Thimerosal-Derived Ethylmercury Is a Mitochondrial Toxin in Human Astrocytes: Possible Role of Fenton Chemistry in the Oxidation and Breakage of mtDNA

Thimerosal generates ethylmercury in aqueous solution and is widely used as preservative. We have investigated the toxicology of Thimerosal in normal human astrocytes, paying particular attention to mitochondrial function and the generation of specific oxidants. We find that ethylmercury not only in...

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Main Authors: Martyn A. Sharpe, Andrew D. Livingston, David S. Baskin
Format: Article
Language:English
Published: Wiley 2012-01-01
Series:Journal of Toxicology
Online Access:http://dx.doi.org/10.1155/2012/373678
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author Martyn A. Sharpe
Andrew D. Livingston
David S. Baskin
author_facet Martyn A. Sharpe
Andrew D. Livingston
David S. Baskin
author_sort Martyn A. Sharpe
collection DOAJ
description Thimerosal generates ethylmercury in aqueous solution and is widely used as preservative. We have investigated the toxicology of Thimerosal in normal human astrocytes, paying particular attention to mitochondrial function and the generation of specific oxidants. We find that ethylmercury not only inhibits mitochondrial respiration leading to a drop in the steady state membrane potential, but also concurrent with these phenomena increases the formation of superoxide, hydrogen peroxide, and Fenton/Haber-Weiss generated hydroxyl radical. These oxidants increase the levels of cellular aldehyde/ketones. Additionally, we find a five-fold increase in the levels of oxidant damaged mitochondrial DNA bases and increases in the levels of mtDNA nicks and blunt-ended breaks. Highly damaged mitochondria are characterized by having very low membrane potentials, increased superoxide/hydrogen peroxide production, and extensively damaged mtDNA and proteins. These mitochondria appear to have undergone a permeability transition, an observation supported by the five-fold increase in Caspase-3 activity observed after Thimerosal treatment.
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institution Kabale University
issn 1687-8191
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publishDate 2012-01-01
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spelling doaj-art-0e771128df044d529c9dcc32aea9cea52025-08-20T03:54:29ZengWileyJournal of Toxicology1687-81911687-82052012-01-01201210.1155/2012/373678373678Thimerosal-Derived Ethylmercury Is a Mitochondrial Toxin in Human Astrocytes: Possible Role of Fenton Chemistry in the Oxidation and Breakage of mtDNAMartyn A. Sharpe0Andrew D. Livingston1David S. Baskin2Department of Neurosurgery, The Methodist Hospital, 6565 Fannin Street, Houston, TX 77030, USADepartment of Neurosurgery, The Methodist Hospital, 6565 Fannin Street, Houston, TX 77030, USADepartment of Neurosurgery, The Methodist Hospital, 6565 Fannin Street, Houston, TX 77030, USAThimerosal generates ethylmercury in aqueous solution and is widely used as preservative. We have investigated the toxicology of Thimerosal in normal human astrocytes, paying particular attention to mitochondrial function and the generation of specific oxidants. We find that ethylmercury not only inhibits mitochondrial respiration leading to a drop in the steady state membrane potential, but also concurrent with these phenomena increases the formation of superoxide, hydrogen peroxide, and Fenton/Haber-Weiss generated hydroxyl radical. These oxidants increase the levels of cellular aldehyde/ketones. Additionally, we find a five-fold increase in the levels of oxidant damaged mitochondrial DNA bases and increases in the levels of mtDNA nicks and blunt-ended breaks. Highly damaged mitochondria are characterized by having very low membrane potentials, increased superoxide/hydrogen peroxide production, and extensively damaged mtDNA and proteins. These mitochondria appear to have undergone a permeability transition, an observation supported by the five-fold increase in Caspase-3 activity observed after Thimerosal treatment.http://dx.doi.org/10.1155/2012/373678
spellingShingle Martyn A. Sharpe
Andrew D. Livingston
David S. Baskin
Thimerosal-Derived Ethylmercury Is a Mitochondrial Toxin in Human Astrocytes: Possible Role of Fenton Chemistry in the Oxidation and Breakage of mtDNA
Journal of Toxicology
title Thimerosal-Derived Ethylmercury Is a Mitochondrial Toxin in Human Astrocytes: Possible Role of Fenton Chemistry in the Oxidation and Breakage of mtDNA
title_full Thimerosal-Derived Ethylmercury Is a Mitochondrial Toxin in Human Astrocytes: Possible Role of Fenton Chemistry in the Oxidation and Breakage of mtDNA
title_fullStr Thimerosal-Derived Ethylmercury Is a Mitochondrial Toxin in Human Astrocytes: Possible Role of Fenton Chemistry in the Oxidation and Breakage of mtDNA
title_full_unstemmed Thimerosal-Derived Ethylmercury Is a Mitochondrial Toxin in Human Astrocytes: Possible Role of Fenton Chemistry in the Oxidation and Breakage of mtDNA
title_short Thimerosal-Derived Ethylmercury Is a Mitochondrial Toxin in Human Astrocytes: Possible Role of Fenton Chemistry in the Oxidation and Breakage of mtDNA
title_sort thimerosal derived ethylmercury is a mitochondrial toxin in human astrocytes possible role of fenton chemistry in the oxidation and breakage of mtdna
url http://dx.doi.org/10.1155/2012/373678
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AT andrewdlivingston thimerosalderivedethylmercuryisamitochondrialtoxininhumanastrocytespossibleroleoffentonchemistryintheoxidationandbreakageofmtdna
AT davidsbaskin thimerosalderivedethylmercuryisamitochondrialtoxininhumanastrocytespossibleroleoffentonchemistryintheoxidationandbreakageofmtdna