Mitochondrial bioenergetics in brain cortex synaptosomes and evaluation of mouse motor performance during aging

LOMBARDI, P., ; KARADAYIAN, A.G.; GUERRA, J.I., ; CUTRERA R., ; LORES ARNAIZ, S.

Buenos Aires

Encuentro; SAN 2022 Meeting; 2022

Sociedad Argentina de Neurociencias

Age-related changes in mitochondrial bioenergetics as well as in motor and cognitive functions have been described, although the mechanisms underlying these changes at synaptic level remain to be elucidated. With the purpose of analyzing the effect of aging in motor performance and mitochondrial function in nerve terminals, 3-, 10- 17- 20-and 24-month-old mice were used. Motor performance was evaluated by tightrope and footprint tests. Brain cortex synaptosomes were isolated by a Ficoll gradient procedure and mitochondrial membrane potential, the activity of enzymatic respiratory complexes and superoxide levels were determined. Behavioral results showed a decrease in neuromuscular coordination at all the ages studied, with maximal changes at 24 months (88%). Mitochondrial membrane potential was unaffected in 10- and 20-months old mice but an increment (37%) was observed at 24 months, together with changes in enzymatic activity of mitochondrial respiratory complexes. A progressive increase in superoxide levels (11-21-25% for 10-, 20- and 24-months) was observed. Motor performance is impaired with aging. Synaptic bioenergetic function seems to be preserved until the age of 20 months, probably by the compensatory changes in mitochondrial respiratory complexes. At more advanced ages, the mechanisms of modulation of mitochondrial function are impaired resulting in alterations in mitochondrial membrane potential and increased levels of superoxide.