Realgar (As2S2 or As4S4) is a traditional Chinese medicine (TCM) containing arsenic. Existing studies have shown that it has genotoxicity under long-term use with large doses. Niuhuang Jiedu (NHJD) ...is a Chinese medicine prescription containing realgar and seven other TCMs. Whether the multiple TCMs combination in NHJD can reduce the genotoxicity induced by realgar in equivalent doses is still unknown.
To research the effect of NHJD on realgar's genotoxicity and the possible mechanism involved based on the arsenic methylation metabolic pathway.
Six groups (control, realgar (0.8 g/kg), NHJD (12.48 g/kg), as well as Glycyrrhiza uralensis Fisch (GU), Scutellaria baicalensis Georg (SB), Rheum palmatum L (RP) plus equivalent doses of realgar, respectively) were set up. ICR mice were intragastric administered for 12 weeks. First, genotoxicology tests were conducted to evaluate the effect of NHJD, GU, SB, and RP on reducing realgar's genotoxicity. The inorganic arsenic (iAs), dimethyl arsenic acid (DMA), and monomethyl arsenic acid (MMA) were determined by HPLC-AFS, and the iAs%, MMA%, DMA%, primary methylation index (PMI), etc. Were calculated. Meanwhile, the S-adenosyl methionine (SAM) and arsenate reductase (ARR) levels, the arsenic (+3)methyltransferase (As3MT), purine-nucleoside phosphorylase (PNP), glutathione S-transfer omega1 (GSTO1) gene expression were detected, aimed to explore the possible alleviation mechanisms of NHJD.
The combination of multiple TCMs in NHJD decreased the levels of MN‰, SPA%, and DNA damage caused by realgar, with similar effects observed when SB, RP, and GU were used separately with realgar. Notably, the iAs% significantly decreased, while DMA% and PMI notably increased in the NHJD and realgar + SB (or RP) groups compared to the realgar-only group (P < 0.05). Increases in SAM and ARR levels were observed across various groups, but only the ARR increase in the NHJD group was statistically significant. Moreover, significant increases in As3MT mRNA and GSTO1 mRNA were noted in the NHJD group, and PNP mRNA levels significantly rose in the realgar + SB group.
This study revealed that NHJD could attenuate the genotoxic effects of realgar. The botanicals SB, RP, and GU within NHJD may be key contributors to this effect. Enhancements in arsenic methylation capabilities through increased levels of SAM and ARR and elevated gene expressions of As3MT, PNP, and GSTO1 suggest potential mechanisms behind these findings.
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•NHJD reduces the increment of MN‰, SPA%, and DNA damage caused by realgar.•NHJD increases arsenic methylation capacity compared to equivalent doses of realgar.•SAM and ARR proteins may play roles in NHJD's alleviating realgar genotoxicity.•As3MT, PNP, and GSTO1 genes may be involved in the detoxification mechanisms of NHJD.•Nine chemical compounds were identified in the prepared NHJD decoction.
Risk assessments are increasingly reliant on information from in vitro assays. The in vitro micronucleus test (MNvit) is a genotoxicity test that detects chromosomal abnormalities, including ...chromosome breakage (clastogenicity) and/or whole chromosome loss (aneugenicity). In this study, MNvit datasets for 292 chemicals, generated by the US EPA’s ToxCast program, were evaluated using a decision tree-based pipeline for hazard identification. Chemicals were tested with 19 concentrations (
n
= 1) up to 200 µM, in the presence and absence of Aroclor 1254-induced rat liver S9. To identify clastogenic chemicals, %MN values at each concentration were compared to a distribution of batch-specific solvent controls; this was followed by cytotoxicity assessment and benchmark concentration (BMC) analyses. The approach classified 157 substances as positives, 25 as negatives, and 110 as inconclusive. Using the approach described in Bryce et al. (Environ Mol Mutagen 52:280–286, 2011), we identified 15 (5%) aneugens. IVIVE (in vitro to in vivo extrapolation) was employed to convert BMCs into administered equivalent doses (AEDs). Where possible, AEDs were compared to points of departure (PODs) for traditional genotoxicity endpoints; AEDs were generally lower than PODs based on in vivo endpoints. To facilitate interpretation of in vitro MN assay concentration–response data for risk assessment, exposure estimates were utilized to calculate bioactivity exposure ratio (BER) values. BERs for 50 clastogens and two aneugens had AEDs that approached exposure estimates (i.e., BER < 100); these chemicals might be considered priorities for additional testing. This work provides a framework for the use of high-throughput in vitro genotoxicity testing for priority setting and chemical risk assessment.
Plastic polymers were largely added with chemical substances to be utilized in the items and product manufacturing. The leachability of these substances is a matter of concern given the wide amount ...of plastic waste, particularly in terrestrial environments, where soil represents a sink for these novel contaminants and a possible pathway of human health risk. In this study, we integrated genetic, molecular, and behavioral approaches to comparatively evaluate toxicological effects of plastic leachates, virgin and oxodegradable polypropylene (PP) and polyethylene (PE), in Drosophila melanogaster, a novel in vivo model organism for environmental monitoring studies and (eco)toxicological research. The results of this study revealed that while conventional toxicological endpoints such as developmental times and longevity remain largely unaffected, exposure to plastic leachates induces chromosomal abnormalities and transposable element (TE) activation in neural tissues. The combined effects of DNA damage and TE mobilization contribute to genome instability and increase the likelihood of LOH events, thus potentiating tumor growth and metastatic behavior ofRasV12 clones. Collectively, these findings indicate that plastic leachates exert genotoxic effects in Drosophila thus highlighting potential risks associated with leachate-related plastic pollution and their implications for ecosystems and human health.
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•Plastic leachates (from both virgin and oxodegradable PP and PE) induce DNA damage in Drosophila.•Exposure to plastic leachates promote Loss of Heterozygosity (LOH) at the tumor suppressor warts gene.•Plastic leachates induce Transposable Element (TE) expression and mobilization.•Plastic leachates synergize with oncogenic RasV12 to promote tumor progression and invasion.
Pesticides especially insecticides are widely used in the field of agricultural development all over the world to increase crop production. Moreover, exposure to such compounds does not only ...influence the intended targets but also induces adverse impacts on a number of unintended targets in animals. This research aimed to determine the toxic impacts of lufenuron (an insecticide) on the health status of fish in terms of measurement of oxidative stress, antioxidant enzymes, DNA damage and histopathological changes in Nile tilapia (Oreochromis niloticus) exposed to different concentrations. For this purpose, Oreochromis niloticus fish, weighing about 75-80g were arbitrarily separated into four different groups and then exposed to lufenuron @ 0.7, 1.2 and 1.7µg/ L for 39 days. The results showed that the fish exposed to the pesticide had significant changes in oxidative stress, antioxidant profile in gills and percentile rate of DNA damage in different visceral organs including liver, kidney, and gills. Results of light microscopic investigations indicated different histological changes in liver (necrosis of hepatocytes, degeneration of hepatocytes, vacuolar degeneration and congestion), gills (necrosis of lamellar epithelial cells, telangiectasia, and atrophy of secondary lamellae), heart (congestion, necrosis of neurons, microgliosis and intracellular edema), brain (congestion, myofibrosis, neutrophilic and myocarditis) and kidneys (necrosis of renal tubules, widening of urinary space, necrosis of renal tubular epithelial cells). A significantly escalate in oxidative stress while lower quantity of antioxidant biomarkers was documented in experimental fish. The findings of this study suggest that long-term exposure to lufenuron has negative health effects via induction of DNA damage, increased oxidative stress, lowering of enzymatic antioxidants profile and histological lesions in visceral organs of Nile tilapita (Oreochromis niloticus).
Background. Studies have proven the effect of several agents, including natural products, to induce, prevent and treat genotoxicity through experimental models and clinical trials. In this study, the ...genotoxic preventive potential of Annona muricata ethanol extract on N-Ethyl-N-Nitrosourea (ENU)-induced pro-leukaemia in mice models using micronuclei formation in bone marrow was assessed.
Materials and methods. Forty-eight mice weighing 18-24g were randomly divided into six groups of eight mice. The mice were intravenously administered 20mg/kg of NEU 48 hourly 3 times, 80mg/kg of NEU 48 hourly 3 times. The negative control was fed with feed and water only. We introduced 0.2ml (0.1g/ml) ethanolic extract of Annona muricata for 3 weeks prior to NEU low dosage administration, 0.2ml (0.1g/ml) ethanolic extract of Annona muricata for 3 weeks prior to ENU high dosage and Annona muricata (ethanolic extract) administration, and gave commercial diet to the adverse/ toxicity group. The bone marrow was harvested, smeared and stained using MayGrumwald. The procedure enabled the determination of micronucleus polychromatic erythrocytes (MNPCEs) microscopically.
Results. Groups exposed to various dosages of the ENU yielded significantly increased MNPCEs, with group B producing higher MNPCEs. The groups treated with the extract displayed a significant reduction in the MNPCEs despite prior exposure to concentrations of NEU. The adverse group displayed no difference in MNPCEs compared with the negative control.
Conclusion. The ENU induced genotoxicity depending on its concentration. The extract displayed a profound capacity to prevent genotoxicity and alleviate leukaemia with good tolerance.
The evaluation of genotoxicity plays an important role within hazard identification and risk assessment of chemicals and consumer products. For genotoxicity assessment, in vitro hepatic cells are ...often used as they have retained certain level of xenobiotic metabolic activity. However, current protocols are designed for the use on 2D monolayer models that are associated with several limitations due to the lack of numerous biological functions, which results in the loss of many hepatic properties. In this respect, an attractive alternative are three-dimensional (3D) models. The aim of our study was to develop physiologically more relevant 3D cell model (spheroids) from the human hepatocellular carcinoma (HepG2) cell line for genotoxicity testing. The spheroids were prepared by the forced floating method, which had been optimized for the production of a large number of uniform spheroids. The sensitivity of the spheroids to detect genotoxicity was determined by the comet assay after the exposure of spheroids to non-cytotoxic concentrations of model indirect acting genotoxic compounds, namely polycyclic aromatic hydrocarbon (B(a)P), mycotoxin (AFB1), two heterocyclic aromatic amines (PhIP and IQ) and a direct acting etoposide (ET). All five tested compounds concentration dependently induced DNA damage. Higher sensitivity of 3D cell model compared to 2D monolayer culture was noticed particularly for detection of the genotoxicity of the heterocyclic aromatic amines and BaP. Deregulation of mRNA expression (qPCR) by genotoxic compounds revealed that HepG2 cells in 3D express important genes encoding phase I and II metabolic enzymes, as well as DNA damage responsive genes in an inducible form. The newly developed HepG2 3D model shows improved sensitivity for detecting genotoxic compounds compared to 2D cultures and can provide a suitable experimental model for genotoxicity assessment.
Debido al alcance de conocer el efecto de los contaminantes atmosféricos sobre el material genético, el Laboratorio de Genotoxicología y Mutagénesis Ambientales, del Instituto de Ciencias de la ...Atmósfera y Cambio Climático (ICAyCC) de la UNAM, durante más de cuatro décadas ha estado analizando el daño producido por los mismos, utilizando biomarcadores en diversos sistemas biológicos de prueba, así como en poblaciones ocupacionalmente expuestas. Estos estudios han merecido reconocimiento tanto a nivel nacional como internacional, siendo una línea de investigación que le ha dado trascendencia al ICAyCC, por el impacto de los resultados generados y contribuyendo de manera relevante a la comprensión del comportamiento de los contaminantes en los diferentes sistemas de evaluación, los cuales, sin lugar a duda, han constituido una aportación a la Genética por los logros obtenidos sobre el daño provocado al DNA. Dichas contribuciones también se han visto reflejadas a través de la formación de recursos humanos mediante la dirección de tesis de Licenciatura, Maestría y Doctorado, lo que ha propiciado la creación de nuevos grupos de investigación, cuyos líderes, colaboradores y alumnos, se han incorporado como miembros a la Sociedad Mexicana de Genética. En esta conferencia se presentará un breve panorama de las investigaciones desarrolladas durante el lapso antes mencionado utilizando distintos ensayos tales como la bacteria Salmonella typhimurium, plantas, cultivos y/o líneas celulares y poblaciones ocupacionalmente expuestas, mediante el empleo de biomarcadores de daño genotóxico para la evaluación del efecto ocasionado por diversos contaminantes ambientales, como hidrocarburos aromáticos policíclicos, metales pesados, plaguicidas, entre otros.
En los últimos años, el herbicida Marvel ha sido utilizado para incrementar la producción de cultivos, sin embargo, existen estudios que evidencian la genotoxicidad de sus componentes, dicamba y ...atrazina. Se evaluó la actividad genotóxica de varias concentraciones del herbicida marvel: 0.76, 7.68, 76.8, 768 µg/1 ml en linfocitos humanos y de ratones cepa Balb-c y eritrocitos de tilapia (Oreochromis niloticus). Se expusieron a cada una de las concentraciones durante 6 horas y luego se evaluó daño genético mediante el ensayo cometa. Todas las concentraciones probadas indujeron un daño genético significativo en comparación con el control negativo (P <0,01). No hubo diferencias entre las células sanguíneas de los organismos estudiados. La longitud de la cola y el momento de la cola aumentaron a partir de 0,76 µg/1 ml, esta es la concentración más baja reportada capaz de producir daño genético. Los datos sugieren que las diferencias reportadas con respecto a la genotoxicidad de marvel y sus ingredientes activos se deben a las marcadas diferencias entre las concentraciones estudiadas y los adyuvantes presentes en las formulaciones comerciales.
El osteosarcoma (OS) es un tumor maligno de hueso, constituye el 75% en pacientes jóvenes, afecta principalmente huesos de las extremidades inferiores. No existe ningún método eficaz para prevenir ...este tipo de cáncer y puede inducir la amputación. El beta-sitosterol (BS) es un compuesto vegetal. Estudios han demostrado propiedades biomédicas inmunomoduladoras, antimutagénicas, antiinflamatorias y antioxidantes. El benzopireno (BZP) es un hidrocarburo, capaz de inducir OS. Considerando estos antecedentes, se planteó este proyecto de investigación. Por lo que el objetivo fue determinar en un modelo de carcinogénesis ósea en ratas, la actividad quimioterapéutica de beta-sitosterol en el desarrollo del osteosarcoma. Se indujeron lesiones neoplásicas mediante la administración perifemoral de BZP. De la 7ª a la 9ª semana se administró por vía oral BS. Se registró el peso de las ratas, periódicamente se tomaron muestras sanguíneas para realizar estudios de genotoxicidad; se realizaron pruebas bioquímicas mediante para determinar velocidad de sedimentación (VSG), fosfatasa alcalina (FA) y deshidrogenasa láctica (DHL) y tomografía axial computarizada (TAC). Al cumplir la novena semana, se realizó eutanasia, se extrajeron los fémures, tibias, hígado y pulmones para su estudio histopatológico. Los resultados parciales en las ratas, evaluado por el estudio histopatológico demuestran la formación de OS en el fémur tratado. Así mismo el peso en ambas cepas, presentó una disminución estadísticamente significativa de la tercera a la 7ª semana, sin embargo, el peso comenzó a estabilizarse a partir de la 8ª semana. El BZP fue altamente genotóxico en ambas cepas de ratas. Las pruebas bioquímicas presentaron diferencias estadísticamente significativas a partir de la 3ª semana de tratamiento con BZP en los valores de la VSG, FA y DHL, en todas las ratas tratadas, sin embargo, a partir de la 8ª semana se observó una disminución de la FA y DHL en algunos animales administrados con BS. Se concluye que la administración de BZP contribuye a la inducción de OS en las ratas tratadas, y el BS puede ayudar a disminuir la actividad carcinogénica del BZP, lo que nos da la pauta para continuar con otros estudios que permitan considerar el uso del BS en personas con OS.
La quercetina es el flavonoide más consumido en el mundo debido a su abundancia en frutas, verduras y otros alimentos; es reconocido por su gran capacidad antioxidante, sin embargo, también existen ...reportes de que en ciertas condiciones puede volverse prooxidante pudiendo causar daños genéticos. Por lo cual, el objetivo de este trabajo fue evaluar la genotoxicidad de la quercetina mediante la prueba SMART en ala de D. melanogaster que permite detectar agentes genotóxicos de forma rápida y económica. Para ello, se realizaron dos cruzas, estándar (CE) y de bioactivación elevada (CBE) que difieren en la expresión de los CYP450; las larvas de ambas cruzas fueron alimentadas con 5 concentraciones de quercetina (0.38, 0.19, 0.095, 0.047 y 0.023 Mm), agua MiliQ, acetonaetanol (2%), Vitamina C (5.6 mM) o 4NQO (2 mM). A los adultos procedentes de las larvas tratadas se les diseccionaron las alas y colocaron en preparaciones permanentes, para su observación en microscopio a 40x, donde se obtuvieron las frecuencias de cada tipo de mancha por tratamiento, y se compararon mediante el programa informático SMART PC-versión 2.1 basado en la prueba de KastenbaumBowman (p˂0.05), la prueba de U de Mann-Whitney (p˂0.05) y la prueba de Kolmogorov-Smirnov (p˂0.05). Los resultados obtenidos mostraron que en la CE la quercetina no fue genotóxica a ninguna concentración, debido a su capacidad antioxidante. En cambio, en la CBE se encontró daño genotóxico, que pudo deberse a que la quercetina es capaz de autooxidarse en anión superóxido y de interferir con la actividad de los CYP450. Finalmente, en ambas cruzas se encontró efecto citotóxico probablemente provocado por la activación enzimática de quercetina que produce o-semiquinona y o-quinona, las cuales facilitan la formación de superóxidos y ð»ð»2ð',ð',2. En conclusión, la quercetina sólo causó genotoxicidad en la CBE reconociendo así la participación de los CYP450 en dicho efecto; mientras que, en ambas cruzas provocó citotoxicidad.
