L-Arginine decreases fluid-percussion injury-induced neuronal nitrotyrosine immunoreactivity in rats.
Peroxynitrite is a powerful oxidant capable of nitrating phenolic moieties, such as tyrosine or tyrosine residues in proteins and increases after traumatic brain injury (TBI). First, we tested the hypothesis that TBI increases nitrotyrosine (NT) immunoreactivity in the brain by measuring the number of NT-immunoreactive neurons in the cerebral cortex and hippocampus of rats subjected to parasagittal fluid-percussion TBI. Second, we tested the hypothesis that treatment with L-arginine, a substrate for nitric oxide synthase, further increases NT immunoreactivity over TBI alone. Rats were anesthetized with isoflurane and subjected to TBI, sham TBI, or TBI followed by treatment with L-arginine (100 mg/kg). Twelve, 24, or 72 h after TBI, brains were harvested. Coronal sections (10 microm) were incubated overnight with rabbit polyclonal anti-NT antibody, rinsed, and incubated with a biotinylated secondary antibody. The antigen-antibody complex was visualized using a peroxidase-conjugated system with diaminobenzidine as the chromagen. The number of NT-positive cortical and hippocampal neurons increased significantly in both ipsilateral and contralateral hemispheres up to 72 h after TBI compared with the sham-injured group. Remarkably, treatment with L-arginine reduced the number of NT-positive neurons after TBI in both cortex and hippocampus. Our results indicate that L-arginine actually prevents TBI-induced increases in NT immunoreactivity.
Avila
Marcela A
MA
Charles R. Allen Research Laboratories, Department of Anesthesiology, University of Texas Medical Branch, Galveston, Texas 77555-0830, USA.
Sell
Stacy L
SL
Kadoi
Yuji
Y
Prough
Donald S
DS
Hellmich
Helen L
HL
Velasco
Marco
M
Dewitt
Douglas S
DS
D000818:Animals; D001120:Arginine / Q000494:pharmacology*; D001930:Brain Injuries / Q000188:drug therapy* / Q000378:metabolism* / Q000473:pathology; D002540:Cerebral Cortex / Q000293:injuries / Q000473:pathology; D006624:Hippocampus / Q000293:injuries / Q000473:pathology; D007150:Immunohistochemistry; D008297:Male; D009474:Neurons / Q000378:metabolism* / Q000473:pathology; D019001:Nitric Oxide Synthase / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D014443:Tyrosine / Q000031:analogs & derivatives* / Q000378:metabolism
C002744:3-nitrotyrosine; D014443:Tyrosine; D001120:Arginine; D019001:Nitric Oxide Synthase