Genotoxic and cytotoxic evaluation of venlafaxine in an acute and a subchronic assay in mouse / Avaliação genotóxica e citotóxica da venlafaxina em ensaio agudo e subcrônico em camundongos

Abstract The present research was made to determine the micronuclei and cytotoxic capacity of the antidepressant venlafaxine in an in vivo acute and subchronic assays in mouse. In the first study, we administered once 5, 50, and 250 mg/kg of the drug, and included a negative and a daunorubicin treated group. Observations were daily made during four days. The subchronic assay lasted 5 weeks with daily administration of venlafaxine (1, 5, and 10 mg/kg) plus a negative and an imipramine administered groups. Observations were made each week. In the first assay results showed no micronucleated polychromatic erythrocytes (MNPE) increase, except with the high dose at 72 h. The strongest cytotoxic effect was found with 250 mg/kg at 72 h (a 51% cytotoxic effect in comparison with the mean control level). In the subchronic assay no MNPE increase was found; however, with the highest dose a significant increase of micronucleated normochromatic erythrocytes was observed in the last three weeks (a mean of 51% respect to the mean control value). A cytotoxic effect with the two high doses in the last two weeks was observed (a polychromatic erythrocyte mean decrease of 52% respect to the mean control value). Results suggest caution with venlafaxine.

Resumo A presente pesquisa foi feita para determinar a capacidade micronuclei e citotóxica do antidepressivo venlafaxina em ensaios agudos e subcrônicos in vivo em camundongos. No primeiro estudo, administramos uma vez 5, 50 e 250 mg/kg do medicamento e incluímos um grupo negativo e um grupo tratado com daunorubicina. As observações foram feitas diariamente durante quatro dias. O ensaio subcrônico durou cinco semanas com administração diária de venlafaxina (1, 5, e 10 mg/kg) mais um grupo negativo e um grupo administrado de imipramina. As observações foram feitas a cada semana. No primeiro ensaio, os resultados não mostraram aumento de eritrócitos policromáticos micronucleados (MNPE), exceto com a dose elevada a 72 h. O efeito citotóxico mais forte foi encontrado com 250 mg/kg a 72 h (um efeito citotóxico de 51% em comparação com o nível médio de controle). No ensaio subcrônico não foi encontrado aumento de MNPE; entretanto, com a dose mais alta, um aumento significativo de eritrócitos normocromáticos micronucleados foi observado nas últimas três semanas (média de 51% em relação ao valor médio de controle). Foi observado um efeito citotóxico com as duas altas doses nas últimas duas semanas (uma diminuição média de 52% em relação ao valor médio de controle dos eritrócitos policromáticos). Os resultados sugerem cautela com a venlafaxina.

Genotoxic and cytotoxic evaluation of venlafaxine in an acute and a subchronic assay in mouse

Abstract The present research was made to determine the micronuclei and cytotoxic capacity of the antidepressant venlafaxine in an in vivo acute and subchronic assays in mouse. In the first study, we administered once 5, 50, and 250 mg/kg of the drug, and included a negative and a daunorubicin treated group. Observations were daily made during four days. The subchronic assay lasted 5 weeks with daily administration of venlafaxine (1, 5, and 10 mg/kg) plus a negative and an imipramine administered groups. Observations were made each week. In the first assay results showed no micronucleated polychromatic erythrocytes (MNPE) increase, except with the high dose at 72 h. The strongest cytotoxic effect was found with 250 mg/kg at 72 h (a 51% cytotoxic effect in comparison with the mean control level). In the subchronic assay no MNPE increase was found; however, with the highest dose a significant increase of micronucleated normochromatic erythrocytes was observed in the last three weeks (a mean of 51% respect to the mean control value). A cytotoxic effect with the two high doses in the last two weeks was observed (a polychromatic erythrocyte mean decrease of 52% respect to the mean control value). Results suggest caution with venlafaxine.

Resumo A presente pesquisa foi feita para determinar a capacidade micronuclei e citotóxica do antidepressivo venlafaxina em ensaios agudos e subcrônicos in vivo em camundongos. No primeiro estudo, administramos uma vez 5, 50 e 250 mg/kg do medicamento e incluímos um grupo negativo e um grupo tratado com daunorubicina. As observações foram feitas diariamente durante quatro dias. O ensaio subcrônico durou cinco semanas com administração diária de venlafaxina (1, 5, e 10 mg/kg) mais um grupo negativo e um grupo administrado de imipramina. As observações foram feitas a cada semana. No primeiro ensaio, os resultados não mostraram aumento de eritrócitos policromáticos micronucleados (MNPE), exceto com a dose elevada a 72 h. O efeito citotóxico mais forte foi encontrado com 250 mg/kg a 72 h (um efeito citotóxico de 51% em comparação com o nível médio de controle). No ensaio subcrônico não foi encontrado aumento de MNPE; entretanto, com a dose mais alta, um aumento significativo de eritrócitos normocromáticos micronucleados foi observado nas últimas três semanas (média de 51% em relação ao valor médio de controle). Foi observado um efeito citotóxico com as duas altas doses nas últimas duas semanas (uma diminuição média de 52% em relação ao valor médio de controle dos eritrócitos policromáticos). Os resultados sugerem cautela com a venlafaxina.

Marking the Micro Details in Potentially Malignant Disorders of Oral Cavity

Background- The malignancy of the oral cavity constitutes the most important group of malignancies in South and Southeast Asia.The risk increases with the use of tobacco products. Materials & Methods- Micronuclei frequency scoring was used as a biomarker to identify different potentially malignant disorders. Results- Mean micronuclei index was found higher using Hematoxylin and Eosin stain than Papanicolaou's stainand May Grunwald's stain. Conclusion- We concluded that the micronuclei frequencies in oral exfoliated epithelial cells using three different stains- Hematoxylin and Eosin stain, Papanicolaou's stain, May Grunwald's stain may be useful in predicting the malignant potential of premalignant lesions.

Ensayo de micronúcleos con bloqueo de la citocinesis como biomarcador de daño genético en poblaciones sobreexpuestas a radiaciones ionizantes / Micronucleus assay as biomarker of DNA damage in population exposed to ionizing radiation

Resumen Introducción: las radiaciones ionizantes (RI) son capaces de perjudicar el ADN; para evaluar este fenómeno es posible utilizar la formación de micronúcleos como biomarcador de efecto temprano del daño radioinducido. El ensayo de micronúcleos con bloqueo de la citocinesis (MNBC) es una técnica citogenética que permite demostrar el impacto de agentes genotóxicos. Propósito: en el presente trabajo se describieron mecanismos moleculares involucrados en la radioinducción de micronúcleos, la técnica del MNBC, los criterios de análisis, sus aplicaciones dentro de la investigación biológica y su extensión a la clínica, con énfasis en su empleo como biomarcador del daño genético en grupos sobreexpuestos a RI. Argumentos para la discusión: el MNBC se considera un método confiable, simple y rápido y existe evidencia de su aplicabilidad para el estudio de los efectos biológicos en casos de riesgo ocupacional y en accidentes radiológicos aislados o a gran escala. Conclusiones: el MNBC es una herramienta valiosa que posibilita estimar las consecuencias por dosis bajas de RI en poblaciones involucradas y, a la vez, orientar la toma de decisiones en cuanto a su prevención o atenuación . De igual forma, puede ser utilizado en análisis del campo de la radiobiología, a fin de detallar las incidencias de las radiaciones ionizantes sobre el ADN.

Abstract Introduction. Ionizing radiation (IR) is capable of causing DNA damage. For the evaluation of this phenomenon it is possible to use chromosomal aberrations as biomarkers. The Cytokinesis-Block Micronucleus assay (CBMN) is a cytogenetic technique that allows to demonstrate the effect of genotoxic agents.Proposition:in the present review, we will describe the molecular mechanisms involved in micronucleus radioinduction, the micronucleus technique and criteria for analysis, its applications within biological research and its extension in clinical research, with emphasis on its application as a biomarker of radioinduced genetic damage. Arguments for discussion: the CBMN is considered a reliable, simple and fast technique and there is evidence of its applicability in the evaluation of biological effects in occupationally exposed personnel and in isolated or large-scale radiological accidents. Conclusions: the CBMN a valuable tool in estimating radiological risk in populations exposed to low doses of IR, allowing to guide decision-making regarding prevention or mitigation of exposure to IR in populations involved. Similarly, the cbmn can be used in research in the field of radiobiology, as a means to describe the effects of ionizing radiation on DNA.

Nuclear cGAS: sequestration and beyond

The cyclic GMP-AMP (cGAMP) synthase (cGAS) has been identified as a cytosolic double stranded DNA sensor that plays a pivotal role in the type I interferon and inflammation responses via the STING-dependent signaling pathway. In the past several years, a growing body of evidence has revealed that cGAS is also localized in the nucleus where it is associated with distinct nuclear substructures such as nucleosomes, DNA replication forks, the double-stranded breaks, and centromeres, suggesting that cGAS may have other functions in addition to its role in DNA sensing. However, while the innate immune function of cGAS is well established, the non-canonical nuclear function of cGAS remains poorly understood. Here, we review our current understanding of the complex nature of nuclear cGAS and point to open questions on the novel roles and the mechanisms of action of this protein as a key regulator of cell nuclear function, beyond its well-established role in dsDNA sensing and innate immune response.

Analysis of cytogenetic indexes in interventional radiology workers exposed to low dose long-term chronic irradiation / 中国职业医学

OBJECTIVE: To observe the effect of low dose long-term chronic irradiation on chromosome aberration and micronucleus in peripheral blood lymphocytes of interventional radiology workers.METHODS: A total of 100 interventional radiology workers in a grade A tertiary hospital of Henan Province were selected as the interventional group using a convenient sampling method, and 78 healthy individuals without radiation exposure were selected as the control group. The incidence of chromosomal aberration and micronucleus of peripheral blood lymphocytes in individuals of these two groups were investigated. RESULTS: The frequencies of cells with acentric fragment(ace), dicentric chromosome(dic), reciprocal translocation(t), chromosome type aberration and total aberration in the interventional group were higher than those in the control group, and the differences were statistically significant(0.55% vs 0.30%, 0.25% vs 0.03%, 0.38% vs 0.01%, 1.21% vs 0.34%, 1.37% vs 0.54%, all P<0.01). In the interventional group, the frequency of cell with chromosome type aberration was higher than that of chromatid type aberration(1.21% vs 0.16%, P<0.01).The frequency of cell with unstable chromosome aberration was higher than that of stable chromosome aberration(0.80% vs 0.41%, P<0.01), and the frequency of cell with chromosomal type aberrant in the interventional group ranked from high to low in order of ace, t, dic and deletion(P<0.01). The incidence of micronuclear cells and micronucleus in the interventional group were higher than those in the control group(0.86‰ vs 0.40‰, 0.89‰ vs 0.41‰, all P<0.01). The incidence of micronuclear cells and micronucleus of female interventional radiology workers were higher than those of male workers(1.12‰ vs 0.62‰, 1.19‰ vs 0.62‰, all P<0.01).CONCLUSION: Low dose and long-term chronic irradiation exposure can affect both chromosome aberration and micronucleus of interventional radiology workers. The main chromosomal aberrations were non-stable chromosomal aberrations ace, dic and stable chromosomal aberrations t.

Análise dos efeitos do glifosato e sua formulação Roundup® nas células e gônadas dos peixes Danio rerio (Cyprinidae) / Analysis of the effects of glyphosate and its formulation Roundup® on the cells and gonads of fish Danio rerio (Cyprinidae)

Os herbicidas estão entre os insumos químicos mais utilizados na agricultura e apresentam ação toxicológica para as plantas. Dentre os herbicidas existentes, o glifosato e a sua formulação comercial Roundup® são os mais utilizados devido à eficácia no controle de ervas daninhas. Entretanto, estudos sugerem que estes herbicidas podem provocar distúrbios a organismos aquáticos, principalmente o Roundup®, que além do glifosato ativo, apresenta na composição componentes surfactantes que aumentariam o seu potencial toxicológico para os seres vivos. Desta forma, o presente estudo teve como objetivo comparar o potencial mutagênico e desenvolvimento gonadal do princípio ativo glifosato e sua formulação Roundup® em peixes Danio rerio. Para isso, exemplares adultos de D. rerio permaneceram em aquários expostos à concentração de 65 µg/L de cada herbicida. Foram realizadas contagens de micronúcleos, calculado o índice gonadossomático (IGS) e verificado os estágios de maturação gonadal. Os resultados demonstraram que os peixes expostos aos herbicidas apresentaram aumentos significativos na frequência de micronúcleos, bem como no IGS, e maior ocorrência de ovários com estágios em maturação e maduros. Não foram verificadas diferenças significativas na comparação dos herbicidas, exceto um aumento na frequência de ovários maduros nas fêmeas expostas ao glifosato. Observou-se que, mesmo em pequenas concentrações, os herbicidas poderiam ter ocasionado efeitos nocivos para os peixes D. rerio, podendo induzir efeitos clastogênicos nos eritrócitos, assim como distúrbios reprodutivos, aumentando a preocupação sobre os impactos que estes herbicidas podem acarretar sobre o ciclo de vida destes organismos.(AU)

The herbicides are among the most used chemical inputs in the agriculture and present a great toxicological action for the plants. Among the existing herbicides, glyphosate and its commercial formulation Roundup® are the most used due to their effectiveness in control of weeds. However, studies suggest that these herbicides can cause disturbances to aquatic organisms, mainly the Roundup®, that besides active glyphosate, it presents in the composition components surfactants that would increase its toxicological potential for the alive beings. Therefore, the aim of this study is to compare the mutagenic potential and gonadal development of the active principle glyphosate and its formulation Roundup® in fish Danio rerio. Thus, adult copies of D. rerio stayed in aquariums exposed to a concentration of 65 µg / L of each herbicide. Micronucleus counts were performed and the Gonadossomatic index (GSI) was calculated and the stages of gonadal maturation were verified. The results demonstrated that the fish exposed to the herbicides, presented significant increases in the micronucleus frequency, as well as in GSI and larger occurrence of ovaries with stages in maturation and mature. There were no significant differences in herbicide comparison, except an increase in the frequency of mature ovaries in the exposed females to glyphosate. It was observed that even in small concentrations, the herbicides could presented harmful effects for the fish D. rerio, could have caused clastogenic effects in the erythrocytes, as well as, reproductive disturbances, increasing the concern about the impacts that these herbicides can have on the life cycle of these organisms.(AU)

Evaluación de riesgo de cáncer en personas expuestas ocupacionalmente a solventes orgánicos / Cancer risk evaluation in individuals occupationally exposed to organic solvents

RESUMEN Objetivo Evaluar la frecuencia de micronúcleos (MN) e influencia de los polimorfismos en los genes del metabolismo GSTM1 y GSTT1 como biomarcadores de riesgo de cáncer en pintores de carros (n=152) con respecto a individuos no expuestos (n=152). Métodos Estudio Epidemiológico Molecular, tipo Corte Transversal analítico, interacción gen-ambiente. La evaluación de MNs y polimorfismos genéticos se determinó con pruebas moleculares en linfocitos de los individuos objeto de estudio. Resultados Se determinó que la frecuencia de MNs es 1.6 más alta en el grupo expuesto con relación al grupo referente (1.39±0.92 versus 0,87±0.78, p<0,0001). No se determinó un incremento en la frecuencia de MNs asociado a los polimorfismos en GSTM1 y GSTT1. Conclusiones El incremento de MNs en pintores de carros sirve para alertar al incremento de riesgo de cáncer en esta población expuesta a solventes orgánicos. Estos resultados pueden servir en Programas de Vigilancia Epidemiológica Ocupacional, como estrategia de prevención y en otros países con un amplio sector informal de individuos expuestos a estos químicos para reducir el riesgo de cáncer.(AU)

ABSTRACT Objective To evaluate the frequency of micronuclei (MNs) and influence of GSTM1 and GSTT1 gene polymorphisms as biomarkers of cancer risk in car painters (n=152) compared to unexposed individuals (n=152). Methods Molecular epidemiology study, cross-sectional analysis of gen and environment interaction. The evaluation of MN and genetic polymorphisms was determined by molecular tests in lymphocytes from subjects involved in the study. Results It was determined that the frequency of MNs is 1.6 higher in the exposed group compared to the reference group (1.39 ± 0.92 versus 0.87 ± 0.78, p<0.0001). There was no increase in the frequency of MNs associated with the polymorphisms in GSTM1 and GSTT1. Conclusions The increase of MNs in car painters serves to alert the increased risk of cancer in this population exposed to organic solvents. These results can be used in Occupational Epidemiological Surveillance Programs, as a prevention strategy and policies to regulate and control the use of solvents at a national level and in other countries with a large informal sector of individuals exposed to these chemicals to reduce the risk of cancer.(AU)

The correlation between micronuclei count and smoking behavior: a hospital-based study / Correlación entre recuento de micronúcleos y hábito tabáquico: un estudio hospitalario

Background: Micronucleus is a microscopically visible cyto-plasmic chromatin mass in the extranuclear vicinity, originating from aberrant mitosis, which consists of eccentric chromosomes that have failed to reach spindle poles during mitosis. The present study was designed to evaluate and compare cytogenetic changes in the buccal mucosa of smokers and non-smokers based on the occurrence of micronuclei. The study aimed to determine the correlation between the micronuclei count and the frequency and duration of smoking habit. Materials and Methods: Two groups (smokers and non-smokers) of 34 individuals each were examined. Cytological buccal smears were taken from participants using a moistened wooden spatula and stained with standard Papanicolaou stain. Presence of micronuclei was assessed at 40X magnification using a light microscope and a count per 500 cells was determined. The results of the study were analyzed statistically using Mann-Whitney U test, Spearman's rank correlation coefficient and Student t-test. Result: Smears from smokers showed a significant increase in the total number of micronuclei per 500 cell count compared to non-smokers. There was a strong positive correlation between the occurrence of micronuclei and the frequency and duration of smoking. A age-related increase in older age groups was also observed. Conclusion: The study reveals a strong positive correlation between the occurrence of micronuclei and the frequency and duration of smoking. This observation is vital in the utilization of the micronuclei detection in smears as a prognostic, educational and interventional tool in the management of patients with smoking habits.

Antecedentes: El micronúcleo es una masa de cromatina citoplasmática microscópicamente visible en el área extranuclear, que se origina a partir de la mitosis aberrante, y que consiste en cromosomas excéntricos que no han podido alcanzar los polos del huso durante la mitosis. El presente estudio fue diseñado para evaluar y comparar los cambios citogenéticos en la mucosa bucal de fumadores y no fumadores en función de la aparición de micronúcleos. El estudio tuvo como objetivo determinar la correlación entre el recuento de micronúcleos y la frecuencia y duración del hábito de fumar. Materiales and Métodos: Se examinaron dos grupos (fumadores y no fumadores) de 34 individuos cada uno. Se tomaron frotis bucales citológicos de todos los participantes con una espátula de madera humedecida y se tiñeron con la tinción estándar de Papanicolaou. La presencia de micronúcleos se evaluó al microscopio óptico con un aumento de 40X y se determinó un recuento por 500 células. Los resultados del estudio se analizaron estadísticamente utilizando la prueba U de Mann-Whitney, el coeficiente de correlación de rango de Spearman y la prueba t de Student. Resultados: Los frotis de fumadores mostraron un aumento significativo en el número total de micronúcleos por 500 células en comparación con los no fumadores. Hubo una fuerte correlación positiva entre la aparición de micronúcleos y la frecuencia y duración del tabaquismo. También se observó un aumento relacionado con la edad en los grupos de mayor edad. Conclusión: el estudio revela una fuerte correlación positiva entre la aparición de micronúcleos y la frecuencia y duración del tabaquismo. Esta observación es vital en la utilización de la detección de micronúcleos en frotis como una herramienta pronostica, educativa e intervencionista en el manejo de pacientes con hábitos de fumar.

Genotoxic Effects of Semi-Synthetic Isodillapiole on Oviposition in Aedes aegypti (Linnaeus, 1762) (Diptera: Culicidae)

Abstract INTRODUCTION: Semi-synthetic dillapiole compounds derived from Piper aduncum essential oil are used as alternative insecticides to control insecticide-resistant Aedes aegypti. Thus, we aimed to evaluate the genotoxic effects of semi-synthetic isodillapiole on the nuclei of neuroblasts (larvae) and oocytes (females) and the mean oviposition rates of the females over four generations (G1, G2, G3, and G4) of Ae. aegypti. METHODS: Larvae were captured in the city of Manaus, Amazonas state, Brazil, and exposed to isodillapiole in bioassays (20, 40, and 60 µg/mL) and a negative control (0.05% DMSO in tap water) for 4 h. The cerebral ganglia were extracted from the larvae and oocytes from the adult females to prepare slides for cytogenetic analysis. Breeding pairs were established and eggs counts were quantified taken after the bioassays. RESULTS: The analysis of 20,000 interphase nuclei of neuroblasts and oocytes indicated significant genotoxicity (micronuclei, budding, polynucleated cells, and other malformations) compared to that of the control. Metaphasic and anaphasic nuclei presented chromosomal breaks; however, no significant variation and damage was observed in the negative control. A significant reduction in mean oviposition rates was also recorded following exposure to isodillapiole over the four generations (G1, G2, G3, and G4). CONCLUSIONS: The toxic and genotoxic effects of isodillapiole on Ae. aegypti were caused by reduced oviposition in the females and nuclear abnormalities over the four generations of the trials. Further studies are required, rather than our in vitro assays, to verify the efficacy of exposure to this compound for controlling Ae. aegypti.

Comparative evaluation of micronuclei in saudi smokers and non-smokers without any visible oral lesions: a pilot study / Evaluación comparativa de micronúcleos en fumadores y no fumadores sauditas sin lesiones orales visibles: un estudio piloto

Objectives: A systematic review was conducted to evaluate effectiveness and safety of beta carotenes for the treatment of oral leukoplakia regarding clinical resolution and prevention of malignant transformation. Material and Methods: The systematic search was conducted in three electronic databases and the study's selection was performed according to pre-set eligibility criteria. Four studies evaluating the efficacy of beta carotenes in oral leukoplakia compared to placebo were included in the review; three of which were assigned for quantitative analysis. Data were extracted, tabulated, quality assessed and statistically analyzed. Results: The meta-analysis revealed that when comparing clinical resolution the beta carotene group favored was favored compared to placebo, with statistically significant difference. However, a meta-analysis comparing beta carotene and placebo groups regarding malignant transformation as a primary outcome failed to show any significant benefit. Furthermore, results showed evidence of beta carotene safety. Conclusion: the overall quality of evidence about efficacy of beta carotene in oral leukoplakia treatment was not high. However, given the obvious safety of this agent, data suggests it could have a promising effect in clinical improvement of oral leukoplakia lesions. However, no evidence supporting its benefits in reducing risk of malignant transformation in these lesions was found. Therefore, further long term, well designed randomized clinical trials are highly recommended.

Introducción: el cáncer oral es un problema grave con alta mortalidad y morbilidad, a pesar de la disponibilidad de los mejores tratamientos. Uno de los factores más importantes para una mortalidad tan alta es su diagnóstico tardío. La mejor manera de enfrentar un problema de este tipo es evitar su aparición creando conciencia entre la población y tenendo un diagnóstico más temprano. El cáncer oral es una enfermedad multifactorial, donde el daño genómico tiene un papel. Se ha demostrado que los micronúcleos (MNi) son un biomarcador importante y en este estudio se utilizó como una herramienta para crear conciencia sobre el riesgo de cáncer oral. Objetivo: evaluar y comparar la frecuencia de MNi en fumadores sin ninguna lesión oral visible (Grupo I) y no fumadores sanos (Grupo II). Materiales y métodos: se obtuvieron citoestimuladores de fumadores sauditas (n = 15, Grupo I) sin ninguna lesión oral visible y no fumadores sanos (n = 15, control, Grupo II) y se tiñeron con hemotoxilina y eosina para evaluar la frecuencia de MNi y las observaciones fueron sometidas a análisis estadístico utilizando la prueba t de Student. Resultados: La frecuencia media de MNi en el Grupo I fue significativamente mayor (p<0.05) que en el Grupo II. El estudio ayuda a educar, motivar y crear conciencia, alentando así a los pacientes a dejar de fumar, y evitando así el cáncer oral antes de su inicio.

Actividad antimutagénica e identificación de compuestos antioxidantes en la planta Poincianella bracteosa (Fabaceae)

Introducción: Poincianella bracteosa (Tul.) L.P. Queiroz. (Fabaceae), conocida como catingueira, es tradicionalmente utilizada en la medicina para tratar diarrea, hepatitis y anemia. Sin embargo, no hay estudios sobre los efectos tóxico genéticos de la P. bracteosa. Objetivo: En el presente estudio se tuvo como objetivo investigar el perfil fitoquímico y el potencial mutagénico y antimutagénico del extracto acuoso de la cáscara de P. bracteosa en Allium cepa y Mus musculus. Métodos: El extracto de la cáscara fue diluido en agua destilada para fornecer las cuatro concentraciones (2, 4, 8 y 16 mg/ml) utilizadas en el bioensayo A. cepa y las tres dosis (10, 20 y 40 mg / Kg) fueron administradas a los ratones (5 animales por grupo). El perfil fito-químico fue realizado por el test colorimétrico para identificar los principales metabólitos secundarios en el extracto de la cáscara. Tras el tratamiento, 5 000 células meristemáticas fueron analizadas para determinar el índice mitótico, el promedio de alteraciones cromosómicas y el porcentaje de reducción de daños. Para ratones, tras 24, 48 y 72 h, la sangre de la cola de cada animal fue recolectado para la preparación de dos láminas por animal. Para cada animal, 2 000 eritrocitos normocromáticos por ratón fueron evaluados para establecer el número de micronúcleos y el efecto protector. Se analizaron los dados por el test de Kruskal-Wallis (P < 0.05). El estudio fito-químico del extracto detectó azúcares reductores y taninos. Resultados: Ninguna de las concentraciones del extracto fue citotóxica y en todos los tratamientos (pre, simultáneo y después) fue observado el efecto citoprotetor en A. cepa. El promedio total de las alteraciones cromosómicas en todas las concentraciones apuntó actividad no mutagénica de la cáscara. El porcentaje de reducción del daño fue observada en los tratamientos pre (de 77.6 al 90.5 %), simultáneo (del 95.6 al 114.7 %) y tras (de 84.8 al 117.7 %). En los ratones, ninguna de las dosis del extracto presentó efecto mutagénico y el porcentaje de reducción del daño osciló de -21.2 al 78.6 % (pre); de 27.5 al 101.3 % (simultánea) y de 85.5 al 120.6 % (tras-tratamiento). Probablemente, los fito-químicos presentes en el extracto no interfirieron en el ciclo celular (A. cepa), tampoco causaron daños al DNA (A. cepa y ratones) y presentaron efecto protector en las dos especies estudiadas. Los datos observados apuntan la importancia del extracto de la cáscara de P. bracteosa para inhibición del daño y quimio prevención. Sin embargo, más estudios deben ser realizados para garantizar su efecto protector sobre el material genético.

Introduction: Poincianella bracteosa (Tul.) L.P. Queiroz. (Fabaceae), known as catingueira, is traditionally used in medicine to treat diarrhea, hepatitis and anemia. However, there are no studies on their toxicogenetic effects. Objective: The present study aimed to investigate the phytochemical profile as well as the mutagenic and antimutagenic potential of P. bracteosa aqueous bark extract in Allium cepa and Mus musculus. Methods: The extract from barks was diluted in distilled water to yield the four concentrations (2, 4, 8 and 16 mg/ml) used in the A. cepa bioassay and the three doses (10, 20 and 40 mg/Kg) administered to the mice (five animals per group). The phytochemical profile was performed by the colorimetric test to identify the main secondary metabolites in the bark extract. After treatment, five-thousand meristematic cells were analyzed to determine the mitotic index, the mean number of chromosome alterations and the percentage of damage reduction. For mice, after 24, 48 and 72 h, tail blood was collected from each animal for the preparation of two slides per animal. For each animal, 2 000 normochromatic erythrocytes per mice were evaluated to establish the number of micronuclei and the protective effect. Data were analyzed by Kruskal-Wallis test (P < 0.05). Results: The phytochemical analysis of the extract detected reducing sugars and tannins. None of the concentrations of extract was cytotoxic and the cytoprotective effect was observed in A. cepa for all treatments (pre-, simultaneous and post-). The total mean of chromosome alterations in all concentrations indicated a non-mutagenic activity of the bark. The percentage of damage reduction was observed in the pre- (77.6 to 90.5 %), simultaneous (95.6 to 114.7 %) and post- (84.8 to 117.7 %) treatments. In mice, none of the dosages of extract presented mutagenic effect and the percentage of damage reduction varied from -21.16 to 78.63 % (pre-); from 27.51 to 101.28 % (simultaneous) and from 85.47 to 120.63 % (post-treatment). Conclusions: Probably, the phytochemicals in the extract did not interfere with the cell cycle (A. cepa) nor caused damage to the DNA (A. cepa and mice), and exhibited protective effect in both studied species. The observed data indicate the importance of P. bracteosa bark extract for the inhibition of damage and chemoprevention. However, more studies should be carried out to ensure its protective effect on the genetic material.

Genotoxicity effects on Geophagus brasiliensis fish exposed to Doce River water after the environmental disaster in the city of Mariana, MG, Brazil / Efeitos da genotoxicidade em peixes da espécie Geophagus brasiliensis expostos a água do Rio Doce após o desastre ambiental na cidade de Marina, MG, Brasil

Abstract The Doce River basin has suffered the largest environmental accident ever occurred in Brazil with the influx of tailings from Fundão and Santarém, belonging to Samarco mining company, due to the disaster in Mariana. A spill between 50 and 60 million m3 of tailings was estimated by the company. According to Samarco, the wastewater was composed mainly of clay, silt and heavy metals like iron, copper and manganese. Thereby, the objective of the present study was evaluated the genotoxic damage in juvenile of Geophagus brasiliensis (Quoy e Gaimard, 1824) exposed to Doce river water before (DRWBA - Doce River water before acident) and after (DRWAA - Doce River water after acident) the influx of tailings from the Germano and Santarém Dam disasters in Mariana, MG, Brazil. For this, 24 individuals of the species G. brasiliensis (obtained on IFES/ALEGRE fish culture) were submitted to a bioassay with three treatments and eight replicates. The treatments were: 1) Control water (water from the urban water supply system, filtered with a 0.45 µm membrane), 2) DRBA and 3) DRAA. After 96 h, these fishes were anesthetized to remove blood for evaluation of genotoxic damage (micronucleus and comet). For the bioassay, a total of 80 L of The Doce River water were collected before the influx of tailings and after the influx and then submitted to metal quantification analysis. Fish exposed to DRWBA and DRWAA treatments showed a significant increase in both the number of erythrocyte micronuclei and the DNA damage index in relation to the control fish; however, they did not present any differences between the two treatments. The results demonstrate that the DRWBA treatment was already genotoxic for the fish, mainly due to dissolved Cu concentrations in the water. The DRWAA treatment probably presented genotoxicity due to the increase in the dissolved fraction and synergistic effects of several metals found in the tailings of the Mariana accident.

Resumo A bacia do Rio Doce sofreu o maior acidente ambiental com o influxo de rejeitos de Fundão e Santarém, pertencentes à empresa de mineração Samarco, devido ao desastre em Mariana. Um derramamento entre 50 e 60 milhões de m3 de rejeitos foi estimado pela empresa. De acordo com a Samarco, o rejeito despejado era composto principalmente de argila, silte e alguns metais pesados como ferro, cobre e manganês. Com isso, o presente estudo teve como objetivo avaliar os danos genotóxicos em juvenis de Geophagus brasilienses expostos a água do rio Doce antes (DRWAA - água do Rio Doce antes do acidente) e depois (DRWBA- água do Rio Doce depois do acidente) da chegada dos rejeitos do rompimento das barragens de Germano e Santarém em Mariana, MG, Brasil. Para isso, 24 indivíduos da espécie G. brasilienses (obtidos na piscicultura do IFES/ALEGRE) foram submetidos a um bioensaio com três tratamentos e oito réplicas. Os tratamentos eram: 1) Controle (com água do abastecimento urbano, filtrada com filtro analítico de 0,45 µm); 2) DRWBA e 3) DRWAA. Após um período de 96 h, esses peixes foram anestesiados para retirada de sangue para avaliação dos danos genotóxicos (micronúcleo e cometa). Para a realização do bioensaio, um total de 80 L de água do Rio Doce foram coletados antes da chegada dos rejeitos e outros 80 L foram coletados depois da chegada dos rejeitos e ambas foram submetidas a análises de quantificação de metal. Os peixes expostos ao DRWBA e ao DRWAA apresentaram um aumento significativo na quantidade de micronúcleos eritrocitários e no índice de danos do DNA em relação aos peixes controle, no entanto não apresentaram diferenças entre si. Os resultados obtidos demonstram que a DRWBA já era genotóxica para os peixes, principalmente, em função das concentrações de Cu dissolvido na água. A DRWAA apresentou genotixicidade, provavelmente, em função do aumento da fração dissolvida e do efeito sinérgico de diversos metais presentes nos rejeitos do acidente de Mariana.

Evaluation of Genotoxicity Induced by Low Dose Oral Exposure of Deltamethrin in Mice Model

The study was conducted to elucidate the genotoxic effect of deltamethrin in Swiss Albino male mice following oral exposure, by comet assay and micronuclei induction test. Deltamethrin was administered at the dose rate of 1.5 mg/kg bwt, 1.0 mg/kg bwt and 0.5 mg/kg body weight. Mean head DNA percentage, mean tail DNA percentage, mean tail length and mean olive moment were the endpoints for the comet assay. Deltamethrin resulted in a significant comet formation at 15, 30 and 60 days of oral exposure in a dose and time dependent manner. Mean tail DNA% at 15, 30 and 60 days of exposure to deltamethrin was 59.28, 57.74 and 63.14, respectively. The results were found to be significantly different in treatment groups as compared to the control groups. Micronucleated normochromatic erythrocytes, micronucleated polychromatic erythrocytes and polychromatic erythrocytes percentage were the endpoints for the micronuclei induction test. Deltamethrin induced significantly higher number of micronuclei in treatment group than the negative control. In conclusion, present study indicates that pesticides are slow poison and even a low dose of pesticide can cause genotoxicity and other biological effects when exposed to for longer duration.

Genotoxic effects of mercury chloride on the Neotropical fish Andinoacara rivulatus (Cichlidae: Cichlasomatini)

Understanding the effects of heavy metals in aquatic ecosystems is of significant importance due to their potential to bioaccumulate at various trophic levels and induce damage in DNA. Mercury is considered one of the most dangerous heavy metals, causing chromosomal breakage (clastogenic event) or spindle dysfunction (aneugenic event), that can lead to the formation of encapsulated chromatin into a separate smaller nucleus, generally referred to as a micronucleus. We evaluated the sensitivity of the micronucleus test in the neotropical cichlid Andinoacara rivulatus (Günther 1860). The fish were divided into four groups of 16 individuals, and each group was placed in separate aquaria (140 L) provided with filtered water and constant aeration. Fish were exposed to mercury chloride (HgCl2) at doses 0.1, 0.25, and 0.50 mg/kg body weight, administered by intraperitoneal (IP) injection. Fish from the control group were injected with a physiologic solution. The following erythrocyte anomalies were identified: erythrocytes with micronuclei varying to some extent in size and position in the cytoplasm, blebbed nucleus, binucleated cell, nuclei showing a deep invagination toward the center (notched nuclei). Examination of blood smears demonstrated a higher level of micronucleus and notched erythrocytes in fish injected with HgCl2 than in the controls. There were significant differences in the frequency of micronucleated and notched erythrocytes among the groups exposed to mercury. Linear regression analysis revealed a positive relationship between the frequency of micronucleated and notched erythrocytes (P< 0.0001), with a moderately strong correlation coefficient (R= 0.737). We propose that, in addition to the two so far known mechanisms of micronucleus formation (spindle apparatus damage and chromosomal ruptures), chromatin fragmentation in notched nuclei resulting from a combination of the cytotoxic effects of mercury and mechanical stress, may be a third mechanism of micronuclei genesis.

Comprender los efectos de los metales pesados en los ecosistemas acuáticos es de gran importancia debido a su potencial de bioacumulación en los diversos niveles tróficos y de inducir daños en el ADN. El mercurio, considerado uno de los metales pesados más peligrosos, causa fracturas cromosómicas (evento clastogénico) o disfunción del huso mitótico (evento aneugénico), y puede conducir a la formación de fragmentos de cromatina encapsulada en un núcleo separado más pequeño, generalmente denominado micronúcleo. En este trabajo se evalúa la sensibilidad del test de micronúcleos en el cíclido neotropical Andinoacara rivulatus (Günther 1860). Los peces fueron divididos en cuatro grupos de 16 individuos, y cada grupo se colocó en acuarios separados (140 L) provistos de agua filtrada y aireación constante. Los peces fueron expuestos al cloruro de mercurio (HgCl2) en dosis de 0.1, 0.25 y 0.50 mg/kg de peso corporal, administrada por inyección intraperitoneal (IP). Los peces del grupo control fueron inyectados con solución fisiológica. Se identificaron las siguientes anomalías en los eritrocitos: micronúcleos que varían en tamaño y posición en el citoplasma, núcleo con evaginaciones, células binucleadas núcleos con muesca (núcleos con una profunda invaginación hacia el centro). El examen de los frotis de sangre demostró un mayor nivel de eritrocitos micronucleados y con muesca en peces inyectados con HgCl2 que en los controles. Fueron detectadas diferencias significativas en la frecuencia de eritrocitos micronucleados y células con núcleos con muescas entre los grupos expuestos al mercurio. El análisis de regresión lineal reveló una relación positiva entre la frecuencia de eritrocitos micronucleados y con muescas (P< 0.0001), con un coeficiente de correlación moderadamente fuerte (R= 0.737). Se propone que, además de los dos mecanismos hasta ahora conocidos de formación de micronúcleos (daño del huso mitótico y rupturas cromosómicas), la fragmentación de la cromatina en núcleos con muesca probablemente a causa de la combinación de los efectos citotóxicos del mercurio y el estrés mecánico, podría ser un tercer mecanismo de génesis de micronúcleos.

Avaliação dos efeitos genotóxicos da exposição ocupacional em frentistas atuantes em postos de gasolina no município de Santarém, Pará / Genotoxic effects of occupational exposure among gas station attendants in Santarem, Para, Brazil

Introdução: Profissionais frentistas encontram-se em situação de risco tóxico pela exposição constante aos vapores dos combustíveis. O benzeno, presente na gasolina, é considerado cancerígeno e prejudicial à saúde desses trabalhadores Objetivo: Avaliar os efeitos genotóxicos decorrentes da exposição ocupacional em células esfoliativas da mucosa oral de frentistas do município de Santarém, Pará; e determinar a taxa de adesão ao uso de equipamentos de proteção individual por esses colaboradores. Métodos: Um total de 126 frentistas, distribuídos em 6 grupos contendo indivíduos expostos foram comparados ao grupo controle utilizando a técnica do ensaio de micronúcleos em células da mucosa oral coradas com as técnicas de Feulgen/Fast-green. Resultados: Os frentistas apresentaram maior frequência de micronúcleos em relação ao grupo não exposto ao benzeno (p<0,01). Frentistas com hábito etílico apresentaram aumento significativo de micronúcleos (p<0,01), quando comparados aos frentistas abstêmios. Verificou-se que 100% dos profissionais entrevistados não fazem uso dos equipamentos de proteção. Conclusão: Constatou-se um aumento na presença de micronúcleos em células esfoliativas de frentistas em comparação ao grupo controle. Esse aumento é ainda maior quando o frentista ingere frequentemente bebidas alcoólicas.

Background: Gas station attendants are at high risk of poisoning due to continuous exposure to fuel fumes. Benzene, present in gasoline, is considered a carcinogen and harmful to the health of gas station attendants. Objective: To investigate genotoxic effects on exfoliated oral mucosa cells in association with occupational exposure among gas station attendants in Santarem, Para, Brazil, and to establish the rate of adherence to personal protective equipment (PPE). Methods: The results of the micronucleus test performed with oral mucosa cells stained by means of the Feulgen and Fast Green methods were compared between 126 exposed gas station attendants distributed across six groups and controls. Results: The frequency of micronuclei was higher among gas station attendants compared to the group not exposed to benzene (p<0.01). The frequency of micronuclei was significantly higher (p<0.01) among the gas station attendants who reported to drink alcohol compared to non-drinkers. None of the participants (0%) used PPE. Conclusion: The frequency of micronuclei in exfoliated oral mucosa cells was higher among gas station attendants compared to controls; frequency was even higher for the gas station attendants who reported to consume alcohol often

Evaluation of antimutagenic and cytotoxic activity of skin secretion extract of Rhinella marina and Rhaebo guttatus (Anura, Bufonidae) / Avaliação da atividade antimutagênica e citotóxica da secreção cutânea de Rhinella marina e Rhaebo guttatus (Anura, Bufonidae)

The skin secretion from toads of the Bufonidae family has great potential in the search for new active compounds to be used as drug candidates in treating some diseases, among them cancer. In this context, this study aimed to evaluate the cytotoxic and antimutagenic activity of the parotoid gland secretion extracts of Rhinella marina and Rhaebo guttatus, as well as biochemically analyze transaminases and serum creatinine for liver and renal damage, respectively. Cytotoxicity was performed by the colorimetric method based on MTT (3- [4, 5-dimethyl-2-thiazolyl]-2, 5-diphenyl-2H-tetrazolium bromide) with different concentrations of the extracts in Walker or splenic tumor cell cultures from rats and mice. The micronucleus test was performed with male Swiss mice treated orally with the extracts for 15 days, and then intraperitoneally with N-ethyl-N-nitrosurea (50 mg kg-1). Micronucleated polychromatic erythrocytes (MNPCE) were evaluated in bone marrow. The extracts showed cytotoxic activity in the evaluated cells. There was a significant reduction in the frequency of MNPCE (R. marina = 56% and R. guttatus = 75%, p < 0.001), indicating antimutagenic potential of the extracts. The groups treated only with extract showed an increase in MNPCE frequency, evidencing mutagenic potential. Biochemical analyzes showed no significant difference between treatments. Thus, under our experimental conditions, the extracts of R. marina and R. guttatus skin secretions presented chemopreventive potential for cancer. (AU)

A secreção cutânea de anuros da família Bufonidae tem grande potencial na busca de novos compostos ativos para utilização como fármacos candidatos no tratamento de algumas doenças, entre elas o câncer. Neste contexto, este estudo teve como objetivo avaliar a atividade citotóxica e antimutagênica dos extratos da secreção da glândula parótida de Rhinella marina e Rhaebo guttatus, bem como a análise bioquímica de transaminases e creatinina séricas, para avaliar dano hepático e renal, respectivamente. A avaliação de citotoxicidade foi realizada pelo método colorimétrico baseado no MTT (3-[4, 5-dimethyl-2-thiazolyl]-2, 5-diphenyl-2H-tetrazolium bromide), com diferentes concentrações dos extratos em culturas de células do Tumor de Walker ou células esplênicas de rato e camundongo. O teste do micronúcleo foi realizado com camundongos Swiss machos que receberam tratamento oral com os extratos durante 15 dias, seguido de tratamento intraperitoneal com N-etil-N-nitrosuréia (50 mg kg-1). A frequência de eritrócitos policromáticos micronucleados (PCEMN) foi determinada em medula óssea. Os extratos apresentaram ação citotóxica nas células avaliadas. Houve uma redução significativa na frequência de PCEMN (R. marina = 56% e R. guttatus = 75%, p < 0,001), observando-se um potencial antimutagênico dos extratos. Os grupos tratados somente com os extratos apresentaram um aumento na frequência de PCEMNs, evidenciando um potencial mutagênico. As análises bioquímicas não apresentaram diferença significativa entre os tratamentos. Assim, nas condições experimentais testadas, as secreções cutâneas de R. marina e R. guttatus apresentaram potencial quimiopreventivo para câncer.(AU)

Comparison of different stains in exfoliated oral mucosal cell micronucleus of potentially malignant disorders of oral cavity

Background: Micronucleus (MN) has been proved to be an important biomarker of genomic damage. Leishman Giemsa (LG) cocktail, being a relatively new staining technique, has not been used in exfoliative cytology. The aim of this study is to observe and compare the micronuclei (MN) frequency in potentially malignant disorders (PMDs) and also to compare the staining efficacy of May-Grünwald Giemsa (MGG), LG cocktail, and Papanicolaou (PAP) for micronuclei in exfoliated oral mucosal cells. Materials and Methods: Three smears were prepared from each 30 controls (buccal mucosa) and 120 patients (40 oral submucous fibrosis, 40 lichen planus, and 40 leukoplakia) clinically diagnosed with having one of the PMDs of the oral cavity stained with PAP, MGG, and LG cocktail stains. MN frequency (No. of MN/1000 cells) was evaluated and compared between the cases and the controls. Comparison between the three different stained smears was also made to determine the clarity and efficacy of the stains. Results: LG cocktail gave comparatively better results followed by PAP and MGG. Statistically significant results (P < 0.05) were obtained, using Mann–Whitney test for comparison of MN frequency between cases and controls. Conclusion: LG cocktail is an easy, cost- effective, and one step technique comparable to PAP staining; however, it warrants further study in its potential application in screening of oral cancer.

Micronucleus Assay Of Buccal Mucosal Cells In Smokers And Non–Smokers

The micronuclei assay (MA) in exfoliated buccal cells is an innovative technique which holds promise for the screening of epithelial carcinogens/mutagens. Micronucleus is the small nucleus that forms whenever a chromosome or a fragment of a chromosome is not incorporated into one of the daughter nuclei during cell division. The micronucleus is thought to be an indicator of DNA damage consequent to possible carcinogen exposure. The objectives of our study were to evaluate the frequency of micronuclei in exfoliated buccal mucosal cells of smokers and non–smokers and to correlate the mean micronuclei with period of smoking. Buccal smears obtained from 68 age matched male subjects (40 smokers, 28 non–smokers) were included in the study. Papanicoloau stained smears were screened for micronuclei as per Tolbert et al criteria, with 1000 cells being examined in both categories. Results showed a statistically significant difference in the mean micronuclei count in buccal cells of smokers as compared to non smokers. Micronucleus assay can be used as a simple bio–marker for screening of pre–malignant changes in cells.

Cytological Grading Of Oral Submucous Fibrosis

Oral submucous fibrosis (OSMF) is a condition that was first described in the 1950s. It is caused as a result of addiction to harmful areca nut products with or without tobacco. The rationale of using exfoliative cytology in our study lies in the epithelial physiology where continuous exfoliation of epithelial cells is a part of physiological turnover. Deeper cells, which are strongly adhered in normal conditions, become loose in the case of malignancy and exfoliate along with superficial cells. Our aim in this study was to compare the cellular changes such as formation of micronuclei within the cell and cytomorphometric analysis of the buccal mucosal cells of OSMF patients with that of normal controls. We identified thirty three such cases of OSMF on the basis of oral inspection and examination. We used exfoliative cytology and liquid based cytogy to obtain buccal cells. The smear thus prepared was stained with feulgan fast green, acridine orange and papanicolou. Micronuclei were identified and cytomorphometric analysis was done using Adelta software. There was a change in the hue of Papanicolou from pink to purplish indicating the degree of keratinization from normal cells to cells affected by OSMF. Acridine orange gave a green emission at wavelength 480-490 to normal cells, while it gave a bright red fluorescence in cells undergoing apoptosis. Mean cellular diameter decreased from normalcells affected oral lesions. Mean nuclear cytoplasmic ratio increased from normal-cells to those affected by oral lesions. Frequency of micronuclei increased from normal to the cells affected by oral lesions. Buccal cell mutations in premalignant and malignant lesions can serve as a useful tool for the bio-monitoring of oral lesions. Exfoliative Cytology being minimally invasive and cost effective can help in mass screening programmes