Hyperbaric oxygen limits infarct size in ischemic rabbit myocardium in vivo.
BACKGROUND
We explored the ability of increased oxygen pressure to modify necrosis in an open-chest rabbit model of myocardial ischemia and reperfusion.


RESULTS
A branch of the left coronary artery was occluded for 30 minutes followed by 3 hours of reperfusion. Infarction was measured by triphenyl tetrazolium staining and expressed as a percentage of the ischemic zone. Untreated rabbits were ventilated with 100% oxygen at 1 atm absolute. Treatment animals were exposed to hyperbaric oxygen at 2.5 atm absolute. The 1.0-atm control hearts developed 41.5 +/- 4.6% infarction of the ischemic zone. Animals exposed to hyperbaric oxygen during ischemia only, reperfusion only, or ischemia and reperfusion had significantly smaller infarcts with respect to control animals (16.2 +/- 2.9%, 14.5 +/- 3.7%, and 9.8 +/- 2.7%, respectively; P < or = .01), indicating that they had been protected by the procedure. When hyperbaric oxygen was begun 30 minutes after the onset of reperfusion, no protection was seen (35.8 +/- 3.8%).


CONCLUSIONS
We conclude that hyperbaric oxygen limits infarct size in the reperfused rabbit heart and that the effect can be achieved when hyperbaric oxygen is begun at reperfusion.
Sterling
D L
DL
Department of Biological Sciences, University of South Alabama, Mobile 36688.
Thornton
J D
JD
Swafford
A
A
Gottlieb
S F
SF
Bishop
S P
SP
Stanley
A W
AW
Downey
J M
JM
D000818:Animals; D005260:Female; D006931:Hyperbaric Oxygenation; D008297:Male; D009203:Myocardial Infarction / Q000473:pathology / Q000517:prevention & control*; D015425:Myocardial Reperfusion; D015428:Myocardial Reperfusion Injury / Q000517:prevention & control*; D009206:Myocardium / Q000473:pathology; D011817:Rabbits; D013997:Time Factors