Chronic high-caloric diet modifies sleep homeostasis in mice.

Abstract

Obesity prevalence and sleep habit changes are commonplace nowadays, due to modern lifestyle. A bidirectional relationship likely exists between sleep quality and metabolic disruptions, which could impact quality of life. In our study, we investigated the effects of a chronic high-caloric diet on sleep architecture and sleep regulation in mice. We studied the effect of 3months high-caloric diet (HCD, 45% fat) on sleep and the sleep electroencephalogram (EEG) in C57BL/6J mice during 24-hr baseline (BL) recordings, and after 6-hr sleep deprivation (SD). We examined the effect of HCD on sleep homeostasis, by performing parameter estimation analysis and simulations of the sleep homeostatic Process S, a measure of sleep pressure, which is reflected in the non-rapid-eye-movement (NREM) sleep slow-wave-activity (SWA, EEG power density between 0.5 and 4.0Hz). Compared to controls (n=11, 30.7±0.8g), mice fed with HCD (n=9, 47.6±0.8g) showed an increased likelihood of consecutive NREM-REM sleep cycles, increased REM sleep and decreased NREM sleep EEG SWA. After SD, these effects were more pronounced. The simulation resulted in a close fit between the time course of SWA and Process S in both groups. HCD fed mice had a slower time constant (Ti =15.98hr) for the increase in homeostatic sleep pressure compared with controls (5.95hr) indicating a reduced effect of waking on the increase in sleep pressure. Our results suggest that chronic HCD consumption impacts sleep regulation.