Micronucleated Cells Research Articles

Revealing the hidden threats: Genotoxic effects of microplastics on freshwater fish

New evidence regarding the risks that microplastics (MP) ingestion pose to human and wildlife health are being revealed with progress made in ecotoxicological research. However, comprehensive and realistic approaches that evaluate multiple physiological responses simultaneously are still scarce despite their relevance to understand whole-organism effects. To address this information gap, we performed an experiment to assess the effects of MP on freshwater fish physiology from the molecular to the organismal level. Using a model species of global commercial importance (Cyprinus carpio) and MP type (recycling industry fragments), size (range between 125-1000 µm), and two concentrations of environmental relevance (0.75 and 8.25 µg/L). Experimental design included 5 blocks containing 3 treatment levels each one: control, low, and high MP concentration, with 6 fish each aquarium (5 blocks x 3 treatments x 6 fish per aquarium = 90 fish). Our results suggest that, under the experimental conditions applied, MP exposure did not cause adverse effects at the morphological (variation in size of gut), metabolic (variation of standard metabolic rate), or ecological (growth performance) levels. Nonetheless, we observed an increased frequency of micronucleated cells with increasing MP concentration (df = 42, t-value = 3.68, p-value < 0.001), showing the potential genotoxicity of MP, which can clearly harm fish health in long-term. Thus, despite being a highly resistant species, exposure to MP may generate negative effects in juvenile C. carpio at cellular or subcellular levels. Our findings highlight that the manifestation of MP effects may vary over time, emphasizing the need for future studies to consider longer exposure durations in experimental designs.

Genotoxicity and Micronucleus Formation as a Result of Panoramic Radiography in Epithelial Cells of the Buccal Mucosa: A Cross-sectional Study in Adults.

To determine the genetic effects of panoramic radiography on the epithelial cells of the buccal mucosa by examining the micronucleus formation in these cells. In this cross-sectional study, exfoliative cytology samples were prepared from the buccal mucosa of 36 patients immediately before and 10 days after panoramic radiography. The samples were prepared using liquid-based cytology with Papanicolaou staining. The slides were simultaneously evaluated by two expert pathologists and the ratio of the number of cells with micronuclei to the total number of cells on the slide was reported as a percentage. Data analysis was done using paired-samples T test, Pearson's correlation coefficient, and covariance analysis (α = 0.05). The study sample consisted of 24 (66.67%) males and 12 females (33.33%) with a mean (SD) age of 27.36 (8.19) years. The frequency of cells with micronucleus before and after panoramic radiography was not statistically different (p = 0.468). Additionally, the frequency of micronucleated cells was not correlated with age (p = 0.737) and sex (p = 0.211). Panoramic exposure slightly increased the frequency of cells with micronucleus in epithelial cells of the buccal mucosa. However, this increase was not statistically significant.

Image-based identification and isolation of micronucleated cells to dissect cellular consequences.

Recent advances in isolating cells based on visual phenotypes have transformed our ability to identify the mechanisms and consequences of complex traits. Micronucleus (MN) formation is a frequent outcome of genome instability, triggers extensive disease-associated changes in genome structure and signaling coincident with MN rupture, and is almost exclusively defined by visual analysis. Automated MN detection in microscopy images has proved extremely challenging, limiting unbiased discovery of the mechanisms and consequences of MN formation and rupture. In this study we describe two new MN segmentation modules: a rapid and precise model for classifying micronucleated cells and their rupture status (VCS MN), and a robust model for accurate MN segmentation (MNFinder) from a broad range of microscopy images. As a proof-of-concept, we define the transcriptome of non-transformed human cells with intact or ruptured MN after inducing chromosome missegregation by combining VCS MN with photoactivation-based cell isolation and RNASeq. Surprisingly, we find that neither MN formation nor rupture triggers a unique transcriptional response. Instead, transcriptional changes are correlated with increased aneuploidy in these cell classes. Our MN segmentation modules overcome a significant challenge to reproducible MN quantification, and, joined with visual cell sorting, enable the application of powerful functional genomics assays, including pooled CRISPR screens and time-resolved analyses of cellular and genetic consequences, to a wide-range of questions in MN biology.

Comparative analysis of chlorhexidine and listerine mouthwashes on buccal cell health: A clinical and cytological investigation

Mouthwashes are used routinely as adjunct to scaling and root planing. Chlorhexidine mouthwash is known as gold standard while Listerine is a widely used essential oil mouthwash. This study was done to evaluate and compare the genotoxic effect of Listerine with Chlorhexidine mouthwash on buccal cells.It was a parallel design study with 20 participants in each group (Group 1: Chlorhexidine mouthwash and Group 2: Listerine mouthwash). Gingival index was recorded and buccal cells scraping were taken at baseline and 3 weeks after use of respective mouthwashes. The buccal cells were assessed for cytotoxicity using micronuclei test (under microscope at 100 x magnification) using Papanicolaou Stain.There was a statistically significant reduction seen in gingival index from baseline to 3 weeks in both the groups (p&amp;#60; 0.001). There was a statistically significant increase in micronuclei count and number of Micronucleated cells in both the groups from baseline to 3 weeks (p&amp;#60; 0.001). The intergroup analysis showed highly significant increase in micronuclei and Micronucleated cells numbers in Chlorhexidine mouthwash group as compared to Listerine group (p&amp;#60; 0.001).After a 3 weeks exposure, Listerine mouthwash showed less cytotoxicity on buccal cells as compared to Chlorhexidine mouthwash.

Application of image-recognition techniques to automated micronucleus detection in the in vitro micronucleus assay

BackgroundAn in vitro micronucleus assay is a standard genotoxicity test. Although the technique and interpretation of the results are simple, manual counting of the total and micronucleus-containing cells in a microscopic field is tedious. To address this issue, several systems have been developed for quick and efficient micronucleus counting, including flow cytometry and automated detection based on specialized software and detection systems that analyze images.ResultsHere, we present a simple and effective method for automated micronucleus counting using image recognition technology. Our process involves separating the RGB channels in a color micrograph of cells stained with acridine orange. The cell nuclei and micronuclei were detected by scaling the G image, whereas the cytoplasm was recognized from a composite image of the R and G images. Finally, we identified cells with overlapping cytoplasm and micronuclei as micronucleated cells, and the application displayed the number of micronucleated cells and the total number of cells. Our method yielded results that were comparable to manually measured values.ConclusionsOur micronucleus detection (MN/cell detection software) system can accurately detect the total number of cells and micronucleus-forming cells in microscopic images with the same level of precision as achieved through manual counting. The accuracy of micronucleus numbers depends on the cell staining conditions; however, the software has options by which users can easily manually optimize parameters such as threshold, denoise, and binary to achieve the best results. The optimization process is easy to handle and requires less effort, making it an efficient way to obtain accurate results.

Soil Contamination and Biomarkers in Ucides cordatus in Mangroves from Baía de Todos os Santos, Bahia, Brazil

The aim of the present study was to analyze the response to exposure to pollutants (trace elements and organic pollutants) using biomarkers (micronucleated cells and glutathione S-transferase and catalase activity) in uçá crab Ucides cordatus. The study was carried out at four sites: Cacha Prego (CP) and Ponta Grossa (PG), areas with low anthropic activity; and Ilha de Maré (IM) and Pitinga (PT), areas affected by industrial activity. At each site, soil and crab samples were collected to analyze the contents of potentially toxic elements (total concentration and chemical partitioning of trace elements), polycyclic aromatic hydrocarbons (PAHs), and polychlorinated biphenyls (PCBs). Both total concentrations and geochemical fractions of Cu, Zn, and Ni in soils were significantly higher in IM. Likewise, higher reactive Pb contents were observed in mangroves both in IM and in PG. Values above quality limits were observed for organic pollutants (PAHs) in soils from CP and PT, while PCB contents were below the maximum permissible levels. Metals in crabs also showed spatial variations, with higher Cu concentrations in all tissues in IM and PT and higher Ni concentrations in hepatopancreas in PT during the dry season. PAH values in crabs did not show spatial variations; however, crustaceans with contents above maximum limits in their muscle tissue were found in CP. Crabs from the Baia de Todos Santos showed different responses in biomarker expression, with higher enzymatic activity and greater numbers of micronucleated cells in crabs from IM, suggesting oxidative stress and genotoxicity in this mangrove forest.

AurkA/TPX2 co-overexpression in nontransformed cells promotes genome instability through induction of chromosome mis-segregation and attenuation of the p53 signalling pathway

The Aurora-A kinase (AurkA) and its major regulator TPX2 (Targeting Protein for Xklp2) are key mitotic players frequently co-overexpressed in human cancers, and the link between deregulation of the AurkA/TPX2 complex and tumourigenesis is actively investigated. Chromosomal instability, one of the hallmarks of cancer related to the development of intra-tumour heterogeneity, metastasis and chemo-resistance, has been frequently associated with TPX2-overexpressing tumours. In this study we aimed to investigate the actual contribution to chromosomal instability of deregulating the AurkA/TPX2 complex, by overexpressing it in nontransformed hTERT RPE-1 cells. Our results show that overexpression of both AurkA and TPX2 results in increased AurkA activation and severe mitotic defects, compared to AurkA overexpression alone. We also show that AurkA/TPX2 co-overexpression yields increased aneuploidy in daughter cells and the generation of micronucleated cells. Interestingly, the p53/p21 axis response is impaired in AurkA/TPX2 overexpressing cells subjected to different stimuli; consistently, cells acquire increased ability to proliferate after independent induction of mitotic errors, i.e. following nocodazole treatment. Based on our observation that increased levels of the AurkA/TPX2 complex affect chromosome segregation fidelity and interfere with the activation of a pivotal surveillance mechanism in response to altered cell division, we propose that co-overexpression of AurkA and TPX2 per se represents a condition promoting the generation of a genetically unstable context in nontransformed human cells.

Micronuclei as an indicator of genotoxic change in epithelial cells of buccal mucosa after panoramic radiographs.

The radiation released at the time of dental panoramic radiographs causes genotoxic and cytotoxic effects on epithelial cells. This research aimed to evaluate the changes in the frequencies of micronucleated cells in patients' buccal epithelial cells following dental panoramic radiography. 74 patients were recruited for the study who were advised for panoramic radiographs. Using a wooden spatula, the buccal epithelial cells were scraped from both cheeks before to panoramic radiation exposure and ten days after the panoramic radiation exposure. Giemsa stain was used to stain the cells, and 500 cells were scored on a slide to determine the frequency of micronuclei. To determine the difference between the frequency of micronuclei before and after radiation exposure, a paired t-test was used in the statistical analysis. The proportion of micronuclei cells was 0.11% before radiation exposure and 0.57% following radiation exposure after 10 days. A statistically significant increase in the frequencies of micronuclei was noted after radiation exposure values. This study revealed the genotoxicity of epithelial cells with dental panoramic radiation exposure. It is advised to reduce the use of such radiographs and to use only when there is no other diagnostic tool that is helpful or when absolutely essential.

Exploratory Study on Micronuclei and Metanuclear Abnormalities in Exfoliated Buccal Cells of COVID-19 Suspected Patients.

SARS-CoV-2 virus causes COVID-19 by infecting nasal and oral cavities primarily by attaching its spike proteins to ACE 2 receptors expressed in epithelial cells. This study was done to evaluate the micronucleated cell count, metanuclear abnormalities, and genotoxic factor in exfoliated buccal mucosal cell among the COVID-19 suspected patients. This cross-sectional study was conducted at AIIMS, Mangalagiri, between August and October 2022. One hundred COVID-19 suspected patients were recruited for this study after obtaining informed and written consent; buccal smear was obtained and stained for papanicolaou test (PAP). The PAP-stained slides were analyzed for micronuclei (MN), pyknotic, karyolytic, and karyorrhexic cell count, respectively. Based on their reverse transcription-polymerase chain reaction (RT-PCR) report, the patients were grouped into COVID-19 positive and negative groups. The genotoxicity factor was calculated using the micronucleated cell count from both the groups using mean and standard deviation. The MN, micronucleated cell, pyknotic, karyolitic, and karyorrhexic cell count in COVID-19 positive patients were 24.12, 15.24, 3.08, 2.88 and 4.40, respectively, than COVID-19 negative patients 5.69, 8.17, 1.08, 1.00 and 2.43, respectively. The genotoxicity factor for SARS-CoV-2 was 2.68 which is a positive genotoxic effect on buccal mucosal cells. SARS-CoV-2 increases the expression of micronucleated cells, pyknotic cells, karyolytic cells, and karyorhexic cells and concludes SARS-CoV-2 is having cytogenotoxic effect on the buccal mucosal cells. This can be used as a reliable marker in identifying the early carcinogenic effects of virus causing COVID-19.

Immune boosting and ameliorative properties of aqueous extract of Vernonia amygdalina Delile against MSG-induced genotoxicity: An in silico and in vivo approach

Vernonia amygdalina (VA) is popularly consumed as food and as medicine due to its nutritional and bioactive constituents. This study assessed the anti-genotoxic effect of aqueous leaf extract of VA against monosodium (MSG) –induced genotoxicity. Crude extraction and phytochemical analysis were done using standard methods. In silico studies was done using compounds in the extract against Bcl-2, NF-kB 50, DNA polymerase lambda, DNA ligase, superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX). Twelve rats were divided into three groups with four rats in each group. Group I was fed on food and water, group II received MSG (4 g/kg) per body weight (pbw) intraperitoneally, group III received MSG (4 g/kg) pbw intraperitoneally followed by oral dose of VA leaf extract (250 mg/kg) per body weight. The number of the micronucleated red blood cells and white blood cells were determined from blood smears microscopically. Results showed that aqueous extract of VA contained in mg/100 g alkaloids (7.04 ± 0.16), saponins (3.91 ± 0.13), flavonoid (1.64 ± 0.16), phenol (3.40 ± 0.12) and tannins (0.07 ± 0.32). In silico studies revealed high binding interaction (ΔG > −8.6) of vernoniosides D and E with all the tested proteins. There was a reduction in the number of micronucleated cells, neutrophils and eosinophils of the treated group compared to the MSG group, while there was an increase in the lymphocyte count. The anti-genotoxic effects of VA leaf extract might be attributed to the synergistic interaction of the various bioactive components in the extract. VA could be a potential plant for the prevention of cancer and other diseases that attenuate the immune system.

Single versus intermittent cycle exposure effect of 6-mercaptopurine in juvenile Sprague-Dawley rat: a germ cell-specific mechanistic study.

Infertility is a frequent long-term adverse effect of cancer therapy for children. Compromised testicular functions in adolescence are frequent observations after chemotherapy and there are currently no well-established alternatives to avoid this damage. Antimetabolites such as 6-mercaptopurine (6-MP) are used to treat a variety of cancer; however, its treatment-associated adverse effects on the male reproductive functions are overlooked. Here, the molecular processes underlying 6-MP-induced male germ cell damage in juvenile Sprague-Dawley (SD) rats (3weeks) have been investigated. Rats were administered with low (5mg/kg), medium (10mg/kg), and high (20mg/kg) doses of 6-MP per orally either singly (1week × 1 cycle) or intermittently (1week treatment followed by 1week remission period × 3 cycles). The toxicity was evaluated in terms of genotoxicity and testes- and sperm-related cellular and molecular parameters. Single cycle of exposure either produced mild or no toxic manifestations at the end of the 6th week. Intermittent cycles of exposure, particularly at the 10 and 20mg/kg, decreased body and organ weights, increased micronucleated cells in the peripheral blood, induced oxidative/nitrosative stress, altered sperm chromatin quality, reduced serum testosterone and follicle stimulating hormone (FSH) levels, increased testicular structural aberrations, DNA damage, and apoptosis, and upregulated TNF-α expression and downregulated p-AMPK and β-catenin expressions. Conclusively, intermittent cycles of exposure at 10 and 20mg/kg doses to the juvenile rats significantly induced oxidative stress, genotoxicity, and cellular and molecular perturbations in the testes and sperm of adult rats.

Screening the micronucleus assay for reliable estimation of the genotoxicity of graphene and other 2D materials

In recent years, the genotoxicity of graphene-related materials (GRMs) and other 2D materials has been evaluated using different models to ensure their safety. The OECD TG 487 in vitro micronucleus (MNu) test is one of the most widely used methods to assess the genotoxicity of nanomaterials (NMs). However, the nature of NMs interferes with the standard MNu process, thus requiring an adaptation to assess this kind of compound. Improvements have been incorporated into the standard method to solve the interferences and build a modified, reliable protocol that can be used to test NMs further. The main interference observed was NM agglomeration, which hinders the correct visualization of micronuclei. Addition of 10% dextran to the culture medium reduced agglomeration but interfered with toxicity by reducing NM-induced cell death. Mechanical shaking during cell incubation with NMs minimized the size and number of agglomerates and avoided their rapid sedimentation and deposition onto cells, thus allowing accurate visualization of the micronucleate cells. Once set up, the proposed method was tested with graphene oxide (GO), few-layer graphene (FLG), molybdenum disulfide (MoS2), and boron nitride (hBN). The novel in vitro MNu test for NMs showed that GO (0.05–5 μg/ml) and hBN (0.05 μg/ml) were genotoxic at sublethal doses, inducing irreparable chromosomal damage. With these adaptations, the modified in vitro MNu test is strongly recommended to test the genotoxicity of NMs. The results obtained with this protocol indicate that GO and hBN represent a risk that should be considered.

Evaluation of In Vitro Genotoxicity of Polystyrene Nanoparticles in Human Peripheral Blood Mononuclear Cells.

According to the trade association PlasticEurope, global plastics production increased to 390.7 million tons in 2021. Unfortunately, the majority of produced plastics eventually end up as waste in the ocean or on land. Since synthetic plastics are not fully biodegradable, they tend to persist in natural environments and transform into micro- and nanoplastic particles due to fragmentation. The presence of nanoplastics in air, water, and food causes ecotoxicological issues and leads to human exposure. One of the main concerns is their genotoxic potential. Therefore, this study aimed to evaluate the internalization rates, cytotoxicity, and genotoxicity of polystyrene nanoparticles (PS-NPs) in human peripheral blood mononuclear cells (PBMCs) in vitro. The uptake of PS-NPs was confirmed with flow cytometry light scattering analysis. None of the tested nanoparticle concentrations had a cytotoxic effect on human PBMCs, as evaluated by a dual ethidium bromide/acridine orange staining technique. However, an alkaline comet assay results revealed a significant increase in the levels of primary DNA damage after 24 h of exposure to PS-NPs in a dose-dependent manner. Moreover, all tested PS-NPs concentrations induced a significant amount of micronucleated cells, as well. The results of this study revealed the genotoxic potential of commercially manufactured polystyrene nanoparticles and highlighted the need for more studies with naturally occurring plastic NPs.

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 &lt; 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.

Fate of micronuclei and micronucleated cells after treatment of HeLa cells with different genotoxic agents

Although micronuclei are well-known biomarkers of genotoxic damage, the biological consequences of micronucleus induction are only poorly understood. To further elucidate these consequences, HeLa cells stably expressing histone 2B coupled with green fluorescent protein were used for long-term live cell imaging to investigate the fate of micronuclei and micronucleated cells after treatment of cells with various genotoxic agents (doxorubicin (20, 30 and nM), tert-butyl hydroperoxide (tBHP, 50, 100 and 150 µM), radiation (0.5, 1 and 2 Gy), methyl methanesulfonate (MMS, 20, 25 and 30 µg/ml) and vinblastine (1, 2 and 3 nM)). Most micronuclei persist for multiple cell cycles or reincorporate while micronucleated cells were more prone to cell death, senescence and fatal mitotic errors compared to non-micronucleated cells, which is consistent with previous studies using etoposide. No clear substance-related effects on the fate of micronuclei and micronucleated cells were observed. To further investigate the fate of micronuclei, extrusion of micronuclei was studied with treatments reported as inducing the extrusion of micronuclei. Since extrusion was not observed in HeLa cells, the relevance of extrusion of micronuclei remains unclear. In addition, degradation of micronuclei was analysed via immunostaining of γH2AX, which demonstrated a high level of DNA damage in micronuclei compared to the main nuclei. Furthermore, transduction with two reporter genes (LC3B-dsRed and LaminB1-dsRed) was conducted followed by long-term live cell imaging. While autophagy marker LC3B was not associated with micronuclei, Lamin B1 was found in approximately 50% of all micronuclei. While degradation of micronuclei was not observed to be a frequent fate of micronuclei, the results show impaired stability of DNA and micronuclear envelope indicating rupture of micronuclei as a pre-step to chromothripsis.

Hematological, Genotoxic and Oxidative Stress Response in Oreochromis niloticus (Nile Tilapia) Exposed to Varying Concentrations of Ethanolic Extract of Commelina benghalensis

This study evaluated the hematological, genotoxic and oxidative stress biomarkers of Oreochromisniloticus exposed to different concentrations of ethanolic extract of Commelina benghalensis(Dayflower). Sublethal exposure at 1% and 10% LC50 was done for twenty-one (21) days with physico-chemical parameters of cultured water and behavioral responses assessed. Hematological; genotoxic; antioxidant enzyme and non-enzyme activities studies were analyzed using standard methods. Results showed increase in the levels of Red blood cells; heamoglobin and white blood cells across extract concentrations compared to control. The number of micronucleated cells increased compared to control; though not significant difference (p&gt;0.05). Superoxide dismutase (SOD); reduced glutathione (GSH) and glutathionde-S-transferase (GST) activities were inhibited by the plant extract; while the level of lipid peroxidation as expressed by malondialdehyde (MDA) increased compared to control. Skin colour change; erratic swimming and mortality were observed at both higher concentration (10%) and lower concentration (1%) of the extract; though behavioral response at 10% extract concentration was higher than 1% extract concentration. In conclusion; the plant C.benghalensis has the potential to exert stress and promote cellular damage in contrast to its ability to boost the blood status of O. niloticus at varying concentration.

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.