Synthesis, characterization and toxicity studies of gelatin modified zinc oxide nanoparticles

Nanostructured zinc oxides are promising materials for numerous biomedical applications where they can serve as therapeutic agents or tools for sensing and imaging. Despite their favorable properties, wider use of zinc oxide nanoparticles in biomedicine is limited by toxicity issues. Therefore, new synthesis approaches should be devised to obtain zinc oxide nanoparticles which are safe-by-design. We present an innovative low-cost wet precipitation synthesis of gelatin modified zinc oxide nanoparticles at the gel/liquid interface. The diffusion of ammonia through the gelatin hydrogels of different porosities induces precipitation of the product in contact with the surface of the aqueous solution of zinc ions. After thermal treatment of the precipitate, adsorbed organic residues of decomposed gelatin act as modifiers of zinc oxide nanoparticles. We characterized the physicochemical properties of obtained gelatin modified zinc oxide nanoparticles by XRD, FTIR, DTA/TG, and SEM. The synthesized nanoparticles show hexagonal wurtzite structure and form flakelike aggregates. FTIR and DTA/TG analyses indicate that the thermal decomposition of adsorbed gelatin depends on the gelatin content of the hydrogel used in the synthesis. We also examined the viability of HepG2 cells, generation of intracellular reactive oxygen species, and genotoxicity using the MTS, DCFH-DA, and alkaline comet assay, respectively. Fabricated gelatin modified zinc oxide nanoparticles show very low toxicity potential at doses relevant for human exposure

[Podaljšana izpostavljenost podgan neletalnim odmerkom mikrocistina-LR povzroči poškodbe DNA v različnih organih]

Background. Microcystins (MCs) are cyclic heptapeptides that are considered tobe liver specific toxins. They are potent tumour promoters and recent studies indicate that they are also genotoxic. In this study we measured DNA damage in lymphocytes, liver, kidney (cortex and medulla), lung, spleen and brain cells of male Fisher F344 rats that were exposed to sublethal dose (every second day 10 Ugžkg b.w.č i.p) of microeysrin-YR (MCYR) for one month. Methods. At the end of exposure the animals were sacrificed, the lymphocytes were isolated from blood taken from jugular vein, liver cells were obtained byperfusion with collagenase A and the cells from other organs were isolated by incubating small tissue pieces with eollagenase A. The DNA damage in isolated cells was measured with the single cells gel electrophoresis (SCGE) also called the comet assay. Results. A significant increase of the % tail DNAin MCYR-exposed animals compared to the nonexposed control ones was observed in brain (2.5 fold), liver (2.1 fold), kidney medulla (1.9 fold), kidney cortex (1.8 fold) and lung (1.7 fold) cells, while the DNA from lymphocytes and spleen cells was not affected. Conclusion. This study demonstrated that subehronic exposure to sublethal doses of MCs can induce systemicgenotoxicity in mammals, and it affects not only the liver but also other vital organs

DNA damage and alterations in expression of DNA damage responsive genes induced by TiO2 nanoparticles in human hepatoma HepG2 cells

We investigated the genotoxic responses to two types of TiO2 nanoparticles (<25 nm anatase: TiO2-An, and <100 nm rutile: TiO2-Ru) in human hepatoma HepG2 cells. Under the applied exposure conditions the particles were agglomerated or aggregated with the size of agglomerates and aggregates in the micrometer range, and were not cytotoxic. TiO2-An, but not TiO2-Ru, caused a persistent increase in DNA strand breaks (comet assay) and oxidized purines (Fpg-comet). TiO2-An was a stronger inducer of intracellular reactive oxygen species (ROS) than TiO2-Ru. Both types of TiO2 nanoparticles transiently upregulated mRNA expression of p53 and its downstream regulated DNA damage responsive genes (mdm2, gadd45α, p21), providing additional evidence that TiO2 nanoparticles are genotoxic. The observed differences in responses of HepG2 cells to exposure to anatase and rutile TiO2 nanoparticles support the evidence that the toxic potential of TiO2 nanoparticles varies not only with particle size but also with crystalline structure

Detection of double-strand breaks in DNA molecules by the γH2AX assay and analysis of the cell cycle after treatment with potential antitumor agents TBQ and its alkylthio and arylthio derivatives.

2-tert-butyl-1,4-benzoquinone (TBQ) and its alkylthio and arylthio derivatives: 2-tert-butyl-5-(isopropylthio)-1,4-ben- zoquinone, 2-tert-butyl-5-(propylthio)-1,4-benzoquinone, 2-tert-butyl-5,6-(ethylenedithio)-1,4-benzoquinone, 2-tert-butyl-5-(phenylthio)-1,4-benzoquinone and 2-tert-butyl-6-(phenylthio)-1,4-benzoquinone were synthe- sized as analogs of biologically active compounds of natural origin with antitumor activity: quinone avarol/avarone. The γH2AX test was used to detect the potential genotoxic effect of TBQ and its derivatives in the HepG2 cell line. In addition, the effect of these substances on the cell cycle was monitored on the same HepG2 model system. Since the phosphorylation of histone H2AX is an early event in the cellular response to DNA double-strand breaks (DSBs), an assay based on the detection of phosphorylated histone H2AX (γH2AX) can be used as a biomarker of genotoxicity and genomic instability. In this work, the γH2AX test and flow cytometry were used to analyze the genotoxic potential and the effect on the cell cycle of TBQ and its derivatives. Double-strand breaks (DSBs) in DNA are detected with γH2AX-specific antibodies, and the cell cycle in the HepG2 cell line is analyzed by flow cytometry. Based on the obtained results, only 2-tert-butyl-5,6- (ethylenedithio)-1,4-benzoquinone induced increased formation of DSBs. Also, the same derivative caused a significantly greater arrest of cells in the G2/M phase of the cell cycle compared to TBQ from about 27% (TBQ) to 34% of the total population with a decrease in the S phase cell population. By forming DSBs, 2-tert-butyl-5,6-(ethylenedithio)-1,4-benzoquinone leads to genomic instability of the HepG2 cell line, which results in cell cycle arrest in the G2/M phase

Chemical and toxicological characterisation of anticancer drugs in hospital and municipal wastewaters from Slovenia and Spain

n/

Hazard characterization of Alternaria toxins to identify data gaps and improve risk assessment for human health

Fungi of the genus Alternaria are ubiquitous plant pathogens and saprophytes which are able to grow under varying temperature and moisture conditions as well as on a large range of substrates. A spectrum of structurally diverse secondary metabolites with toxic potential has been identified, but occurrence and relative proportion of the different metabolites in complex mixtures depend on strain, substrate, and growth conditions. This review compiles the available knowledge on hazard identification and characterization of Alternaria toxins. Alternariol (AOH), its monomethylether AME and the perylene quinones altertoxin I (ATX-I), ATX-II, ATX-III, alterperylenol (ALP), and stemphyltoxin III (STTX-III) showed in vitro genotoxic and mutagenic properties. Of all identified Alternaria toxins, the epoxide-bearing analogs ATX-II, ATX-III, and STTX-III show the highest cytotoxic, genotoxic, and mutagenic potential in vitro. Under hormone-sensitive conditions, AOH and AME act as moderate xenoestrogens, but in silico modeling predicts further Alternaria toxins as potential estrogenic factors. Recent studies indicate also an immunosuppressive role of AOH and ATX-II; however, no data are available for the majority of Alternaria toxins. Overall, hazard characterization of Alternaria toxins focused, so far, primarily on the commercially available dibenzo-α-pyrones AOH and AME and tenuazonic acid (TeA). Limited data sets are available for altersetin (ALS), altenuene (ALT), and tentoxin (TEN). The occurrence and toxicological relevance of perylene quinone-based Alternaria toxins still remain to be fully elucidated. We identified data gaps on hazard identification and characterization crucial to improve risk assessment of Alternaria mycotoxins for consumers and occupationally exposed workers.The European Partnership for the Assessment of Risks from Chemicals has received funding from the European Union’s Horizon Europe research and innovation program under Grant Agreement No 101057014 and has received co-funding of the authors’ institutions. Views and opinions expressed are, however, those of the author(s) only and do not necessarily reflect those of the European Union or the Health and Digital Executive Agency. Neither the European Union nor the granting authority can be held responsible for them.info:eu-repo/semantics/publishedVersio

Author Correction: DNA damage in circulating leukocytes measured with the comet assay may predict the risk of death (Scientific Reports, (2021), 11, 1, (16793), 10.1038/s41598-021-95976-7)

Link to the corrected article: [https://farfar.pharmacy.bg.ac.rs/handle/123456789/3944

DNA damage in circulating leukocytes measured with the comet assay may predict the risk of death

The comet assay or single cell gel electrophoresis, is the most common method used to measure strand breaks and a variety of other DNA lesions in human populations. To estimate the risk of overall mortality, mortality by cause, and cancer incidence associated to DNA damage, a cohort of 2,403 healthy individuals (25,978 person-years) screened in 16 laboratories using the comet assay between 1996 and 2016 was followed-up. Kaplan–Meier analysis indicated a worse overall survival in the medium and high tertile of DNA damage (p < 0.001). The effect of DNA damage on survival was modelled according to Cox proportional hazard regression model. The adjusted hazard ratio (HR) was 1.42 (1.06–1.90) for overall mortality, and 1.94 (1.04–3.59) for diseases of the circulatory system in subjects with the highest tertile of DNA damage. The findings of this study provide epidemiological evidence encouraging the implementation of the comet assay in preventive strategies for non-communicable diseases.This article has been corrected. Link to the correction: [https://farfar.pharmacy.bg.ac.rs/handle/123456789/3975

Characterization of In vitro 3D cell model developed from human hepatocellular carcinoma (HepG2) cell line

In genetic toxicology, there is a trend against the increased use of in vivo models as highlighted by the 3R strategy, thus encouraging the development and implementation of alternative models. Two-dimensional (2D) hepatic cell models, which are generally used for studying the adverse effects of chemicals and consumer products, are prone to giving misleading results. On the other hand, newly developed hepatic three-dimensional (3D) cell models provide an attractive alternative, which, due to improved cell interactions and a higher level of liver-specific functions, including metabolic enzymes, reflect in vivo conditions more accurately. We developed an in vitro 3D cell model from the human hepatocellular carcinoma (HepG2) cell line. The spheroids were cultured under static conditions and characterised by monitoring their growth, morphology, and cell viability during the time of cultivation. A time-dependent suppression of cell division was observed. Cell cycle analysis showed time-dependent accumulation of cells in the G0/G1 phase. Moreover, time-dependent downregulation of proliferation markers was shown at the mRNA level. Genes encoding hepatic markers, metabolic phase I/II enzymes, were time-dependently deregulated compared to monolayers. New knowledge on the characteristics of the 3D cell model is of great importance for its further development and application in the safety assessment of chemicals, food products, and complex mixtures