Frequency Of Micronucleated Cells Research Articles

Development of a micronucleus test using the EpiAirway™ organotypic human airway model

BackgroundThe use of organotypic human tissue models in genotoxicity has increased as an alternative to animal testing. Genotoxicity is generally examined using a battery of in vitro assays such as Ames and micronucleus (MN) tests that cover gene mutations and structural and numerical chromosome aberrations. At the 7th International Workshop on Genotoxicity Testing, working group members agreed that the skin models have reached an advanced stage of maturity, while further efforts in liver and airway models are needed [Pfuhler et al., Mutat. Res. 850–851 (2020) 503135]. Organotypic human airway model is composed of fully differentiated and functional respiratory epithelium. However, because cell proliferation in organotypic airway models is thought to be less active, assessing their MN-inducing potential is an issue, even in the cytokinesis-blocking approach using cytochalasin B (CB) [Wang et al., Environ. Mol. Mutagen. 62 (2021) 306–318]. Here, we developed a MN test using EpiAirway™ in which epidermal growth factor (EGF) was included as a stimulant of cell division.ResultsBy incubating EpiAirway™ tissue with medium containing various concentrations of CB, we found that the percentage of binucleated cells (%BNCs) almost plateaued at 3 μg/mL CB for 72 h incubation. Additionally, we confirmed that EGF stimulation with CB incubation produced an additional increase in %BNCs with a peak at 5 ng/mL EGF. Transepithelial electrical resistance measurement and tissue histology revealed that CB incubation caused the reduced barrier integrity and cyst formation in EpiAirway™. Adenylate kinase assay confirmed that the cytotoxicity increased with each day of culture in the CB incubation period with EGF stimulation. These results indicated that chemical treatment should be conducted prior to CB incubation. Under these experimental conditions, it was confirmed that the frequency of micronucleated cells was dose-dependently increased by apical applications of two clastogens, mitomycin C and methyl methanesulfonate, and an aneugen, colchicine, at the subcytotoxic concentrations assessed in %BNCs.ConclusionsWell-studied genotoxicants demonstrated capability in an organotypic human airway model as a MN test system. For further utilization, investigations of aerosol exposure, repeating exposure protocol, and metabolic activation are required.

Evaluation of Respiratory, Genotoxic and Cytotoxic Effects from Occupational Exposure to Typography Activities

This cross-sectional study was structured to allow the evaluation of the respiratory, genotoxic, and cytotoxic effects of occupational exposure to products resulting from the activity of printers in typographies and, to determine the risk of genotoxicity associated with such exposure. This study comprised 69 subjects, 25 individuals occupationally exposed to the products of typographies (study group), and 44 individuals non-exposed to the environment studied (reference group). The frequency of micronucleated cells and other nuclear anomalies (binucleated, karyolitic, pyknotic, and karyorrhectic cells) in the oral epithelia of each subject were analyzed. The frequency of micronucleated cells was significantly higher in the study group when compared to the reference one (12.96 MN/2000 cells vs. 4MN/2000 cells, respectively). Occupational exposure to products of typography is a risk factor for the occurrence of micronucleated cells in the study group (RR = 3.2; 95% CI, 2.7–3.9; p < 0.001). The results of the spirometry test did not reveal significant respiratory effects between the reference and study groups.

Use of liquid-based cytology samples reveals genomic instability and cell death in patients undergoing orthodontic treatment.

To examine the use of liquid-based exfoliative cytology to determine the presence of genomic instability and cell death in the oral mucosa of patients with orthodontic appliances. Fifty-four oral mucosa samples were collected from 18 patients and divided into three stages: T0, before fixation of orthodontic appliances; T1, 25 days after appliance fixation; T2, 90 days after appliance fixation. All samples were Papanicolaou-stained and observed by microscopy (1,000 cells/sample) to ascertain the frequency of micronucleated cells (MN) and nuclear abnormalities (nuclear buds (NB), binucleated (BN), condensed chromatin (CC), karyorrhexis (KR), and karyolysis (KL)). Differences were analyzed statistically using the Mann-Whitney, Wilcoxon, Kruskal-Wallis and chi-squared tests. After placement of orthodontic appliances, significant differences were observed for genomic instability biomarkers (MN and NB) and cell death (CC, KR and KL) (P < 0.05). Female patients and older patients exhibited a higher frequency of MN. Liquid-based cytology has revealed that orthodontic appliances induce genomic instability and cell death in epithelial tissue of the oral mucosa, facilitating sample preservation and yielding more than one preparation per sample. Future studies should investigate whether such cell damage can be reversed through cell repair or whether cell alterations evolve and lead to disease.

Protective Effect of Protocatechuic Acid in Genotoxicity-Induced by Carbon Tetrachloride: A Preliminary Study

Carbon tetrachloride (CCl4) is commonly utilized as a solvent, a refrigerant, and a dry-cleaning agent. However, its genotoxic effect has been well documented. The present work was designed to assess the genotoxic effect of carbon tetrachloride in the bone marrow of rats. The safety and the possible protective effect of protocatechuic acid (PCA) in the genotoxicity induced by carbon tetrachloride (CCl4) were evaluated using a micronucleus assay. Rats were divided into six groups where groups I and II served as the control. Group III was exposed to CCl4 only at 3mL/kg intraperitoneally. Groups IV and V rats were pretreated with PCA at 10mg/kg and 20 mg/kg respectively before administering CCl4. Group VI received PCA only (20mg/kg) for 7 consecutive days. At the end of the experiment, a micronucleus assay was carried out. There was a significant MnPCE in the bone marrow of CCl4-treated rats as compared with control (p&lt;0.05). The administration of PCA at the doses of 10 and 20mg/kg significantly reduced the MnPCE when compared with the group treated with CCl4 (3ml/kg) only (p&lt;0.05). The data provided in this study considered PCA to be relatively safe, non-genotoxic and can modulate the genetic damage involved in CCl4 toxicity by decreasing the frequency of micronucleated cells.

Assessing the genotoxicity of oral zinc oxide nanoparticle administration in male rats using micronuclei and comet assay

Zinc oxide nanoparticles (ZnO-NPs) are regularly utilized in the food and fertilizers industries. In our investigation, rats received oral administration of ZnO NPs with a particle size of 30±5 nm once daily at doses of 100, 200, 300, 400, and 600 mg/kg for ten weeks in order to assess the genotoxic effect. Impacts on hematological markers, genotoxic impact, and growth were investigated. The findings showed that ZnO-NPs significantly reduced body weight gain, red blood cell count (RBC), hemoglobin concentration (Hb), hematocrit value (HCT), and platelet count (PLT), while increasing white blood cell (WBC), mean capsular volume (MCV), mean capsular hemoglobin (MCH), and mean capsular hemoglobin concentration (MCHC) in the treated rats. Our results for the comet assay and micronuclei test show a dosage-dependent increase in DNA fragmentation, which was supported by an increase in the percentage of DNA that is tailed, the length and intensity of DNA tails, and the tail moment, especially at the dose of 600 mg/kg. According to the findings, the frequency of micronucleated cells has increased.

Cellular, molecular and genomic alterations in the hatchlings of Labeo rohita after exposure to Triclosan

Triclosan 5-chloro-2-(2, 4-dichlorophenoxy) phenol (TCS) is widely used as a biocide in human and veterinary medicines, personal care products and household articles. To obtain biomarkers for the acute stress of Triclosan, the hatchlings of Labeo rohita were exposed for 96 h to 0.06, 0.067 and 0.097 mg/L TCS. Morphological deformities, cell viability, frequency of micronucleated and aberrant cells, transcriptomic and biomolecular alterations were recorded after exposure and a depuration period of 10 days. The exposed hatchlings had a pointed head, curved trunk, lean body, deformed caudal fin, haemorrhage, hypopigmentation and tissue degeneration at 0.067 and 0.097 mg/L only. The frequency of viable cells declined but that of necrotic, apoptotic, micronucleated and abnormal cells increased (p ≤ 0.01) in a concentration dependent manner after exposure as well as the depuration period. After recovery, the frequency of viable and micronucleated cells increased, but that of necrotic, apoptotic, and aberrant cells declined in comparison to their respective 96 h values. The mRNA level of HSP47, HSP70, HSc71 and α-tropomyosin increased (p ≤ 0.01), while that of HSP60, HSP90, DHPR, myosin light polypeptide 3, desmin b and lamin b1 declined (p ≤ 0.01) after exposure. Ten days post exposure, a significant increase (p ≤ 0.01) over control was observed in the expression of all the heat shock and cytoskeletal genes and the values (except for HSc71) were higher than the respective 96 h values also. Infrared spectra showed that band area of amide A, amide I, amide II and phospholipids increased significantly (p ≤ 0.01) but peak intensity of lipid, glycogen and nucleic acids decreased after exposure. After recovery, area of the peaks for most of the biomolecules [except lipids (2924–2925, 1455–1457 cm−1) and glycogen (1163–1165 cm−1)] declined significantly over control and 96 h values. Collectively these changes seem to be responsible not only for the onset of paralysis but also for the concentration dependent increase in larval and cellular abnormalities as well as no/sporadic swimming movement in exposed hatchlings. It is evident that HSP60, HSc71, HSP90, α-tropomyosin and DHPR were strongly affected but DHPR can be used as the most sensitive marker for the toxicity of TCS. This is the first study reporting effect of TCS on the selected heat shock and cytoskeletal genes in a single model.

Evaluation of a 4-day repeated-dose micronucleus test in rat glandular stomach and colon using aneugens and non-genotoxic non-carcinogens

BackgroundWe previously developed a rodent gastrointestinal (GI) tract micronucleus (MN) test using the glandular stomach and/or colon, and evaluated this test method using several genotoxic carcinogens (clastogens) and genotoxic non-carcinogens; we demonstrated that this test method could detect genotoxic stomach and/or colon carcinogens with target organ specificity. In the present study, we further evaluated the sensitivity and specificity of the MN test for the rat glandular stomach and colon using three aneugens (colchicine, vinblastine sulfate, and docetaxel hydrate) and two non-genotoxic non-carcinogens (sodium chloride and sucrose).ResultsMale Crl:CD (SD) rats were administered test compounds through clinical administration route (orally or intravenously) for four consecutive days and then examined for the micronucleated cell frequencies in the glandular stomach and colon. We observed that all three aneugens significantly and dose-dependently increased the micronucleated cell frequencies in the stomach and colon. In contrast, neither of the two non-genotoxic non-carcinogens increased the micronucleated cell frequency in these tissues. Notably, an increase in cell proliferation was observed in the glandular stomach of rats administered a stomach toxicant, sodium chloride, but this increase did not affect the induction of micronuclei in the gastric cells.ConclusionsIn the present study, it was demonstrated that the glandular stomach and colon MN tests could detect aneugens as positive and could adequately evaluate non-genotoxic non-carcinogens as negative, including a chemical that enhances cell proliferation. These results provide important evidence supporting good performance of the rat glandular stomach and colon MN tests with a 4-day treatment regimen.

DNA damage as indicator of the environmental vulnerability of bats in Brazil's Caatinga drylands.

Brazil's Caatinga drylands is under extensive environmental deterioration, with 38% of its natural cover already lost. There is a need for a better understanding of the effects of such degradation on Caatinga's rich and singular biota. Bats form a large part of this biota, and are pointed as good bioindicators. Here, we used the micronucleus test-an easy-to-use, accessible and cost-effective in vivo approach-to detect DNA damage in cells from bats of different species and feeding habits in three protected areas in the Caatinga, comparing them with samples from an industrial sugarcane plantation. We hypothesized that environmental disturbance would reflect in DNA damage, with lower levels of damage in the less disturbed protected areas. The frequency of micronucleated cells differed significantly between sites and feeding habits (carnivores > insectivores > frugivores > nectarivores > hematophagous) but did not differ between sexes. Alarmingly, the highest levels of DNA damage were in two strictly protected areas (Seridó and Raso da Catarina Ecological Stations). Glossophaga and Anoura were the genera with more damaged cells, and had, respectively, 1.48 and 3.53 times more micronucleated cells (average of 19.33 and 22.67 cells, respectively) than individuals from the same genera from the area with least damaged cells (average of 7.80 and 5.00 cells, respectively). Our analysis is a warning call for an in-depth investigation on the effects of both genotoxic contamination and environmental stressors on bats and other species in Brazil's Caatinga, including the role that historical human-induced processes-like the intense use of agrochemicals-may have had in the region.

Early Diagnosis of Oral Mucosal Alterations in Smokers and E-Cigarette Users Based on Micronuclei Count: A Cross-Sectional Study among Dental Students.

The presence of micronuclei in oral epithelial cells is considered a marker of genotoxicity, which can be identified using exfoliative cytology. The aim of this study was to investigate cytotoxic damage through the evaluation of micronuclei in the oral mucosa of smokers and e-cigarette users compared to nonsmokers. We obtained smears from the buccal mucosa of 68 participants divided in 3 groups (smokers, e-cigarette users and nonsmokers), which were further processed with Papanicolaou stain. The frequencies of micronuclei and micronucleated cells were recorded and statistically analyzed at a level of significance of p < 0.05. The mean micronuclei values per 1000 cells were 3.6 ± 1.08 for smokers, 3.21 ± 1.12 for e-cigarette users and 1.95 ± 1.05 for nonsmokers. The mean values of micronucleated cells per 1000 cells were 2.48 ± 0.91 for smokers, 2.39 ± 1.07 for e-cigarette users and 1.4 ± 0.68 for nonsmokers. Smokers and e-cigarette users had significantly higher values of micronuclei and micronucleated cells compared to nonsmokers, but there were no significant differences between smokers and e-cigarette users. We concluded that the micronuclei count can be used as an early indicator for alterations of oral mucosa and exfoliative cytology represents an accessible tool which could be applied for mass screening.

Genotoxic effects of Dukhan: A smoke bath from the wood of Acacia seyal used traditionally by Sudanese women

Smoke from the wood of Acacia seyal Delile has been used by Sudanese women for making a smoke bath locally called Dukhan. The ritual is performed to relieve rheumatic pain, smooth skin, heal wounds and achieve general body relaxation. The present study was designed to investigate the in vitro anti-inflammatory effect of the smoke condensate using cyclooxygenase -1 (COX-1) and -2 (COX-2) as well as its potential genotoxic effects using the bacterial-based Ames test and the mammalian cells-based micronucleus/cytome and comet assays. The smoke was prepared in a similar way to that commonly used traditionally by Sudanese women then condensed using a funnel. Cyclooxygenase assay was used to evaluate its in vitro anti-inflammatory activity. The neutral red uptake assay was conducted to determine the range of concentrations in the mammalian cells-based assays. The Ames, cytome and comet assays were used to assess its potential adverse (long-term) effects. The smoke condensate did not inhibit the cyclooxygenases at the highest concentration tested. All smoke condensate concentrations tested in the Salmonella/microsome assay induced mutation in both TA98 and TA100 in a dose dependent manner. A significant increase in the frequency of micronucleated cells, nucleoplasmic bridges and nuclear buds was observed in the cytome assay as well as in the % DNA damage in the comet assay. The findings indicated a dose dependent genotoxic potential of the smoke condensate in the bacterial and human C3A cells and may pose a health risk to women since the smoke bath is frequently practised. The study highlighted the need for further rigorous assessment of the risks associated with the smoke bath practice.

Micronuclei and Other Nuclear Anomalies in Exfoliated Buccal Mucosa Cells in Breast Cancer

Objectives: This study designed to assess the genomic instability between healthy women and women with breast cancer by means of buccal cells micronucleus (MN) cytome assay. Methods: The current study comprised 25 healthy women and 30 breast cancer patients. The exfoliated cells of buccal mucosa were taken after each participants rinse their mouths with tap water. The micronucleated cell and nuclear anomalies were analyzed under a total magnification of X1000, 2000 cells per subjects ( patient and control group) were scored and the frequencies of nuclear anomalies including MN, binucleates (BN), Pycnotic cell, karyolysis (KL) and karyorrhexis (KR) were evaluated in exfoliated buccal mucosa cells of women with primary BC and healthy women. Results: The frequencies of micronuclei and all nuclear anomalies in buccal cells of BC patients were significantly increased compared with the controls. (For Binucleates cells only, p&lt;0.001; in all other cases, P &lt; 0.0001). The mean scores of micronuclei and all nuclear anomalies for the breast cancer patients were (10.66±0.3845, 6.20±0.26, 8.40±0. 22, 18.40±0. 34, 19.13 ±0.40) were significantly higher than that of healthy women). Conclusion: Elevated frequency of micronucleated cells and all nuclear anomalies in the buccal mucosa of breast cancer patients reveal the genomic instability. These findings propose that the buccal MN-cytome assay can be used to measure both genotoxic and cytotoxic effects in primary cancer patients.

Mutagenicity of a novel 2-phenylbenzotriazole (non-chlorinated 2-phenylbenzotriazole-9) in mice.

Dinitrophenylazo dyes can form 2-phenylbenzotriazoles (PBTAs) in the textile dyeing process upon the addition of chemical reducing agents. Some dinitrophenylazo dyes, as well as their respective reduced (non-chlorinated) and chlorinated PBTAs, are now found in rivers owing to wastewater from textile plants. This study aimed to investigate the genotoxicity of a new PBTA derived from C.I. Disperse Violet 93 azo dye, namely non-Cl PBTA-9. Primary DNA damage in the blood, liver, and colon cells, micronucleated cells in the bone marrow, and gene expression (NAT2, CYP1A1, TRP53, and CDKN1A) in liver cells were observed in mice, at acute oral exposure (gavage) doses of 5, 50, and 500 μg/kg body weight (b.w.). The non-chlorinated PBTA-9 caused DNA damage in the blood and liver (at 500 μg/kg b.w.) and in colon cells (at 5, 50, and 500 μg/kg), and increased the frequency of micronucleated cells in the bone marrow (at 5 and 50 μg/kg). No histological alterations or gene expression changes were observed. In conclusion, in vivo exposure to non-chlorinated PBTA-9 induced genetic damage in various rodent tissues, corroborating results previously obtained from the Ames test. Because this compound has been detected in rivers, exposure to humans and biota is a major concern.

Cytotoxicity, genotoxicity, and cellular metal accumulation caused by professionally applied fluoride products in patients with fixed orthodontic appliances: A randomized clinical trial

Corrosion of metal orthodontic appliances caused by professional fluoride products has been recently concerned. Therefore, the objective of this study was to evaluate the cytotoxic and genotoxic effect of these products on buccal mucosal cells from patients wearing fixed orthodontic appliances. A total of 44 patients, aged 12 to 35 years, who began orthodontic treatment with fixed appliances were included in this single-center, prospective, randomized clinical trial. Patients were randomly allocated into 4 parallel groups according to the type of professional fluoride treatment applied after placing the appliances: acidulated phosphate fluoride gel (APF); neutral fluoride gel (NGel); fluoride varnish (FVa); and without fluoride treatment (control). Buccal cells were collected before treatment (T1) and 3 months after appliance placement (T2). The cells were assayed for cell viability and underwent Papanicolaou staining. Cells with micronuclei and degenerative nuclear alterations were scored using a light microscope. Cell metal content was quantified by inductively coupled plasma-mass spectrometry. The data were analyzed with the Kruskal-Wallis test. The intracellular nickel content in the APF group significantly increased (P < 0.05), whereas that of the control, NGel, and FVa groups did not. The changes in chromium concentration in all groups were not significantly different compared with control. Use of APF resulted in a significantly higher decrease in cell viability and increase in morphologic signs of cell death compared with control (P < 0.05). The change in frequency of micronucleated cells was not significantly different from that in the control group. Applying APF gel on fixed orthodontic appliances increased the cell metal content and decreased cell viability; however, genotoxic effects were absent. FVa and NGel are suggested as the products of choice to use during orthodontic treatment.

Roadmap for translating results from the micronucleus assay into clinical practice: From observational studies to randomized controlled trials

According to the definition delivred by the WHO, a biomarker, independently from its role that may be indicative of exposure, response or effect, is inevitably linked to a clinical outcome or to a disease. The presence of a continuum from early biological events to therapy, and prognosis is the unifying mechanism that justifies this conclusion. Traditionally, the technical and inter-individual variability of the assays, together with the long duration between early pathogenetic events and the disease, prevented clinical applications to these biomarkers. These limitations became less important with the emerging of personalized preventive medicine because of the focus on disease prediction and prevention, and the recommended use of all data concerning measurable patient's features. Several papers have been published on the best validation procedures for translating biomarkers to real life. The history of cholesterol concentration is extensively discussed as a reliable example of a biomarker that - after a long and controversial validation process - is currently used in clinical practice. The frequency of micronucleated cells is a reliable biomarker for the pathogenesis of cancer and other non-communicable diseases, and the link with clinical outcomes is substantiated by epidemiological evidence and strong mechanistic basis. Available literature concerning the use of the micronucleus assay in clinical studies is discussed, and a suitable three-levels road-map driving this biomarker towards clinical practice is presented. Under the perspective of personalized medicine, the use of the micronucleus assays can play a decisive role in addressing preventive and therapeutic strategies of chronic diseases. In many cases the MN assay is either currently used in clinical practice or classified as adequate to consider translation into practice. The roadmap to clinical validation of the micronucleus assay finds inspiration from the history of biomarkers such as cholesterol, which clearly showed that the evidence from prospective studies or RCTs is critical to achieve the required level of trust from the healthcare profession. (307 words)

An Integrated Analysis of the Response of Colorectal Adenocarcinoma Caco-2 Cells to X-Ray Exposure.

Colorectal cancer is among the three top cancer types for incidence and the second in terms of mortality, usually managed with surgery, chemotherapy and radiotherapy. In particular, radiotherapeutic concepts are crucial for the management of advanced rectal cancer, but patients’ survival remains poor, despite advances in treatment modalities. The use of well-characterized in vitro cell culture systems offers an important preclinical strategy to study mechanisms at the basis of cell response to therapeutic agents, including ionizing radiation, possibly leading to a better understanding of the in vivo response to the treatment. In this context, we present an integrated analysis of results obtained in an extensive measurement campaign of radiation effects on Caco-2 cells, derived from human colorectal adenocarcinoma. Cells were exposed to X-rays with doses up to 10 Gy from a radiotherapy accelerator. We measured a variety of endpoints at different post-irradiation times: clonogenic survival after ~ 2 weeks; cell cycle distribution, cell death, frequency of micronucleated cells and atypical mitoses, activation of matrix metalloproteases (MMPs) and of different proteins involved in DNA damage response and cell cycle regulation at earlier time points, up to 48 h post-exposure. Combined techniques of flow cytometry, immunofluorescence microscopy, gelatin zymography and western blotting were used. For selected endpoints, we also addressed the impact of the irradiation protocol, comparing results obtained when cells are plated before irradiation or first-irradiated and then re-plated. Caco-2 resistance to radiation, previously assessed up to 72 h post exposure in terms of cell viability, does not translate into a high clonogenic survival. Survival is not affected by the irradiation protocol, while endpoints measured on a shorter time frame are. Radiation mainly induces a G2-phase arrest, confirmed by associated molecular markers. The activation of death pathways is dose- and time-dependent, and correlates with a dose-dependent inhibition of MMPs. Genomic aberrations are also found to be dose-dependent. The phosphorylated forms of several proteins involved in cell cycle regulation increase following exposure; the key regulator FoxM1 appears to be downregulated, also leading to inhibition of MMP-2. A unified molecular model of the chain of events initiated by radiation is proposed to interpret all experimental results.

Cytomorphometry and morphology analysis of human papillomavirus type 16 in liquid-based cervical cytology samples.

Human papillomavirus (HPV) is the main causal factor of cervical carcinoma. HPV 16 is one of the most prominent oncogenic types. We aimed to evaluate the cytomorphometric and morphological alterations caused by HPV 16 in liquid-based cytology (LBC). The Cobas 4800 HPV system was used for the detecting and typing HPV DNA in cervical specimens. In this study, 30 HPV 16 positive and 30 HPV 16 negative cervical samples were evaluated for micronuclei (MN), nonclassical cytologic abnormalities, and the nuclear-to-cytoplasmic ratio. Nuclear and cellular areas were evaluated using image analysis software and the nuclear-to-cytoplasm ratio was calculated. All analyses were performed blinded to the patients' HPV status. Statistical evaluation was carried out using the χ2 and Fisher test; P-values < .05 were considered significant. The frequencies of micronucleated cells and koilocytes were higher in the HPV 16 infected group (P < .05). Cells with perinuclear halo in control group were higher than the HPV 16 infected group (P < .05). The mean nuclear-to-cytoplasm ratio in HPV 16 patients was higher than the control value, but the difference was not statistically significant. LBC can be used to detect morphological and morphometric changes. HPV 16 induces the formation of MN and koilocytosis. The evaluation of MN could provide additional information in monitoring genomic instability and of koilocytes could provide information about damage to the cytoskeleton filaments in HPV infection. Further studies are needed to investigate the effects of HPV-18 and other high-risk HPV types on the cell size and nucleus-to-cytoplasm ratio.

Feeding Habit and Lifestyle Influence the Baseline Micronuclei Frequency of Crab Species in Pristine Mangroves

Metals are harmful inorganic pollutants in aquatic environments when their concentrations are higher than expected (or tolerated) and, in low concentrations, they can lead sublethal genetic injuries. Baseline frequencies of micronucleated cells (MN‰) of three mangrove crab species were established in a pristine mangrove (Jureia-Itatins Ecological Station, JIES). Aratus pisonii, Ucides cordatus and Goniopsis cruentata belong to different functional groups, regarding the diet and lifestyle. Overall, the baseline MN‰ of G. cruentata (1.7 ± 1.2; mean ± sd) was higher than that of A. pisonii (0.9 ± 1.1) and U. cordatus (1.3 ± 0.9). These differences can be explained by the diet (gl, green leaves; sl, senescent leaves; a, animal items; or their combination) and lifestyle of these species, as their degree of contact with abiotic compartments (w, water; s, sediment). Aratus pisonii is an arboreal crab and specialist herbivore, associated with few compartments (w + gl); Ucides cordatus is a digger crab, generalist herbivore, using three compartments (w + s + sl); and Goniopsis cruentata is a cursorial crab, omnivorous, exploring more compartments (w + s + sl + a). Thus, using a broader range of compartments and a more diverse diet were correlated with a higher genotoxicity. Metals in JIES were registered in environmentally safe concentrations but seem to influence the baseline MN‰ in crab species. Higher genotoxicity was registered in species that interact with more compartments (especially the sediment), a fact that should be considered in monitoring processes.

Genotoxic damage evaluation in agricultural workers by exposure to pesticides in Vicente Guerrero-Tlaxcala, Mexico

Pesticides are one of the main inputs in agricultural activities; however, their exposure has been linked to the generation of various health effects. Today, many studies show the ability of pesticides to induce genotoxic damage. The aim of this study was to evaluate the level of genotoxic damage of agricultural workers from Vicente Guerrero-Tlaxcala community, Mexico, exposed to pesticides. The study was composed by 50 agricultural workers from the Vicente Guerrero community and 16 non-exposed individuals. To assess genotoxic damage, the micronucleus (MN) test was applied to exfoliated buccal cell samples by analyzing their frequency and that of other nuclear abnormalities. The agricultural workers showed a frequency of micronucleated cells (P&lt;0,05) and nuclear outbreaks (P&lt;0,05) higher than the control group. The types of pesticides most referred to by the producers were herbicides, belonging to the chemical groups chlorophenoxy and triazine. The exposure time is more than 6 years in more than half of the workers, while the use of personal protective equipment is low. The detected anomalies did not show statistical associations with age, diseases, alcohol, and tobacco consumption. The study revealed that the significant increase in the frequency of MN observed in the exposed group is induced by exposure to pesticides. The application of biomarkers of genotoxicity represents a useful tool to estimate the genetic risk of a population when exposed to a complex mixture of chemicals.

Cytogenesis Effects on Sub-chronic administration of Cypermethrin in Albino Wistar Rats by different Mammalian Bio-assays

The cytogenotoxic effects of cypermethrin on bone marrow cells and lymphocytes of Wistar rats are reported. During four weeks of experimentation, cypermethrin admistration at 1/25th and 1/50th of LD50 by oral intubation showed a dose-dependent increase in the frequency of sister chromatid exchange (SCEs) and micro-nucleated cells. A dose dependent increase in chromosomal aberrations like fragmentation, breakage and gaps in all the treated rats was ovserved. Increased tail length of lymphocytic comets in treated rats revealed that chronic exposure of cypermethrin resulted in carcinogenic and mutagenic effects.

Biomarkers of susceptibility and effect in car painters exposed to organic solvents.

Introduction: Car painters are routinely exposed to organic solvents classified as carcinogenic and mutagenic substances. Objective: To characterize the population susceptibility and evaluate the genotoxic effects of exposure to organic solvents. Methods: A cross-sectional study comparing a group of car painters exposed to organic solvents with a non-exposed group. CYP2E1 polymorphisms and the presence of micronuclei in lymphocytes were determined. Results: One hundred twenty-two workers participated in the study: 62 who worked in car paint shops and were exposed to solvents, and 60 who were not exposed. There were statistically significant differences between the two groups regarding micronucleated cells and nucleoplasmic bridges frequencies (p= 0.042 and p= 0.046, respectively; exact likelihood ratio). Significant differences were found at the interaction between the CYP2E1 genotype c1c1 and occupational exposure to solvents, with higher frequencies of micronuclei (p= 0.013) and micronucleated cells (p= 0.015). However, when the frequencies of micronuclei, micronucleated cells and nucleoplasmic bridges in the exposure group were compared between the c1c1 and c2c2/c1c2 allele groups of the CYP2E1 polymorphism, statistically significant differences were found. Conclusions: This study confirms that when workers with CYP2E1 polymorphisms, specifically the c1c1 genotype, are exposed to organic solvents, they are more likely to have somatic cell mutations, a condition associated with increased susceptibility to diseases such as cancer