Key Laboratory of Regenerative Biology, South China Institute of Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, China

Abstract 

Objective
It has been shown that there are extensive interactions between the central nervous system and the immune system. The present study focused on the effects of lipopolysaccharide (LPS) on memory retrieval, to explore the interaction between immune activation and memory.
Methods
C57BL/6J mice (8 weeks old) were first trained in the Morris water maze to reach asymptotic performance. Then mice were tested 24 h after the last training session and LPS was administered (1.25 mg/kg, i.p.) 4 h prior to the testing. The retrieval of spatial memory was tested by probe trial, and the time spent in the target quadrant and the number of platform location crosses were recorded. ELISA was performed to detect interleukin-1β (IL-1β) protein level in the hippocampus of mice tested in the water maze.
Results
Although LPS induced overt sickness behavior and a significant increase in the level of IL-1β in the hippocampus of mice, there was no significant difference in the time spent in the target quadrant or in the number of platform location crosses between LPS-treated and control groups in the probe trial testing.
Conclusion
Immune activation induced by LPS does not impair the retrieval of spatial memory.

Keywords

lipopolysaccharide; immune activation; sickness behavior; hippocampus; interleukin-1β; Morris water maze; spatial memory; memory retrieval

[SpringerLink]