Relation of aging with oxidative protein damage parameters in the rat skeletal muscle

An increase in oxidative stress may contribute to the development of oxidative protein damage in the aging rat skeletal muscle. Our aim was to reveal protein carbonyl (PCO), advanced oxidation protein products (AOPP), a novel marker of oxidative stress, and protein thiol (P-SH) levels as markers of protein oxidation, as well as lipid hydroperoxide (LHP) levels as a marker of lipid peroxidation, and relation of nitrotyrosine (NT) levels with these markers in skeletal muscle tissue of young, adult, and old male Wistar rats. Design and methods In the present study, we investigated the relation between aging and oxidative protein damage parameters such as PCO, NT, AOPP, and P-SH, as well as oxidative stress parameters such as total thiol, nonprotein thiol, and LHP in the skeletal muscle tissue of young, adult, and old Wistar rats. Results PCO and NT levels of old rats were significantly increased compared with those of young and adult rats. Skeletal muscle AOPP levels were significantly increased in old rats compared with those of adult rats. P-SH levels were significantly decreased in old rats compared with those of young rats. Conclusions The finding that the increase in PCO levels of young vs. old group was more significant than that of adult vs. old group may suggest that PCO formation is an early specific marker of aging process in skeletal muscle. In addition, increased levels of nitrotyrosine in the skeletal muscle of the old rat group may be a novel specific marker of oxidative protein damage in the aging muscle. The absence of correlation between oxidative protein damage markers mentioned above and LHP levels may indicate that protein oxidation and lipid peroxidation in the aging rat skeletal tissue are two distinct mechanisms.