Restoration of Spatial Learning Through Oral Administration of Lipopolysaccharides in Diabetes-related Cognitive Dysfunction.

Background/Aim: In a previous report, our group showed that oral administration of lipopolysaccharides (LPS) from Pantoea agglomerans can prevent the progression of streptozotocin (STZ)-induced diabetes-related cognitive dysfunction (DRCD) in mice without causing significant sideeffects. However, the treatment effects of oral administration of LPS to DRCD remain unknown. Materials and Methods: We modified our previous animal experimental model to investigate whether oral administration of LPS can recover cognitive function after DRCD onset. Results: The Morris water maze (MWM) revealed a significant decrease in learning and memory abilities at 13 days after intracerebroventricular administration of STZ, thereby providing evidence of the occurrence of DRCD in the animal model. Oral administration of LPS (1 mg/kg per day) started after cognitive impairment was observed. After 28 days of treatment, mice receiving LPS via the oral route showed significant recovery of spatial learning ability, a symptom of early dementia, while only a trend toward recovery was seen for spatial memory compared to the untreated group. Conclusion: These results, limited to MWM, suggest that oral administration of LPS is a promising therapeutic strategy for restoring decreased spatial learning ability. [ABSTRACT FROM AUTHOR]