title: Hypertonic saline reduces lipopolysaccharide-induced mouse brain edema through inhibiting aquaporin 4 expression.
abstract: BACKGROUND
  Three percent sodium chloride (NaCl) treatment has been shown to reduce brain edema and inhibited brain aquaporin 4 (AQP4) expression in bacterial meningitis induced by Escherichia coli. Lipopolysaccharide (LPS) is the main pathogenic component of E. coli. We aimed to explore the effect of 3% NaCl in mouse brain edema induced by LPS, as well as to elucidate the potential mechanisms of action.
  
  
  METHODS
  Three percent NaCl was used to treat cerebral edema induced by LPS in mice in vivo. Brain water content, IL-1β, TNFα, immunoglobulin G (IgG), AQP4 mRNA and protein were measured in brain tissues. IL-1β, 3% NaCl and calphostin C (a specific inhibitor of protein kinase C) were used to treat the primary astrocytes in vitro. AQP4 mRNA and protein were measured in astrocytes. Differences in various groups were determined by one-way analysis of variance.
  
  
  RESULTS
  Three percent NaCl attenuated the increase of brain water content, IL-1β, TNFα, IgG, AQP4 mRNA and protein in brain tissues induced by LPS. Three percent NaCl inhibited the increase of AQP4 mRNA and protein in astrocytes induced by IL-1β in vitro. Calphostin C blocked the decrease of AQP4 mRNA and protein in astrocytes induced by 3% NaCl in vitro.
  
  
  CONCLUSIONS
  Osmotherapy with 3% NaCl ameliorated LPS-induced cerebral edema in vivo. In addition to its osmotic force, 3% NaCl exerted anti-edema effects possibly through down-regulating the expression of proinflammatory cytokines (IL-1β and TNFα) and inhibiting the expression of AQP4 induced by proinflammatory cytokines. Three percent NaCl attenuated the expression of AQP4 through activation of protein kinase C in astrocytes.
authors.forename: C
authors.initials: C
authors.lastname: Cao
authors.forename: X
authors.initials: X
authors.lastname: Yu
authors.forename: Z
authors.initials: Z
authors.lastname: Liao
authors.forename: N
authors.initials: N
authors.lastname: Zhu
authors.forename: H
authors.initials: H
authors.lastname: Huo
authors.forename: M
authors.initials: M
authors.lastname: Wang
authors.forename: G
authors.initials: G
authors.lastname: Ji
authors.forename: H
authors.initials: H
authors.lastname: She
authors.forename: Z
authors.initials: Z
authors.lastname: Luo
authors.forename: S
authors.initials: S
authors.lastname: Yue
mesh_terms: D000818:Animals; D051401:Aquaporin 4 / Q000037:antagonists & inhibitors* / Q000096:biosynthesis*; D001929:Brain Edema / Q000139:chemically induced / Q000378:metabolism* / Q000517:prevention & control*; D005786:Gene Expression Regulation; D008070:Lipopolysaccharides / Q000633:toxicity*; D051379:Mice; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D012462:Saline Solution, Hypertonic / Q000494:pharmacology / Q000627:therapeutic use*
chemical_list: C496031:Aqp4 protein, mouse; D051401:Aquaporin 4; D008070:Lipopolysaccharides; D012462:Saline Solution, Hypertonic