Aging modifies daily variation of antioxidant enzymes and oxidative status in the hippocampus

LACOSTE, MARÍA GABRIELA; PONCE, IVANA TAMARA; GOLINI, REBECA LAURA; DELGADO, SILVIA MARCELA; ANZULOVICH, ANA CECILIA

EXPERIMENTAL GERONTOLOGY

PERGAMON-ELSEVIER SCIENCE LTD

Año: 2017 vol. 88 p. 42 - 50

0531-5565

Background Aging is a complex and multifactorial biological process that leads to the progressive deterioration of physiological systems, including the circadian system. In addition, oxidative stress has been associated with the aging of the normal brain and the development of late-onset neurodegenerative diseases. Even though, functional weakening of circadian rhythms and antioxidant function has been observed during aging, the mechanisms by which the circadian system signaling and oxidative stress are interrelated have not yet been elucidated. The objectives of this study were to evaluate the consequences of aging on the temporal organization of the antioxidant defense system and oxidative status as well as to analyze the endogenous clock activity, in the hippocampus of aged rats. Methods Young adults (3-month-old) or older (22-month-old) male Holtzman rats were maintained under constant darkness conditions, during 15 days before the sacrifice. Levels of catalase (CAT) and glutathione peroxidase (GPx) mRNA and activity, reduced glutathione (GSH), lipoperoxidation (LPO) and BMAL1 protein were analyzed in hippocampus samples isolated every 4 h during a 24-h period. Locomotor activity was recorded during 20 days before the experiment. Results Our results show that aging modifies temporal patterns of CAT and GPx expression and activity in the hippocampus in a different way. On the one hand, it abolishes the oscillating CAT expression and specific enzymatic activity while, on the other, it increases the mesor of circadian GPx activity rhythm (p