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Age-related changes in tissue content of malondialdehyde-modified proteins
A D Mooradian1, C C Lung, G Shah
1St. Louis V.A. Medical Center, MO.
Abstract:
One of the possible mechanisms of the age-related modifications of proteins is the result of reaction with malondialdehyde (MDA), a lipid peroxidation byproduct. To determine the effect of age on the extent of MDA derivatization of proteins in plasma and various tissues, male Fisher 344 rats at 4, 12 and 26 months of age were studied. Protein electrophoresis and immunoblotting was carried out using a specific antiserum against MDA-protein complexes. The concentration of MDA-proteins in plasma (mean +/- SD of optical density in 50 micrograms protein) was 201.6 +/- 47.7 in 4 month old rats, 197.4 +/- 67 in 12 month old rats and 101.4 +/- 22.7 in 26 month old rats (P < 0.01). The MDA protein content of testicle, liver and heart was increased in 12 month old rats compared to 4 and 26 months old rats. There were no age-related differences in MDA-protein content of lung, brain, and kidney. Because of the interindividual variability of MDA-protein profiles within an age group distinct age-related changes in the distribution of various MDA protein bands could not be documented.
Insights
Aging affects protein modification by malondialdehyde (MDA). Plasma MDA-proteins decreased with age, while some tissues showed increased levels in middle-aged rats, indicating complex age-related changes.
Area of Science:
- Biochemistry
- Gerontology
- Molecular Biology
Background:
- Protein modification by malondialdehyde (MDA), a lipid peroxidation byproduct, is a proposed mechanism for age-related cellular changes.
- Understanding these modifications is crucial for comprehending the aging process and associated pathologies.
Purpose of the Study:
- To investigate the impact of aging on the extent of MDA derivatization of proteins in plasma and various tissues.
- To quantify age-related changes in MDA-protein adducts in male Fisher 344 rats.
Main Methods:
- Studied male Fisher 344 rats at three age points: 4, 12, and 26 months.
- Utilized protein electrophoresis and immunoblotting techniques.
- Employed a specific antiserum to detect and quantify MDA-protein complexes.
Main Results:
- Plasma MDA-protein concentration significantly decreased in older rats (26 months) compared to younger ones (4 months) (P < 0.01).
- MDA-protein content in testicles, liver, and heart was elevated in 12-month-old rats relative to 4- and 26-month-old rats.
- No significant age-related differences in MDA-protein content were observed in lung, brain, and kidney tissues.
Conclusions:
- Aging exhibits a complex, tissue-specific effect on protein modification by MDA.
- Plasma shows a reduction in MDA-protein adducts with age, contrasting with increases in certain organs during middle age.
- Interindividual variability limited the documentation of distinct age-related changes in specific MDA-protein band distributions.