uu.seUppsala University Publications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Evaluation of α-tocopherols effect on catechol and o-phenylenediamine induced DNA damage: An in vitro study using two different staining techniques in the comet assay
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmaceutical Biosciences.
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmaceutical Biosciences.
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmaceutical Biosciences.
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmaceutical Biosciences.
(English)Article in journal (Refereed) Submitted
Abstract [en]

Using the alkaline comet assay, the effect of a physiologically relevant concentration of a-tocopherol (20 mM) on the DNA damaging effects of catechol and o-phenylenedi- amine (OPD) was evaluated in mouse lymphoma L5178Y TK+/- cells. For compara- tive purposes, a third mutagenic agent, 4-nitro-o-phenylenediamine (4-NOPD), was also included in the study. a-Tocopherol was found to be without DNA damaging effects of its own after three hours exposure when tested in concentrations up to 500 mM, and this vitamin was also found to significantly reduce the DNA damage induced by 1 mM catechol. However, a-tocopherol did not reduce the level of DNA damage induced by OPD, indicating that catechol and OPD induce DNA damage by different mechanisms of action. As in a previous study, 4-NOPD did not increase the level of DNA damage, and a-tocopherol did not affect the level of damage when the cells were concomitantly exposed to both agents. The results from a separate ex- periment using different staining techniques for cells that had been exposed to dif- ferent concentrations of catechol, clearly indicated that the more hazardous chemical ethidium bromide could be substituted with the less hazardous chemical GelRedTM in the comet assay.

Keyword [en]
α-tocopherol, catechol, OPD, DNA damage, comet assay, mouse lymphoma cells, GelRed
National Category
Pharmacology and Toxicology
Research subject
Toxicology
Identifiers
URN: urn:nbn:se:uu:diva-211514OAI: oai:DiVA.org:uu-211514DiVA: diva2:674271
Available from: 2013-12-03 Created: 2013-11-25 Last updated: 2014-04-29Bibliographically approved
In thesis
1. Effects of Antioxidants and Pro-oxidants on Oxidative Stress and DNA Damage using the Comet Assay: Studies on Blood Cells from Type 2 Diabetes Subjects and Mouse Lymphoma Cells
Open this publication in new window or tab >>Effects of Antioxidants and Pro-oxidants on Oxidative Stress and DNA Damage using the Comet Assay: Studies on Blood Cells from Type 2 Diabetes Subjects and Mouse Lymphoma Cells
2014 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Diet and oral supplements comprise two distinct sources of antioxidants known to prevent oxidative stress. Beneficial effects from antioxidants have been seen for patients at risk for type 2 diabetes.

The aim of this thesis was to evaluate the positive effects of antioxidants against oxidative stress and DNA damage in type 2 diabetes subjects. We also used antioxidants as tools to determine the mechanisms behind genotoxicity induced by mutagenic pro-oxidative agents in mouse lymphoma cells. Several techniques were used to measure oxidative stress and DNA damage, but the main technique used was alkaline comet assay.

The results showed that the fruit and vegetable intake was inversely related to oxidative stress in type 2 diabetes subjects. However, oral supplementary intake of 20 antioxidants did not decrease oxidative stress biomarkers.

In studies on mouse lymphoma cells, using the alkaline comet assay, DNA damage was induced by catechol and o-phenylenediamine (OPD), while 4-nitro-o-phenylenediamine (4-NOPD) induced only oxidative damage, showing different mechanisms of action behind the mutagenicity of the compounds. Also, oxidative stress was induced by catechol and 4-NOPD, whereas imbalances in the nucleotide pool were seen after exposure to OPD or 4-NOPD. Addition of antioxidants together with these pro-oxidants showed that β-carotene was able to reduce DNA damage at low concentrations of catechol, but increased DNA damage at high concentration. In comparison, addition of α-tocopherol slightly decreased catechol-induced DNA damage at all concentrations of catechol. However, no effect of α-tocopherol was seen on OPD-or 4-NOPD-induced DNA damage.

In conclusion, antioxidants from fruits and vegetables, but not from oral supplements, reduced oxidative stress in type 2 diabetes patients, suggesting fruits and vegetables being a healthier source for antioxidant-intake, as compared to oral supplements. Different mechanisms of action for mutagenic pro-oxidants were shown in mouse lymphoma cells, introducing the nucleotide pool as an interesting target for oxidative stress. Reduction of catechol-induced DNA damage by β-carotene or α-tocopherol was shown, with a pro-oxidative action of β-carotene at high concentration of catechol, Interestingly, α-tocopherol was not able to decrease OPD- or 4-NOPD-induced DNA damage, supporting different mechanisms of action behind the genotoxicity from the three pro-oxidants.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2014. 78 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Pharmacy, ISSN 1651-6192 ; 185
Keyword
metabolic syndrome, fruit and vegetable intake, plasma antioxidants, beta-carotene, alpha-tocopherol, inflammation, oxidative DNA damage, lipid peroxidation, mouse lymphoma assay, ROS, nucleotide pool, viability, DNA dye
National Category
Pharmacology and Toxicology
Research subject
Toxicology
Identifiers
urn:nbn:se:uu:diva-217886 (URN)978-91-554-8877-2 (ISBN)
Public defence
2014-03-28, A1:107a, Biomedical center, Husargatan 3, Uppsala, 09:15 (Swedish)
Opponent
Supervisors
Available from: 2014-03-06 Created: 2014-02-05 Last updated: 2014-04-29

Open Access in DiVA

No full text

Authority records BETA

Åsgård, RikardHellman, Björn

Search in DiVA

By author/editor
Åsgård, RikardHellman, Björn
By organisation
Department of Pharmaceutical Biosciences
Pharmacology and Toxicology

Search outside of DiVA

GoogleGoogle Scholar

urn-nbn

Altmetric score

urn-nbn
Total: 416 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf