Temporal, regional, and cell-specific changes of iNOS expression after intrastriatal microinjection of interferon gamma and bacterial lipopolysaccharide.
Here we study expression of the inducible isoform of nitric oxide synthases after intrastriatal microinjection of interferon-gamma and bacterial lipopolysaccharide in the rat at different time points to detect time- and localisation-dependent changes of iNOS expression. Three different areas in the striatum and the corpus callosum were evaluated. Antibodies against the glial fibrillary acidic protein and the microglia/brain macrophage epitope ED1 were used to detect colocalization of inducible nitric oxide synthase with astrocytes or activated microglia/brain macrophages, respectively. Inducible nitric oxide synthase-positive cells occurred first in intravascular and perivascular cells at 4 h. Perivascular and parenchymal inducible nitric oxide synthase expression increased up to 24 h in the striatum, whereas in the corpus callosum inducible nitric oxide synthase expression was maximal after 16 h. Inducible nitric oxide synthase was still present in perivascular cells 7 days after immunostimulation. At all time points, inducible nitric oxide synthase was predominantly detected in ED1-positive microglia/brain. Nitrotyrosine immunohistochemistry was performed to detect NO-mediated nitration of proteins at all time points. Nitrotyrosine-positive neurons and microglial cells were detected from 24 h until 7 days after immunostimulation and were absent in controls. Detailed knowledge of the changes in the time course and cellular source of inducible nitric oxide synthase expression following brain immunostimulation provide a basis for establishing treatment strategies and windows of therapeutic intervention during neuroinflammation.
Heneka
M T
MT
Department of Neurology, University of Bonn, Sigmund-Freud Strasse 25, 53105, Bonn, Germany. m.heneka@uni-bonn.de
Dumitrescu
L
L
Löschmann
P A
PA
Wüllner
U
U
Klockgether
T
T
D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D001253:Astrocytes / Q000737:chemistry / Q000187:drug effects / Q000201:enzymology*; D003337:Corpus Callosum / Q000166:cytology; D003342:Corpus Striatum / Q000166:cytology; D005904:Glial Fibrillary Acidic Protein / Q000032:analysis; D020287:In Situ Nick-End Labeling; D007371:Interferon-gamma / Q000494:pharmacology*; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008297:Male; D017628:Microglia / Q000737:chemistry / Q000187:drug effects / Q000201:enzymology; D008845:Microinjections; D009443:Neuritis / Q000201:enzymology; D019001:Nitric Oxide Synthase / Q000378:metabolism*; D052247:Nitric Oxide Synthase Type II; D051381:Rats; D017208:Rats, Wistar; D014443:Tyrosine / Q000031:analogs & derivatives / Q000032:analysis
D000970:Antineoplastic Agents; D005904:Glial Fibrillary Acidic Protein; D008070:Lipopolysaccharides; C002744:3-nitrotyrosine; D014443:Tyrosine; D007371:Interferon-gamma; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496318:Nos2 protein, rat