Inhibitor of nitric oxide synthesis reduces hypoxic-ischemic brain damage in the neonatal rat.
We evaluated the neuroprotective effect of the nitric oxide synthesis inhibitor, NG-nitro-L-arginine in a neonatal hypoxic-ischemic rat model. Unilateral hypoxic-ischemic injury was produced in the brain of 7-d-old rats using a combination of a common carotid artery ligation and a hypoxic (8% oxygen) exposure for 2.5 h. In our experimental condition, rectal temperatures did not differ between NG-nitro-L-arginine-treated and saline-injected pups. We killed the animals 72 h later and assessed the hypoxic-ischemic brain damage histologically. NG-nitro-L-arginine (2 mg/kg) administered intraperitoneally 1.5 h before hypoxia resulted in 77% reduction of the infarcted hemispheric volume and 87% reduction of the infarcted striatal volume compared to saline injected controls. NG-nitro-L-arginine given 1.5 h before the insult also significantly prevented hypoxic-ischemic damage in the five hippocampal structures examined, dentate gyrus, CA4, CA3, CA1, and subiculum. NG-nitro-L-arginine administered immediately after hypoxia did not prevent hypoxic-ischemic brain damage. These results indicate that nitric oxide plays a key role in producing neonatal hypoxic-ischemic brain damage.
Hamada
Y
Y
Department of Pediatrics, Faculty of Medicine, Kyoto University, Japan.
Hayakawa
T
T
Hattori
H
H
Mikawa
H
H
D000818:Animals; D000831:Animals, Newborn; D001120:Arginine / Q000031:analogs & derivatives / Q000494:pharmacology; D002545:Brain Ischemia / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D004195:Disease Models, Animal; D005260:Female; D002534:Hypoxia, Brain / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D008297:Male; D009569:Nitric Oxide / Q000096:biosynthesis*; D019335:Nitroarginine; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors
D019335:Nitroarginine; D009569:Nitric Oxide; D001120:Arginine