A sleep disturbance method by novel objects in the home cage to minimize stress

Background

The increasing prevalence of low sleep quality is a significant issue, particularly among adolescents, necessitating a deeper understanding of its biological consequences. In sleep research, various protocols are used for sleep deprivation or disturbance, each presenting its own set of confounding factors crucial to consider.

New Method

We developed a standardized seven-day sleep disturbance (SD) protocol using daily four-hour exposures to novel objects to minimize rodent stress. Objects were selected and characterized for wake-promoting properties, and exposure timing was structured to reduce variability and enhance experimental reliability and reproducibility.

Results

During the four hours of SD, the mice were efficiently sleep-deprived on the first and seventh day of SD. Thus, the selected objects efficiently sleep restricted the mice. On the first day of SD, the protocol induced sleep deprivation effect when measured over 24h, but by the seventh day, the mice recovered the sleep loss. Thus, this method is a sub-chronic sleep disturbance and not sleep deprivation. Fecal corticosterone concentrations remained unchanged during the seven days of SD.

Comparison with existing methods

This approach reduced the risk of stress through voluntary rather than forced wakefulness. Previously, novel objects have been exchanged randomly during mouse sleep initiation causing protocol variability and very frequent disturbances. Our protocol minimizes this by introducing the novel object in a structured manner.

Conclusion

We effectively disturbed the sleep of the mice during seven days without inflicting substantial stress. We further demonstrate the value of validating the efficiency of an SD protocol with 24h recordings.

Highlights

• Standardized sleep disruption method by object exposure in mice

• Mice are sleep-restricted during the four-hour SD intervention all 7 days

• Mice habituate to a subchronic sleep deprivation setup by recovering sleep outside of the SD period

• Fecal corticosterone samples showed no difference before and after SD intervention