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Postlabeling analysis of indigenous aromatic DNA adducts in mouse myocardium during aging
1Department of Biochemistry, University of South Alabama, College of Medicine, Mobile 36688.
Abstract:
The possible presence of aromatic chemicals covalently linked to DNA (aromatic adducts) was investigated in heart cells during aging of the C57BL/6Nia mouse. Heart DNAs were isolated from untreated mice of different ages and analyzed by 32P-postlabeling assays. To determine low levels of adducts, assays were carried out in which aromatic adducts were first isolated by phase transfer to 1-butanol, then labeled with excess, carrier-free [gamma-32P]ATP. This analysis showed that the number and frequency of aromatic adducts varied between DNA samples. Several adducts were present in all mouse DNA preparations and were more abundant in 32P-maps of senescent heart DNA. The results suggest that genomes of myocytes have a higher steady-state level of DNA damage in old animals which could adversely affect cell function.
Insights
Aromatic adducts, or DNA damage, increase in mouse heart cells with age. This accumulation of DNA damage in older animals may negatively impact heart cell function.
Area of Science:
- Molecular biology
- Gerontology
- Cardiovascular research
Background:
- Aging is associated with cellular damage.
- DNA damage can accumulate over time, potentially affecting cell function.
- Aromatic adducts are specific types of DNA damage.
Purpose of the Study:
- To investigate the presence and levels of aromatic adducts in mouse heart DNA during aging.
- To determine if aromatic adducts accumulate in heart cells as mice age.
Main Methods:
- Isolation of heart DNA from C57BL/6Nia mice of varying ages.
- Analysis using 32P-postlabeling assays.
- Enrichment of aromatic adducts via phase transfer to 1-butanol before labeling with [gamma-32P]ATP.
Main Results:
- The number and frequency of aromatic adducts varied among DNA samples.
- Several aromatic adducts were consistently found in all mouse heart DNA samples.
- Aromatic adducts were more abundant in DNA from senescent (older) mice.
Conclusions:
- Myocyte (heart cell) genomes accumulate higher levels of DNA damage in aged animals.
- This age-related increase in DNA damage may adversely affect heart cell function.
- Aromatic adducts serve as a biomarker for age-related DNA damage in cardiac myocytes.