Age-related changes in the tissue antioxidant system of the northern birch mouse (Sicista betulina, Rodentia) at the northern periphery of its habitat area

The study was aimed at determining tissue antioxidant levels in juvenile and adult the northern birch mouse (Sicista betulina Pallas, 1779) at the northern periphery of its range (Republic of Karelia). Our results are indicating a mixed pattern of age-related changes in the antioxidant defense system: aging was accompanied by a decrease the catalase activity in the kidneys as well as an increase in heart catalase activity and kidney, cardiac and skeletal muscle superoxide dismutase activity. The levels of low-molecular antioxidants – reduced glutathione (GSH) (kidneys and heart) and α-tocopherol (heart and skeletal muscle) were lower in the of the northern birch mouse young compared to adult animals, which is probably associated not only with the active growth and high mobility of the juvenile mouse during the dispersal period, but also with the stress of physiological systems due to living in the Northern conditions and preparing for hibernation. Higher levels of GSH and α-tocopherol were found in the hearts of adult northern birch mouse compared to other small mammal species of the order Rodentia living in the Republic of Karelia, which indicates the important role of low-molecular weight antioxidants in protecting tissues against oxidative injury in this species.