Frequency Of Micronuclei Research Articles

Genotoxicity assessment of eight nitrosamines using 2D and 3D HepaRG cell models.

N-nitrosamine impurities have been increasingly detected in human drugs. This is a safety concern as many nitrosamines are mutagenic in bacteria and carcinogenic in rodent models. Typically, the mutagenic and carcinogenic activity of nitrosamines requires metabolic activation by cytochromes P450 enzymes (CYPs), which in many in vitro models are supplied exogenously using rodent liver homogenates. There are only limited data on the genotoxicity of nitrosamines in human cell systems. In this study, we used metabolically competent human HepaRG cells, whose metabolic capability is comparable to that of primary human hepatocytes, to evaluate the genotoxicity of eight nitrosamines [N-cyclopentyl-4-nitrosopiperazine (CPNP), N-nitrosodibutylamine (NDBA), N-nitrosodiethylamine (NDEA), N-nitrosodimethylamine (NDMA), N-nitrosodiisopropylamine (NDIPA), N-nitrosoethylisopropylamine (NEIPA), N-nitroso-N-methyl-4-aminobutyric acid (NMBA), and N-nitrosomethylphenylamine (NMPA)]. Under the conditions we used to culture HepaRG cells, three-dimensional (3D) spheroids possessed higher levels of CYP activity compared to 2D monolayer cells; thus the genotoxicity of the eight nitrosamines was investigated using 3D HepaRG spheroids in addition to more conventional 2D cultures. Genotoxicity was assessed as DNA damage using the high-throughput CometChip assay and as aneugenicity/clastogenicity in the flow-cytometry-based micronucleus (MN) assay. Following a 24-h treatment, all the nitrosamines induced DNA damage in 3D spheroids, while only three nitrosamines, NDBA, NDEA, and NDMA, produced positive responses in 2D HepaRG cells. In addition, these three nitrosamines also caused significant increases in MN frequency in both 2D and 3D HepaRG models, while NMBA and NMPA were positive only in the 3D HepaRG MN assay. Overall, our results indicate that HepaRG spheroids may provide a sensitive, human-based cell system for evaluating the genotoxicity of nitrosamines.

The Long-Term Impact of Ionizing Radiation on DNA Damage in Patients Undergoing Multiple Cardiac Catheterizations.

Ionizing radiation (IR) exposures have increased exponentially in recent years due to the rise in diagnostic and therapeutic interventions. A number of small-scale studies investigated the long-term effect of IR on health workers or immediate effects of IR on patients undergoing catheterization procedures; however, the long-term impact of multiple cardiac catheterizations on DNA damage on a patient population is not known. In this study, the effects of IR on DNA damage, based on micronuclei (MN) frequency and 8-hydroxy-2'-deoxyguanosine (8-OHdG) as markers in peripheral lymphocytes, were evaluated in patients who previously underwent multiple cardiac catheterization procedures. Moreover, genetic polymorphisms in genes PARP1 Val762Ala, OGG1 Ser326Cys, and APE1 Asn148Glu as a measure of sensitivity to radiation exposure were also investigated in the same patient population. The patients who underwent ≥ 3 cardiac catheterization procedures revealed higher DNA injury in comparison to the patients who underwent ≤ 2 procedures, documented with the presence of higher level of MN frequency (6.4 ± 4.8 vs. 9.1 ± 4.3, p = 0.002) and elevated serum 8-OHdG levels (33.7 ± 3.8ng/mL vs. 17.4 ± 1.9ng/mL, p = 0.001). Besides, OGG1 Ser326Cys and APE1 Asn148Glu heterozygous and homozygous polymorphic types, which are related with DNA repair mechanisms, were significantly associated with MN frequency levels (p = 0.006 for heterozygous and p = 0.001 for homozygous with respect to OGG1 Ser326Cys, p = 0.007 for heterozygous and p = 0.001 for homozygous with respect to APE1 Asn148Glu). There was no significant difference in terms of PARP1 Val762Ala gene polymorphism between two groups.

Effect of hexavalent chromium exposure on the reproductive status and biomarker responses of female Geloina erosa.

Hexavalent chromium (Cr (VI)) is widely distributed in the marine environment of Hainan Province, China and poses a potential threat to its mangrove ecosystems. However, the mechanisms underlying Cr-induced stress and reproductive toxicity in clams remain largely unknown. In this study, the clams, Geloina erosa, were exposed to 4.34, 8.69, 17.38 and 34.76 mg/L Cr (VI) for 24, 48 and 72 h. The gonad-somatic index (GSI) was determined and histological alterations of the ovaries were quantified by light microscopy. The micronucleus test was performed which quantifies the genotoxic presence of small cytoplasmic bodies in eukaryotic cells. Enzymatic assays for catalase (CAT), glutathione reductase (GR), and malondialdehyde (MDA) activities were done. Quantitative real-time PCR (qRT-PCR) was used to quantify the expression of glutathione-S-transferase (GST), heat shock protein 70 (HSP70) and vitellogenin (Vtg) in ovaries of G. erosa. The results showed that the micronucleus frequency was significantly increased when clams were exposed to Cr (VI). Cr (VI) exposure induced the accumulation of MDA and affected CAT and GR enzyme activities. The high Cr (VI) concentration of 34.76 mg/L significantly increased the levels of GR activity, GST expression and HSP70 expression and inhibited Vtg expression and CAT activity. MDA content was significantly increased after 72 h at the high Cr (VI) exposure (34.76 mg/L). Therefore, Cr (VI) exposure may be toxic to the development of ovaries of G. erosa.

Mutagenicity, hepatotoxicity, and neurotoxicity of glyphosate and fipronil commercial formulations in Amazon turtles neonates (Podocnemis expansa)

Pesticides are considered one of the main causes of the population decline of reptiles worldwide, with freshwater turtles being particularly susceptible to aquatic contamination. In this context, we investigated the potential mutagenic, hepatotoxic, and neurotoxic effects in neonates of Podocnemis expansa exposed to substrate contaminated with different concentrations of glyphosate and/or fipronil during embryonic development. Eggs collected from the natural environment were artificially incubated in sand moistened with pure water, water added with glyphosate Atar 48® at concentrations of 65 and 6500 μg/L (groups G1 and G2, respectively), water added with fipronil Regent® 800WG at 4 and 400 μg/L (groups F1 and F2, respectively) and, water added with the combination of 65 μg/L glyphosate and 4 μg/L fipronil or with 6500 μg/L glyphosate and 400 μg/L fipronil (groups GF1 and GF2, respectively). For mutagenicity analysis, we evaluated the frequency of micronuclei (MN) and other erythrocyte nuclear abnormalities (ENAs), while for evaluation of hepatotoxicity and neurotoxicity, livers and encephalon were analyzed for histopathological alterations. Exposure to pesticides, alone or in combination, increased the frequency of erythrocyte nuclear abnormalities, particularly blebbed nuclei, moved nuclei, and notched nuclei. Individuals exposed to fipronil exhibited congestion and inflammatory infiltrate in their liver tissue, while, in the encephalon, congestion, and necrosis were present. Our study confirms that the incubation of eggs in substrate polluted with glyphosate and fipronil causes histopathological damage and mutagenic alteration in P. expansa, highlighting the importance of using different biomarkers to evaluate the ecotoxicological effects of these pesticides, especially in oviparous animals.

Single and Mixture Cytogenetic Effects Evaluation of Atrazine and Glyphosate Herbicides at Environmentally Relevant Concentrations on Allium cepa Root Meristem Cells

The mixture of pesticides is employed to obtain other mechanisms of action on target organisms. The herbicides atrazine and glyphosate are used worldwide to control weeds in agricultural crops, and their indiscriminate use results in their constant presence in the environment. In this sense, this study aimed to evaluate the cytotoxic potential, the presence of chromosomal aberrations and nuclear abnormalities, and the frequency of micronuclei of active ingredients and commercial formulations of the herbicides atrazine (AT = 2 and 25 μg L-1) and glyphosate (GF = 65 and 160 μg L-1) isolated and in mixture (MIX = 2 + 65 and 25 + 160 μg L-1). Allium cepa root meristem cells were used as the test organism to evaluate environmentally relevant concentrations. Treatments containing the herbicides inhibited the mitotic index (ATAI2: 9.40 ± 1.36; GFAI65: 8.58 ± 1.10; MIXAI2+65: 6.99 ± 0.57; GFAI160: 9.77 ± 1.08; ATCOM25: 7.40 ± 1.38; GFCOM160: 8.26 ± 0.79) and showed chromosomal aberrations and nuclear abnormalities (ATAI2: 0.85 ± 0.17; ATCOM2: 0.97 ± 0.18; GFCOM65: 1.00 ± 0.18; MIXCOM2+65: 1.09 ± 0.25; ATAI25: 0.82 ± 0.17; GFAI160: 0.87 ± 0.23; MIXAI25+160: 0.95 ± 0.19; ATCOM25: 0.67 ± 0.19; MIXCOM25+160: 0.80 ± 0.25), indicating the cytotoxic/genotoxic potential of these herbicides. Mutagenic effects were seen in the mixture of the active ingredients of the herbicides at the lowest concentration tested (MIXAI2+65: 0.70 ± 0.57). These results indicate that the isolated herbicides and their mixture directly affect the genetic material. Therefore, we suggest reviewing the acceptable limits of these herbicides in the environment, emphasizing the importance and care required for properly handling these products to minimize environmental and human health risks.

The goby fish Sicydium spp. as valuable sentinel species towards the chemical stress in freshwater bodies of West Indies

Implementation of the European Water Framework Directive in tropical areas such as the French West Indies (FWI) requires to select relevant aquatic sentinel species for investigating the ecological status of surface waters. The present work aimed to study the biological response of the widespread fish Sicydium spp. towards river chemical quality in Guadeloupe island through a set of proper biomarkers. During a 2-year survey, the hepatic EROD activity, the micronucleus formation and the level of primary DNA strand breaks in erythrocytes were measured respectively as an enzymatic biomarker of exposure and genotoxicity endpoints in fish living upstream and downstream of two chemically-contrasted rivers. Hepatic EROD activity was shown to be variable along the time but always significantly higher in fish from the most contaminated river (Rivière aux Herbes) compared to the low contaminated one (Grande Rivière de Vieux-Habitants). Fish size did not influence EROD activity. Female fish exhibited a lower EROD activity compared to males depending on the catching period. We observed significant temporal variation in micronucleus frequency and primary DNA damage level measured in fish erythrocytes that did not depend on the fish size. Micronucleus frequency and to a lesser extent DNA damage were significantly higher in fish from the Rivière aux Herbes compared to the Grande Rivière de Vieux-Habitants. Our results argue for the interest of using Sicydium spp. as sentinel species to assess river quality and chemical pressures in FWI.

Genotoxicity and genomic instability in oral epithelial cells of agricultural workers exposed to pesticides using micronucleus and comet assay in Nineveh, Iraq

In agriculture, pesticides are used to preserve plants, but they might be dangerous for farmers and the environment. The present study aimed to use the comet assay and the micronucleus (MN) test to assess the genotoxic effects on lymphocytes and buccal exfoliation in pesticide-exposed male agricultural workers. The samples were collected from 102 workers having exposure to pesticides (Roundup SL, Weed waster, and paraquat 20% SL) and 100 control individuals (without pesticide exposure) from different Mosul, Iraq, neighbourhoods. With the help of the comet assay and the MN test, exfoliated buccal cells from the individuals were analyzed for DNA damage. Each individual's lymphocytes and epithelial baseline cells had their comet tail length assessed, along with any other nuclear abnormalities such as nuclear buds, karyolysis, karyorrhexis, and binucleate cells. The results showed that the frequency of MN considerably rose in the exposed group, and that group also revealed nuclear anomalies linked to cytotoxic or genotoxic effects. There were significant disparities in the amount of DNA damage between recently exposed employees and controls and recently exposed and followed-up cases. In comparison to controls, there was a considerable increase in the and frequency of cells that migrated in exposed workers. However, it was shown that confounding factors, such as age and the varying length of pesticide exposure, substantially impacted DNA damage. Educational programs for agricultural workers are critical to limit the use of chemicals in agriculture, given the evidence of a genetic risk associated with exposure brought on by the extensive use of pesticides.

Assessment of imidacloprid induced genotoxicity in Pethia conchonius (Rosy barb), a common freshwater fish of India

Imidacloprid is one of the highly efficient, globally used neonicotinoid groups of insecticides. The indiscriminate use of imidacloprid is contaminating large water bodies affecting not only the target organisms but also non-target organisms including fish. The present study aimed to assess the extent of nuclear DNA damage by imidacloprid in Pethia conchonius a freshwater fish in India using comet and micronucleus assays. The LC50 value of imidacloprid was estimated to be 227.33 mg L−1. Based on the LC50-96 h value, three sub-lethal concentrations of imidacloprid, SLC I −18.94 mg L−1, SLC II −28.41 mg L−1 and SLC III −56.83 mg L−1 were used to detect its genotoxic effect at DNA and cellular level. The imidacloprid exposed fishes exhibited higher DNA damage and nuclear abnormalities (p < 0.05) than the control. The %head DNA, %tail DNA, tail length and the frequency of micronuclei with other nuclear abnormalities like blebbed and notched nuclei were significantly higher than the control in a time and concentration-dependent manner. The DNA damage parameters such as %head DNA (29.107 ± 1.843), %tail DNA (70.893 ± 1.843), tail length (361.431 ± 8.455) micronucleus (1.300 ± 0.019), notched (0.844 ± 0.011) and blebbed (0.811 ± 0.011) nuclei were found to be highest for SLC III (56.83 mg L−1) at 96 h. The findings indicate that IMI is highly genotoxic in fish and other vertebrates leading to mutagenic/clastogenic effects. The study will be helpful in optimization of the imidacloprid use.

Investigation of the potential role of fusicoccin, a fungal phytotoxin, in mitigating salt stress in onion roots

Fusicoccin is a diterpene glycoside that plays an important role in the regulation of plant growth and development. Fusicoccin produced by Fusicoccum amydali fungus is known to affect plant growth positively with external applications due to its potential to stimulate the tolerance system of plants under stress conditions. In this study, it was aimed to reduce the negative effects of salt (0.15 M NaCl) stress on the germination and growth of onion (Allium cepa L.) bulbs by external fusicoccin (3 µM) application. For this purpose, the germination percentage, root length, root number, fresh weight, mitotic activity, micronucleus frequency, chromosomal abnormality, antioxidant enzyme activity, osmolyte accumulation, cell membrane damage and root anatomical structure were investigated in the current study. Salt stress caused a statistically significant difference (p < 0.05) in all examined parameters. External application of fusicoccin to onion bulbs germinated under salt stress conditions was found to be promising as a plant growth promoter and mitosis stimulator. In addition, fusicoccin application alleviated the harmful effects of salt stress on the chromosome structure and root anatomical structure and protected the cells from the cytotoxic and genotoxic effects of salt. Moreover, this application contributed to the fight against reactive oxygen species of onion plant and increased salt tolerance by regulating the accumulation of osmolyte substances such as proline and antioxidant enzymes such as superoxide dismutase and catalase, and by minimizing cell membrane damage in root cells. In conclusion, this study showed that exogenous application of 3 µM fusicoccin reduced the damage caused by oxidative stress in onion bulbs and served for healthy germination and growth.

The impact of chemical pollution on the European eel (Anguilla anguilla) from a Mediterranean hypersaline coastal lagoon

The European eel (Anguilla anguilla) is a critically endangered species. The impact of environmental contamination on this species has been highlighted as contributing to the decline in recruitment. The Mar Menor hypersaline coastal lagoon (SE Spain) is one of the most productive fisheries of European eel in Europe, making it a critical habitat for species conservation. The present study aimed to provide an initial overview of the impact of organic chemical contaminants on the European eel and the potential sublethal effects of chemical pollution on pre-migrating eels in this hypersaline habitat. We investigated muscle bioaccumulation of main persistent and hazardous organic contaminants (including some current-use pesticides) and genotoxicity, neurotoxicity, and xenobiotic detoxification system responses. The findings show that lagoon eels were exposed to high levels of legacy organochlorine contaminants, recently banned pesticides (chlorpyrifos), and some emerging chemicals. Some individuals surpassed the maximum levels of CBs authorized by the European Commission for human consumption. In this species, residuals of chlorpyrifos, pendimethalin, and chlorthal dimethyl have been reported for the first time. This field study provides relevant data to stock management and human health consumption and provides the first biomarker responses in European eel under permanent hypersaline conditions. Furthermore, the high frequency of micronuclei in peripheral erythrocytes of lagoon eels indicates sublethal genotoxic effects on the organism. Overall, the European eels growing and maturing in the Mar Menor lagoon are exposed to toxic and carcinogenic chemicals. The lack of seafood safety regulations for human consumption for some legacy chemicals that were measured in high concentrations in our study requires special action. Further biomonitoring and research are recommended to protect the animal, public, and environmental health.

Gallic acid: a polyphenolic compound potentiates the therapeutic efficacy of cisplatin in human breast cancer cells.

Gallic acid (GA) is a natural polyhydroxyphenolic compound with antioxidant, antimutagenic, anti-inflammatory, and antineoplastic activities. Cisplatin (CPT) is a platinum-based chemotherapeutic drug, and it is the treatment of choice for breast, ovarian, testicular, head, and neck cancers. However, the use of anticancer drugs has undesirable effects on patients due to associated toxicities. Thus, it is necessary to search for alternatives that reduce unintended side effects and enhance anticancer potential. The use of natural compounds with the conventional chemotherapeutic drug is a new aspect of cancer therapy. In the present study, we evaluated the ability of GA in the modulation of anticancer effects of CPT in human breast adenocarcinoma cells (MCF-7) by performing MTT, apoptosis, clonogenic cell survival, and micronucleus assays. GA and CPT showed significant cytotoxic activities in MCF-7 cells in a dose-dependent manner. In combination therapy (GA 2.5, 5.0, and 10μg/mL+CPT10 μg/mL), GA synergistically reduced the MCF-7 cell viability in contrast to the individual therapies. Cancer cells death by GA is through the induction of apoptosis as observed in the acridine orange and ethidium bromide dual staining method. The frequency of micronuclei (MN) was decreased significantly (P<0.001) in combinational therapy, possibly reducing the risk of chemotherapy-induced MN. Moreover, GA in mono or combinational therapy did not induce any cytotoxic effects in normal breast epithelial cells (MCF-10A). GA did not show any significant difference in colony inhibition compared to CPT. This outcome shows its differential effects in normal and cancerous cells. Hence, the combination GA with chemotherapeutic drugs could represent a promising alternative therapy in cancer treatment with minimal side effects.

Evaluating the role of cytokinesis-block micronucleus assay as a biomarker for oxidative stress-inducing DNA damage in type 2 diabetes mellitus patients

BackgroundType 2 Diabetes Miletus (T2DM) is a common metabolic and lifestyle disorder leading to increased oxidative stress and DNA damage. The present study aims to evaluate the feasibility of utilizing the cytokinesis-block micronucleus assay (CBMN) as a biomarker for assessing the DNA damage induced due to variations in oxidative stress.MethodologyThe study group includes diabetic (n = 50) and non-diabetic (n = 50) subjects. The assays for the diabetes-like fasting blood sugar, postprandial glucose and hemoglobin A1c (HbA1c), lipid profiling, and serum ferritin level along with c-reactive protein (CRP) were applied. Further, the CBMN assay was performed to evaluate the micronuclei present in the lymphocytes of control and T2DM groups.ResultsSignificant imbalance in the glycaemic index, dyslipidemia, increased ferritin levels, and CRP levels, with a significant increase of micronucleus frequency, was found in T2DM patients compared with the control group. Results suggest a trend of positive correlation between HbA1c and the micronuclei, indicating the assay’s potential importance as a biomarker for T2DM-induced risk assessment.ConclusionFrom the observed results, it can be suggested that the CBMN assay could be used to assess the risk of oxidative stress-induced DNA damage in high glycaemic index diabetic patients.

CONNOTATION OF MICRONUCLEUS AS A BIOMARKER IN CERVICAL INTRAEPITHELIAL LESIONS AND CARCINOMA

Introduction: The Pap smears study is the most rampant and cost-effective method for cervical cancer screening. The role of micronuclei in exfoliated cells of pap smears is the greater beneficial tool used in the screening of cervical cancers. They are intracytoplasmic inclusions made up of chromatin fragments that suggest instability in the chromosomes and they are found in great numbers in carcinogen-exposed tissues long before any clinical signs occur. Aims: To evaluate the predominance of Micronuclei as a biomarker in various premalignant and malignant lesions of cervixand to explore the association between various grades of cervical lesions and micronuclei frequency. Materials &amp;Methods:A prospective study was done in the cytopathology section on 250 cervical pap smears collected in the Pathology laboratoryRajarajeswari medical college, Bangalore. The study period was from January 2021 to June 2021. Slides containing the cell material were stained with Papanicolaou stain, The results were analyzed as per the Micronuclei Scoring done per 1000 exfoliated squamous cells under light microscopy Results: In this study of 250 cervical pap smear screening, there was a stepwise gradual increase in micronuclei count(MN score)from Inflammatory lesions to carcinoma cervix. Inflammatory 2.04 ± 0.43, Atypicalsquamous cells of undetermined significance 3.9 ± 1.73, Atypical squamous cells - High grade5.64 ±1.83,Low grade squamous intraepithelial lesion 7.68 ±1.48, High grade squamous intraepithelial lesion08 12.32 ± 2.68and Intraepithelial Carcinoma 18.60 ± 2.83. Conclusion: MN scoring on cervix squamous epithelial cells is a simple and reliable objective test that may be performed on routine Pap-stained smears and can be used as adjunctive to the screening of cervical cancers and provide a potential pathway for disease monitoring in the future.

A study on Amygdalin's Genotoxicological Safety and Modulatory Activity in Human Peripheral Lymphocytes in vitro.

Amygdalin (AMY), a plant secondary metabolite containing nitrile, is a major component of the seeds of Rosaceae family plants. It is known that this compound has many pharmacological activities such as cancer prevention, antipyretic, and cough suppressant. In this study, the genotoxic and modulatory effects of amygdalin were assessed by chromosomal aberration (CA), sister chromatid exchange (SCE), and cytokinesis-block micronucleus assay (CBMN) assays using human peripheral lymphocytes (HPLs) in the absence and presence of metabolic activator (S9 mix). Lymphocytes were exposed to various concentrations of amygdalin (0.86, 1.72, 3.43, 6.86, and 13.75 μg/mL) alone and in combination with mitomycin-C (MMC, 0.20 μg/mL) or cyclophosphamide (CP, 12 μg/mL). The mitotic index (MI), replication index (RI), cytokinesis-block proliferation index (CBPI), and cytostasis were also evaluated to determine cytotoxicity. Amygdalin alone did not exhibit genotoxic and cytotoxic effects at all the tested concentrations both in the absence and presence of the S9 mix. In contrast, amygdalin significantly reduced the frequencies of CA (especially at 48 h treatments), SCE, and MN (except 0.86 μg/mL in pre- and simultaneous treatment) induced by MMC in all the tested concentrations and treatment protocols. It has also considerably decreased CP-induced CA and SCE frequencies at all the concentrations (except 0.86 μg/mL) in simultaneous treatment. This study demonstrated that amygdalin alone was not genotoxic, on the contrary, it has revealed modulatory effects against chemotherapy agents that induced genomic damage in human lymphocytes, suggesting its chemopreventive potential. This article is protected by copyright. All rights reserved.

EVALUATION OF CYTOGENIC DAMAGE IN ORAL EXFOLIATED BUCCAL CELLS OF TOBACCO USERS AND PATIENTS WITH POTENTIALLY MALIGNANT DISORDERS USING MICRONUCLEUS ASSAY - A PROSPECTIVE STUDY

Background: Cytogenic methods acts with complex type mutations, known as structural mutations (aberrations)and a special type of chromosomal damage, known as micronucleus. So, micronucleus (MN) assay has been used as a biomarker of genetic damage in buccal mucosa cells. Aim and Objectives: To evaluate micronucleus in the exfoliated cells of buccal mucosa of individuals with potentially malignant disorders and different tobacco related habits and in control group. To observe the incidence of micronucleus count based on duration, frequency and type of tobacco usage and also auto immune condition of Lichen planus. Materials and Method: The study population is divided into 3 groups. Group I : 15 healthy subjects (control), Group II : 15 smokers or chewers with habits andno evidence of lesion Group III : 30 Patients clinically diagnosed as having PMD of the oral cavity. Smears stained with DNA specific Feulgen stain. Association of micronucleus between all groups and its mean and standard deviation was assessed with ANOVA with p&lt;0.05 was considered as significant level. Results: The mean MN revealed that individuals with potentially malignant disorders had 26.8±5.1, individuals with tobacco habit (smokers/chewers) had 11.0±5.5 and controls had 0.2±0.5. The ANOVA test for association and mean frequency of micronucleus between all groups revealed significant value of &lt;0.001. Conclusion: Hence, MN assay in oral exfoliated buccal cells can be conveniently used as a biomarker for screening of potentially malignant disorders of oral cavity. And also provides an insight into the importance of early detection and prevention of OPMDs.

Oxidative stress, genotoxic effects, and other damages caused by chronic exposure to silver nanoparticles (Ag NPs) and zinc oxide nanoparticles (ZnO NPs), and their mixtures in zebrafish (Danio rerio)

This study assessed the oxidative stress impacts of Ag NPs and ZnO NPs and their mixtures in zebrafish (Danio rerio). Zebrafish were exposed to sublethal concentrations of each NP and a mixture for 28 days followed by a 28-day recovery period (without NP exposure) and measurements made on hepatic levels of antioxidant enzymes (CAT, SOD, and GPx), MDA levels, expression of the genes for the Hsp70 and Hsp90, and MT, blood biochemical parameters (total protein, globulin, albumin, AST, ALT, ALP, and LDH), and genotoxicity in erythrocytes (via measurement of micronuclei (MN) and nuclear (NA) abnormalities). There was a tendency for an increase in the variation in the responses of antioxidant defense systems and there were higher MDA levels with increasing exposure concentration of Ag NPs and with increasing exposure time. Total protein, globulin, and albumin decreased during the exposure period, especially on the days of 28. Moreover, levels of AST and LDH increased significantly in the NPs co-exposure treatments, while levels of ALT and ALP significantly decreased. The highest expression levels for these genes occurred on day 14 and in the NPs co-exposure treatments. For exposure to both NPs individually and as a mixture, the frequency of MN and other NA were significantly increased (p < 0.05). During the recovery periods, most of the effects seen were reduced, most notably in the individual NPs treatments. The overall results suggest that the toxic effects of Ag NPs and ZnO NPs in combination significantly increase their toxicity in zebrafish.

Evaluation of micronuclei and antioxidant status in hospital radiation workers occupationally exposed to low-dose ionizing radiation

PurposeThere is scientific evidence that ionizing radiation (IR) can be responsible for various health hazards that are one of the concerns in occupational exposure. This study was performed to evaluate DNA damage and antioxidant status in hospital workers who are occupationally exposed to low doses of IR.Materials and methodsIn this study, twenty occupationally exposed to low doses of IR (CT and angiography) comprising with control groups which matched them. In order to investigate the effects of chronic irradiation of radiation workers, Micronuclei (MN) frequency and the antioxidant activity of Superoxide Dismutase (SOD), Catalase (CAT) and Total Antioxidant Capacity (TAC) were measured. Then, to check adaptation against high challenge dose, the samples (in all groups) were irradiated in vitro and MN frequency was compared. Finally, to investigated the effect of the high dose after the acute and chronic low dose of ionizing radiation, MN frequency was compared in two groups (the control group that was to in-vitro irradiated (acute low dose + high dose) and radiation workers (chronic low dose + high dose)).ResultsMN frequency in the occupationally exposed group (n = 30) increased significantly when compared to the control group (p-value < 0.0001). However, chronic irradiation of radiation workers could not lead to an adaptive Sresponse, while acute low-doses could produce this effect (p-value ˂ 0.05). In addition, the activity levels of antioxidant enzymes SOD, CAT, and TAC were not statistically different between the radiation workers and the control group (p-value > 0.05).ConclusionsWe observed that exposure to low doses of IR leads to increased cytogenetic damage, could not cause an adaptive-response, and improve antioxidant capacity in radiation workers. Controlling healthcare workers' exposure is the first step to improving the health of hospital workers and the quality of patient care, thus decreasing human and economic costs.

DNA fragmentation and multifaceted toxicity induced by high-dose vanadium exposure determined by the bioindicator Allium test

In this study, the toxicity of vanadium (VCI3) in Allium cepa L. was studied. Germination-related parameters, mitotic index (MI), catalase (CAT) activity, chromosomal abnormalities (CAs), malondialdehyde (MDA) level, micronucleus (MN) frequency and superoxide dismutase (SOD) activity were investigated. The effects of VCI3 exposure on the DNA of meristem cells were investigated with the help of comet assay, and the relationships between physiological, cytogenetic and biochemical parameters were revealed by correlation and PCA analyses. A. cepa bulbs were germinated with different concentrations of VCI3 for 72 h. As a result, the maximum germination (100%), root elongation (10.4 cm) and weight gain (6.85 g) were determined in the control. VCI3 treatment caused significant decreases in all tested germination-related parameters compared to the control. The highest percentage of MI (8.62%) was also observed in the control. No CAs were found in the control, except for a few sticky chromosomes and unequal distribution of chromatin (p > 0.05). VCI3 treatment caused significant decreases in MI and increases in the frequencies of CAs and MN, depending on the dose. Similarly, the comet assay showed that DNA damage scores increased with increasing VCI3 doses. The lowest root MDA (6.50 µM/g) level and SOD (36.7 U/mg) and CAT (0.82 OD240nmmin/g) activities were also measured in the control. VCI3 treatment caused significant increases in root MDA levels and antioxidant enzyme activities. Besides, VCI3 treatment induced anatomical damages such as flattened cell nucleus, epidermis cell damage, binuclear cell, thickening in the cortex cell wall, giant cell nucleus, damages in cortex cell and unclear vascular tissue. All examined parameters showed significant negative or positive correlations with each other. PCA analysis confirmed the relations of investigated parameters and VCI3 exposure.

In Vitro Genotoxicity Evaluation of PAHs in Mixtures Using Experimental Design.

Settled dusts are sinks for environmental pollutants, including Polycyclic Aromatic Hydrocarbons (PAHs) that are ubiquitous, persistent, and carcinogenic. To assess their toxicity in mixtures, Toxic Equivalent Factors (TEFs) are routinely used and based on the hypothesis of additive effects, although PAH interactions may occur and remain an open issue. This study investigated genotoxic binary interaction effects for six PAHs in mixtures using two in vitro assays and estimated Genotoxic Equivalent Factors (GEFs) to roughly predict the genotoxicity of PAH in mixtures. The Design of the Experiment approach was used with the micronucleus assay for cytostasis and micronuclei frequency and the alkaline comet assay for DNA damage. GEFs were determined for each PAH independently and in a mixture. For the cytostasis endpoint, no PAHs interaction was noted. BbF and BaP had a synergistic effect on DNA damage. All the PAH interacted between them regarding chromosomal damage. Although the calculated GEFs were similar to the TEFs, the latter may underestimate the genotoxic potential of a PAH mixture. GEFs calculated for PAH alone were lower than GEFs for PAHs in mixtures; thus, mixtures induce greater DNA/chromosomal damage than expected. This research helps to advance the challenging issue of contaminant mixtures' effects on human health.

Studies on triazophos-induced oxidative stress and genotoxicity in freshwater fish Cyprinus Carpio following sublethal exposures

Triazophos (TAP), an organophosphorus insecticide, is widely used in agricultural practice for controlling various insect pests. The present research work aimed to elucidate the impact of TAP on the antioxidant status and DNA content of the freshwater fish Cyprinus carpio. The fish were grouped into batches (n=6) and received a sublethal dose of 0.3mg/L for a duration of 1 (E1), 10 (E2), 20 (E3) and 30 days (E4). Another group, devoid of any toxicant, was maintained as the control (C). Changes in the enzymatic threshold of the selected antioxidants and malondialdehyde (MDA) levels suggested the conformation of oxidative stress in the livers of the freshwater fish C. carpio due to TAP exposure. Additionally, comet assays and micronucleus tests performed on the peripheral blood of the fish suggested increased damage in the form of the percentage of tail DNA formation and a high frequency of micronucleus as compared to the control. A positive correlation was seen between the decline in antioxidant activity, the elevation in MDA and the comet length and micronucleus frequency. The study thus highlights the impact of TAP on antioxidant levels in the livers and genotoxicity in the blood of the freshwater fish C. carpio. The findings of the study confirm that the antioxidant status, along with the comet assay and micronucleus tests could be used as tools in determining the potential genotoxicity due to the TAP impact. It is therefore suggested that extensive use of TAP should be avoided as it may contribute to the decline in the C. carpio population in its natural habitats.