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Hypertonic preconditioning inhibits macrophage responsiveness to endotoxin. J Immunol 2002 Feb 01;168(3):1389-96

Date

01/22/2002

Pubmed ID

11801680

DOI

10.4049/jimmunol.168.3.1389

Scopus ID

2-s2.0-0036467350   66 Citations

Abstract

Hypertonic saline has been shown to modulate cell shape and the response of components of the innate immune response. However, the effect of hypertonic saline on the macrophage remains unknown. We hypothesized that hypertonic preconditioning would impair subsequent inflammatory mediator signaling through a reduction in stress fiber polymerization and mitogen-activated protein kinase activity after LPS stimulation. Rabbit alveolar macrophages were stimulated with 100 ng/ml of LPS. Selected cells were preconditioned with 40-100 mM of NaCl, mannitol, or urea for 4 h and returned to isotonic medium before LPS stimulation. Cellular protein was harvested and subjected to Western blot analysis for the dually phosphorylated active forms of p38 and extracellular signal-related kinase (ERK) 1/2. TNF production was determined by an L929 bioassay, and stress fiber polymerization was evaluated by confocal microscopy. Preconditioning of macrophages with NaCl or mannitol resulted in dose-dependent reduction in ERK 1/2 phosphorylation with no effect on p38 phosphorylation. Urea preconditioning had no effect on either mitogen-activated protein kinase. A dose-dependent attenuation of TNF production was seen with NaCl and mannitol preconditioning (p < 0.05), but not with urea. NaCl and mannitol preconditioning resulted in failure of LPS-induced stress fiber polymerization, whereas urea did not. Extracellular hypertonic conditions (i.e., NaCl and mannitol) have an immunomodulatory effect on macrophages, demonstrated through failure of optimal stress fiber polymerization, ERK 1/2 activity, and TNF production. Intracellular hypertonic conditions (i.e., urea) had no significant effect. Hypertonic saline or mannitol resuscitation, therefore, may help protect against multiple-organ dysfunction syndrome as a result of this reduced proinflammatory responsiveness.

Author List

Cuschieri J, Gourlay D, Garcia I, Jelacic S, Maier RV

Author

David M. Gourlay MD Chief, Professor in the Surgery department at Medical College of Wisconsin




MESH terms used to index this publication - Major topics in bold

Animals
Diuretics, Osmotic
Dose-Response Relationship, Drug
Dose-Response Relationship, Immunologic
Enzyme Activation
Lipopolysaccharides
Macrophages, Alveolar
Male
Mannitol
Mitogen-Activated Protein Kinase 1
Mitogen-Activated Protein Kinase 3
Mitogen-Activated Protein Kinases
Polymers
Rabbits
Saline Solution, Hypertonic
Stress Fibers
Time Factors
Tumor Necrosis Factor-alpha
Urea
p38 Mitogen-Activated Protein Kinases