Effects of Circadian Rhythm Disorder on Learning and Memory in Mice

Objective: The change of learning and memory was explored in circadian rhythm disorder mice induced by irregular light/ dark cycle. Methods: Mice model of circadian rhythm disorder induced by irregular light/dark cycle. Twenty-four male ICR mice were raised under different light/dark cycles including LD 12h/12h (Group 1: Normal circadian rhythm group), light 3h next to darkness 5h and light 5h next to dark 3h alternate every other day (Group 2: Circadian rhythm disorder group). The twenty-four ICR mice were randomly assigned to these two groups and feed six months. Each group included twelve. Morris Water-maze task was used as the judging criteria for spatial learning and memory. Result: The learning and memory was significantly decreased in circadian rhythm disorder mice induced by irregular light/ dark cycle (P<0.05). Conclusion: Circadian rhythm disorders impaired learning and memory.