Nitrosative stress in primary glial cultures after induction of the inducible isoform of nitric oxide synthase (i-NOS).
Primary glial cultures are able to express the inducible isoform of nitric oxide synthase (i-NOS) upon stimulation by bacterial lipopolysaccharides (LPS) and gamma-interferon (gamma-IfN). Immunocytochemical studies revealed, that under our experimental conditions i-NOS is expressed exclusively by the microglial cells and not in the astrocytes. Nitric oxide (NO) formation represents an oxidative load for the microglial cells, as observed by the oxidation rate of the ROS- and peroxynitrite indicator dichloro-dihydrofluorescein (DCF-H) in these cells. However, cell viability was not affected by the nitric oxide formation, indicating some form of protection against the higher oxidative load. Upregulation of Mn-SOD in the mitochondria in the course of the induction of i-NOS and, compared to the astrocytes, higher GSH levels in the microglial cells probably explain the resistance of the cultures against nitrosative stress. Increased SOD-activities in the mitochondria could lower the superoxide concentration in this organelle and may prevent an oxidative and/or nitrosative damage via a decreased peroxynitrite formation. The higher GSH-levels in the microglial cells of unstimulated cultures represents a buffer which, under the conditions of i-NOS catalyzed NO-formation, prevents a decline of the microglial GSH-levels below that of the astrocytes.
Noack
H
H
Institute for Medical Neurobiology, Otto-von-Guericke University Magdeburg, Leipziger Str. 44, 39120 Magdeburg, Germany. heiko.noack@medizin.uni-halle.de
Possel
H
H
Chatterjee
S
S
Keilhoff
G
G
Wolf
G
G
D000818:Animals; D000831:Animals, Newborn; D002478:Cells, Cultured; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism; D007371:Interferon-gamma / Q000494:pharmacology; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology; D009457:Neuroglia / Q000166:cytology / Q000187:drug effects / Q000201:enzymology*; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000378:metabolism*; D052247:Nitric Oxide Synthase Type II; D009573:Nitrites / Q000378:metabolism; D015538:Nitrosation; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D051381:Rats; D017208:Rats, Wistar; D013482:Superoxide Dismutase / Q000378:metabolism
D005904:Glial Fibrillary Acidic Protein; D008070:Lipopolysaccharides; D009573:Nitrites; D009569:Nitric Oxide; D007371:Interferon-gamma; D007770:L-Lactate Dehydrogenase; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496318:Nos2 protein, rat; D013482:Superoxide Dismutase; D005978:Glutathione