Effect of hyperbaric oxygen on apoptosis in neonatal hypoxia-ischemia rat model.
We have previously demonstrated that a transient exposure to hyperbaric oxygen (HBO) attenuated the neuronal injury after neonatal hypoxia-ischemia. This study was undertaken to determine whether HBO offers this neuroprotection by reducing apoptosis in injured brain tissue. Seven-day-old rat pups were subjected to unilateral carotid artery ligation followed by 2 h of hypoxia (8% oxygen). Apoptotic cell death was examined in the injured cortex and hippocampus tissue. Caspase-3 expression and activity increased at 18 and 24 h after the hypoxia-ischemia insult. At 18-48 h, poly(ADP-ribose) polymerase (PARP) cleavage occurred, which reduced the band at 116 kDa and enhanced the band at 85 kDa. There was a time-dependent increase in the number of terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling (TUNEL)-positive cells. A single HBO treatment (100% oxygen, 3 ATA for 1 h) 1 h after hypoxia reduced the enhanced caspase-3 expression and activity, attenuated the PARP cleavage, and decreased the number of TUNEL-positive cells observed in the cortex and hippocampus. These results suggest that the neuroprotective effect of HBO is at least partially mediated by the reduction of apoptosis.
Calvert
John W
JW
Department of Neurosurgery, Louisiana State University Health Sciences Center-Shreveport, Shreveport, Lousiana 71130, USA.
Zhou
Changman
C
Nanda
Anil
A
Zhang
John H
JH
D000818:Animals; D000831:Animals, Newborn; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D053938:DNA Fragmentation; D004195:Disease Models, Animal; D005260:Female; D006931:Hyperbaric Oxygenation; D020925:Hypoxia-Ischemia, Brain / Q000378:metabolism / Q000473:pathology* / Q000628:therapy*; D020287:In Situ Nick-End Labeling; D008297:Male; D009410:Nerve Degeneration / Q000378:metabolism / Q000473:pathology / Q000628:therapy; D009929:Organ Size; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley
D011065:Poly(ADP-ribose) Polymerases; C505410:Casp3 protein, rat; D053148:Caspase 3; D020169:Caspases