The day-night differences in cognitive and anxiety-like behaviors of mice after chronic sleep restriction.

Animal behavioral tests are often conducted during the day. However, rodents are nocturnal animals and are primarily active at night. The aim of this study was to determine whether there are diurnal changes in cognitive and anxiety-like performance of mice following chronic sleep restriction (SR). We also investigated whether this phenotypic difference is related to the diurnal variation of glymphatic clearance of metabolic wastes. Mice received 9-day SR by the use of the modified rotating rod method, followed by the open field, elevated plus maze, and Y-maze tests conducted during the day and at night, respectively. Brain ß-amyloid (Aß) and tau protein levels, the polarity of aquaporin4 (AQP4), a functional marker of the glymphatic system, and glymphatic transport ability were also analyzed. SR mice exhibited cognitive impairment and anxiety-like behaviors during the day, but not at night. AQP4 polarity and glymphatic transport ability were higher during the day, with lower Aß1-42 , Aß1-40 , and P-Tau levels in the frontal cortex. These day-night differences were totally disrupted after SR. These results reveal the diurnal changes in behavioral performance after chronic SR, which may be related to circadian control of AQP4-mediated glymphatic clearance of toxic macromolecules from the brain.

The Effects of Aerobic Exercise on Cognitive Function of Alzheimer's Disease Patients.

To evaluate the effect of moderate intensity of aerobic exercise on elderly people with mild Alzheimer's disease, we recruited fifty volunteers aged 50 years to 80 years with cognitive impairment. They were randomized into two groups: aerobic group (n=25) or control group (n=25). The aerobic group was treated with cycling training at 70% of maximal intensity for 40 min/d, 3 d/wk for 3 months. The control group was only treated with heath education. Both groups were received cognitive evaluation, laboratory examination before and after 3 months. The results showed that the Minimum Mental State Examination score, Quality of Life Alzheimer's Disease score and the plasma Apo-a1 level was significantly increased (P<0.05), the Alzheimer's Disease Assessment Scale-cognition score, Neuropsychiatric Inventory Questionnaire score was significantly decreased.(P<0.05) in aerobic group before and after 3 months in aerobic group. For the control group, there was no significant difference in scores of Alzheimer's Disease Assessment Scale-cognition, Neuropsychiatric Inventory Questionnaire, Quality of Life Alzheimer's Disease, Apo-a1 (P>0.05), while Minimum Mental State Examination scores decreased significantly after 3 months (P<0.05). In conclusion, moderate intensity of aerobic exercise can improve cognitive function in patients with mild Alzheimer's disease.