title: Glycyrrhizin alleviates neuroinflammation and memory deficit induced by systemic lipopolysaccharide treatment in mice.
abstract: The present study investigated the effects of glycyrrhizin (GRZ) on neuroinflammation and memory deficit in systemic lipopolysaccharide (LPS)-treated C57BL/6 mice. Varying doses of GRZ was orally administered (10, 30, or 50 mg/kg) once a day for 3 days before the LPS (3 mg/kg) injection. At 24 h after the LPS injection, GRZ significantly reduced TNF-α and IL-1β mRNA at doses of 30 and 50 mg/kg. COX-2 and iNOS protein expressions were significantly reduced by GRZ at doses of 30 and 50 mg/kg. In the Morris water maze test, GRZ (30 mg/kg) significantly prolonged the swimming time spent in the target and peri-target zones. GRZ also significantly increased the target heading and memory score numbers. In the hippocampal tissue, GRZ significantly reduced the up-regulated Iba1 protein expression and the average cell size of Iba1-expressing microglia induced by LPS. The results indicate that GRZ ameliorated the memory deficit induced by systemic LPS treatment and the effect of GRZ was found to be mediated through the inhibition of pro-inflammatory mediators and microglial activation in the brain tissue. This study supports that GRZ may be a putative therapeutic drug on neurodegenerative diseases associated with cognitive deficits and neuroinflammation such as Alzheimer's disease.
authors.forename: Jeong-Ho
authors.initials: JH
authors.lastname: Song
authors.forename: Ju-Won
authors.initials: JW
authors.lastname: Lee
authors.forename: Beomsoo
authors.initials: B
authors.lastname: Shim
authors.forename: Chang-Yeol
authors.initials: CY
authors.lastname: Lee
authors.forename: Sooyong
authors.initials: S
authors.lastname: Choi
authors.forename: Chulhun
authors.initials: C
authors.lastname: Kang
authors.forename: Nak-Won
authors.initials: NW
authors.lastname: Sohn
authors.affiliation: Department of East-West Medical Science, Graduate School of East-West Medical Science, Kyung Hee University, Yongin 446-701, Korea. shinarago@khu.ac.kr.
authors.forename: Jung-Won
authors.initials: JW
authors.lastname: Shin
mesh_terms: D000818:Animals; D001921:Brain / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D051546:Cyclooxygenase 2 / Q000235:genetics / Q000378:metabolism; D016207:Cytokines / Q000235:genetics / Q000378:metabolism; D004195:Disease Models, Animal; D004660:Encephalitis / Q000139:chemically induced / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects; D019695:Glycyrrhizic Acid / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D007858:Learning / Q000187:drug effects; D008070:Lipopolysaccharides / Q000009:adverse effects; D008297:Male; D008569:Memory Disorders / Q000139:chemically induced / Q000188:drug therapy*; D051379:Mice; D017628:Microglia / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000235:genetics / Q000378:metabolism
chemical_list: D016207:Cytokines; D008070:Lipopolysaccharides; D019695:Glycyrrhizic Acid; D052247:Nitric Oxide Synthase Type II; D051546:Cyclooxygenase 2