Changes in motor function and brain cortex mitochondrial active oxygen species production in aged mice

Neuronal ageing is a complex physiological process, associated to metabolic and motor changes. In this study, 3 and 17 months old male Swiss mice were used. Aged mice exhibited a significant reduction in motor performance and walking footprint pattern. Synaptosomes and mitochondrial fractions were isolated from mouse brain cortex. Active oxygen species and cardiolipin content were measured in both subcellular fractions. Synaptosomal acetylcholinesterase activity was measured in both animal age groups. Results showed that superoxide levels were 42.9% lower in synaptosomes from old mice as compared with young animals, while no changes were observed in non-synaptic mitochondria. Succinate-glutamate dependent H₂O₂ production rate was 27.5% decreased in non-synaptic mitochondria from aged mice. Cardiolipin content was 21% decreased in synaptosomes from 17-months old animals, while no changes were observed in non-synaptic mitochondria. Acetylcholinesterase activity decreased 16% in 17-months old mice, as compared with young animals. Age-related alterations in neuronal function could be associated with changes in active oxygen species at synapses, with parallel motor deficiencies.