Assessing Genotoxicity of Ten Different Engineered Nanomaterials by the Novel Semi-Automated FADU Assay and the Alkaline Comet Assay

Increased engineered nanomaterial (ENM) production and incorporation in consumer and biomedical products has raised concerns about the potential adverse effects. The DNA damaging capacity is of particular importance since damaged genetic material can lead to carcinogenesis. Consequently, reliable and robust in vitro studies assessing ENM genotoxicity are of great value. We utilized two complementary assays based on different measurement principles: (1) comet assay and (2) FADU (fluorimetric detection of alkaline DNA unwinding) assay. Assessing cell viability ruled out false-positive results due to DNA fragmentation during cell death. Potential structure–activity relationships of 10 ENMs were investigated: three silica nanoparticles (SiO2-NP) with varying degrees of porosity, titanium dioxide (TiO2-NP), polystyrene (PS-NP), zinc oxide (ZnO-NP), gold (Au-NP), graphene oxide (GO) and two multi-walled carbon nanotubes (MWNT). SiO2-NPs, TiO2-NP and GO were neither cytotoxic nor genotoxic to Jurkat E6-I cells. Quantitative interference corrections derived from GO results can make the FADU assay a promising screening tool for a variety of ENMs. MWNT merely induced cytotoxicity, while dose- and time-dependent cytotoxicity of PS-NP was accompanied by DNA fragmentation. Hence, PS-NP served to benchmark threshold levels of cytotoxicity at which DNA fragmentation was expected. Considering all controls revealed the true genotoxicity for Au-NP and ZnO-NP at early time points.

Effect of occupational exposure to antineoplastic drugs on DNA damage in nurses: a cross-sectional study

BackgroundAlthough the therapeutic effect of antineoplastic drugs is incontestable, these agents can also potentially act as carcinogens, mutagens and/or teratogens in people. The aim of this study was to assess the effect of occupational exposure to antineoplastic drugs on DNA damage, assessed by the comet assay and cytokinesis-block micronucleus (CBMN) assay, in nurses.MethodsThe cross-sectional study enrolled 305 nursing staff members from 7 public hospitals in Shenzhen who handled antineoplastic drugs, and 150 healthy nursing staff members who were not exposed to antineoplastic drugs as the control group. DNA damage was assessed by the comet and CBMN assay. Multiple linear regressions and logistic regressions models were used to analyse the effect of occupational exposure to antineoplastic drugs on DNA damage.ResultsAfter adjustment for confounding factors, compared with non-exposure to antineoplastic drugs, exposure to antineoplastic drugs was positively related to tail moment, olive moment, tail length and tail DNA per cent, and adjusted β or OR (95% CI) was 0.17 (0.08 to 0.26), 0.18 (0.10 to 0.27), 1.03 (0.47 to 1.60) and 1.16 (1.04 to 1.29) (all p<0.05). Moreover, similar significant relationships were observed for the biomarkers of the CBMN assay. Additionally, other than age, there was no interaction between antineoplastic drug exposure and other variables for the levels of biomarkers of the CBMN assay and the comet assay.ConclusionsThe present results showed that exposure to antineoplastic drugs was positively related to the risk of DNA damage in nurses. The results imply that occupational exposure to antineoplastic agents is an important global public health problem that requires urgent attention.

Effect of Imidocarb Application on Oxidative DNA Damage Caused by Anaplasmosis

This study was aimed to evaluate DNA fragmentation by using Comet assay in naturally infected sheep with Anaplasmosis before and after treatment with the Comet method, which shows DNA damage specifically. In the study, blood samples were collected from 10 Anaplosmosis infected and 10 healthy sheep. The anaplosmosis was diagnosed by clinical signs and symptoms. The infection was confirmed by Giemsa staining. The blood was collected from control group and infected group before and after the treatment, from the vena jugularis with the appropriate method. The DNA fragmentation was checked by using the Comet assay of blood cells. The data were analysed throught ANNOVA one-way. The result showed higher DNA fragmentation in sick animals diagnosed with anaplasmosis; tail length and tail moment values were found to be statistically significantly higher than the control group. When the data obtained after imidocarb (IMD) application were compared with obtained during the disease, a decreased DNA damage and tail moment was determined, however, these values higher than control. In this study, DNA damage and the extent of this damage were investigated by the Comet assay method using a healthy control group before and after treatment in animals with Anaplasmosis. When the findings obtained from the study were evaluated, it was seen that Anaplasma agents caused DNA damage and with the imidocarb application given for treatment, DNA damage was reduced and results close to healthy individuals were obtained.

Antigenotoxic and antimutagenic activities of Psittacanthus calyculatus (Loranthaceae) leaves water extract

Mistletoe (<i>Psittacanthus calyculatus</i>) is used for the prevention and treatment of numerous diseases. Samples of leaves from <i>P. calyculatus</i> were collected in April of 2019, and prepared an aqueous extract. The extract was lyophilized, and its polyphenols, flavonoids, and anthocyanins content were determined. Then, concentrations of lyophilized extract were prepared (5, 50 and 100 ppm) and assessed their antigenotoxic, antimutagenic and genotoxicity activities in human lymphocytes were evaluated using the comet assay system. The dry aqueous extract contained 73.54 mg of polyphenols AGE per g sample, 39.37 mg of flavonoid CE per g, and 0.1 mg of anthocyanins Cy-3-gluc E per g. No significant genotoxic activity was observed, with the exception of the concentration of 100 ppm at 10 hours of exposure (p <0.05). There was also significant (p <0.05) antigenotoxic and antimutagenic activity (p <0.05). Clearly, low concentrations and short-duration exposures to lyophilized <i>P. calyculatus</i> do not induce genetic damage; however, high concentrations are genotoxic. The antigenotoxic and antimutagenic effects were due to a protective effect not only against induced DNA damage but also against basal genetic damage.

New insight on some selected nanoparticles as an effective adsorbent toward diminishing the health risk of deltamethrin contaminated water

Deltamethrin is a widely used insecticide that kills a wide variety of insects and ticks. Deltamethrin resistance develops as a result of intensive, repeated use, as well as increased environmental contamination and a negative impact on public health. Its negative impact on aquatic ecology and human health necessitated the development of a new technique for environmental remediation and wastewater treatment, such as the use of nanotechnology. The co-precipitation method was used to create Zn-Fe/LDH, Zn-AL-GA/LDH, and Fe-oxide nanoparticles (NPs), which were then characterized using XRD, FT-IR, FE-SEM, and HR-TEM. The kinetic study of adsorption test revealed that these NPs were effective at removing deltamethrin from wastewater. The larval packet test, which involved applying freshly adsorbed deltamethrin nanocomposites (48 hours after adsorption), and the comet assay test were used to confirm that deltamethrin had lost its acaricidal efficacy. The kinetics of the deltamethrin adsorption process was investigated using several kinetic models at pH 7, initial concentration of deltamethrin 40 ppm and temperature 25°C. Within the first 60 min, the results indicated efficient adsorption performance in deltamethrin removal, the maximum adsorption capacity was 27.56 mg/L, 17.60 mg/L, and 3.06 mg/L with the Zn-Al LDH/GA, Zn-Fe LDH, and Fe Oxide, respectively. On tick larvae, the results of the freshly adsorbed DNC bioassay revealed larval mortality. This suggests that deltamethrin’s acaricidal activity is still active. However, applying DNCs to tick larvae 48 hours after adsorption had no lethal effect, indicating that deltamethrin had lost its acaricidal activity. The latter result corroborated the results of the adsorption test’s kinetic study. Furthermore, the comet assay revealed that commercial deltamethrin caused 28.51% DNA damage in tick cells, which was significantly higher than any DNC. In conclusion, the NPs used play an important role in deltamethrin decontamination in water, resulting in reduced public health risk. As a result, these NPs could be used as a method of environmental remediation.