Purpose: Intracranial administration of lipopolysaccharide (LPS) is known to elicit a rapid innate immune response, activate glial cells in the brain, and induce depression-like behavior. However, no study has focused on the changes in glial cells induced by intraperitoneal injection of LPS in vivo.
Methods: Ten adult male Fischer F344 rats underwent [11C]PK11195 PET before and 2 days after intraperitoneal injection of LPS to evaluate the changes in glial cells. The difference in standardized uptake values (SUV) of [11C]PK11195 between before and after injection was determined.
Results: There was a cluster of brain regions that showed significant reductions in SUV. This cluster included the bilateral striata and bilateral frontal regions, especially the somatosensory areas.
Conclusions: Changes in activity of glial cells induced by the intraperitoneal injection of LPS were detected in vivo by [11C]PK11195 PET. Intraperitoneal injection of LPS is known to induce depression, and further studies with [11C]PK11195 PET would clarify the relationships between neuroinflammation and depression.
Keywords: Glial cells; Lipopolysaccharides; Positron emission tomography; Somatosensory area; [11C]PK11195.