Cytotoxic, genotoxic, and oxidative stress-related effects of lysergic acid diethylamide (LSD) and phencyclidine (PCP) in the human neuroblastoma SH-SY5Y cell line

Lysergic acid diethylamide (LSD) is a classic hallucinogen, widely abused for decades, while phencyclidine (PCP) has increased in popularity in recent years, especially among the adolescents. Very little is known about the general toxicity of these compounds, especially about their possible neurotoxic effects at the cell level. The aim of this study was to address these gaps by assessing the toxic effects of 24-hour exposure to LSD and PCP in the concentration range of 0.39–100 μmol/L in the human neuroblastoma SH-SY5Y cell line. After cell viability was established, cells treated with concentrations that reduced their viability up to 30 % were further subjected to the alkaline comet assay and biochemical assays that enable estimation of oxidative stress-related effects. Treatment with LSD at 6.25 μmol/L and with PCP at 3.13 μmol/L resulted with 88.06±2.05 and 84.17±3.19 % of viable cells, respectively, and led to a significant increase in primary DNA damage compared to negative control. LSD also caused a significant increase in malondialdehyde level, reactive oxygen species (ROS) production, and glutathione (GSH) level, PCP significantly increased ROS but lowered GSH compared to control. Treatment with LSD significantly increased the activities of all antioxidant enzymes, while PCP treatment significantly increased superoxide dismutase (SOD) and glutathione peroxidase (GPx) but decreased catalase (CAT) activity compared to control. Our findings suggest that LSD has a greater DNA damaging potential and stronger oxidative activity than PCP in SH-SY5Y cells.

The study of primary DNA damage in the bone marrow of mice under the combined action of pesticides

Introduction. The study of the potential negative effects of combinations of several pesticide active ingredients is an important and understudied area of toxicological and hygienic research. The initial phase of the genotoxicant action on the genetic structures in cells is the primary DNA damage, the identification of which makes it possible to assess the early stages of the genotoxic effect of xenobiotics and their mixtures. The DNA comet assay is widely used for these purposes. The aim of the research is to assess the primary DNA damage under the combined action of pesticides. Materials and methods. To assess DNA damage the experiments on CD-1 mice of both sexes were performed using alkaline comet analysis. The concentration of active products reacting with thiobarbituric acid (TBA) in the blood serum of white outbred rats was assessed as a marker of lipid peroxidation. Results. It was found that mixtures of 2,4-D-acid + glyphosate and thiram + carbendazim did not cause the formation of breaks and alkali-labile sites in the DNA of mice bone marrow cells. Exposure to the combination of the technical grade active ingredients captan and fludioxonil induced the breaks and alkali-labile sites in the DNA of animal bone marrow cells. The comparison of the genotoxicity assessment results obtained by the comet assay and results of analysis of the TBA-active product concentrations in the rat blood serum suggests that the observed primary DNA damage upon exposure to the captan and fludioxonil combination can be mediated by the induction of lipid peroxidation and subsequent interaction of the resulting products with nucleic acids. Conclusion. The results indicate that some pesticides in combination can damage hereditary material in mammalian cells. Therefore, in order to ensure the safe use of pesticides for public health it is necessary to take into account the data on the genotoxicity not only of individual pesticide technical grade active ingredients but also their combinations.

Protective effects of olive oil phenolics oleuropein and hydroxytyrosol against hydrogen peroxide-induced DNA damage in human peripheral lymphocytes

This study investigates antioxidant capacity and protective effects of phenolic compounds oleuropein (OLP) and hydroxytyrosol (HT), present in olive oil and olive leaves, against H2O2-induced DNA damage in human peripheral lymphocytes. Antioxidant potency was determined using the measurement of radical-scavenging activity (ABTS∙+ assay), ferric reducing power (FRAP assay) and cupric reducing antioxidant capacity (CUPRAC assay). Both substances were found to be potent antioxidant agents due to their free radical-scavenging activities. Antigenotoxic effects of oleuropein and hydroxytyrosol against H2O2-induced damage in human lymphocytes were evaluated in vitro by alkaline comet assay. At tested concentrations (1, 5, 10 µmol L−1), oleuropein and hydroxytyrosol did not induce a significant increase of primary DNA damage in comparison with the negative control. Pretreatment of human lymphocytes with each of the substances for 120 min produced a dose-dependent reduction of primary DNA damage in the tested cell type. Hydroxytyrosol showed a better protective effect against H2O2-induced DNA breaks than oleuropein which could be associated with their free radical-scavenging efficacy.

B-Comet Assay (Comet Assay on Buccal Cells) for the Evaluation of Primary DNA Damage in Human Biomonitoring Studies

Many subjects perceive venous blood collection as too invasive, and thus moving to better-accepted procedures for leukocytes collection might be crucial in human biomonitoring studies (e.g., biomonitoring of occupational or residential exposure to genotoxins) management. In this context, primary DNA damage was assessed in buccal lymphocytes (BLs), fresh whole venous, and capillary blood leukocytes, and compared with that in peripheral blood lymphocytes (PBLs)—the most frequently used cells—in 15 young subjects. Mouthwashes were collected after the volunteers rinsed their mouths with normal saline, and BLs were isolated by density gradient centrifugation. Blood samples were collected by venipuncture or by lancet. Anthropometric and lifestyle information was obtained by the administration of a structured questionnaire. As shown in the Bland-Altman plots, the level of agreement between BLs and PBLs lied within the accepted range, we thus enrolled a wider population (n = 54) to assess baseline DNA damage in BLs. In these cells, mean values of tail length (µm), tail intensity (%), and tail moment were 25.7 ± 0.9, 6.7 ± 0.4 and 1.0 ± 0.1, respectively. No significant association was observed between sex and smoking habit with any of the DNA damage parameters. Conversely, underweight subjects displayed significantly higher genomic instability compared with normal weight group (p < 0.05). In conclusion, we successfully managed to set up and update a non-invasive and well-accepted procedure for the isolation of BLs from saliva that could be useful in upcoming biomonitoring studies.

Extent of Primary DNA Damage Measured by the Comet Assay in Health Professionals Exposed to Antineoplastic Drugs: A Systematic Review and Meta-Analysis

Background: Antineoplastic drugs (ANDs) are a broad group of chemicals showing, at the same time, carcinogenic effects. The potential, albeit true, risk of side effects cannot be accepted, especially if resulting from occupational exposure. The aim of this study was to evaluate the association between occupational exposure to ANDs and the extent of primary DNA damage in health professionals. Methods: A systematic review and meta-analysis was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. PubMed/Medline, Web of Science, and Scopus were used to perform the literature search. The databases were examined in July 2019. Sub-group, moderator, and cumulative analyses were conducted. The trim and fill method was used in the case of potential publication bias. Results: Twenty studies were included in the qualitative analysis, and 19 in quantitative evaluation. The pooled effect size was 1.27 [(95% confidence interval (CI) = 0.66–1.88), p = 0.000] based on 1569 subjects. The moderator analysis by duration of exposure showed a positive association between duration of exposure and primary DNA damage. Conclusions: This systematic review clearly shows a significant association between occupational exposure to ANDs and the extent of primary DNA damage in health professionals. Considering these results, health professionals should be warned against this potential occupational risk.

Comet assay study of the genotoxic effect of T-2 and HT-2 toxins in chicken hepatocytes

Background and aims The aim of this study was to verify that the comet assay can be used to investigate the DNA damaging effects of T-2 and HT-2 toxins in the liver of broiler chickens. The comet assay is a favorable genotoxic analysis because it is cheap, simple, and can be used in many organisms and different tissues. Materials and methods Male broiler chickens were fed with T-2/HT-2 toxins-contaminated diet for 14 days. The comet assay was successfully adapted to chicken liver cells, and the DNA damage was determined by a decrease in the comet parameter (DNA % in the tail) in the experimental groups. Results The method of evaluation was found to be critical because DNA damage could not be detected exactly using the CometScore software, due to inaccurate separation of head and comet. However, this problem can be solved by visual evaluation. Conclusion In the case of the visual evaluation, each toxin-treated group differed significantly from the control group, indicating that the assay can be useful for the assessment of primary DNA damage caused by T-2/HT-2 toxins.