Long-Term Dietary Extra-Virgin Olive Oil Rich in Polyphenols Reverses Age-Related Dysfunctions in Motor Coordination and Contextual Memory in Mice: Role of Oxidative Stress

Abstract

The aim of this study was to evaluate the effects of olive oil phenols on brain aging in mice and to verify whether the antioxidant and antiinflammatory activities of these polyphenols were involved. C57Bl/6J mice were fed from middle age to senescence with extra-virgin olive oil (10% wt/wt dry diet) rich in phenols (total polyphenol dose/day, 6 mg/kg). Behavioral tests were employed to assess cognitive, motor, and emotional behavior after 6 or 12 months of treatment. Parameters of oxidative status and inflammation were measured in different brain areas at the same times and evaluated for correlation with behavioral changes. The treatment with olive oil phenols improved contextual memory in the step-down test to levels similar to young animals and prevented the age-related impairment in motor coordination in the rotarod test. This motor effect was correlated with reduced lipid peroxidation in the cerebellum (p<0.05), whereas the memory effect did not correlate with oxidation or inflammation parameters. In conclusion, this work points out that natural polyphenols contained in extra-virgin olive oil can improve some age-related dysfunctions by differentially affecting different brain areas. Such a modulation can be obtained with an olive oil intake that is normal in the Mediterranean area, provided that the oil has a sufficiently high content of polyphenols.