Comparative analysis of cyto-genotoxicity of zinc using the comet assay and chromosomal abnormality test.

In this study, the toxicity of the trace element zinc (Zn) in Allium cepa L. test material was examined. Toxicity was investigated in terms of physiological, cytogenetic, biochemical, and anatomical aspects. Germination percentage, root length, weight gain, mitotic index (MI), micronucleus (MN) frequency, chromosomal abnormalities (CAs), malondialdehyde (MDA), proline and chlorophyll levels, superoxide dismutase (SOD) and catalase (CAT) enzyme activities, and meristematic cell damage were used as indicators of toxicity. Additionally, the comet test was used to measure the degree of DNA damage. Four groups of A. cepa bulbs-one for control and three for applications-were created. While the bulbs in the treatment groups were germinated with Zn at concentrations of 35, 70, and 140 mg/L, the bulbs in the control group were germinated with tap water. Germination was carried out at room temperature for 72 h and 144 h. When the allotted time was over, the root tips and leaf samples were collected and prepared for spectrophotometric measurements and macroscopic-microscopic examinations. Consequently, Zn treatment led to significant reductions in physiological indicators such as weight gain, root length, and germination percentage. Zn exposure caused genotoxicity by decreasing the MI ratios and increasing the frequency of MN and CAs (p < 0.05). Zn promoted various types of CAs in root tip cells. The most observed of CAs was the sticky chromosome. Depending on the dose, Zn was found to cause an increase in tail lengths in comet analyses, which led to DNA damage. Exposure to Zn led to a significant decrease in chlorophyll levels and an increase in MDA and proline levels. It also promoted significant increases in SOD and CAT enzyme activities up to 70 mg/L dose and statistically significant decreases at 140 mg/L dose. Additionally, Zn exposure caused different types of anatomical damage. The most severe ones are epidermis and cortex cell damage. Besides, it was found that the Zn dose directly relates to all of the increases and decreases in physiological, cytogenetic, biochemical, and anatomical parameters that were seen as a result of Zn exposure. As a result, it has been determined that the Zn element, which is absolutely necessary in trace amounts for the continuation of the metabolic activities of the organisms, can cause toxicity if it reaches excessive levels.

Evaluation of the in vivo acute toxicity and in vitro genotoxicity and mutagenicity of synthetic ß-carboline alkaloids with selective cytotoxic activity against ovarian and breast cancer cell lines.

The aim of this study was to evaluate the in vitro cytotoxic, genotoxic, and mutagenic potential and to determine the in silico ADME parameters of two synthetic ß-carboline alkaloids developed as prototypes of antitumor agents (NQBio-06 and NQBio-21). Additionally, acute toxicity of the compounds was evaluated in mice. The results from the MTT assay showed that NQBio-06 presented higher cytotoxicity in the ovarian cancer cell line TOV-21 G (IC50 = 2.5 µM, selectivity index = 23.7). NQBio-21 presented an IC50 of 6.9 µM and a selectivity index of 14.5 against MDA-MB-231 breast cancer cells. Comet assay results showed that NQBio-06 did not induce chromosomal breaks in vitro, but NQBio-21 was genotoxic with and without metabolic activation (S9 fraction). Micronucleus assay showed that both compounds were mutagenic. In addition, metabolic activation enhanced this effect in vitro. The in silico predictions showed that the compounds met the criteria set by Lipinski's rules, had strong prediction for intestinal absorption, and were possible substrates for P-glycoprotein. The in vivo results demonstrated that both the compounds exhibited low acute toxicity. These results suggest that the mechanisms underlying the cytotoxicity of NQBio-06 and NQBio-21 are related to DNA damage induction and that the use of S9 enhanced these effects. In vivo analysis showed signs of toxicity after a single administration of the compounds in mice. These findings highlight the potential of ß-carboline compounds as sources for the development of new anticancer chemotherapeutic agents.

Detection of DNA Breaks in Dividing Human Cells by Neutral Comet Assay.

DNA replication is constantly challenged by a wide variety of endogenous and exogenous stressors that can damage DNA. Such lesions encountered during genome duplication can stall replisomes and convert replication forks into double-strand breaks. If left unrepaired, these toxic DNA breaks can trigger chromosomal rearrangements, leading to heightened genome instability and an increased likelihood of cellular transformation. Additionally, cancer cells exhibit persistent replication stress, making the targeting of replication fork vulnerabilities in tumor cells an attractive strategy for chemotherapy. A highly versatile and powerful technique to study DNA breaks during replication is the comet assay. This gel electrophoresis technique reliably detects the induction and repair of DNA breaks at the single-cell level. Herein, a protocol is outlined that allows investigators to measure the extent of DNA damage in mitotically dividing human cells using fork-stalling agents across multiple cell types. Coupling this with automated comet scoring facilitates rapid analysis and enhances the reliability in studying induction of DNA breaks.

The Allium cepa comet assay for environmental sample assessment: a scoping review.

The purposes of this review were to investigate the application of the comet assay in Allium cepa root cells to assess the genotoxicity of environmental samples and to analyse the experimental procedures employed. A literature search was performed selecting articles published between January 2000 and October 2023 from online databases using the combined search terms 'comet assay' and 'A. cepa'. Only 18 papers met the inclusion criteria. None of these were published in the first eight years (2000-2007), highlighting the increasing interest in using the comet assay on A. cepa to analyse environmental samples over the last decade. The majority of the selected studies (15/18, 83%) were performed on samples belonging to the water compartment on onion bulbs. Half of the selected studies (9/18) were conducted to demonstrate the DNA damaging effect of the sample, while the other half of the studies not only recognized the presence of genotoxic agents but also addressed possible remediation measures. Detailed analysis of the experimental procedures revealed heterogeneity in many key steps, such as exposure time, test controls, nuclei isolation solutions, duration of electrophoresis, and number of nuclei scored. This literature review has shown that the comet assay on A. cepa, although recognized as an appropriate tool, is underutilized in environmental toxicology. Greater standardization could lead to its more widespread use, providing valuable information on the genotoxicity of environmental samples and the ability of different processes to mitigate their negative effects on plants.

Assessment of cytotoxic and genotoxic effects of glyphosate-based herbicide on glioblastoma cell lines: Role of p53 in cellular response and network analysis.

Glyphosate, the world's most widely used herbicide, has a low toxicity rating despite substantial evidence of adverse health effects. Furthermore, glyphosate-based formulations (GBFs) contain several other chemicals, some of which are known to be harmful. Additionally, chronic, and acute exposure to GBFs among rural workers may lead to health impairments, such as neurodegenerative diseases and cancer. P53 is known as a tumor suppressor protein, acting as a key regulator of the cellular response to stress and DNA damage. Therefore, mutations in the TP53 gene, which encodes p53, are common genetic alterations found in various types of cancer. Therefore, this study aimed to evaluate the cytotoxicity and genotoxicity of GBF in two glioblastoma cell lines: U87MG (TP53-proficient) and U251MG (TP53-mutant). Additionally, the study aimed to identify the main proteins involved in the response to GBF exposure using Systems Biology in a network containing p53 and another network without p53. The MTT assay was used to study the toxicity of GBF in the cell lines, the clonogenic assay was used to investigate cell survival, and the Comet Assay was used for genotoxicity evaluation. For data analysis, bioinformatics tools such as String 12.0 and Stitch 5.0 were applied, serving as a basis for designing binary networks in the Cytoscape 3.10.1 program. From the in vitro test analyses, it was observed a decrease in cell viability at doses starting from 10 ppm. Comet Assay at concentrations of 10 ppm and 30 ppm for the U251MG and U87MG cell lines, respectively observed DNA damage. The network generated with systems biology showed that the presence of p53 is important for the regulation of biological processes involved in genetic stability and neurotoxicity, processes that did not appear in the TP53-mutant network.

Designing and applying a methodology to assess sperm cell viability and DNA damage in a model amphipod.

Sperm quality is defined as the sperm cell ability to successfully fertilize eggs and allow normal embryo development⁠. Few studies explore sperm quality using aquatic invertebrates. Parhyale hawaiensis is a marine amphipod with a circumtropical distribution and considered a model for evolution, development, and ecotoxicological studies. We aimed to develop a methodology to collect sperm cells of P. hawaiensis and evaluate their viability and DNA damage (comet assay). We directly exposed the sperm cells to different mutagenic agents to optimize/develop the protocols. Then, as a proof of concept, we exposed the males to mutagenic compounds (EMS, benzo[a]pyrene (BaP), azo and anthraquinone dyes) at non-lethal concentrations verified by the proposed viability test and analyzed their sperm cells for DNA damage (comet assay). Organisms exposed to EMS presented a clear concentration response in the DNA damage response. We also showed that BaP was able to induce a statistically significant increase in DNA damage of the sperm cells. For the two dyes, although DNA damage increased, statistically differences were not observed. We believe we successfully developed a test to detect genotoxicity of chemicals in sperm cells using an invertebrate model. The protocol for sperm cell viability needs to be further explored with different chemicals to verify its utility as a toxicity endpoint. The developed genotoxicity test has the advantages to employ organisms that are easily cultivated in reduced space, use simple laboratory resources and reduced amount of material and reagents. Positive responses with this model could be used to disclose new germ cell mutagen candidates which could be further confirmed in vertebrates' systems.

Mechanistic insights into acetamiprid-induced genotoxicity on the myocardium and potential ameliorative role of resveratrol.

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.

Impact of environmental concentrations of fipronil on DNA integrity and brain structure of Bombus atratus bumblebees.

Fipronil (FP) is an insecticide used in the treatment and control of pests, but it also adversely affects bees. Currently, there is no data on the genotoxic effects of FP in the brain of bumblebees. Thus, through the comet assay and routine morphological analysis, we analyzed the morphological effects and potential genotoxicity of environmentally relevant concentrations of FP on the brain of Bombus atratus. Bumblebees were exposed at concentrations of 2.5 µg/g and 3.5 µg/g for 96 hours. After the exposure, the brains were removed for morphological and morphometric analysis, and the comet assay procedure - used to detect DNA damage in individual cells using electrophoresis. Our data showed that both concentrations (2.5 µg/g and 3.5 µg/g) caused DNA damage in brain cells. These results corroborate the morphological data. We observed signs of synapse loss in the calyx structure, intercellular spaces between compact inner and non-compact inner cells, and cell swelling. This study provides unprecedented evidence of the effects of FP on DNA and cellular structures in the brain of B. atratus and reinforces the need to elucidate its toxic effects on other species to allow future risk assessments and conservation projects.

Biomarker dosimetry of acute low level of thermal neutrons and radiation adaptive response effect on rats.

In this paper, we demonstrated the biological effects of acute low-dose neutrons on the whole body of rats and investigated the impact of that level of neutron dose to induce an in vivo radio-adaptive response. To understand the radio-adaptive response, the examined animals were exposed to acute neutron radiation doses of 5 and 10 mSv, followed by a 50 mSv challenge dose after 14 days. After irradiation, all groups receiving single and double doses were kept in cages for one day before sampling. The electron paramagnetic resonance (EPR) method was used to estimate the radiation-induced radicals in the blood, and some hematological parameters and lipid peroxidation (MDA) were determined. A comet assay was performed beside some of the antioxidant enzymes [catalase enzyme (CAT), superoxide dismutase (SOD), and glutathione (GSH)]. Seven groups of adult male rats were classified according to their dose of neutron exposure. Measurements of all studied markers are taken one week after harvesting, except for hematological markers, within 2 h. The results indicated lower production of antioxidant enzymes (CAT by 1.18-5.83%, SOD by 1.47-17.8%, and GSH by 11.3-82.1%). Additionally, there was an increase in red cell distribution width (RDW) (from 4.61 to 25.19%) and in comet assay parameters such as Tail Length, (from 6.16 to 10.81 µm), Tail Moment, (from 1.17 to 2.46 µm), and percentage of DNA in tail length (DNA%) (from 9.58 to 17.32%) in all groups exposed to acute doses of radiation ranging from 5 to 50 mSv, respectively. This emphasizes the ascending harmful effect with the increased acute thermal neutron doses. The values of the introduced factor of radio adaptive response for all markers under study reveal that the lower priming dose promotes a higher adaptation response and vice versa. Ultimately, the results indicate significant variations in DNA%, SOD enzyme levels, EPR intensity, total Hb concentration, and RDWs, suggesting their potential use as biomarkers for acute thermal neutron dosimetry. Further research is necessary to validate these measurements as biodosimetry for radiation exposure, including investigations involving the response impact of RAR with varied challenge doses and post-irradiation behavior.

Multiple factors influence telomere length and DNA damage in individuals environmentally exposed to a coal-burning power plant.

Coal is a mixture of several chemicals, many of which have mutagenic and carcinogenic effects and are a key contributor to the global burden of mortality and disease. Previous studies suggest that coal is related to telomeric shortening in individuals occupationally exposed, however little is known about the effects of mining and burning coal on the telomeres of individuals living nearby. Therefore, the primary objective of this investigation was to assess the impact of proximity to coal power plants and coal mines on the genomic instability of individuals environmentally exposed, while also exploring potential associations with individual characteristics, oxidative stress, inflammatory responses, and the presence of inorganic elements. This study involved 80 men participants from three cities around a thermoelectric power plant and one city unexposed to coal and byproducts. DNA was extracted from peripheral blood samples obtained from each participant, and the telomeres length (TL) was assessed using quantitative real-time polymerase chain reaction (qPCR) methodology. No significant difference was observed between exposed individuals (6227 ± 2884 bp) when compared to the unexposed group (5638 ± 2452 bp). Nevertheless, TL decrease was associated with age and risk for cardiovascular disease; and longer TL was found to be linked with increased concentrations of silicon and phosphorus in blood samples. No correlations were observed between TL with comet assay (visual score), micronucleus test, oxidative stress, and inflammatory results. Additional research is required to ascertain the potential correlation between these changes and the onset of diseases and premature mortality.

Evaluation of genotoxic effects in workers and residents of rural areas exposed to pesticides in Brazil.

Brazil is one of the world's largest consumers of pesticides. This intense use impacts the environment and exposes a wide range of individuals to pesticides, including rural workers who are occupationally exposed and rural residents who are environmentally exposed. We aimed to evaluate the effects of occupational exposure to pesticides on the health of rural workers and rural residents. We conducted an epidemiological study with 104 farmers and 23 rural residents of Casimiro de Abreu (Rio de Janeiro, Brazil). A comparison group (urban residents) comprised 103 residents of the urban area of the same city. We determined the activity of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) using a modified version of Ellman's method to evaluate exposure. In addition, we performed genotoxic and mutagenic analyses with the comet assay and the cytokinesis-block micronucleus (CBMN) assay. There was a reduction in cholinesterase activity, mainly BChE, in rural workers and rural residents compared with urban residents (p = 0.002). There was an increase in genotoxic effects in rural workers compared with urban residents (comet assay, p < 0.001; CBMN assay, p < 0.001). In addition, there was a greater chance of genotoxic changes in rural workers exposed to pesticides based on the comet assay (odds ratio [OR] 7.6, 95 % confidence interval [CI] 6.6-15.9) and the CBMN assay (OR 22.7, 95 % CI 10.3-49.9). We found that individuals occupationally exposed to pesticides are more likely to have genotoxic effects. These findings are useful for the development of programs to monitor populations exposed to genotoxic substances and allow the development of strategies for the prevention, control, and surveillance of effects that result from occupational and environmental exposures to pesticides.

The use of the micronucleus test and comet assay in wild rodents: a historical review and future perspectives.

Rodents are considered good models for investigating genotoxic damage and mutagenic alterations caused by xenobiotic agents, due to their occupation of a wide variety of habitats. However, relatively few in situ studies have focused on DNA damage in wild rodents associated with environmental exposure. In this review, we investigate trends in the application of the micronucleus test and comet assay in in situ studies of wild rodents. A total of 33 papers were identified, distributed across 14 different countries. Brazil and Spain had the most published studies (six each), followed by Bulgaria (n = 5), Mexico (n = 4) and Italy (n = 3). Only 24 of the 2,652 recognized rodent species have been the subject of in situ studies, which have most frequently focus on species of the genus Mus. The protocols used for the micronucleus test and comet assay varied widely, although blood and bone marrow were the primary types of tissue used. Given the paucity of studies on wild rodents, we recommend further research, particularly focusing on the use of this group as bioindicators of environmental quality and the standardization of protocols.

Toxicity of zinc oxide nanoparticles: Cellular and behavioural effects.

Due to their extensive use, the release of zinc oxide nanoparticles (ZnO NP) into the environment is increasing and may lead to unintended risk to both human health and ecosystems. Access of ZnO NP to the brain has been demonstrated, so their potential toxicity on the nervous system is a matter of particular concern. Although evaluation of ZnO NP toxicity has been reported in several previous studies, the specific effects on the nervous system are not completely understood and, particularly, effects on genetic material and on organism behaviour are poorly addressed. We evaluated the potential toxic effects of ZnO NP in vitro and in vivo, and the role of zinc ions (Zn2+) in these effects. In vitro, the ability of ZnO NP to be internalized by A172 glial cells was verified, and the cytotoxic and genotoxic effects of ZnO NP or the released Zn2+ ions were addressed by means of vital dye exclusion and comet assay, respectively. In vivo, behavioural alterations were evaluated in zebrafish embryos using a total locomotion assay. ZnO NP induced decreases in viability of A172 cells after 24 h of exposure and genetic damage after 3 and 24 h. The involvement of the Zn2+ ions released from the NP in genotoxicity was confirmed. ZnO NP exposure also resulted in decreased locomotor activity of zebrafish embryos, with a clear role of released Zn2+ ions in this effect. These findings support the toxic potential of ZnO NP showing, for the first time, genetic effects on glial cells and proving the intervention of Zn2+ ions.

In vitro effect of Lenzites betulinus mushroom against therapy-induced DNA damage in peripheral blood lymphocytes of patients with acute coronary syndrome.

ETHNOPHARMACOLOGICAL RELEVANCE: Acute coronary syndrome (ACS) represents a group of diseases that are the result of reduced blood flow to the heart. There are natural products, based on mushrooms, used traditionally in the treatment of cardiovascular diseases. AIM OF THE STUDY: Assessment of the potential protective effect of L. betulinus mushroom against therapy-induced DNA damage in lymphocytes of patients with ACS in relation to the phytochemical properties of the mushroom. MATERIALS AND METHODS: The study included 30 ACS patients and 30 healthy controls. The genotoxic potential of acetone and ethanol extract of L. betulinus was evaluated using the comet assay. The contents of minerals were determined by inductively coupled plasma optical emission spectrometry. Determination of sugars and organic acids was performed using a DIONEX ICS 3000 DP liquid chromatography system. Analysis of fatty acids was performed at Focus GC coupled with PolarisQ mass spectrometer. The total phenolic and flavonoid contents in the mushroom extracts were measured using spectrophotometric methods. The qualitative and quantitative content of polyphenolic compounds was investigated by the UHPLC-DADMS/MS method. RESULTS: The comet assay showed that both mushroom extracts did not increase the level of DNA damage in the lymphocytes of healthy individuals, while they significantly decreased the %DNA damage and genetic damage index (p < 0.0005) in the therapy-induced lymphocytes of patients. The mushroom was very rich in phytochemical composition. The results showed that the most abundant components in the mushroom were phosphorus, potassium, sodium, sulfur, and calcium among minerals and glucose, fructose, galactose, sorbitol, and turanose among carbohydrates. Among organic acids were present in higher concentrations malic, citric, and maleic acids, while among fatty acids, the most abundant were trans-linoleic, cis-oleic, palmitic, docosahexaenoic and eicosadienoic acids. The results showed that the highest amount of total phenols and flavonoids in the mushroom extracts were obtained in the acetone extract. The most abundant polyphenolic compounds were chlorogenic acid and quercetin in both extracts of mushroom. CONCLUSIONS: This study indicates that L. betulinus can be considered a mushroom with a high nutritional and functional value. Extracts of the mushroom were not genotoxic in tested concentrations in cultured human lymphocytes of healthy individuals, while in ACS patients they manifested a protective effect against therapy-induced DNA damage. The acetone extract showed a stronger protective effect against therapy-induced DNA damage, which is consistent with its phytochemical composition.

In vitro evaluation of the selective cytotoxicity and genotoxicity of three synthetic ortho-nitrobenzyl derivatives in human cancer cell lines, with and without metabolic activation.

Although the presence of nitro groups in chemicals can be recognized as structural alerts for mutagenicity and carcinogenicity, nitroaromatic compounds have attracted considerable interest as a class of agents that can serve as source of potential new anticancer agents. In the present study, the in vitro cytotoxicity, genotoxicity, and mutagenicity of three synthetic ortho-nitrobenzyl derivatives (named ON-1, ON-2 and ON-3) were evaluated by employing human breast and ovarian cancer cell lines. A series of biological assays was carried out with and without metabolic activation. Complementarily, computational predictions of the pharmacokinetic properties and druglikeness of the compounds were performed in the Swiss ADME platform. The MTT assay showed that the compounds selectively affected selectively the cell viability of cancer cells in comparison with a nontumoral cell line. Additionally, the metabolic activation enhanced cytotoxicity, and the compounds affected cell survival, as demonstrated by the clonogenic assay. The comet assay, the cytokinesis-block micronucleus assay, and the immunofluorescence of the γ-H2AX foci formation assay have that the compounds caused chromosomal damage to the cancer cells, with and without metabolic activation. The results obtained in the present study showed that the compounds assessed were genotoxic and mutagenic, inducing double-strand breaks in the DNA structure. The high selectivity indices observed for the compounds ON-2 and ON-3, especially after metabolic activation with the S9 fraction, must be highlighted. These experimental biological results, as well as the theoretical properties predicted for the compounds have shown that they are promising anticancer candidates to be exploited in additional studies.

Comparison of DNA damage in fresh and frozen blood samples: implications for the comet assay in human biomonitoring studies.

The use of the comet assay in large biomonitoring studies may present logistical and technical challenges because of the processing of numerous samples. Proper sample preservation becomes imperative to prevent spurious DNA breakage. Previous research has shown the feasibility of conducting the comet assay on frozen blood samples, highlighting the potential of freezing at - 80 °C in preserving DNA integrity. Nonetheless, this approach presents challenges, including potential DNA damage during freezing and thawing, variability in processing, and the need for standardized protocols. Our objective was to evaluate whether there are comparable results in DNA migration assessed by the comet assay between fresh and frozen blood samples on a larger scale (N = 373). In our findings, elevated DNA migration was evident in frozen samples relative to fresh ones. Additionally, smoking, alcohol consumption, and season were linked to increased DNA damage levels in whole blood cells. Based on our results and available literature, conducting the comet assay on frozen blood samples emerges as a practical and efficient approach for biomonitoring and epidemiological research. This method enables the assessment of DNA damage in large populations over time, with samples, if properly cryopreserved, that may be used for years, possibly even decades. These observations hold significant implications for large-scale human biomonitoring and long-term epidemiological studies, particularly when samples are collected during fieldwork or obtained from biobanks. Continued method optimization and validation efforts are essential to enhance the utility of this approach in environmental and occupational health studies, emphasizing caution when comparing data obtained between fresh and frozen blood samples.

Impact of high (1950 MHz) and extremely low (50 Hz) frequency electromagnetic fields on DNA damage caused by occupationally relevant exposures in human derived cell lines.

Epidemiological studies indicate that electromagnetic fields (EMF) are associated with cancer in humans. Exposure to mobile phone specific high frequency fields (HF-EMF) may lead to increased glioma risks, while low frequency radiation (LF-EMF) is associated with childhood leukemia. We studied the impact of HF-EMF (1950 MHz, UMTS signal) on DNA stability in an astrocytoma cell line (1321N1), and the effect of LF-EMF (50 Hz) in human derived lymphoma (Jurkat) cells. To find out if these fields affect chemically induced DNA damage, co-exposure experiments were performed. The cells were exposed to HF-EMF or LF-EMF and treated simultaneously and sequentially with mutagens. The compounds cause DNA damage via different molecular mechanisms, i.e. pyrimidine dimers which are characteristic for UV light (4-nitroquinoline 1-oxide, 4NQO), bulky base adducts (benzo[a]pyrene diolepoxide, BPDE), DNA-DNA and DNA-protein cross links and oxidative damage (NiCl2, CrO3). DNA damage was measured in single cell gel electrophoresis (comet) assays. We found a moderate reduction of basal and 4NQO-induced DNA damage in the astrocytoma line, but no significant alterations of chemically induced DNA migration by the HF and LF fields under all other experimental series. The biological consequences of the moderate reduction remain unclear, but our findings indicate that acute mobile phone and power line specific EMF exposures do not enhance genotoxic effects caused by occupationally relevant chemical exposures.

Toxicity evaluation of water-accommodated fraction of heavy and light oils on the rainbow trout fish cell line RTL-W1.

Fish are currently used models for the toxicity assessment of chemicals, including polycyclic aromatic hydrocarbons (PAHs). Alternative methods including fish cell lines are currently used to provide fast and reliable results on the toxic properties of chemicals while respecting ethical concerns about animal testing. The Rainbow trout liver cell line RTLW1 was used to analyze the effects of two water-accommodated fractions from two crude oils: Arabian Light crude oil (LO) and refined oil from Erika (HO). Several toxicity endpoints were assessed in this study, including cytotoxicity, EROD activity, DNA damage (comet and micronucleus assays), and ROS production. RTL-W1 cells were exposed for 24 h at two or three dilutions of WAF at 1000 µg/L (0.1% (1 µg/L), 1% (10 µg/L), and 10% (100 µg/L)) for cytotoxicity and EROD activity and 1% and 10% for ROS production and genotoxicity). Exposure of RTL-W1 cells to LO WAF induced a significant increase of EROD activity and ROS production and altered DNA integrity as revealed by both the comet assay and the micronucleus test for 10 µg/L of LO. On the other hand, HO WAF exhibited limited toxic effects except for an EROD induction for 1% WAF dilution. These results confirmed the usefulness of RTL-W1 cells for in vitro toxicological assessment of chemical mixtures.

Assessment of growth, reproduction, and vermi-remediation potentials of Eisenia fetida on heavy metal exposure.

Heavy metal pollution is a significant environmental concern with detrimental effects on ecosystems and human health, and traditional remediation methods may be costly, energy-intensive, or have limited effectiveness. The current study aims were to investigate the impact of heavy metal toxicity in Eisenia fetida, the growth, reproductive outcomes, and their role in soil remediation. Various concentrations (ranging from 0 to 640 mg per kg of soil) of each heavy metal were incorporated into artificially prepared soil, and vermi-remediation was conducted over a period of 60 days. The study examined the effects of heavy metals on the growth and reproductive capabilities of E. fetida, as well as their impact on the organism through techniques such as FTIR, histology, and comet assay. Atomic absorption spectrometry demonstrated a significant (P < 0.000) reduction in heavy metal concentrations in the soil as a result of E. fetida activity. The order of heavy metal accumulation by E. fetida was found to be Cr > Cd > Pb. Histological analysis revealed a consistent decline in the organism's body condition with increasing concentrations of heavy metals. However, comet assay results indicated that the tested levels of heavy metals did not induce DNA damage in E. fetida. FTIR analysis revealed various functional group peaks, including N-H and O-H groups, CH2 asymmetric stretching, amide I and amide II, C-H bend, carboxylate group, C-H stretch, C-O stretching of sulfoxides, carbohydrates/polysaccharides, disulfide groups, and nitro compounds, with minor shifts indicating the binding or accumulation of heavy metals within E. fetida. Despite heavy metal exposure, no significant detrimental effects were observed, highlighting the potential of E. fetida for sustainable soil remediation. Vermi-remediation with E. fetida represents a novel, sustainable, and cutting-edge technology in environmental cleanup. This study found that E. fetida can serve as a natural and sustainable method for remediating heavy metal-contaminated soils, promising a healthier future for soil.

Genotoxicity and cytotoxicity evaluation of a heat-not-burn product.

'Heat-not-burn' products (HnBP) contain lower levels of harmful substances than traditional cigarettes, but the use of these products warrants further toxicological evaluation. We have compared the cytotoxicity and genotoxicity of a heat-not burn product with conventional cigarettes, in vivo and in vitro. Male Sprague Dawley rats were exposed to mainstream smoke from conventional cigarettes or a HnBP, for 4 or 28 days, followed by isolation of bone marrow polychromatic erythrocytes (PCE) and histological examination of the testes. Chinese hamster lung fibroblast cells were exposed in vitro to total particulate matter from cigarette smoke obtained through Cambridge filters. The cytotoxicity and genotoxicity of total particulate matter were assessed by the neutral red uptake assay, chromosome aberration assay, in vitro micronucleus test, comet assay, and Ames assay. In the short-term exposure rat models, only the conventional-cigarettes group showed a significant increase in the ratio of micronuclei to total PCE. There was no significant difference in rat testis histology in the long-term exposure models. In vitro, in the neutral red uptake assay, the HnBP product showed lower cytotoxicity than conventional cigarettes. Conventional cigarettes showed greater genotoxicity in the chromosome aberration assay, high-dose Ames tests with exogenous metabolic activation, and micronucleus tests. In summary, our results suggest that HnBP have lower cytotoxicity and genotoxicity than conventional cigarettes.