Extra Virgin Olive Oil Improves Learning and Memory in SAMP8 Mice

Article type: Research Article

Authors: Farr, Susan A.^{a; b; *} | Price, Tulin O.^c | Dominguez, Ligia J.^d | Motisi, Antonio^d | Saiano, Filippo^e | Niehoff, Michael L.^b | Morley, John E.^{a; b} | Banks, William A.^{g; h} | Ercal, Nuranⁱ | Barbagallo, Mario^d

Affiliations: [a] Geriatric Research Educational and Clinical Center (GRECC), VA Medical Center, St. Louis, MO, USA | [b] Department of Internal Medicine, Division of Geriatric Medicine, St. Louis University School of Medicine, St. Louis, MO, USA | [c] Department of Internal Medicine, Division of Endocrinology, St. Louis University School of Medicine, St. Louis, MO, USA | [d] Division of Geriatric Medicine, University of Palermo, Palermo, Italy | [e] Department DEMETRA, Agronomy Faculty, University of Palermo, Palermo, Italy | [f] Department of Agro-Environmental Systems, University of Palermo, Palermo, Italy | [g] Geriatric Research Educational and Clinical Center (GRECC), Veterans Affairs Puget Sound Health Care System, Seattle, WA, USA | [h] Department of Internal Medicine, Division of Gerontology and Geriatric Medicine, University of Washington School of Medicine, Seattle, WA, USA | [i] Department of Chemistry, Missouri University of Science and Technology, Rolla, MO, USA

Correspondence: [*] Correspondence to: Susan A. Farr, Ph.D., Associate Professor/ Research Health Scientist, St. Louis University School of Medicine/VA Medical Center, St. Louis, 915 North Grand Blvd. 151/JC, St. Louis, MO 63106, USA. Tel.: +314 289 7608; Fax: +314 289 7046; E-mail: farrsa@slu.edu.

Abstract: Polyphenols are potent antioxidants found in extra virgin olive oil (EVOO); antioxidants have been shown to reverse age- and disease-related learning and memory deficits. We examined the effects of EVOO on learning and memory in SAMP8 mice, an age-related learning/memory impairment model associated with increased amyloid-β protein and brain oxidative damage. We administered EVOO, coconut oil, or butter to 11 month old SAMP8 mice for 6 weeks. Mice were tested in T-maze foot shock avoidance and one-trial novel object recognition with a 24 h delay. Mice which received EVOO had improved acquisition in the T-maze and spent more time with the novel object in one-trial novel object recognition versus mice which received coconut oil or butter. Mice that received EVOO had improve T-maze retention compared to the mice that received butter. EVOO increased brain glutathione levels suggesting reduced oxidative stress as a possible mechanism. These effects plus increased glutathione reductase activity, superoxide dismutase activity, and decreased tissue levels of 4-hydroxynoneal and 3-nitrotyrosine were enhanced with enriched EVOO (3 × and 5 × polyphenols concentration). Our findings suggest that EVOO has beneficial effects on learning and memory deficits found in aging and diseases, such as those related to the overproduction of amyloid-β protein, by reversing oxidative damage in the brain, effects that are augmented with increasing concentrations of polyphenols in EVOO.

Keywords: Extra virgin olive oil, learning, memory, object recognition, oxidative stress, SAMP8, T-maze

DOI: 10.3233/JAD-2011-110662

Journal: Journal of Alzheimer's Disease, vol. 28, no. 1, pp. 81-92, 2012