissues of mice. <i>In vitro</i>, GCM improved cell viability, reduced LDH release, and inhibited Caspase-1 activation and pyroptosis in LPS+NIG-induced AML12 cells. GCM restored autophagic flux, alleviated oxidative stress, and mitigated mitochondrial damage <i>in vivo</i> and <i>in vitro</i>. Autophagy inhibition partially counteracted the effects of GCM on promoting autophagy, protecting against mitochondrial damage, and suppressing NLRP3 inflammasome-induced pyroptosis.</p><p><strong>Conclusion: </strong>GCM protects against AIH by restoring autophagic flux and mitigating oxidative stress, thereby suppressing NLRP3 inflammasome-mediated pyroptosis.</p>","PeriodicalId":23177,"journal":{"name":"Toxicology Mechanisms and Methods","volume":" ","pages":"1115-1129"},"PeriodicalIF":2.7,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148278953","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tobacco-specific nitrosamine '4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)': toxicological mechanisms, carcinogenicity, and chemopreventive approaches.","authors":"Divya Kumari, Pracheta Janmeda, Devendra Singh","doi":"10.1080/15376516.2026.2668531","DOIUrl":"10.1080/15376516.2026.2668531","url":null,"abstract":"<p><p>The tobacco-specific nitrosamine, 4-(methyl-nitrosamino)-1-(3-pyridyl)-1-butanone has been identified as potent lung carcinogen in laboratory animals. Bioactivation of nicotine-derived nitrosamine ketone occurs <i>via</i> cytochrome P450-mediated hydroxylation of carbon atoms adjacent to the nitrosamino group, generating reactive methylating and pyridyloxobutylating intermediates. NNK can be metabolically reduced to NNAL, which retains carcinogenic potential and undergoes similar activation. Like NNK, NNAL also requires the metabolic activation to DNA alkylating agents. When NNAL is methyl hydroxylated, pyridinyl-hydroxy-butyl DNA adducts are formed, and methylene hydroxylation results in DNA methyl adducts. NNK's metabolic complexity leads to a variety of DNA lesions, increasing its overall carcinogenic potency. From this angle, the chemistry and genotoxic properties of many DNA adduct generated from NNK are discussed. Adducts that contribute to the genotoxic effects of NNK include the gene targeted for mutation, amounts, and genetic variants of critical repair enzymes. NNK, present in modern smokeless tobacco products, plays a central role in cancer risk among users. The mechanisms by which NNK induces cancer in humans are discussed in this paper, along with the factors influencing NNK development at various phases of tobacco manufacturing.</p>","PeriodicalId":23177,"journal":{"name":"Toxicology Mechanisms and Methods","volume":" ","pages":"1059-1089"},"PeriodicalIF":2.7,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147843226","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Computational toxicology analysis of candidate drivers and pathways in HRZE-associated drug-induced liver injury.","authors":"Yehua Lai, Xinyi Yang, Hua Tian, Yuhong Zhou, Fu Liu","doi":"10.1080/15376516.2026.2670504","DOIUrl":"10.1080/15376516.2026.2670504","url":null,"abstract":"<p><p>The first-line anti-tuberculosis regimen HRZE (isoniazid (INH), rifampicin (RIF), pyrazinamide (PZA), ethambutol (EMB)) frequently causes drug-induced liver injury (DILI). However, the mechanisms underlying this combination hepatotoxicity remain unclear. Therefore, this study used a hierarchical network toxicology and molecular docking approach to systematically investigate the hepatotoxic mechanisms of the HRZE regimen, aiming to identify core and non-core hepatotoxic drugs and elucidate their synergistic effects. We identified 315 DILI-related targets associated with the HRZE regimen. Protein-protein interaction network analysis revealed seven hub genes, and enrichment analysis identified the biological processes involved and signaling pathways. Isoniazid, RIF, and PZA were classified as core hepatotoxic drugs due to the significant enrichment of their targets in DILI pathways and their high clinical risk. In contrast, EMB was identified as a non-core hepatotoxic drug, with lower target enrichment and a lower risk of liver injury. The targets of the core hepatotoxic drugs were widely distributed across major DILI pathways, while EMB may synergistically modulate pathway activity through a limited set of targets, including carbonic anhydrase II (CA2). Molecular docking confirmed that all four drugs bind stably to cytochrome P450 family 2 subfamily E member 1 (CYP2E1); the high affinity of EMB for CA2 suggests its involvement in cholestatic injury. In conclusion, HRZE-induced hepatotoxicity is a multi-pathway process driven predominantly by INH, RIF, and PZA, with EMB playing a synergistic role and potentially contributing to cholestatic injury. By establishing a multi-level toxicological framework, this study provides a theoretical basis for understanding combination hepatotoxicity and offers potential targets for DILI intervention.</p>","PeriodicalId":23177,"journal":{"name":"Toxicology Mechanisms and Methods","volume":" ","pages":"1226-1242"},"PeriodicalIF":2.7,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147869483","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"E-cigarette aerosols as systemic metabolic disruptors: integrated mitochondrial, circadian, and neurobehavioral mechanisms.","authors":"Ardie Barry Sailis","doi":"10.1080/15376516.2026.2658739","DOIUrl":"10.1080/15376516.2026.2658739","url":null,"abstract":"<p><p>E-cigarettes are promoted as reduced-harm alternatives to combustible tobacco, yet their aerosols contain metals, aldehydes, solvents, and other bioactive chemicals capable of disrupting metabolic regulation. This review synthesizes evidence from cellular, animal, and early human studies on how e-cigarette aerosol exposure affects metabolic homeostasis across mitochondrial, redox, circadian, and neurobehavioral systems. A systems-level model is proposed in which mitochondrial dysfunction, oxidative stress, circadian misalignment, and neurobehavioral alterations form a feed-forward network that drives metabolic inflexibility. Across experimental systems, e-cigarette exposure is associated with mitochondrial impairment, oxidative stress, AMPK suppression, disrupted lipid oxidation, adipose inflammation, and reduced thermogenic capacity, changes consistent with insulin resistance. Evidence also indicates disruption of circadian clock signaling and modulation of reward and appetite circuits, further biasing energy balance. These findings support a model in which e-cigarette aerosols act as multi-system metabolic disruptors affecting both peripheral organs and central regulatory pathways. However, important uncertainties remain regarding dose-response relationships, exposure patterns, device variability, and long-term human risk. This review provides an integrated framework to clarify potential links between e-cigarette aerosol exposure and metabolic dysfunction and highlights priorities for future translational and human research.</p>","PeriodicalId":23177,"journal":{"name":"Toxicology Mechanisms and Methods","volume":" ","pages":"1003-1028"},"PeriodicalIF":2.7,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147692315","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quantitative methods for the risk assessment of drinking water contact chemicals following the NSF/ANSI/CAN 600 Standard - Part II: advanced methods.","authors":"Bradley Lampe, J Caroline English, L T Haber, Kelly Magurany","doi":"10.1080/15376516.2026.2672014","DOIUrl":"10.1080/15376516.2026.2672014","url":null,"abstract":"<p><p>Health-based criteria have been developed using quantitative methods for over 370 unregulated chemicals that have been detected in extraction testing of products certified or being certified to NSF/ANSI/CAN 60 (<i>Drinking Water Treatment Chemicals - Health Effects</i>) and NSF/ANSI/CAN 61 (<i>Drinking Water System Components - Health Effects</i>), public health-based drinking water standards. These criteria are derived in accordance with the requirements of NSF/ANSI/CAN 600, <i>Health Effects Evaluation and Criteria for Chemicals in Drinking Water</i> and undergo external peer review by an independent Health Advisory Board. However, a complete and unified description of how these criteria are derived is not available in the scientific literature. This is the second part of a two-part publication that describes specialized methods that may be applied in drinking water risk assessments conducted according to NSF/ANSI/CAN 600, depending on data availability and understanding of the mode of action. The specialized methods discussed herein include the use of data-derived extrapolation factors (including dosimetric adjustment factors and chemical-specific adjustment factors), inhalation-to-oral route extrapolation, the use of threshold versus non-threshold approaches in evaluating dose-response, study mortality adjustments, benchmark dose modeling, and carcinogen-specific approaches such as the use of the cancer slope factor and lifestage adjustment for cancer potency.</p>","PeriodicalId":23177,"journal":{"name":"Toxicology Mechanisms and Methods","volume":" ","pages":"1090-1114"},"PeriodicalIF":2.7,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148138960","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nephroprotective role of edaravone against polystyrene nanoplastic-induced endoplasmic reticulum stress in Wistar rats.","authors":"Rachna Yadav, Ashok Jangra, Dinesh Dhingra, Sapana Kushwaha, Itishree Dubey, Dinesh Kumar","doi":"10.1080/15376516.2026.2664035","DOIUrl":"10.1080/15376516.2026.2664035","url":null,"abstract":"<p><strong>Background: </strong>Plastics in particular nanoplastics pose the major environmental threat worldwide. Nanoplastics refers to smaller plastic components with size less than 100 nm. Previous studies indicated that plastics could accumulate in blood and various other tissues, leading to hepatotoxicity, nephrotoxicity, neurotoxicity, and reproductive toxicity. Endoplasmic Reticulum (ER) stress disrupts the functionality of ER due to various factors, leading to the accumulation of unfolded and misfolded proteins inside the ER. The current study aimed to investigate the protective effect of edaravone against nephrotoxicity induced by Polystyrene Nanoplastics (PSNPs) through ER-Stress pathway. In this study, we examined the role of ER Stress in PSNPs induced renal damage for the first time.</p><p><strong>Methods: </strong>A total of thirty-two female Wistar rats were used (<i>n</i> = 8), where the first group served as vehicle-control. The second group was administered with PSNPs (10-mg/kg, orally) over a duration of five weeks. The third and fourth groups received PSNPs combined with edaravone at dosages of 5-mg/kg and 10-mg/kg respectively during the period (Day 22^nd-35^th). After five weeks, animals were euthanized and samples were collected.</p><p><strong>Results: </strong>Compared to vehicle-control rats, PSNPs exposed rats demonstrated a significant elevation in creatinine, MDA and nitrite alongside a decrease in body weight, kidney weight and GSH concentration. PSNPs administered group showed significant abnormalities in kidney histopathology and increased protein expression levels of GRP78, CHOP and caspase-12, whereas edaravone treatment decreased renal oxidative stress, histopathological abnormalities and protein expression of GRP78, CHOP and caspase-12.</p><p><strong>Conclusion: </strong>Edaravone may serve as a therapeutic intervention for PSNPs induced nephrotoxicity.</p>","PeriodicalId":23177,"journal":{"name":"Toxicology Mechanisms and Methods","volume":" ","pages":"1130-1144"},"PeriodicalIF":2.7,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147781977","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation of perfluorooctanoic acid exposure induced renal dysfunction associated with oxidative stress, fibrosis, and impaired angiogenic signaling in male Wistar rats.","authors":"Lavanya Hongal, M David","doi":"10.1080/15376516.2026.2673546","DOIUrl":"10.1080/15376516.2026.2673546","url":null,"abstract":"<p><p>Perfluorooctanoic acid (PFOA), a persistent per- and polyfluoroalkyl substance, is widely detected in environmental and biological systems and has been associated with renal toxicity. However, the integrated relationship between oxidative stress, erythropoietic regulation, angiogenic signaling and fibrotic remodeling remains insufficiently defined. This study evaluated dose- and duration-dependent nephrotoxic effects of sub-chronic PFOA exposure in male Wistar albino rats. Animals received oral administration of PFOA at 48 or 96 mg/kg body weight over exposure periods of 30, 60 and 90 days. Renal toxicity was assessed using serum biochemical markers, hematological parameters, electrolyte levels and erythropoietin concentration. Oxidative stress was evaluated through lipid peroxidation and antioxidant enzyme activities. Histopathological changes were examined using hematoxylin-eosin, Masson's trichrome, Periodic Acid-Schiff and Alcian blue staining, while immunohistochemistry was performed for Vimentin and vascular endothelial growth factor (VEGF). PFOA exposure resulted in significant renal dysfunction, including increased serum urea, uric acid and blood urea nitrogen levels, accompanied by enhanced lipid peroxidation and reduced antioxidant defenses (<i>p</i> < 0.05). Histological examination revealed glomerular atrophy, tubular degeneration, inflammatory infiltration and collagen deposition. Increased Vimentin expression and reduced VEGF immunoreactivity indicated epithelial-mesenchymal transition and impaired angiogenic signaling. Collectively, the findings demonstrate that PFOA-induced nephrotoxicity involves coordinated disruption of redox balance, hypoxia-responsive signaling and angiogenic pathways rather than isolated oxidative injury. This integrative framework provides mechanistic insight into PFAS-associated renal disease and identifies the erythropoietin-VEGF axis as a potential target for early intervention.</p>","PeriodicalId":23177,"journal":{"name":"Toxicology Mechanisms and Methods","volume":" ","pages":"1243-1265"},"PeriodicalIF":2.7,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147964732","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Neurotoxic and metabolic effects of chronic aspartame consumption in rodent models: a systematic review and meta-analysis.","authors":"Arbind Kumar Choudhary, Nishant Singh","doi":"10.1080/15376516.2026.2662931","DOIUrl":"10.1080/15376516.2026.2662931","url":null,"abstract":"<p><p>Aspartame (ASP), a widely used artificial sweetener, remains the subject of scientific scrutiny regarding its long-term safety. While regulatory agencies assert safety at established acceptable daily intake (ADI) levels, accumulating preclinical rodent data suggests potential adverse effects under chronic exposure conditions. This systematic review and meta-analysis synthesized evidence from 13 rodent studies investigating neurotoxic and metabolic endpoints. Our quantitative meta-analysis of the oxidative stress domain (<i>k</i> = 8) demonstrated a very large and statistically significant increase in oxidative damage (pooled Hedges' g = +4.44; 95% CI: 2.94 to 5.94), suggesting oxidative stress as a major hypothesized mechanism of aspartame-induced injury. Qualitatively, chronic exposure was associated with neurobehavioural deficits, including spatial learning and memory impairments, alongside metabolic dysfunction such as glucose intolerance and dyslipidaemia. Notably, these effects were observed in several studies utilizing doses equivalent to the human ADI. However, the interpretation of these findings is constrained by high statistical heterogeneity (I² = 85.4%) and a lack of detailed reporting in primary studies, resulting in uncertain internal validity across several risk-of-bias domains. While these results provide a critical signal regarding the neurotoxic and metabolic potential of aspartame, they underscore the urgent need for improved reporting standards in preclinical toxicology and long-term human epidemiological studies to fully clarify its safety profile.</p>","PeriodicalId":23177,"journal":{"name":"Toxicology Mechanisms and Methods","volume":" ","pages":"1045-1058"},"PeriodicalIF":2.7,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147730138","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characterization of unusual immunoassay cross-reactive cannabinoid metabolites in canine urine via gas chromatography-mass spectrometry.","authors":"Chris Pickard, John P Buchweitz, Andreas F Lehner","doi":"10.1080/15376516.2026.2665315","DOIUrl":"10.1080/15376516.2026.2665315","url":null,"abstract":"<p><p>Recent increases in cannabis use and dog ownership have elevated the risk of canine cannabis intoxication, prompting a need for efficient diagnostic tools. Enzyme immunoassays (EIAs) that employ monoclonal antibodies specific to 11-nor-9-carboxy-Δ⁹-tetrahydrocannabinol (THC-COOH) are commonly employed for preliminary screening and frequently return positive results in canine urine, yet these are not corroborated by gas chromatography-mass spectrometry (GC-MS), suggesting immunoassay cross-reactivity that raises concerns about false positives. The present study incorporated confirmatory GC-MS and GC-MS/MS analyses with mass spectral deconvolution to investigate EIA-positive, GC-MS-negative samples. Two novel compounds with molecular weights of 446 and 460 were identified following trimethylsilylation in the corresponding urine samples. Structural analysis suggests these compounds may be metabolic derivatives of tetrahydrocannabivarin (THCV), a cannabinoid with growing presence in consumer products. These compounds are structurally distinct from Δ⁹-THC-COOH yet exhibit EIA-reactivity. Ion fragmentation patterns, derivatization behavior, and comparison to established mass spectral libraries support the possibility of 11-hydroxylated and 9-carboxylated THCV analogs. The findings point to THCV metabolism as a plausible source of EIA-cross-reactivity in canines, raising important implications for veterinary toxicology and drug screening protocols. This study contributes crucial insights into canine cannabinoid metabolism and highlights limitations of existing immunoassays when influenced by structurally similar analytes.</p>","PeriodicalId":23177,"journal":{"name":"Toxicology Mechanisms and Methods","volume":" ","pages":"1162-1182"},"PeriodicalIF":2.7,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147821177","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}