Hyperoxia with 100% oxygen following hypoxia-ischemia increases brain damage in newborn rats.
OBJECTIVE
To describe the effect of reoxygenation with 100% O2 as compared to the effect of room air in newborn rat brains after asphyxia.


METHODS
Experimental asphyxia (carotid artery ligation followed by hypoxic exposure with 8% O2 for 2 h) was performed on 7-day-old rats. After hypoxia-ischemia the rats were reoxygenated with either 100% O2 (hyperoxia group) or 21% O2 (room air group) for 24 h and then returned to the dam. The rats were killed 1 week after the experiment to study the cerebral cortex and hippocampus.


RESULTS
Rats reoxygenated with 100% O2 post-asphyxia showed more frequency of cortical damage (10 of 24 rats) than those reoxy genated with room air (3 of 24 rats) (chi2 test, p = 0.02).


CONCLUSIONS
We consider that hyperoxia with 100% oxygen after hypoxia-ischemia can cause more damage in the cerebral cortex than room air in newborn rats.
Shimabuku
Roberto
R
Instituto Especializado de Salud del Niño, Lima, Peru. shimabuku@viabcp.com
Ota
Arturo
A
Pereyra
Sonia
S
Véliz
Betty
B
Paz
Edith
E
Nakachi
Graciela
G
More
Mario
M
Oliveros
Miguel
M
D000818:Animals; D000831:Animals, Newborn; D002339:Carotid Arteries; D002540:Cerebral Cortex / Q000473:pathology; D006624:Hippocampus / Q000473:pathology; D018496:Hyperoxia / Q000150:complications*; D002534:Hypoxia, Brain / Q000209:etiology* / Q000473:pathology; D020925:Hypoxia-Ischemia, Brain / Q000150:complications*; D008026:Ligation; D010100:Oxygen / Q000008:administration & dosage* / Q000009:adverse effects*; D051381:Rats
D010100:Oxygen