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Quantification of Wild-Type Mitochondrial DNA and Its 4.8-kb Deletion in Rat Organs

1997; Elsevier BV; Volume: 233; Issue: 1 Linguagem: Inglês

10.1006/bbrc.1997.6409

1090-2104

Nicole Stella Filser, Christiane Margue, Christoph Richter,

Metabolism and Genetic Disorders

Oxidative damage to mitochondrial DNA (mtDNA) is considered a major contributor in aging. An age-dependent increase of oxidative damage and of the quantity of partially deleted mtDNA was reported for several rat and human organs. Here, a systematic investigation of ten different tissues and organs of 20-months-old rats was performed. The amount of mtDNA and age-dependent 4.8 kb deletion (ΔmtDNA4834) was determined by competitive polymerase chain reaction, along with the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSHPx). The data were related to the corresponding metabolic rates. MtDNA content was highest in heart and lowest in spleen. ΔmtDNA4834was detected in all ten tissues and organs, and its amount was highest in liver and lowest in intestine. In heart, lung, muscle, and bone-marrow the deletion could not be quantified because of a point mutation, an A→T transition at position 8107. Activities of SOD and GSHPx were highest in liver and lowest in intestinal mucosa. A negative correlation between mtDNA content and ΔmtDNA4834, and a positive correlation between metabolic rate, GSHPx, and the deletion was found. These results suggest that the occurrence of ΔmtDNA4834in rat is related to oxidative stress.