TEMPORAL PATTERNS OF ANTIOXIDANT DEFENSES ARE MODIFIED IN THE CEREBELLUM OF AGED RATS

CASTRO-PASCUAL, I; LACOSTE MG; ALTAMIRANO FG; RANDAZZO G; ANZULOVICH AC; FERRAMOLA, M.

Congreso; XXXII Reunión Anual de la Soc. de Biología de Cuyo; 2014

Motor and cognitive performance declines in older adults have been related to the cerebellum and the biological clock alterations. The presence of circadian clock components in the rat neocortex and cerebellum has been shown recently. The molecular clock activity depends on an optimal cellular redox state. The objectives of this study were to investigate whether the catalase (CAT) and glutathione peroxidase (GPx) enzymatic activity as well as GSH levels display a circadian variation in the cerebellum, and to evaluate whether this circadian rhythmicity is altered in aged rat. Holtzman rats from young (3-month old) and aged (22-month old) groups were maintained under 12h-dark:12h-dark (constant darkness) conditions, during 10 days before the experiment. CAT and GPx enzymatic activity were determined by kinetic assays, GSH levels were assessed espectrophotometrically, in cerebellum isolated every 4 h during a 24h period. CAT activity varied significantly in a 24h period in young and aged rats. However, we observed a phase delay as well as higher amplitude in the circadian rhythm of aged rats. We also observed GSH levels oscillate on a circadian basis in the cerebellum of young animals; such rhythm was lost in aged rats. On the other hand, we didn`t observe a 24h period variation in GPx activity, neither in young or aged rats, although we observed an increase in GPx activity in the cerebellum of 22-month old rats. Modifications in 24h-patterns of antioxidant defenses could lead to oxidative stress and alteration of the circadian clock in the cerebellum of aged individuals.