0044 DIFFERENTIAL EFFECTS OF PARADOXICAL SLEEP DEPRIVATION ON ADOLESCENT AND ADULT MICE

Abstract

Sleep insufficiency has become a serious health issue. In the modern society, most of the people, including the adolescence, do not obtain enough sleep. Since adolescence is a critical period for brain development, the consequences of insufficient sleep during adolescence should be concerned. The current study emphasized the effects of 72-hour paradoxical sleep deprivation (SD) on behavioral and morphological aspects in adolescent mice and used adult mice for comparison. In this study, we examined the acute effects of 72-hour paradoxical SD. 5 weeks old and 10–12 weeks old male C57/BL6 mice were used. The two time points were chosen to represent the periods of adolescence and adulthood, respectively. SD for 72 hours were conducted using modified multiple platform method. For mice kept in the home cage and on big platforms, sleep time was not limited and used as controls. Mice of SD and control groups were examined in behavioral, neurochemical and histological aspects. Our results showed that the short-term spatial memory, examined by Y-maze spontaneous alternation test, was affected by 72-hour paradoxical SD in adolescent mice but not in adult mice. The complexity of granule cells in dentate gyrus (DG) was reduced after SD in adolescent but minimal changes were observed in adult animals. There was an increase of spine density in DG granule cell after 72-hour paradoxical SD in adolescent and not in adult SD animals. Hippocampal neurogenesis in the DG was reduced by SD in both adolescent and adult groups. Results from this study revealed that SD negatively impacted the cognitive function by impairing the spatial working memory in adolescent but not in adult mice. Moreover, the analyses of dendritic complexity and spine density of granule cells in the hippocampal DG also indicated age-related morphological alterations after 72-hour sleep deprivation. Our results indicated the adolescent mice are relatively more sensitive to SD than the adult mice. It is the first study, to our knowledge, that compared the differential effects of SD on adolescent and adult mice. None.