Voluntary exercise reduces plasma cortisol levels and improves transitory memory impairment in young and aged Octodon degus

• Published in: Behavioural brain research 2019-11, Vol.373, p.112066-112066, Article 112066
• Main Authors: Estrada, Cristina, Cuenca, Lorena, Cano-Fernandez, Lorena, Gil-Martinez, Ana Luisa, Sanchez-Rodrigo, Consuelo, González-Cuello, Ana Maria, Fernandez-Villalba, Emiliano, Herrero, Maria Trinidad
• Format: Article
• Language: English
• Subjects: Alzheimer’s disease; Cortisol; Memory impairment; O. degus; Sleep deprivation; Voluntary exercise
• ISSN: 0166-4328; 1872-7549
• DOI: 10.1016/j.bbr.2019.112066

•Memory impairment induced by SD is improved with voluntary physical exercise.•Physical exercise reduces plasma cortisol levels, independently of the age.•Exercise is a promising non-pharmacologic approach, combined with other therapies. Sleep deprivation (SD) has been reported to induce transient cognitive impairment in functional domains commonly affected in dementia, including memory. Indeed, sleep disturbance has been proposed as an early marker for Alzheimer’s disease (AD). SD emulates many aging-related modifications, including important memory dysfunctions possibly caused by triggers of stress such as cortisol. Although exercise is widely assumed to be beneficial for overall health, only recently has the research community focused its attention on its possible effects on brain functions such as cognition. Octodon degus (O. degus) is a recent rodent model considered suitable for the study of neurodegenerative diseases, since it spontaneously develops several histopathological hallmarks observed in AD. We aimed to uncover the interaction between stress, exercise, age and transient memory impairments after SD insult. In this study, animals had free individual access to wheels to practice voluntary exercise. The Barnes Maze (BM) task was conducted with young and aged O. degus animals after combining voluntary exercise and either normal sleep or SD. Plasma cortisol levels were measured after each condition. SD impaired hippocampus-dependent memory in both young and old animals, while cortisol levels did not significantly differ between non-SD and SD animals. However, voluntary exercise for 45 days improved the cognitive impairment caused by SD compared with the control condition. Moreover, voluntary exercise decreased plasma cortisol levels in both conditions, independently of the age.