Chromosomal Aberration Assay Research Articles

Effects of the DNA repair inhibitors, cytosine arabinoside and 3-aminobenzamide, on the frequency of radiation-induced micronuclei, nuclear buds, and nucleoplasmic bridges.

Micronuclei (MN), nuclear bud (NBud), and nucleoplasmic bridge (NPB) are suggested as biomarkers for radiation exposure; however, they have not been extensively studied to understand the underlying mechanisms responsible for their formation. To (1) validate NBud and NPB within the cytokinesis-blocked micronucleus (CBMN) assay as biomarkers for radiation exposure and (2) determine the effects of the DNA repair inhibitors, cytosine arabinoside (Ara C) and 3-aminobenzamide (3-AB) on radiation-induced MN, NBud, and NPB formation. Human blood samples were irradiated with 0-3Gy X-rays and subsequently treated with Ara C and 3-AB. CBMN and chromosome aberration assays were carried out to measure MN, NBud, and NPB and dicentric chromosomes, respectively. The frequency of radiation-induced MN, NBud, and NPB increased in a dose-dependent manner. The frequency of MN, NBud, and NPB was highly and positively correlated with the dicentric chromosome, a standard biomarker for biodosimetry (r > 0.98, p < 0.0001). Furthermore, Ara C increased the frequency of MN, NBud, and NPB, whereas 3-AB increased the frequency of MN and NPB, but not NBud. Further, the potentiating effect of Ara C on the frequency of MN, NBud, and NPB was greater than that of 3-AB. Our results validate NBuds and NPBs as independent valuable markers of radiation exposure. Additionally, we suggest that different mechanisms are likely involved in the formation of NBuds and NPBs following X-irradiation; however, additional studies are warranted to better understand the contribution of distinct DNA repair pathways to the formation of radiation-induced damages.

Toxicological evaluation of, red rice yeast extract, Xuezhikang: Acute, 26-week chronic and genotoxicity studies

Xuezhikang (XZK), an extract derived from red yeast rice, is commonly employed as a traditional Chinese medicine for treating coronary heart disease, improving endothelial function, decreasing blood lipids and preventing other cardiovascular events both within China and globally. However, there have not been studies of the toxicity associated with XZK. In this publication we hope to summarize and evaluate an acute study, a 26-week chronic toxicity study, and the genetic toxicity potential of XZK. Firstly, Sprague Dawley (SD) rats were treated with XZK at dose of 10 g/kg to observe the acute toxicity. Then, we sought to assess the toxicity of XZK (0, 500, 1000, and 2000 mg/kg) in SD rats for 26 weeks with a 4-week recovery period. Lastly, we assessed the genotoxicity of XZK utilizing an Ames test, chromosomal aberration assay, and mammalian micronucleus test. The results of the acute study, XZK did not induce toxicity up to the maximum doses of 10 g/kg in rats, so an LD50 could not be determined. In the chronic study, XZK administrated via gavage did not alter weight, food intake, urinalysis parameters, hematological analysis parameters, organ weight, organ to weight ratio, microscopic and macroscopic examination of organs. Also, we found no genotoxicity markers at any dose of XZK tested. The results revealed that the no observed adverse effect level (NOAEL) for XZK, based on the 26-week toxicity study, was 2000 mg/kg.

The in vitro cytotoxic, genotoxic, and oxidative damage potentials of the oral artificial sweetener aspartame on cultured human blood cells

Background/aimAspartame (APM, L-aspartyl-L-phenylalanine methylester) is a low-calorie, nonsaccharide artificial sweetener widely used in foods and beverages. When metabolized by the body, APM is broken down into aspartic acid, phenylalanine amino acids, and a third substance, methanol. Since the amino acid phenylalanine serves as a neurotransmitter building block affecting the brain, and methanol is converted into toxic formaldehyde, APM has deleterious effects on the body and brain. Thus, its safety and, toxicity have been the subjects of concern ever since it was first discovered. Although many studies have been performed on it, due to the presence of conflicting data in the literature, there are still numerous question marks concerning APM. Therefore, the safety of aspartame was tested using in vitro methods.Materials and methodsWe aimed to evaluate the in vitro cytotoxic effects by using 3-(4,5-dimetylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and lactate dehydrogenase release tests, genotoxic damage potential by using chromosome aberration (CA) assay, and antioxidant/oxidant activity by using total antioxidant capacity (TAC) and total oxidative stress (TOS) analysis in primary human whole blood cell cultures.ResultsThe results of the MTT test showed that APM led to significant decreases in cell viability in a clear concentration-dependent manner. Moreover, an increase in CA frequency was found in the cells treated with APM. However, APM treatments did not cause any significant changes in TAC and TOS levels in whole blood cultures.ConclusionOverall, the obtained results showed that APM had genotoxicity potential and a concentration-dependent cytotoxic activity in human blood cells.

Mutagenic effect of imidacloprid insecticide: The ameliorative effect of pre and post exposure to olive oil.

Imidacloprid, a systemic chloro-nicotinyl insecticide belong to neonicotinoid insecticides. In this study 120 rats were divided into four groups, the first group used as a control group, the second group was administered imidacloprid at a dose of 22.5mg/kgb.w. for 4, 8, and 12weeks. The third group was treated with olive oil (OLO) in a dose of 10ml/kg body weight for 2weeks before the oral dose of imidacloprid for 4, 8, and 12weeks. The fourth group was given OLO in a dose of 10ml/kgb.w. for 2weeks after exposure to imidacloprid for 4, 8, and 12weeks. Bone marrow was collected for micronucleus and chromosomal aberrations assays. The results revealed that imidacloprid induced a mutagenic effect in the 8th and 12th weeks of exposure and OLO decreased the mutagenic effect of imidacloprid in albino rats but not completely revert them to normal. PRACTICAL APPLICATIONS: Using OLO as a protective or therapeutic agent due to it has an ameliorative effect on mutagenicity induced by IMI.

Genotoxic potential of a novel PDE-4B inhibitor Apremilast by chromosomal aberration and micronucleus assay in mice

ObjectiveResearchers have confirmed that chronic administration of drugs at high doses causes genotoxicity which serve as first step in development of cancers. Apremilast, a phosphodiesterase-4 inhibitor is Food and Drug Administration (FDA) approved drug for Psoriatic Arthritis. The present study designed to conduct genotoxicity testing using the genotoxic study which give simple, sensitive, economical and fast tools for the assessment of damage of genetic material. MethodsTo conduct genotoxicity study of Apremilast, 60 Swiss albino male mice divided into 6 groups (n = 10). Group1 served as a normal control group without any treatment, Group 2 treated as a disease control and administered with cyclophosphamide 40 mg/kg, IP. Group 3, 4, 5 and 6 treated as test groups and received 10, 20, 40 and 80 mg/kg/day Apremilast respectively. The total duration of study was 13 weeks. At termination day animals were sacrificed and chromosomal aberration assay (BMCAA) and micronucleus assay (BMMNA) were performed to know the genotoxicity potential of Apremilast. ResultsThe results indicates significant rise in chromosomal aberrations (CA) frequency in bone marrow cells and decrease in the MI of the disease control animals as well as Apremilast treated groups. Further significant (p < 0.001; p < 0.0001) increase in score of micronucleated polychromatic erythrocytes (MNPCEs) and percentage of micronucleated PCEs per 1000 PCEs and decrease in the ratio of polychromatic/normochromatic erythrocytes (PCE/NCE) was observed in micronucleus assay. Genotoxic effect increases with the increase of Apremilast dose. Conclusion: Finding of present indicates that Apremilast shows genotoxic potential on high administration although further detailed toxicity studies required for confirmations.

In vivo assessment of genotoxic potential of brown shammah (smokeless tobacco) in bone marrow cells of mice

This study was aimed to assess the genotoxicity of brown shammah (BS), a local form of smokeless tobacco, popular in Middle East countries including Yemen, Saudi Arabia and Sudan. The genotoxicity was explored using in vivo chromosomal aberration (CA), micronucleus (MN) and sperm abnormality (SA) assays. In addition, oxidative stress was also determined using various hepatic markers. Swiss albino mice were selected for the study, which were divided in to 5 groups of six animals each. They include, negative control (NC, received only vehicle) as well as positive control group (PC, received vehicle for 2 weeks followed by administration of cyclophosphamide, CP). Depending upon their dose, three BS treated animal groups were BS-100, 300 and 900 mg/kg. Doses of BS were obtained by suspending BS in 0.5% CMC (carboxy methyl cellulose) and orally administered once a day for 2 weeks. Significant augmentation of the average percentage of aberrant metaphase (AM), CA per cells and suppressed mitotic activity was observed on post administration of BS. In addition, BS increased the occurrence of MNPCEs (micronucleated polychromatic erythrocytes) formation, induced cytotoxicity and increased percentage of abnormal sperms as compared to NC. Moreover, BS also induced oxidative stress as the activities of hepatic superoxide dismutase (SOD) and glutathione (GSH) were reduced and malondialdehyde (MDA) content were increased by BS. Cyclophosphamide was utilized as clastogen, showed anticipated positive results and confirmed the sensitivity of test system. Therefore, it may be deduced from the study that the BS possesses genotoxic effects on mice bone marrow and germ cells in vivo.

Analysis of Chromosomal Aberrations and Micronuclei in Type 2 Diabetes Mellitus Patients

Introduction: Type 2 diabetes mellitus is a metabolic disorder characterized by insulin resistance and disrupted insulin secretion. It is often linked to injuries, malfunction and failure of several organs in the long term. The elevated chromosomal disruptions and genetic complications in diabetic patients are due to the increased production of reactive oxygen species.Materials and Methods: The current study used chromosomal aberration assay and micronucleus assay to analyze the extent of abnormalities in the subjects.Results: The results showed increase in frequency of chromosomal aberrations in diabetic patients when compared to the control group (2.76±1.65 and 0.47±0.75 respectively). They also showed higher levels of micronuclei formation than the control participants (13.28±8.63 and 4.12±8.89 respectively).The correlation analysis indicated positive relationship between total aberrations and duration of diabetes.Conclusion: These results indicate that diabetes is associated with genomic instability and studies at a genetic level can be employed for early detection.

Preclinical safety assessment of pathogen reduced red blood cells treated with amustaline and glutathione.

ABSTRACTBACKGROUNDThe nucleic acid targeted pathogen reduction (PR) system utilizing amustaline (S‐303) and glutathione (GSH) is designed to inactivate blood‐borne pathogens and leukocytes in red blood cell concentrates (PR‐RBCC). Inactivation is attained after amustaline intercalates and forms covalent nucleic acid adducts preventing replication, transcription, and translation. After pathogen inactivation, amustaline spontaneously hydrolyzes to S‐300, the primary negatively charged reaction product; amustaline is below quantifiable levels in PR‐RBCC. GSH quenches free unreacted amustaline.STUDY DESIGN AND METHODSThe genotoxic and carcinogenic potential of PR‐RBCC, the reaction by‐products, and S‐300 were assessed in accordance with the International Conference on Harmonization (ICH) guidelines and performed in compliance with the Food and Drug Administration (FDA) good laboratory practice standards, 21 CFR Part 58. in vitro bacterial reverse mutagenicity and chromosomal aberration assays were performed with and without exogenous S9 metabolic activation, and in in vivo clastogenicity and carcinogenic assays using validated murine models.RESULTSPR‐RBCCs were not genotoxic in vitro and in vivo and were non‐carcinogenic in p53+/− transgenic mice transfused over 26 weeks. Estimated safety margins for human exposure ranged from >90 to >36 fold for 2 to 5 PR‐RBCCs per day, respectively. PR‐RBCCs and S‐300 did not induce chromosome aberration in the in vivo murine bone marrow micronucleus assay at systemically toxic doses.CONCLUSIONSPR‐RBCCs did not demonstrate genotoxicity in vitro or in vivo and were not carcinogenic in vivo. These studies support the safety of PR‐RBCCs and suggest that there is no measurable genotoxic hazard associated with transfusion of PR‐RBCCs.

Identification of Radiation-Dose-Dependent Expressive Genes in Individuals Exposed to External Ionizing Radiation.

For victims of radiological accidents, rapid dose estimation and damage prediction are essential. Administering the gold-standard biodosimetry chromosome aberration assay requires highly skilled individuals and several days of labor; consequently, rapid turnaround is an important concern. Identification of new dose estimation markers and damage-predicting in vivo molecules to replace the chromosome aberration assay is crucial to improving the delivery time of medical treatment. Here, we investigated the applicability of mRNA levels using a mouse model. Female C57BL/6J mice were X-ray irradiated at various doses, and a DNA microarray was then performed to identify differentially expressed mRNAs in whole blood. The microarray analysis identified 14 radioresponsive mRNAs with more than fourfold differences by pattern matching in the expression at 24 h postirradiation. In particular, mRNA expression of Slfn4, Itgb5, Smim3, Tmem40, Litaf, Gp1bb and Cxx1c was significantly increased in a radiation-dose-dependent manner, as validated by reverse transcription quantitative polymerase chain reaction. We also performed an analysis using the cBioPortal for Cancer Genomics and found that the overall survival of ovarian adenocarcinoma patients with alterations in Smim3 and that of thymoma patients with alterations in Cxx1c had a worse prognosis than patients without these alterations. These findings suggest that the expression of several genes in whole blood was a sensitive and specific biomarker of radiation exposure and can be used as a rapid and reliable prospective molecular biomarker in radiological emergencies.

Toxicological assessment of β-galactosidase shows no adverse effects in vivo and in vitro

A safety assessment for β-galactosidase derived from Aspergillus oryzae (GODO-FAL) was performed. The test article was a concentrated, purified β-galactosidase diluted in glycerin and water with an activity of 10,000 U/mL. A series of genotoxicology tests including micronucleus assay, chromosome aberration assay, and reverse mutagenesis (Ames) assay confirmed that GODO-FAL was not clastogenic or mutagenic at any of the concentrations used, up to 2000 µg/mL for the chromosome aberration assay and 5000 mg per plate in the Ames assay. GODO-FAL was not toxic in acute, repeated oral toxicity, and sub-chronic toxicity assays in Sprague–Dawley rats at any dose used, up to 2000 mg/kg/day. Based on results from the subchronic toxicology assay, the no observed adverse effects level for GODO-FAL was at least 2000 mg/kg/day.

Antioxidant and Genotoxic Effects of Aqueous and Methanol Extracts from Two Edible Mushrooms from Turkey in Human Peripheral Lymphocytes.

This study reported the genetic and oxidative effects of aqueous and methanol extracts from two edible mushrooms, Lepista nuda (Bull.) Cooke and Pleurotus ostreatus (Jacq.) P. Kummer, in cultured human lymphocytes. Chromosome aberration (CA) and micronucleus (MN) assays were used for genotoxic influences estimation. In addition, the changes of total antioxidant capacity (TAC) and total oxidative stress (TOS) in the cells were monitored. The fungal extracts at all applied concentrations did not indicate significant differences (p > 0.05) in CA and MN analyses. Furthermore, while the treatments with maximum concentration of aqueous extract of L. nuda statistically (p < 0.05) increased TAC especially, TOS levels in the cells were reduced by them in comparison with negative control. Based on TAC analysis, low IC50 values belonging to aqueous (5.43 mg/L) and methanol (10.88 mg/L) extracts of L. nuda were remarkable. Our data demonstrated that the extracts obtained from P. ostreatus and especially L. nuda can be a new resource for therapeutics with their nonmutagenic and antioxidant features.

Examination of some toxicological parameters of dimethylamylamine when consumed alone or with caffeine

Dimethylamylamine (DMAA) is a bodybuilding supplement with fat-burner or performance-enhancing properties. DMAA is often combined with caffeine to enhance its effectiveness and this can have serious adverse effects on health. In this study, we examined for the first time the cytotoxic, oxidative and genotoxic effects of DMAA in the presence or absence of caffeine in lymphocytes cultured from human blood, and its vascular irritant effects in a hen's chorioallantoic membrane egg test. Cytotoxic effects were observed by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT), lactate dehydrogenase release (LDH), which serves as a measure of cell membrane damage, changes in the mitotic index (MI) and proliferative rate index (PRI) assays. Oxidative changes were evaluated by the total antioxidant activity and the total oxidative status assay. Genotoxic damage was analyzed by chromosomal aberration and micronucleus assays. DMAA and its combination with caffeine (cDMAA) had no genotoxic effects. DMAA (1000 mg/L) and cDMAA (500 and 1000 mg/L) decreased cell viability while significantly increasing LDH activity, MI and the oxidative level. DMAA and cDMAA caused weak and moderate vascular irritant effects, respectively. In conclusion, DMAA exhibits cytotoxic effects via membrane dysfunction and mitotic disturbance following increased oxidative stress in a dose- and caffeine-dependent manner.

Safety evaluation of arabinase (arabinan endo-1,5-α-L-arabinanase) from Aspergillus tubingensis.

Arabinase is an enzyme recognized for its ability to degrade arabinan, a plant cell wall constituent. It has been applied in the food industry most commonly for juice processing. One commercial source of arabinase is Aspergillus tubingensis (A. tubingensis), a black Aspergillus species. Given the intended use in food for human consumption, and noting its potential presence at trace levels in finished products, a series of safety studies including in vitro Ames and chromosome aberration assays, in vivo mammalian erythrocyte micronucleus and alkaline comet assays, and a 90‐day rat oral toxicity study were conducted. No test article‐related mutagenic activity was observed in the Ames assay. Although positive activity was observed in the chromosome aberration assay, this was not replicated in the in vivo genotoxicity assays including in preabsorptive cells. In the subchronic toxicity study, no test article‐related adverse effects were observed following oral administration of arabinase at doses of 15.3, 153, or 1,530 mg total organic solids (TOS)/kg body weight/day to Sprague Dawley rats. The no‐observed‐adverse‐effect level was considered to be the highest dose tested (1,530 mg TOS/kg body weight/day). The results of the genotoxicity studies and the subchronic toxicity study support the safe use of arabinase from A. tubingensis in food production.

Assessment of biotic and abiotic behaviour of engineered SiO2 nanoparticles for predicting its environmental providence

Silica oxide (SiO2) nanoparticles and their CTAB, CTAC, CPB and CPC modified counterparts are among the most commonly used nanoparticles. However, their potential environmental toxicity and fate in the environment are not known. To assess the overall risk possessed by these nanoparticles, the biotic and abiotic effects of these emergent pollutants have been evaluated. In this study, four different in vitro toxicity assessment methods have been used to assess the toxicity of SiO2 nanoparticles. The seed germination of V. radiata reduced to 53.33, 43.33, 40 and 33.33 for CTAB, CTAC, CPB and CPC coated Silica nanoparticles from 66.66 for control. Also the reduction in chlorophyll content (17–19%), HE, RE and RC values; MI and RMI values in Allium cepa chromosomal aberrations assay showed the toxic nature of the nanoparticles. The final fate of the particles in the environment has been assessed through the sorption and degradation behavior in the nature-identical laboratorial conditions. The nanoparticles showed a significant aggregation beyond 100 mM salt concentrations. A very high concentration i.e. about 40–55% of the nanoparticles was found to be sorbed by the soil particles and <1.2% concentration was found to be photodegradable. These results are meaningful for improved understanding and prediction of the behavior and fate of SiO2 nanoparticles in the environment.

Genotoxic property of poly herbal formulation of annona squomosa, zingiber officinalis and triticum aestivum plant extracts by in vitro chromosomal aberration test

The present study was aimed to evaluate the genotoxic potential of polyherbal formulations by chromosomal aberration test. Cancer being the second most cause of death among all ailments even after the improvised medications needs alternative sources of treatment. Herbal sources were always among the one as prime treatment sources. Polyherbal formulations were taking the lead in medications because of their broad spectrum of activity and synergic effects. Annona squamosa, Zingiber Officinalis, and Triticum Aestivum formulation with 1:2:3 ratio has shown significant results in the definitive and confirmatory chromosome aberration assays. Indicated the test article PF3 did not induce a statistically significant increase in the percentage of cells with aberrations both in the presence and absence of metabolic activation. PF3 was found non-clostagenic at a maximum dose of 15 µg/ml in the CHO cell line. Inhibition of chromosomal aberration, DNA fragmentation, and maintenance of cellular integrity may prevent the genotoxic effect. Further optimization and in vivo authenticated studies need to be proven.

Toxicity Assessment of Biologically Degraded Product of Textile Dye Acid Red G

Azo dyes are of environmental concern due to their recalcitrant nature. Several azo dyes and their decolorized and degraded products exert toxic and mutagenic effects on the flora and fauna. The toxic properties of these azo dyes are due to nature and position of the substitution with respect to the aromatic rings and amino nitrogen atoms. Several studies have thus far been emphasized on biodegradation of azo dye pollutants, though role of their biodegraded product is rarely studied. Given a lack of this understanding, we have analyzed the effects of degraded products of a di-azo textile dye Acid Red G by newly isolated bacterial species, Pseudomonas aeruginosa PFK10 and Brevibacillus choshinensis PFK11. The genotoxicity and cytotoxicity of Acid Red G and their degraded products were tested on HeLa cell line and Human lymphocyte cell, respectively. The data of MTT assay has been shown that activity of degraded products of the Acid Red G were comparable to their parent dye. But chromosome aberration assay and sister chromatid exchange assay did not show any significant changes in chromosomes as compared to positive control mitomicine.

Genotoxic effects of tobacco use in residents of hilly areas and foot hills of Western Ghats, Southern India

Smoking and smokeless tobacco consumption is a significant risk factor that provokes genetic alterations. The present investigation was to evaluate the biomarkers of genotoxicity including micronucleus (MN), chromosome aberrations (CA) and DNA strand breaks among tobacco consumers and control individuals residing in hilly areas of Western Ghats, Tamilnadu, South India. This study included 268 tobacco consumers with equal number of controls. The tobacco consumers were divided into Group I (<10 years of tobacco consumption with an age range from 15 to 35 years) and group II (>10 years consumption above 35 years of age). Chromosome aberration (CA) and comet assay were performed using blood and micronucleus assay from exfoliated buccal epithelial cells obtained from tobacco consumers and controls. Elevated levels of CA were found in group II (Chromatid type: 2.39 ± 1.13 and chromosome type: 1.44 ± 1.24) exposed subjects, high micronucleus and DNA damage (TL:4.48 ± 1.24 and TM:3.40 ± 1.58) levels were significantly (p < 0.05) observed in both smoking and smokeless tobacco consumers when comparison with group I and controls. This study also observed a lack of awareness among the tobacco consumers about the harmful health effects of tobacco. Tobacco consumption contributes to the significant alteration in genetic materials. In addition, a high rate of spontaneous abortion was also seen in the studied population.

Cytogenotoxic effects of cypermethrin on root growth: Allium sativum as a model system

Cypermethrin is a pyrethroid pesticide used on agricultural farms in Nigeria to control pests of fruits and vegetables but this is highly toxic to aquatic organisms. To determine toxicity of chemicals, Allium cepa is commonly used as an established bioassay however the bulb is used whole. Allium sativum in contrast is able to be split into cloves of smaller units hence this research aims to validate the potential of Allium sativum as a model plant for genotoxicity assessment. In this study, root growth inhibition test and chromosome aberration assay were used and the effective concentration (EC50) of cypermethrin was determined from the root growth curve. Furthermore, the mitotic activities of the root meristem were assessed using light microscopy. Treatment of root meristem of A. sativum with various concentrations of cypermethrin (0.25, 0.50, 0.75 and 1.0 mg/ml) revealed a reduction in the root length and EC50 of 0.44 mg/ml. Also morphological changes such root wilting, dark spots, tenderness of the clove bases and discoloration of the roots were observed. Cytological studies showed a reduction in mitotic index with increasing cypermethrin concentration. Chromosomal aberrations ranging from abnormal metaphases: c-metaphases, disturbed spindles and vagrant metaphases; to abnormal anaphases: laggard chromosomes, chromosome breaks and multipolarities were also recorded. These aberrations reduced with increased concentration of the pesticide leading to the production of lesser number of dividing cells. These show that cypermethrin is genotoxic to the root meristem and A. sativum is a suitable model plant for detecting pyrethroid genotoxicity in plant.

English

One of the primary objectives in agriculture is providing high-quality crops to consumers. Multiple techniques and methods are utilized to achieve this objective, including nanotechnology that depends on the use of very small materials, which will help in decreasing the amounts usually used with similar effects. Nanomaterials are used as fertilizers and also as component of nano-pesticides for plants. Despite their benefits, however, studies have noted their potential for cytotoxicity and genotoxicity. In this study, five nanoparticles (NPs) were tested to assess their effects on plants. The chromosomal aberration assay was used. The results showed that some NPs decreased the mitotic index (MI) significantly, which indicates the NPs’ potential cytotoxicity. In addition, different NPs’ treatments caused different types of chromosomal abnormalities e.g., chromosomes stickiness and disturbance of the metaphase and anaphase, lagging chromosomes, bridges, disturbed poles, micronuclei, s-metaphase, s-telophase, c- metaphase and bi-nucleus cells. All treatments had significant effects at p≤005. Treatments with NPs concentrations for 24 h affected the DNA content, AlO2 and Fe3O4 NPs’ increased the DNA content, while CeO2, TiO2 and Ag NPs’ decreased it. High concentrations of the tested NPs decreased the DNA content. The study results showed that CeO2 was the most harmful NP compared to the control and other NPs. Some types of chromosome abnormalities such as lagging chromosomes, bridge, and micronuclei indicate potential genotoxicity for these NPs. Despite of the positive effects, they also had negative side effects such as decreasing the MI and increasing the occurrence of different types of chromosomal abnormalities. Key words: Cytotoxicity, genotoxicity, nanoparticles, mitotic chromosomes abnormalities.

Caffeic Acid Genotoxicity: Correlation of the Pig-a Assay with Regulatory Genetic Toxicology In Vivo Endpoints.

Caffeic acid is found in variety of fruits and vegetables. It is considered as possible human carcinogen (Group 2B). It is negative in Ames and mouse micronucleus (MN), but positive in mouse lymphoma and chromosomal aberration assays. The objective of this study was to evaluate the in vivo genotoxicity of caffeic acid using three different endpoints: in vivo MN, Pig-a, and comet assay. Two sets of six rats per group were administered vehicle (0.5% hydroxypropyl methylcellulose), 500, 1,000, or 2,000 mg/kg/day of caffeic acid for three consecutive days via oral gavage. One set of animals was used for the Pig-a and MN assay and the other set was used for the comet assay. N-Ethyl N-Nitrosourea was used as positive control for the Pig-a and MN assay, and ethyl methanesulfonate for the comet assay. From one set of animals, peripheral blood was collected on Days -1, 14, and 30 for the Pig-a assay and on Day 4 for the MN assay. The other set of animals was euthanized 3 hr after the last dose; liver and blood were collected for the comet assay. A statistically significant increase in the MN frequency was observed at 2,000 mg/kg/day. No increase in the red blood cells (RBCCD59- ) or reticulocytes (RETCD59- ) Pig-a mutant frequencies was observed on Days 14 or 30. No increase in DNA strand breaks was observed in the peripheral blood or liver in the comet assay. Environ. Mol. Mutagen. 2019. © 2019 Wiley Periodicals, Inc.