Estimation of genotoxicity threshold induced by acute exposure to neodymium nitrate in mice using benchmark dose / 环境与职业医学

Background The benchmark dose (BMD) method calculates the dose associated with a specific change in response based on a specific dose-response relationship. Compared with the traditional no observed adverse effect level (NOAEL) method, the BMD method has many advantages, and the 95% lower confidence limit of benchmark dose lower limit (BMDL) is recommended to replace NOAEL in deriving biological exposure limits. No authority has yet published any health-based guideline for rare earth elements. Objective To evaluate genotoxicity threshold induced by acute exposure to neodymium nitrate in mice using BMD modeling through micronucleus test and comet assay. Methods SPF grade mice (n=90) were randomly divided into nine groups, including seven neodymium nitrate exposure groups, one control group (distilled water), and one positive control group (200 mg·kg−1 ethyl methanesulfonate), 10 mice in each group, half male and half female. The seven dose groups were fed by gavage with different concentrations of neodymium nitrate solution (male: 14, 27, 39, 55, 77, 109, and 219 mg·kg−1; female: 24, 49, 69, 97, 138, 195, and 389 mg·kg−1) twice at an interval of 21 h. Three hours after the last exposure, the animals were neutralized by cervical dislocation. The bone marrow of mice femur was taken to calculate the micronucleus rate of bone marrow cells, and the liver and stomach were taken for comet test. Results The best fitting models for the increase of polychromatophil micronucleus rate in bone marrow of female and male mice induced by neodymium nitrate were the exponential 4 model and the hill model, respectively. The BMD and the BMDL of female mice were calculated to be 31.37 mg·kg−1 and 21.90 mg·kg−1, and those of male mice were calculated to be 58.62 mg·kg−1 and 54.31 mg·kg−1, respectively. The best fitting models for DNA damage induced by neodymium nitrate in female and male mouse hepatocytes were the exponential 5 model and the exponential 4 model, respectively, and the calculated BMD and BMDL were 27.15 mg·kg−1 and 11.99 mg·kg−1 for female mice, and 16.28 mg·kg−1 and 10.47 mg·kg−1 for male mice, respectively. The hill model was the best fitting model for DNA damage of gastric adenocytes in both female and male mice, and the calculated BMD and BMDL were 36.73 mg·kg−1 and 19.92 mg·kg−1 for female mice, and 24.74 mg·kg−1 and 14.08 mg·kg−1 for male mice, respectively. Conclusion Taken the micronucleus rate of bone marrow cells, DNA damage of liver cells and gastric gland cells as the end points of genotoxicity, the BMDL of neodymium nitrate is 10.47 mg·kg−1, which can be used as the threshold of genotoxic effects induced by acute exposure to neodymium nitrate in mice.

Analysis of micronucleus rate in 394 radiation workers with cytokinesis-block micronucleus method / 中国辐射卫生

Objective To analyze the micronucleus rate of radiation workers and to provide accurate occupational health monitoring basis in radiation workers exposed to low-level ionizing radiation for a long time. Methods The radiation group consisted of 353 radiation workers who had been exposed to ionizing radiation during work, while the control group consisted of 41 radiation workers who had not yet been exposed to ionizing radiation before work. The cytokinesis-block micronucleus method was used to determine the micronucleus rate. Results The average micronucleus rate in the radiation group was significantly higher than that in the control group (t = −2.95, P < 0.05). In the radiation group, the micronucleus rate gradually increased with age, and the difference was statistically significant (F = 8.36, P < 0.05). The micronucleus rates of workers with > 10 and > 30 years of service were significantly higher than those of workers with < 10 years of service (χ2 = −44.79, −60.47, P < 0.05). The micronucleus rate in females was significantly higher than that in males (t = 3.93, P < 0.05). The micronucleus rates in the diagnostic radiology group and the industrial detection group were significantly higher than that in the control group (t = 3.51, 3.65, P < 0.05). Conclusion The micronucleus rate has increased among the radiation workers exposed to low-level ionizing radiation for a long time. It is necessary to further strengthen occupational health monitoring and radiation protection education for radiation workers, especially the medical workers that constitute the largest population of radiation exposure workers.

Analysis of factors influencing lymphocyte micronucleus in industrial radiation workers in Gansu Province, China / 中国辐射卫生

Objective To analyze micronucleus abnormalities in the peripheral blood lymphocytes of industrial radiation workers and the influencing factors, and to provide a reference for radiation protection. Methods The occupational health monitoring data of 661 industrial radiation workers were collected from the occupational health examination system of Gansu Provincial Center for Disease Control and Prevention. The abnormalities in the micronucleus of peripheral blood lymphocytes were analyzed. The influencing factors were identified by logistic regression. Results The micronucleus abnormality rate was 6.05% for the 661 industrial radiation workers. There was no significant difference in micronucleus abnormality rate between sexes (P > 0.05). Comparison of age groups showed that the rate of micronucleus abnormality increased with age, and workers over 50 years of age has the highest rate of micronucleus abnormalities (17.81%); there was a significant difference between age groups (P < 0.05). There was a significant difference in micronucleus abnormality rate between occupational categories (P < 0.05). There was a significant difference in micronucleus abnormality rate between groups with different years of work (P < 0.05). Logistic regression analysis showed that age and years of work were the risk factors for micronucleus abnormality rate (P < 0.05); age was an independent risk factor for micronucleus abnormality rate (P < 0.05). Conclusion The effect of low-dose ionizing radiation on micronucleus abnormality rate of industrial radiation workers is related to age and working years. Attention should be paid to occupational health monitoring of radiation workers, especially those with advanced age.

Role of micronucleus-activated cGAS-STING signaling in antitumor immunity / 浙江大学学报·医学版

cGAS-STING signaling is a significant component of the innate immune system and functions as a vital sentinel mechanism to monitor cellular and tissue aberrations in microbial invasion and organ injury. cGAS, a cytosolic DNA sensor, is specialized in recognizing abnormally localized cytoplasmic double-stranded DNA (dsDNA) and catalytically synthesizes the second messenger cyclic-GMP-AMP (cGAMP), which initiates a cascade of type I interferon and inflammatory responses mediated by STING. Micronucleus, a byproduct of chromosomal missegregation during anaphase, are also significant contributors to cytoplasmic dsDNA. These unstable subcellular structures are susceptible to irreversible nuclear envelope rupture, exposing genomic dsDNA to the cytoplasm, which potently recruits cGAS and activates STING-mediated innate immune signaling and its downstream activities, including type I interferon and classical nuclear factor-κB (NF-κB) signaling pathways lead to senescence, apoptosis, autophagy activating anti-cancer immunity or directly killing tumor cells. However, sustained STING activation-induced endoplasmic reticulum stress, activated chronic type I interferon and nonclassical NF-κB signaling pathways remodel immunosuppressive tumor microenvironment, leading to immune evasion and facilitating tumor metastasis. Therefore, activated cGAS-STING signaling plays a dual role of suppressing or facilitating tumor growth in tumorigenesis and therapy. This review elaborates on research advances in mechanisms of micronucleus inducing activation of cGAS-STING signaling and its implications in tumorigenesis and therapeutic strategies of malignant tumors.

Establishing a dose-response curve for 60Co γ-ray irradiation-induced micronuclei in human peripheral blood cells using artificial intelligence-based color recognition / 中华放射医学与防护杂志

Objective:To identify micronuclei through the cytochalasin B blocking micronucleus method-based assay using scanning microscope, combined with the slide scanning software Metafer 4 and, accordingly, to establish a dose-response relationship between the dose of 60Co γ-rays and the frequency of micronuclei in human peripheral blood lymphocytes using artificial intelligence-based color recognition. Methods:Blood samples were collected from four healthy individuals (two men and two women) and were then exposed to varying doses of 60Co γ-ray radiation (0, 0.25, 0.5, 1, 2, 3, 4, 5 Gy) at a dosage rate of 0.74 Gy/min. Micronucleus slides were prepared as per the GBZ 128-2023 standard. The numbers of binuclear cells and micronuclei were recorded using an artificial intelligence-based color recognition analysis system. The dose-response curve was determined through fitting using the CABAS software. Then, the doses to both independent samples were estimated based on the curve. Results:Within a dose range of 0 to 5 Gy, the fitted micronucleus dose-response curve aligned with a quadratic polynomial model, with a regression equation of y = 0.032 1 D2+ 0.023 7 D+ 0.012 7 ( D denoting the dose, correlation coefficient R2=0.998). The dose estimations from the validation samples closely corresponded to the actual irradiation doses. Conclusions:Establishing the micronucleus dose-response curve provides a feasible method and basis for the rapid and accurate estimation of radiation biological doses in laboratory automation.

Biomonitoring of air quality in the Bodoquena microregion, Mato Grosso Do Sul: mutagenic and morphoanatomical alterations in Tradescantia pallida (rose) D.R. Hunt var. purpurea

Abstract The objective of this study was to assess air quality in relation to vehicular traffic flow in cities located at different elevations in the Bodoquena microregion, state of Mato Grosso do Sul, Brazil. To do so, a micronucleus test was carried out using the TRAD-MCN bioassay on young Tradescantia buds collected from February to November 2018 in seven cities of the microregion with different traffic flow intensities. Meteorological parameters were evaluated, and vehicular traffic was counted to determine traffic flow in each city. With data from the Shuttle Radar Topography Mission (SRTM) and processing in Esri ArcGIS® software version 10.5.1, the regions was mapped based on an Elevation Model. Morphoanatomical analyses were performed according to standard methodology. Measurements were taken of thickness, length and width of tissues and structures, including the upper and lower cuticle, upper and lower epidermis, hypodermis and mesophyll. The greatest traffic flow was found in the cities of Bodoquena, Guia Lopes da Laguna, Jardim, and Porto Murtinho, with the period from 5:00 to 6:00 p.m. showing the highest traffic flow. The greatest frequency of mutagenic alterations was found in the city of Guia Lopes da Laguna, although the results did not differ significantly from Bonito, Caracol, and Jardim. Throughout the biomonitoring, the summer and autumn seasons showed the greatest micronuclei frequencies in all evaluated cities. Variations in the tissue/structure thickness was observed across cities and seasons, but with a decrease in thickness during autumn. In general, the tissues/structures were smaller for the cities of Nioaque and Porto Murtinho, while the anatomical and morphological characteristics of leaf length and thickness showed no differences among cities. We found limited correlation between micronuclei frequency and traffic flow, supporting the hypothesis that although mutagenic alterations are observed in T. pallida, in this microregion the changes are numerically lower when compared to other regions of the state. In light of the genotoxic and morphoanatomical factors assessed herein, the Bodoquena microregion appears to be well preserved in terms of air quality, presenting low micronuclei frequency and a limited reduction in tissues and leaf structures, regardless of the season.

Resumo O objetivo deste trabalho foi avaliar a qualidade do ar com base no fluxo veicular das cidades localizadas em diferentes altitudes na microrregião da Bodoquena, no estado de Mato Grosso do Sul, Brasil. Para tal, foi realizado o teste de micronúcleo, por meio do bioensaio TRAD-MCN em botões jovens de Tradescantia coletadas no período entre fevereiro a novembro de 2018 em sete cidades da microrregião da Bodoquena, com diferentes intensidades de fluxo veicular. Foram avaliados os parâmetros meteorológicos, os veículos foram contados para determinar o tráfego de veículos em cada cidade e altitude. A partir da topografia Shuttle Radar (SRTM) e processamento no software Esri ArcGIS® versão 10.5.1 foi possível mapear a área com base no Modelo de Elevação. As análises morfoanatômicos foram realizadas conforme metodologia padrão. As mensurações de espessura, comprimento, largura dos tecidos e estruturas como a cutícula superior, cutícula inferior, face superior e face inferior da epiderme, hipoderme e mesófilo foram avaliadas. O maior fluxo veicular foi encontrado nas cidades de Bodoquena, Guia Lopes da Laguna, Jardim e Porto Murtinho. O horário das 17:00 às 18:00h foi o que apresentou maiores fluxo de veículos. A maior frequência de alterações mutagênicas foi encontrada na cidade de Guia Lopes, não diferindo de Bonito, Caracol e Jardim. Ao longo do biomonitoramento observou-se que as estações de verão e outono foram as que apresentaram maiores frequências de micronúcleo independente da cidade avaliada. Observou-se que a correlação entre a frequência de micronúcleos e o fluxo veicular foi baixa, apoiando a tese de que essa microrregião, embora apresente alterações mutagênicas em T. pallida, as alterações numericamente são pequenas quando comparadas a outras regiões do estado de Mato Grosso do Sul. Observou-se uma variação na espessura dos tecidos/estruturas que é variável entre as diferentes cidades e estações do ano. De forma geral os tecidos/estrutura apresentaram redução na espessura para as cidades de Nioaque e Porto Murtinho quanto aos aspectos anatômicos e morfológicos, sendo que, para o comprimento e espessura foliar não foi observado diferenças entre as cidades. Em relação as estações do ano, observou-se que no outono a espessura dos tecidos/estruturas são menores. Diante dos fatores genotóxicos e morfoanatômicos aqui avaliados, a microrregião da Bodoquena parece estar bem preservada em termos de qualidade do ar, apresentando baixa frequência de micronúcleos e redução limitada de tecidos e estruturas foliares, independentemente da estação do ano.

Acute and subchronic effects of petroleum on the freshwater fish Hoplias aff. malabaricus

Abstract Petroleum water soluble fraction (WSF) impairs organisms, but damages may vary among cell and tissue levels. The aim of the present study was to evaluate the acute (24 h, 48 h, 72 h) and subchronic effects (36 days) of WSF (0%, 25% and 100%) in juveniles of the Neotropical top predator fish Hoplias aff. malabaricus. The effects of WSF were evaluated at a molecular level using the comet assay and micronucleus test for genome damage; and at a morphological level through histological identification of liver pathologic lesions. In both acute and subchronic exposure we found low levels of DNA damage ( 10% of comet tail) and non-significant frequency of micronucleus in WSF exposed fish. The most significant liver lesions in WSF exposed fish were fatty vacuolization, hypertrophy and focal necrosis. Since these tissue injuries were progressive and persistent, their irreversibility may negatively affect fish recruitment, even in a such resistant top predator.

Resumo A fração solúvel de petróleo (WSF) prejudica os organismos, porém os danos podem variar entre os níveis celular e tecidual. O objetivo do presente estudo foi avaliar o efeito agudo (24 h, 48 h e 72 h) e subcrônico (36 dias) da WSF (0%, 25% e 100%) em juvenis do peixe neotropical predador topo Hoplias aff. malabaricus. Os efeitos da WSF foram avaliados no nível molecular utilizando o ensaio do cometa e o teste do micronúcleo para o dano genômico e no nível morfológico através da identificação histológica de lesões patológicas no fígado. Em ambas exposições (aguda e subcrônica) encontramos baixos níveis de dano no DNA ( 10% de DNA na cauda do cometa) e frequência de micronúcleos não significativa em peixes expostos a WSF. As lesões mais significativas no fígado dos peixes expostos a WSF foram a vacuolização lipídica, hipertrofia e focos de necroses. Como estas lesões foram progressivas e persistentes, sua irreversibilidade pode afetar negativamente o recrutamento dos peixes, mesmo sendo um predador topo resistente.

Isolation of 4-nerolidylcatechol from leaves of Piper peltatum L., and evaluation of larvicidal activity in mosquito vectors, with emphasis on Aedes aegypti (Diptera: Culicidae)

ABSTRACT Synthetic chemical insecticides are widely used in population control of pests. Aedes aegypti is the primary vector of dengue, Zika, chikungunya and yellow fever to humans, and has proven resistance to chemical insecticides. As an alternative vector control method, the ethanolic extract of the leaves of Piper peltatum L. (Piperaceae) showed larvicidal activity against Ae. aegypti. Despite the wide medicinal use of this plant, the biological activity of its isolated constituents remains unexplored. In this sense, we isolated, identified and evaluated the larvicidal activity of 4-nerolidylcatechol (4-NC) from P. peltatum against Ae. aegypti, Culex quinquefasciatus and Anopheles darlingi, focusing on the larvicidal, adulticidal and genotoxic potential of 4-NC on Ae. aegypti. Larvae were captured in the city of Manaus, Amazonas state, Brazil. 4-NC was isolated from the extract of the leaves of P. peltatum via silica gel chromatography. This was identified using nuclear magnetic resonance spectroscopy and tested in Artemia franciscana (6.25, 12.5, 25, 50, 100 and 200 µg/mL). In the toxicity bioassay, Ae. aegypti larvae were exposed to 30, 50, 70, 90, and 110 µg/mL of 4-NC, while Cx. quinquefasciatus and An. darlingi were exposed to 6.25, 12.5, 25, 50 and 100 µg/mL. Ae. aegypti larvae were also subjected to 40 and 60 µg/mL of 4-NC (genotoxicity bioassay), and adult females to 62.5 to 1,000 µg/mL (adulticidal bioassay). The results of the 4-NC toxicity assays showed that there was 100% mortality in larvae of Ar. franciscana at the concentration of 200 µg/mL, with an LC50 of 8.0 μg/mL. In the larvae of Ae. aegypti, mortality was 100%, with an LC50 of 62 μg/mL. In larvae of Cx. quinquefasciatus, 97% mortality occurred, with an LC50 of 52.3 μg/mL, and in An. darlingi larvae there was an 83% mortality rate, with an LC50 of 55.8 μg/mL. In adults of Ae. aegypti, however, there was no adulticidal activity. In the larvae of Ae. aegypti, the genotoxic effect of 4-NC (40 and 60 µg/mL) showed significant frequency (p < 0.05) of cellular abnormalities (micronuclei, budding and nuclear bridges) of interphasic nuclei of neuroblasts and oocytes in relation to the negative control. This result may be associated with a decrease in oviposition of females, which was observed in two generations. We can confirm that 4-NC has larvicidal activity against Ae. aegypti, Cx. quinquefasciatus and An. darlingi. Although it does not present adulticidal activity in Ae. aegypti, it reduced the oviposition of females. Therefore, 4-NC seems to be a strong candidate for the development of an alternative method for the control of these mosquitoes in the immature phase.

Acute and subchronic effects of petroleum on the freshwater fish Hoplias aff. malabaricus / Efeitos agudo e subcrônico do petróleo no peixe de água doce Hoplias aff. malabaricus

Abstract Petroleum water soluble fraction (WSF) impairs organisms, but damages may vary among cell and tissue levels. The aim of the present study was to evaluate the acute (24 h, 48 h, 72 h) and subchronic effects (36 days) of WSF (0%, 25% and 100%) in juveniles of the Neotropical top predator fish Hoplias aff. malabaricus. The effects of WSF were evaluated at a molecular level using the comet assay and micronucleus test for genome damage; and at a morphological level through histological identification of liver pathologic lesions. In both acute and subchronic exposure we found low levels of DNA damage (< 10% of comet tail) and non-significant frequency of micronucleus in WSF exposed fish. The most significant liver lesions in WSF exposed fish were fatty vacuolization, hypertrophy and focal necrosis. Since these tissue injuries were progressive and persistent, their irreversibility may negatively affect fish recruitment, even in a such resistant top predator.

Resumo A fração solúvel de petróleo (WSF) prejudica os organismos, porém os danos podem variar entre os níveis celular e tecidual. O objetivo do presente estudo foi avaliar o efeito agudo (24 h, 48 h e 72 h) e subcrônico (36 dias) da WSF (0%, 25% e 100%) em juvenis do peixe neotropical predador topo Hoplias aff. malabaricus. Os efeitos da WSF foram avaliados no nível molecular utilizando o ensaio do cometa e o teste do micronúcleo para o dano genômico e no nível morfológico através da identificação histológica de lesões patológicas no fígado. Em ambas exposições (aguda e subcrônica) encontramos baixos níveis de dano no DNA (< 10% de DNA na cauda do cometa) e frequência de micronúcleos não significativa em peixes expostos a WSF. As lesões mais significativas no fígado dos peixes expostos a WSF foram a vacuolização lipídica, hipertrofia e focos de necroses. Como estas lesões foram progressivas e persistentes, sua irreversibilidade pode afetar negativamente o recrutamento dos peixes, mesmo sendo um predador topo resistente.

Evaluation on genotoxicities of raceanisodamine hydrochloride injection / 药学实践与服务

Objective To study the genotoxicities of raceanisodamine hydrochloride injection. Methods Bacterial reverse mutation test, in vitro Chromosomal aberration test and in vivo Micronucleus test were performed to investigate the genotoxicities of raceanisodamine hydrochloride injection. Results The Ames test showed that raceanisodamine hydrochloride injection did not increase mutagenicity for TA1535, TA102, TA100, TA98 and TA97 strains at the dosage of 0.5, 5, 50, 500, 5000 μg per plate under two parallel system conditions (±S9). Results of CA test indicated that there was no statistical difference between raceanisodamine hydrochloride injection groups (doses of 58.75,117.5 and 235.0 μg/ml) and the solvent control group under two parallel system conditions (±S9). In MNT test, with doses of 7.5, 15.0 and 30.0 mg/kg respectively, the micronucleus induction rate of bone marrow of ICR mice was not statistically significant (P>0.05) when compared with that of vehicle control group in all dose groups. Conclusion Under the conditions of these study, the results indicated that raceanisodamine hydrochloride injection had no mutagenicity to Salmonella typhimurium, had no aberration effect on the chromosome of mammalian cultured cells, and had no effect on inducing micronucleus of bone marrow polychromatic erythrocytes in ICR mouse. All test results showed that raceanisodamine hydrochloride injection had no potential carcinogenicities and genetic toxicities under the test conditions.

Analysis of chromosome aberration and micronucleus frequencies in 102 patients with cancer before and after radiotherapy and chemotherapy / 中国辐射卫生

@#<b>Objective</b> To investigate the changes of chromosome aberration and micronucleus frequencies in the peripheral blood of patients with cancer before and after treatment, and to provide a basis for clinical prevention and treatment. <b>Methods</b> We collected the physical examination data of 102 patients with cancer before and after treatment from 2016 to 2021 to analyze the changes of chromosome aberration and micronucleus frequencies in peripheral blood. <b>Results</b> Before and after treatment, there were significant differences in chromosome aberration frequency and micronucleus frequency in peripheral blood lymphocytes in patients having radiotherapy or chemoradiotherapy (all <i>P</i> < 0.05), but no significant difference was observed in either index for patients having chemotherapy (both <i>P</i> > 0.05). Before and after radiotherapy, there were significant differences in the numbers of patients with abnormal chromosome aberration frequency and those with abnormal micronucleus frequency in lymphocytes (both <i>P</i> < 0.001). Before and after chemotherapy, there was no significant difference in the number of patients with abnormal chromosome aberration frequency (<i>P</i> = 0.100) or those with abnormal micronucleus frequency (<i>P</i> = 0.110). <b>Conclusion</b> Radiotherapy can cause abnormalities in chromosome aberration and micronucleus frequencies in peripheral blood lymphocytes, which can be useful for monitoring radiotherapy injury to formulate effective emergency plans and evaluate radiation dose in each course of treatment.

Changes in body-related indices in people exposed to long-term low-dose nuclear radiation / 中国辐射卫生

@#<b>Objective</b> To investigate the effects of low-dose nuclear radiation exposure on the body by analyzing the antioxidant indices, immune indices, lymphocyte proliferation activity, and blood biochemical indices of persons exposed to long-term low-dose nuclear radiation, and to provide a basis for radiation protection and occupational health monitoring. <b>Methods</b> Eighty nuclear radiation workers were selected as the exposure group, and another 30 non-exposure personnel were selected as the control group. In both groups, blood biochemistry, serum total antioxidant capacity (T-AOC), malondialdehyde (MDA), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), lymphocyte proliferation activity, proliferating cell nuclear antigen (PCNA), apoptosis factors Bcl-2 and Bax, lymphocyte transformation rate, and lymphocyte micronucleus rate were measured. <b>Results</b> Compared with the control group, T-AOC, GSH-Px, SOD, cell proliferation activity, PCNA, Bcl-2, lymphocyte transformation rate, white blood cell count, and platelet count in the exposure group were significantly decreased, while MDA and Bax were significantly increased (<i>P</i> < 0.05). The lymphocyte micronucleus rate showed no significant difference between the two groups (<i>P</i> > 0.05). <b>Conclusion</b> Long-term low-dose exposure to nuclear radiation has certain effects on related indices of workers, but does not cause significant damage. The personnel exposed to nuclear radiation should enhance the awareness of protection and strengthen scientific protection to reduce radiation damage.

Genomic instability in long-term culture of human adipose-derived mesenchymal stromal cells

Mesenchymal stromal/stem cells stem (MSC) have been widely studied due to their great potential for application in tissue engineering and regenerative and translational medicine. In MSC-based therapy for human diseases, cell proliferation is required to obtain a large and adequate number of cells to ensure therapeutic efficacy. During in vitro culture, cells are under an artificial environment and manipulative stress that can affect genetic stability. Several regulatory agencies have established guidelines to ensure greater safety in cell-based regenerative and translational medicine, but there is no specific definition about the maximum number of passages that ensure the lowest possible risk in MSC-based regenerative medicine. In this context, the aim of this study was to analyze DNA damage and chromosome alterations in adipose-derived mesenchymal stromal cells (ADMSC) until the eleventh passage and to provide additional subsidies to regulatory agencies related to number of passages in these cells. Thus, two methods in genetic toxicology were adopted: comet assay and micronucleus test. The comet assay results showed an increase in DNA damage from the fifth passage onwards. The micronucleus test showed a statistically significant increase of micronucleus from the seventh passage onwards, indicating a possible mutagenic effect associated with the increase in the number of passages. Based on these results, it is important to emphasize the need to assess genetic toxicology and inclusion of new guidelines by regulatory agencies to guarantee the safety of MSC-based therapies for human diseases.

Toxic effects of Arianor Ebony hair dye on human cells

To evaluate the risks of hair dye exposure, we investigated cellular and molecular effects of Arianor Ebony dye, which is a mixture of azo and anthraquinone dyes, used in the composition of the black color. Cytotoxicity, genotoxicity, and gene expression of relevant molecules of apoptotic and oxidative stress mechanisms were investigated in HepG2 cells exposed to Arianor Ebony. Results showed that the dye did not induce cytotoxicity to exposed cells at a concentration up to 50 µg/mL compared to the negative control. However, genotoxic assays indicated that the dye was able to damage the genetic material at a concentration of 25 µg/mL, with induction factor values of exposed cells two- to five-fold higher than those recorded for the negative control. Moreover, the lowest observed effect concentration was 12.5 µg/mL. For gene expression, relevant changes were observed in cytochrome c and caspase 9, which decreased in cells incubated with the dye in a dose-dependent manner when compared with the negative control. In parallel, the expression of genes for antioxidant enzymes was increased in exposed cells, suggesting the presence of metabolic routes that protect cells against the toxic effect of the dye, avoiding exacerbated cellular death. Results suggested that the dye disrupted cellular homeostasis through mitochondrial dysfunction, which may be hazardous to human health. Thus, further investigations are necessary to deeply understand the mechanisms of action of the dye, considering its toxic potential found in our ex vivo assays.

Cytogenetic changes in oral mucosal cells of human immunodeficiency virus-infected children and adolescents undergoing antiretroviral treatment

SUMMARY OBJECTIVE: The objective of this study was to evaluate possible cytogenetic changes in children and adolescents with human immunodeficiency virus on antiretroviral therapy, through the micronucleus test in oral mucosa. METHODS: This was a prospective study consisted of 40 individuals, of whom 21 comprised the human immunodeficiency virus group and 19 comprised the control group. Children and adolescents with human immunodeficiency virus were enrolled. The inclusion criteria were <18 years old and consent in participating in the study. The exclusion criteria were the presence of numerous systemic comorbidities, oral lesions, the habit of smoking, alcohol consumption, and X-rays or CT scans taken within 15 days prior to sample collection. A gentle scraping was performed on the inner portion of the jugal mucosa on both sides. A total of 2,000 cells per slide were analyzed for the determination of mutagenicity parameters as follows: micronuclei, binucleation, and nuclear buds. For measuring cytotoxicity, the following metanuclear changes were evaluated: pyknosis, karyolysis, and karyorrhexis, in a double-blind manner. The repair index was also evaluated in this setting. RESULTS: The human immunodeficiency virus group showed high frequencies of micronuclei (p=0.05), binucleated cells (p=0.001), and nuclear buds (p=0.03). In the cytotoxicity parameters, represented by the cell death phases, there was an increase with statistical difference (p≤0.05) in the karyorrhexis frequency (p=0.05). Additionally, repair index was decreased in the human immunodeficiency virus group. CONCLUSION: These results indicate that human immunodeficiency virus -infected individuals undergoing antiretroviral therapy have cytogenetic changes in oral mucosal cells.

The use of micronucleus assay in exfoliated oral cells in patients undergoing fixed orthodontic therapy: a systematic review with meta-analysis

Abstract The aim of this systematic review was to evaluate published papers regarding the micronucleus assay in oral mucosal cells of patients undergoing orthodontic therapy (OT). A search of the scientific literature was made in the PubMed, Scopus, and Web of Science databases for all data published until November, 2021 using the combination of the following keywords: "fixed orthodontic therapy," "genetic damage", "DNA damage," "genotoxicity", "mutagenicity", "buccal cells", "oral mucosa cells," and "micronucleus assay". The systematic review was designed according to the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines. Nine studies were retrieved. Some authors demonstrated that OT induces cytogenetic damage in oral mucosal cells. Out of the nine studies included, two were classified as strong, five as moderate, and two as weak, according to the quality assessment components of the Effective Public Health Practice Project (EPHPP). Meta-analysis data revealed no relationship between mutagenicity in oral cells and OT in different months of treatment. At one month, the SMD = 0.65 and p = 0.08; after three months of OT, the SMD = 1.21 and p = 0.07; and after six months of OT, the SMD = 0.56 and p = 0.11. In the analyzed months of OT, I2 values were >75%, indicating high heterogeneity. In summary, this review was not able to demonstrate that OT induces genetic damage in oral cells. The study is important for the protection of patients undergoing fixed OT, given that mutagenesis participates in the multi-step process of carcinogenesis.

Cytogenetic changes in oral mucosa cells from individuals submitted to oral human immunodeficiency virus pre-exposure prophylaxis use

SUMMARY OBJECTIVE: The objective of this study was to evaluate cytogenetic changes in individuals submitted to oral human immunodeficiency virus pre-exposure prophylaxis use through the micronucleus test in oral mucosa. METHODS: This study consisted of 37 individuals, of whom 17 comprised the pre-exposure prophylaxis group and 20 comprised the control group. A total of 2,000 cells per slide were analyzed for the determination of micronuclei, binucleation, nuclear buds, and cytotoxicity parameters: pyknosis, karyolysis, and karyorrhexis (KR), in a double-blind manner. The repair index was also evaluated in this setting. RESULTS: In the mutagenicity parameters, the pre-exposure prophylaxis group showed increased frequencies of micronuclei (p=0.0001), binucleation (p=0.001), and nuclear buds (p=0.07). Regarding the cytotoxicity parameters, there was an increase with a statistical difference (p≤0.05) in the karyorrhexis frequency (p=0.001). Additionally, the repair system efficiency decreased in the pre-exposure prophylaxis group. CONCLUSION: These results indicate that individuals undergoing pre-exposure prophylaxis use have geno- and cytotoxicity in oral mucosal cells.

Evaluation of Genotoxic and Cytotoxic Effects of Gluten in Male Albino Mice

Gluten is a protein commonly found in daily diets in the form of wheat, barley, rye, and other grains. It serves as the structural component in flour, providing the binding qualities that maintain the shape and texture of food items. This study aimed to investigate the genotoxic and cytotoxic effects of gluten on bone marrow chromosomes and DNA of male albino mice. The animals were divided into four groups: a control group, a negative control group that received an oral dose of 0.02M glacial acetic acid, and two groups that were treated with gluten dissolved in 0.02M glacial acetic acid at doses of 1.5 g/kg and 3.0 g/kg body weight. The treated animals received oral doses with non-consecutively three times a week for a period of four weeks. The study evaluated chromosomal aberrations in the bone marrow, micronucleus test, and DNA damage using the comet assay. The results of the study showed that treatment with 1.5 and 3.0g/kg body weight of gluten induced chromosomal aberrations and damage in DNA content, with an increase in the severity of effects at a higher dose of gluten. The chromosomal aberrations seen included deletion, fragment, centromeric attenuation, centric fusion, ring formation, end to end association, chromosomal gap, beaded chromosomes, and polyploidy. The micronucleus test revealed toxicity in the bone marrow, as shown by appearance of micronuclei in polychromatic erythrocytes and a reduction in the ratio of polychromatic erythrocytes. The comet assay showed a significant increase of DNA damage in the tail length of the comet cells. This study concluded that the treatment with gluten has detrimental effects on the bone marrow chromosomes and DNA of mice, as demonstrated by the increased chromosomal aberrations, micronuclei, and DNA damage observed in the treated mice. So, the use of gluten should be within an acceptable and safe range.

Estudio comparativo de biomonitoreo citogenético en personal veterinario expuesto ocupacionalmente a radiaciones ionizantes mediante el ensayo de micronúcleos con bloqueo de la citocinesis

Introducción: las radiaciones ionizantes (RI) pueden inducir la formación de micronúcleos (MN). La frecuencia de MN se utiliza como biomarcador de daño genético inducido por (RI). Objetivo: evaluar el daño al ADN resultante de la exposición ocupacional a RI en personal de clínicas veterinarias o afines. Metodología: se utilizó el ensayo de micronúcleos con bloqueo de la citocinesis (MNBC) para comparar la frecuencia observada del biomarcador en 40 individuos expuestos ocupacionalmente a RI con respecto a un grupo control de 32 participantes, ambos grupos pertenecen a personal veterinario. Además, se registraron variables demográficas, de estilo de vida y ocupacionales que pudieran influir en la formación de MN. Resultados: el análisis univariado no registró diferencias significativas en la frecuencia de MN entre los grupos de estudio (p=0,118). Mediante análisis multivariado se obtuvo que aproximadamente un 27% (R2 ajustado= 0,269) de la variabilidad de la frecuencia de MN puede explicarse por la influencia conjunta de la edad, el sexo y el número de radiografías realizadas por el individuo. La edad es la variable de mayor importancia relativa (β = 0,504), seguida del sexo del participante (β = -0,316) y el número de radiografías realizadas por día (β = 0,214). Conclusiones: La frecuencia de MN tiende a aumentar en mujeres, a medida que aumenta la edad del participante y a mayor número de radiografías realizadas.

Introduction: Ionizing radiation (RI) can induce the formation of micronuclei (MN). The formation of MN is used as a biomarker of radiation-induced genetic damage. Objective: assess DNA damage resulting from occupational exposure to RI in veterinary personnel. Methodology: the cytokinesis-block micronucleus assay (MNBC) was used to compare the observed frequency of MN in 40 individuals occupationally exposed to ionizing radiation with respect to a control group of 32 participants, both groups belonging to veterinary personnel. In addition, demographic, lifestyle and occupational variables that could influence the formation of MN were recorded. Results: univariate analysis did not show significant differences in the frequency of MN between the study groups (p=0.118). Using multivariate analysis, it was found that approximately 27% (adjusted R2= 0.269) of the variability in the frequency of MN can be explained by the joint influence of age, sex and the number of radiographic images performed by the participant. Age is the variable with the greatest relative importance (β = 0.504), followed by the sex of the participant (β = -0.316) and the number of X-rays performed per day (β = 0.214). Conclusions: the frequency of MN tends to increase in women, as the participant's age increases and as the number of radiographic images performed increases.

Mutagenicity in oral cells of individuals exposed to radiofrequency generated by different smartphones

Aim: This study aimed to investigate whether non-ionizing radiation emitted by smartphones is likely to cause genotoxic effects on oral epithelial cells. Methods: Thirty adults were distributed into two groups according to the mobile phone brand used, namely Samsung (Samsung, Seoul, South Korea) and Apple (Apple, California, USA). The material was collected with gentle swabbing of the right and left buccal mucosa using a cervical brush, then the micronucleus test was performed. Results: The Mann-Whitney test with a 5% significance level did not reveal statistically significant differences in micronuclei frequency between the exposed and non-exposed sides (p=0.251). The different brands do not seem to cause risks of inducing genetic damage because there were no statistically significant differences between them (p=0.47). Conclusion: Therefore, our results suggest no correlations of micronuclei frequency in the exposed buccal cells of mobile phone users at the exposure standard levels observed