The macrophage system in the intestinal muscularis externa during inflammation: an immunohistochemical and quantitative study of osteopetrotic mice.
Intestinal inflammation results in disturbed intestinal motility in humans as well as in animal models. This altered function of smooth muscle cells and/or the enteric nervous system may be caused by activation of macrophages in muscularis externa and a thereby following release of cytokines and chemokines that causes influx of mononuclear cells and neutrophilic granulocytes. We subjected osteopetrotic (op/op) mice that lack certain macrophage subtypes, e.g. macrophages in the muscularis externa and +/+ mice to LPS to induce inflammatory cell influx. The densities of F4/80+, MHCII+, and myeloperoxidase+ cells were quantified using stereological sampling. In +/+ mice we found that MHCII+ cells outnumber F4/80+ cells and that LPS injection increased the density of MHCII+ cells temporarily but not that of F4/80+ cells. This indicates that an upregulation of MHCII antigen takes place and that two or more macrophage subtypes with comparable morphologies exist. Osteopetrotic mice lacked MHCII+, CD169+, and F4/80+ cells after either treatment, which indicate that these cells are CSF-1-dependent. LPS induced VCAM-1 activation of the vessels, modest influx of granulocytes, as well as an iNOS-activation in a cell type different from macrophages in both +/+ and op/op mice.
Mikkelsen
H B
HB
Department of Cellular and Molecular Medicine, The Panum Building, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3, 2200, Copenhagen N, Denmark. hannem@sund.ku.dk
Larsen
J O
JO
Hadberg
H
H
D000818:Animals; D000943:Antigens, Differentiation / Q000276:immunology; D005260:Female; D000949:Histocompatibility Antigens Class II / Q000276:immunology; D007249:Inflammation / Q000276:immunology* / Q000473:pathology; D007583:Jejunum / Q000276:immunology* / Q000473:pathology; D008070:Lipopolysaccharides / Q000276:immunology; D008262:Macrophage Activation / Q000276:immunology*; D008264:Macrophages / Q000276:immunology*; D051379:Mice; D008817:Mice, Mutant Strains; D009130:Muscle, Smooth / Q000276:immunology* / Q000473:pathology; D010022:Osteopetrosis / Q000276:immunology
D000943:Antigens, Differentiation; D000949:Histocompatibility Antigens Class II; D008070:Lipopolysaccharides; C036763:monocyte-macrophage differentiation antigen