A Chronic Sleep Fragmentation Model using Vibrating Orbital Rotor to Induce Cognitive Deficit and Anxiety-Like Behavior in Young Wild-Type Mice

Summary

Presented here is a protocol for chronic sleep fragmentation (CSF) model achieved by an electrically controlled orbital rotor, which could induce confirmed cognitive deficit and anxiety-like behavior in young wild-type mice. This model can be applied to explore the pathogenesis of chronic sleep disturbance and related disorders.

Abstract

Sleep disturbance is generally common in populations as a chronic disease or a complained event. Chronic sleep disturbance is proposed to be closely linked to the pathogenesis of diseases, especially neurodegenerative diseases. We recently found that 2 months of sleep fragmentation initiated Alzheimer’s disease (AD)-like behavioral and pathological changes in young wild-type mice. Herein, we present a standardized protocol to achieve chronic sleep fragmentation (CSF). Briefly, CSF was induced by an orbital rotor vibrating at 110 rpm and operating with a repetitive cycle of 10 s-on, 110 s-off, during light-ON phase (8:00 AM–8:00 PM) continuously for up to 2 months. Impairments of spatial learning and memory, anxiety-like but not depression-like behavior in mice as consequences of CSF modeling, were evaluated with Morris water maze (MWM), Novel object recognition (NOR), Open field test (OFT) and Forced swimming test (FST). In comparison with other sleep manipulations, this protocol minimizes the handling labors and maximizes the modeling efficiency. It produces stable phenotypes in young wild-type mice and can be potentially generated for a variety of research purposes.

Introduction

Sleep disturbance is increasingly common both in patients with sleep-disturbing conditions and healthy people with sleep-disturbing events. It has been observed that patients with neurodegenerative diseases, chronic pain, emotional stress, respiratory system diseases, urinary system diseases, etc., usually complain about unpleasant sleep experiences^1,2,3,4,5. Obstructive sleep apnea (OSA), periodic limb movements in sleep (PLMS), sleep maintenance insomnia among other sleep disorders are the most commo....

Protocol

This protocol was approved by the Institutional Animal Care and Use Committee of Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology.

1. Mice screening and preparation for the experiment

1. Select wild-type adult (8–10 weeks old) male mice with weight of 20–28 g for the whole experiment.
   NOTE: Wild-type C57BL/6 mice are obtained from the Hubei Research Center for Laboratory Animals, Hubei, China.
2. Randomly assign all mice to the CSF and the control group. House 3–5 mice in each cage to avoid social isolation stress. The number of mice housed in the control cages i....

Results

All the representative results and figures were reproduced from our recent publication²¹. The reuse of the figures was permitted by the original journal.

The entire experimental design is illustrated in the order of time, which indicates the timing of CSF modeling, behavioral tests of MWM, NOR, OFT, and FST (Figure 1A). We obtained weights of mice every week from the CSF and the control groups, to monitor their general conditions during the.......

Discussion

Critical steps in the current protocol include setting up sleep fragmentation machines with the optimized parameters according to the study purpose and maintaining the mice in comfortable and quiet living environment throughout the entire modeling sessions. It is also crucial to decide the proper timing to interrupt or stop sleep fragmentation and arrange behavioral tests for those mice. Like other sleep manipulation models, it is important to perform the protocol in a dedicated room with controlled light cycles and void.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Any-maze behavior tracking system	Stoelting,Inc,USA	-	A video-tracking system which was used to record the behavior track of mice.
C57BL/6J mice	Hubei Research Center for Laboratory Animals, Hubei, China.	-	healthy male C57BL/6J mice aged 10-12 weeks were purchased from Hubei Research Center for Laboratory Animals
Graphpad Prism 6.0 Software	Graphpad Software,Inc.USA	-	Graphpad Prism 6.0 software was used to draw statistical graphs.
Morris water maze system	Shanghai XinRuan Information Technology Co.,Ltd,China	XR-XM101	The system was used to perform Morris water maze test
Orbial rotor	Shanghai ShiPing Laboratory Equipment Co.,Ltd,China	SPH-331	The orbital rotor was used to establish the chronic sleep fragmentation model
Solid state timer	OMRON Corporation, Kyoto, Japan	H3CR-F8-300	The solid state time was used to control the frequency and time of the rotor running
Wooden Lusterless Tank	-	-	length 30 cm, width 28 cm, height 35 cm The tank was used to perform open field test and novel object recognition test