A Single Intraperitoneal Injection of Endotoxin Changes Glial Cells in Rats as Revealed by Positron Emission Tomography Using [11C]PK11195
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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.
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.
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.
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[11C]PK11195 Glial cells Lipopolysaccharides Positron emission tomography Somatosensory area
The authors thank Mr. Makoto Funasaka for his expert technical assistance with the PET experiments.
Compliance with Ethical Standards
Conflicts of Interest
Miho Ota was supported by a Grant-in-Aid for Scientific Research from the Japan Society for the Promotion of Science (C) (16 K10234). Jun Ogura, Shintaro Ogawa, Koichi Kato, Hiroshi Matsuda, and Hiroshi Kunugi declare that they have no conflicts of interest.
All experimental procedures were in accordance with the guidelines of the United State’s National Institutes of Health (1996) (http://oacu.od.nih.gov/regs/guide/guide.pdf) and were approved by the Ethics Review Committee for Animal Experimentation at the National Institute of Neuroscience, National Center of Neurology and Psychiatry, Japan, and performed with every effort to minimize the number of animals and their suffering.
The Ethics Review Committee for Animal Experimentation of our institution approved this study, and the requirement to obtain informed consent was waived.
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