Effects of Naphthalene Quinonoids on the Induction of Oxidative DNA Damage and Cytotoxicity in Calf Thymus DNA and in Human Cultured Cells

Analysis of oxidative damage to DNA bases by GC-MS enables identification of a range of base oxidation products, but requires a derivatization procedure. However, derivatization at high temperature in the presence of air can cause ‘artifactual ’ oxidation of some undamaged bases, leading to an overestimation of their oxidation products, including 8-hydroxyguanine. Therefore derivatization conditions that could minimize this problem were investigated. Decreasing derivatization temperature to 23 °C lowered levels of 8-hydroxyguanine, 8-hydroxyadenine, 5-hydroxycytosine and 5-(hydroxymethyl)uracil measured by GC–MS in hydrolysed calf thymus DNA. Addition of the reducing agent ethanethiol (5%, v/v) to DNA samples during trimethylsilylation at 90 °C also decreased levels of these four oxidized DNA bases as well as 5-hydroxyuracil. Removal of guanine from hydrolysed DNA samples by treatment with guanase, prior to derivatization, resulted in 8-hydroxyguanine levels (54–59 pmol/mg of DNA) that were significantly lower than samples not pretreated with guanase, independent of the derivatizationconditions used. Only hydrolysed DNA samples that were derivatized at 23 °C in the presence of ethanethiol produced 8-hydroxyguanine levels (56±8 pmol/mg of DNA) that were as low as those of guanase-pretreated samples. Levels of other oxidized bases were similar to samples derivatized at 23 °C without ethanethiol, except for 5-hydroxycytosine and 5-hydroxyuracil, which were further decreased by ethanethiol. Levels of 8-hydroxyguanine, 8-hydroxyadenine and 5-hydroxycytosine measured in hydrolysed calf thymus DNA by the improved procedures described here were comparable with those reported previously by HPLC with electrochemical detection and by GC–MS with prepurification to remove undamaged base. We conclude that artifactual oxidation of DNA bases during derivatization can be prevented by decreasing the temperature to 23 °C, removing air from the derivatization reaction and adding ethanethiol.

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Long-Term Effects of Polystyrene Nanoplastics in Human Intestinal Caco-2 Cells

Biomolecules ◽

10.3390/biom11101442 ◽

2021 ◽

Vol 11 (10) ◽

pp. 1442

Author(s):

Josefa Domenech ◽

Mariana de Britto ◽

Antonia Velázquez ◽

Susana Pastor ◽

Alba Hernández ◽

...

Keyword(s):

Dna Damage ◽

Oxidative Dna Damage ◽

Cultured Cells ◽

Culture Media ◽

Short Exposure ◽

Long Term Effects ◽

Potential Health ◽

Exposure Conditions

The increasing presence of micro- and nanoplastics (MNPLs) in the environment, and their consequent accumulation in trophic niches, could pose a potential health threat to humans, especially due to their chronic ingestion. In vitro studies using human cells are considered pertinent approaches to determine potential health risks to humans. Nevertheless, most of such studies have been conducted using short exposure times and high concentrations. Since human exposure to MNPLs is supposed to be chronic, there is a lack of information regarding the potential in vitro MNPLs effects under chronic exposure conditions. To this aim, we assessed the accumulation and potential outcomes of polystyrene nanoparticles (PSNPs), as a model of MNPLs, in undifferentiated Caco-2 cells (as models of cell target in ingestion exposures) under a relevant long-term exposure scenario, consisting of eight weeks of exposure to sub-toxic PSNPs concentrations. In such exposure conditions, culture-media was changed every 2–3 days to maintain constant exposure. The different analyzed endpoints were cytotoxicity, dysregulation of stress-related genes, genotoxicity, oxidative DNA damage, and intracellular ROS levels. These are endpoints that showed to be sensitive enough in different studies. The obtained results attest that PSNPs accumulate in the cells through time, inducing changes at the ultrastructural and molecular levels. Nevertheless, minor changes in the different evaluated genotoxicity-related biomarkers were observed. This would indicate that no DNA damage or oxidative stress is observed in the human intestinal Caco-2 cells after long-term exposure to PSNPs. This is the first study dealing with the long-term effects of PSNPs on human cultured cells.

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Electrochemical Sensor Based on Oxidation of 2,8-Dihydroxyadenine to Monitor DNA Damage in Calf Thymus DNA

Electroanalysis ◽

10.1002/elan.201000753 ◽

2011 ◽

Vol 23 (6) ◽

pp. 1383-1390 ◽

Cited By ~ 3

Author(s):

Rajendra N. Goyal ◽

Sanghamitra Chatterjee ◽

Anoop Raj Singh Rana

Keyword(s):

Dna Damage ◽

Electrochemical Sensor ◽

Calf Thymus Dna ◽

Calf Thymus

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Characterization of DNA Damage at Purine Residues in Oligonucleotides and Calf Thymus DNA Induced by the Mutagen 1-Nitrosoindole-3-acetonitrile

Chemical Research in Toxicology ◽

10.1021/tx000179r ◽

2001 ◽

Vol 14 (2) ◽

pp. 158-164 ◽

Cited By ~ 11

Author(s):

Lynda T. Lucas ◽

David Gatehouse ◽

George D. D. Jones ◽

David E. G. Shuker

Keyword(s):

Dna Damage ◽

Calf Thymus Dna ◽

Calf Thymus

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Acrylamide Exposure and Oxidative DNA Damage, Lipid Peroxidation and Fasting Plasma Glucose Alteration: Association and Mediation Analyses in Chinese Urban Adults

10.2337/figshare.12076134 ◽

2020 ◽

Author(s):

Bin Wang ◽

Weihong Qiu ◽

Shijie Yang ◽

Limin Cao ◽

Chunmei Zhu ◽

...

Keyword(s):

Lipid Peroxidation ◽

Dna Damage ◽

Plasma Glucose ◽

Fasting Plasma Glucose ◽

Oxidative Dna Damage ◽

Adult Population ◽

Prostaglandin F2α ◽

Mediation Analyses ◽

Mediating Role ◽

Fasting Plasma

<a>OBJECTIVE: </a>Acrylamide exposure from daily-consumed food has raised global concern. We aimed to assess the exposure-response relationships of internal acrylamide exposure with oxidative DNA damage, lipid peroxidation and fasting plasma glucose (FPG) alteration, and investigate the mediating role of oxidative DNA damage and lipid peroxidation in the association of internal acrylamide exposure with FPG. RESEARCH DESIGN AND METHODS: FPG and urinary biomarkers of oxidative DNA damage (8-hydroxy-deoxy-guanosine, 8-OHdG), lipid peroxidation (8-iso-prostaglandin-F2α, 8-iso-PGF2α) and acrylamide exposure (N-acetyl-S-(2-carbamoylethyl)-L-cysteine, AAMA; N-acetyl-S-(2-carbamoyl-2-hydroxyethyl)-L-cysteine, GAMA) were measured for 3,270 general adults from the Wuhan-Zhuhai cohort. The associations of urinary acrylamide metabolites with 8-OHdG, 8-iso-PGF2α and FPG were assessed by linear mixed models. The mediating roles of 8-OHdG and 8-iso-PGF2α were evaluated by mediation analysis. RESULTS: We found significant linear positive dose-response relationships of urinary acrylamide metabolites with 8-OHdG, 8-iso-PGF2α and FPG (except GAMA with FPG), and 8-iso-PGF2α with FPG. Each 1-unit increase in log-transformed level of AAMA, ΣUAAM (AAMA+GAMA) or 8-iso-PGF2α was associated with a 0.17-, 0.15- or 0.23-mmol/L increase in FPG, respectively (P or/and P trend<0.05). Each 1% increase in AAMA, GAMA or ΣUAAM was associated with a 0.19%, 0.27% or 0.22% increase in 8-OHdG, respectively, and a 0.40%, 0.48% or 0.44% increase in 8-iso-PGF2α, respectively (P and P trend<0.05). Increased 8-iso-PGF2α rather than 8-OHdG significantly mediated 64.29% and 76.92% of the AAMA and ΣUAAM associated-FPG increases, respectively. CONCLUSIONS: Exposure of general adult population to acrylamide was associated with FPG elevation, oxidative DNA damage and lipid peroxidation, which in turn partly mediated acrylamide-associated FPG elevation.

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