Impact of Sleep Deprivation on the Brain's Inflammatory Response Triggered by Lipopolysaccharide and Its Consequences on Spatial Learning and Memory and Long-Term Potentiation in Male Rats.

Introduction: Both sleep deprivation (SD) and inflammation can negatively affect cognitive function. This study aimed to investigate how SD impacts the brain's inflammatory response to lipopolysaccharide (LPS) and its subsequent effects on cognitive functions.

Methods: To this end, male rats were tested through a Morris water maze (MWM) to assess their spatial learning and memory. Also, in vivo field potential recordings (to evaluate synaptic plasticity) were done in the Saline, SD, LPS1 (1 mg/kg/7 days), and LPS1+SD groups. Cytokine levels were measured using an enzyme-linked immunosorbent assay (ELISA).

Results: Based on the results, the LPS1+SD group showed increased total distance and escape latency compared to the other groups in the MWM test. Besides, the LPS1+SD group exhibited a significant decrease in long-term potentiation (LTP) induction and maintenance in the CA1 area of the brain. Finally, the inflammatory cytokine interleukin-1β (IL-1β) levels were significantly higher in the LPS1+SD group than in the Saline group.

Conclusion: These findings suggest that the combined effects of SD and brain inflammatory response can have more harmful effects on cognitive function, LTP, and inflammatory factors than either SD or LPS1 alone.