Influence of circadian disorder on structures and functions of neurons in hippocampus of mice

Abstract

Objective: This study explored the effect of circadian disorder on structure and function of neurons in hippocampus of mice. Methods: Forty male ICR mice were randomly divided into rhythm disorder group (RDG) and normal rhythm group (NRG). The RDG was treated with 3 h light/5 h dark and 5 h light/3 h dark light–dark (LD) cycle alternately. The normal rhythm group was treated with 12/12 h LD cycle. Electron microscope was used to detect the mouse hippocampal cell ultrastructure. Morris water maze was used to test mice cognitive function. The brain slice electric physiological techniques were used to detect synapses in the hippocampal Long-term potentiation (LTP) effect. Results: The time of through central area of RDG was less than that of NRG. The axoplasm in anterior-posterior membranes of synapses of RDG was dissolved and synaptic vesicles of RDG were decreased. Conclusion: Circadian rhythm disorder induced by irregular light–dark circle can lead to the structural damage of hippocampal neurons and damage the cognitive function in mice.

Keywords:

• Circadian rhythm
• praxiology
• structures and functions
• hippocampus neurons
• cognitive function

Acknowledgements

The authors thank the staff of the Key Laboratory of Chronobiology of Health Ministry in Basic and Forensic School of Sichuan University, and the Department of Geriatrics of the third hospital of Mianyang, and the College of Electronic Engineering, Chengdu University of Information Technology, and all study participants (as well as their legal proxies) for their great contributions.