Chromosome aberrations (CAs), a genotoxic potential of carcinogens, are believed to contribute to tumorigenesis by chromosomal rearrangements through micronucleus formation. However, there is no direct evidence that proves the involvement of CAs in tumorigenesis in vivo. In the current study, we sought to clarify the involvement of CAs in chemical carcinogenesis using a rat model with a pure CA-inducer hepatocarcinogen, acetamide. Whole-genome analysis indicated that hepatic tumors induced by acetamide treatment for 26-30 weeks showed a broad range of copy number alterations in various chromosomes. In contrast, hepatic tumors induced by a typical mutagen (diethylnitrosamine) followed by a nonmutagen (phenobarbital) did not show such mutational patterns. Additionally, structural alterations such as translocations were observed more frequently in the acetamide-induced tumors. Moreover, most of the acetamide-induced tumors expressed c-Myc and/or MDM2 protein due to the copy number gain of each oncogene. These results suggest the occurrence of chromosomal rearrangements and subsequent oncogene amplification in the acetamide-induced tumors. Taken together, the results indicate that CAs are directly involved in tumorigenesis through chromosomal rearrangements in an acetamide-induced hepatocarcinogenesis rat model.

Humans have been using plants in the treatment of various diseases for millennia. Currently, even with allopathic medicines available, numerous populations globally still use plants for therapeutic purposes. Although plants constitute a safer alternative compared to synthetic agents, it is well established that medicinal plants might also exert adverse effects. Thus, the present investigation aimed to assess the phytotoxic, cytotoxic, and genotoxic potential of two plants from the Brazilian Cerrado used in popular medicine, Davilla nitida (Vahl) Kubitzki, and Davilla elliptica (A. St.-Hil.). To this end, germination, growth, and cell cycle analyses were conducted using the plant model Lactuca sativa. Seeds and roots were treated with 0.0625 to 1 g/L for 48 hr under controlled conditions. The germination test demonstrated significant phytotoxic effects for both species at the highest concentrations tested, while none of the extracts produced significant effects in the lettuce growth test. In the microscopic analyses, the aneugenic and cytotoxic action of D. elliptica was evident. In the case of D. nitida greater clastogenic action and induction of micronuclei, (MN) were noted suggesting that the damage initiated by exposure to these extracts was not repaired or led to apoptosis. These findings indicated that the observed plant damage was transmitted to the next generation of cells by way of MN. These differences in the action of the two species may not be attributed to qualitative variations in the composition of the extracts as both are similar, but to quantitative differences associated with synergistic and antagonistic interactions between the compounds present in these extracts.

Cyto/genotoxicity have been widespread utilized for the safety risk assessment of synthetic/natural chemicals. Plants can protect organisms from harmful effects of xenobiotics. On the other hand, plants can extract toxic molecules from the environment which may disrupt mitosis and cytokinesis. However, the precise role of Cirsium steriolepis during this process is unknown. We showed that steriolepis didn\'t cause cyto/genotoxicity. Findings showed powerful inhibition in micronucleus formation and they are safe for healthy human lymphocytes in terms of their capacity to generate chromosomal aberrations. They caused significant increases in sister chromatid exchange (SCE) compared to control but they were able to decrease SCE frequency caused by H2O2. Additionally, the antibacterial efficiencies of the samples against Escherichia coli and Staphylococcus aureus were up to 50% of the effectivity of penicillin/streptomycin. Steriolepis was able to protect the organism from the oxidative damage and didn\'t affect the normal developmental phases of Drosophila melanogaster.

BACKGROUND: Di(2-ethylhexyl) phthalate (DEHP) is a plasticizer commonly used in a wide variety of products, including medical devices. It is rapidly metabolized in the liver into various metabolites upon absorption through oral ingestion, dermal absorption, and inhalation. DEHP is classified as a non-genotoxic hepatocarcinogen in rodents, as its chronic exposure has been associated with the development of liver cancer in these animals, but most genotoxicity studies have been negative. Epidemiologic studies in humans suggest that long-term high intakes of DEHP may be a risk factor for liver dysfunction. The repeated-dose liver micronucleus (RDLMN) assay is a well-established method for assessing chromosomal changes caused by hepatic genotoxins and/or carcinogens. It is particularly valuable for detecting substances that undergo metabolic activation, especially when the metabolite has a short half-life or does not reach the bone marrow effectively. Therefore, we investigated whether the RDLMN assay could detect DEHP-induced micronucleus formation in the liver following a 14 or 28-day treatment.
RESULTS: We report that the RDLMN assay demonstrated an increased frequency of hepatic micronuclei in rats exposed to DEHP for 14 or 28 days. The increases in micronuclei correlated with hepatomegaly, an established response to phthalates in the liver. Conversely, no such increases were observed in the micronucleus assay using bone marrow from these rats.
CONCLUSIONS: The detection of DEHP-induced micronuclei by the RDLMN assay suggests that this assay could detect the potential genotoxicity and hepatocarcinogenicity of DEHP. It also demonstrated the utility of the RDLMN assay in identifying metabolically activated hepatic carcinogens.

Papillary thyroid carcinoma (PTC) is a common endocrine cancer with a good prognosis. Radioactive iodine is thought to be useful for individuals who have had a total or almost total thyroidectomy, but its effects are still controversial. The effects of radioactive iodine-131 (I-131) treatment on oxidative and chromosomal damage in PTC patients were examined in this study, which was carried out with 16 patients newly diagnosed with PTC and 20 healthy control subjects with similar age and gender. Blood samples were taken from patients with PTC at five sampling times (before total thyroidectomy, after total thyroidectomy, and seven days, six months, and one year after treatment) and from control subjects. The cytokinesis block micronucleus cytome (CBMN-cyt) assay parameters in peripheral blood lymphocytes of patients with PTC and controls were evaluated and plasma 8-hydroxydeoxyguanosine (8-OHdG) levels were measured. Furthermore, genome instability and oxidative DNA damage in peripheral blood lymphocytes and plasma of patients with PTC were evaluated before total thyroidectomy (n=16), after total thyroidectomy (before I-131 treatment) (n=16), seven days (n=10), six months (n=5), and one year after treatment (n=5). The numbers of CBMN-cyt assay parameters (micronucleus; MN and nucleoplasmic bridges; NPB) and 8-OHdG levels in patients with PTC were determined to be significantly higher than in those of the control subjects and these values significantly decreased after total thyroidectomy (before I-131 treatment). While the number of MN, apoptotic, and necrotic cells increased after I-131 treatment, it significantly decreased after six months and one year after treatment. The results achieved in this study suggest that I-131 treatment may pose a threat to cells and that radioactive iodine therapy should be avoided (if possible) for patients with PTC after total thyroidectomy.

The current study aimed to explore the genotoxic impacts of the insecticide acetamiprid (ACP) on the myocardium and assess the ameliorative role of resveratrol (RSV). Male rats (10/group) were treated via oral route for 90 days: control; ACP (25 mg/kg); RSV (20 mg/kg); ACP+RSV. Peripheral blood micronucleus test, oxidative stress analysis, comet assay, 8-hydroxydeoxyguanosine and gene expression assessment were performed. The findings revealed that ACP has myocardial genotoxic effects, as demonstrated by increased micronucleus and 8-hydroxydeoxyguanosine formation and increased all comet parameters. Oxidative stress analysis demonstrated that ACP elevated H2O2 and NO levels while decreasing catalase and GST activities. Acetamiprid dysregulated the expression of genes related to oxidative stress and DNA damage response. However, RSV co-treatment resulted in significant protection against these genotoxic impacts. Resveratrol reduced DNA damage and restored the oxidative balance in the myocardium. Moreover, RSV modulated the Nrf2/HO-1 and Atm/P53 pathways, potentiating antioxidant defense and DNA repair.

The presence of arsenic in the environment is a public health problem. Groundwater of certain regions of Argentina contains arsenic of natural origin in concentrations that exceed the guide level recommended by World Health Organization (WHO, 10 µg/L). Pathologies derived from chronic arsenic consumption justify the planning of human biomonitoring. Hence, the aim of this study was to evaluate oxidative damage and genotoxicity and its relationship with nutritional variables in populations exposed to arsenic through drinking water in Santa Fe province, Argentina. A total of 322 participants were analyzed for arsenic in urine together with biomarkers of genotoxicity (Comet assay in blood and frequency of Micronuclei and other Nuclear Abnormalities in exfoliated buccal cells) and oxidative stress (modified Comet assay with Endonuclease III, Lipid peroxidation and antioxidant enzyme activity), as well as nutritional and biochemical variables. Results showed that 45 % of participants excreted arsenic in the urine. Consumption of water with arsenic, whether currently or previously, was associated with statistically significant increase of oxidative DNA damage and lipid peroxidation. MN in exfoliated buccal cells serve as an early biomarker of genotoxicity and showed significant differences in the current exposed group. Biochemical results indicate dyslipidemias potentially linked to dietary choices, and insufficient intake of fruits and vegetables rich in antioxidants, was also noted. This study advocates risk communication to the population, educators, and health authorities, emphasizing the need for preventive health strategies and improved food education.

The use of effect biomarkers has contributed to the understanding of the sublethal effects of contaminants on different organisms. However, the analysis of genotoxic markers as an indicator of organism and environmental health in sharks is underexplored. Thus, the present study investigated the relationship between the genomic damage frequency in erythrocytes and metal(loid) concentrations in whole blood of three shark species (Galeocerdo cuvier, Negaprion brevirostris and Ginglymostoma cirratum), taking into account climatic seasonality. The results showed that G. cuvier, an apex predator, presented the highest total erythrocyte genomic damage frequencies together with the highest mean whole blood concentrations of Al, Cd, Cr, Fe, Mn, Ni, Pb and Zn. The shark N. brevirostris also presented high levels of metal(loid), indicating a greater susceptibility to these contaminants in species that preferentially feed on fish. In contrast, G. cirratum, a mesopredator, presented the lowest erythrocyte damage frequencies and whole blood metal(loid) concentrations. The presence of micronuclei was the most responsive biomarker, and Al, As and Zn had an important effect on the genomic damage frequencies for all species evaluated. Zn concentration influenced the binucleated cells frequencies and Al concentration had an effect on the total damage and micronuclei frequencies in G. cuvier and N. brevirostris. Binucleated cells and blebbed nuclei frequencies were affected by As concentration, especially in G. cirratum, while showing a strong and positive correlation with most of the metals analyzed. Nonetheless, baseline levels of metal(loid) blood concentrations and erythrocyte genomic damage frequencies in sharks have not yet been established. Therefore, minimum risk levels of blood contaminants concentrations on the health of these animals have also not been determined. However, the high genomic instability observed in sharks is of concern considering the current health status of these animals, as well as the quality of the environment studied.

Genetic toxicity testing assesses the potential of compounds to cause DNA damage. There are many genetic toxicology screening assays designed to assess the DNA damaging potential of chemicals in early drug development aiding the identification of promising drugs that have low-risk potential for causing genetic damage contributing to cancer risk in humans. Despite this, in vitro tests generate a high number of misleading positives, the consequences of which can lead to unnecessary animal testing and/or the abandonment of promising drug candidates. Understanding chemical Mode of Action (MoA) is vital to identifying the true genotoxic potential of substances and, therefore, the risk translation into the clinic. Here we demonstrate a simple, robust protocol for staining fixed, human-lymphoblast p53 proficient TK6 cells with antibodies against ɣH2AX, p53 and pH3S28 along with DRAQ5™ DNA staining that enables analysis of un-lysed cells via microscopy approaches such as imaging flow cytometry. Here, we used the Cytek® Amnis® ImageStream®X Mk II which provides a high-throughput acquisition platform with the sensitivity of flow cytometry and spatial morphological information associated with microscopy. Using the ImageStream manufacturer\'s software (IDEAS® 6.2), a masking strategy was developed to automatically detect and quantify micronucleus events (MN) and characterise biomarker populations. The gating strategy developed enables the generation of a template capable of automatically batch processing data files quantifying cell-cycle, MN, ɣH2AX, p53 and pH3 populations simultaneously. In this way, we demonstrate how a multiplex system enables DNA damage assessment alongside MN identification using un-lysed cells on the imaging flow cytometry platform. As a proof-of-concept, we use the tool chemicals carbendazim and methyl methanesulphonate (MMS) to demonstrate the assay\'s ability to correctly identify clastogenic or aneugenic MoAs using the biomarker profiles established.

Every day, millions of individuals are exposed to formaldehyde (FA) due to its extensive presence and versatile use. Many in vivoand in vitroexperiments revealed that the mechanism of genotoxicity induced by FA exposure is complex yet toxicity upon whole-body exposure (WBE) to FA is less. As teachers, students, and skilled assistants in the health care sectors are also extensively exposed to FA vapors, it might result in genotoxicity. However, the effects of subchronic exposure to FA at low concentrations are not clear. Hence, analysis of the micronucleus (MN) was necessary to study the genetic toxicity triggered by FA in the bone marrow of male and female experimental rats. The present study is a gender- and duration of exposure-based assessment of the geno- and cytotoxicity in bone marrow cells of Wistar rats to study the effect of WBE to 10% FA on polychromatic erythrocytes/normochromatic erythrocytes (PCE/NCE) ratio and micronucleated polychromatic erythrocytes (MnPCE) in experimental rats. The obtained result clearly showed that WBE to FA for 60 days at concentrations between 1 and 1.1 ppm (0, 1, and 1.5 h) induced genotoxic effects in both male and female rats by altering the MnPCE% and significantly increasing the ratio of PCE/NCE (1.07 ± 0.23, 1.20 ± 0.20, 1.22 ± 0.14). The PCE/NCE ratio in male rats was lesser (0.98, 1.12, and 1.18) when compared with female rats (1.17, 1.29, and 1.26) with 0, 1, and 1.5 h exposure, respectively. Thus, the genetic/cellular sensitivity to FA differs among the sexes and also depends on the exposure duration.