Korean J Physiol Pharmacol.
1997 Dec;1(6):749-758.
Pretreatment of hyperbaric oxygenation increases the activities of
myocardial antioxidant enzymes and protects the ischemia-reperfusion
injury of the heart
- Affiliations
-
- 1Department of Internal Medicine, Gangdong Sacred Heart Hospital, College of Medicine, Hallym University, Seoul 110-799 South Korea.
- 2Department of Pharmacology, College of Medicine, Seoul National University, Seoul 110-799, South Korea.
Abstract
-
Myocardial ischemia-reperfusion injury is known to be mediated by
reactive oxygen species. The myocardial cell is equipped with
endogenous antioxidant defensive system which can be adaptively
stimulated by various oxidative stress. It is postulated that an
increased oxygen partial pressure induced by hyperbaric oxygenation
impose an oxidative stress on the cells, resulting alterations in the
endogenous antioxidant system. In this study we investigated the effect
of hyperbaric oxygenation on the activities of myocardial antioxidant
enzymes and observed whether the hyperbaric oxygenation could protect
the ischemia-reperfusion injury of heart. Rats or rabbits were
pretreated with hyperbaric oxygenation (2 ~ 3 atm O2/1 ~ 3
hrs/1 ~ 10 days). The changes in activities of major antioxidant
enzymes(superoxide dismutase, catalase, glutathione peroxidase,
glutathione reductase, glucose-6-phosphate dehydrogenase), functional
recovery and infarct size were observed in the experimentally induced
ischemia-reperfused hearts. in the hearts isolated from rats pretreated
with 2 atm O2/1 ~ 2 hrs for 5 days, the functional recovery after
reperfusion (20 min) following global ischemia (25 min) was
significantly increased without any observable oxygen toxicity. Lactate
dehydrogenase release was also significantly reduced in this hyperbaric
oxygenated rat hearts. In in vivo regional ischemia (30 min) model of
rabbit hearts, pretreatment with 2 atm O2/1 hr for 5 days significantly
limited the infarct size. Among the myocardial antioxidant enzymes of
rat hearts pretreated with the hyperbaric oxygenation, the activities
of catalase, superoxide dismutase and glucose-6-phosphatase
dehydrogenase were increased, while those of glutathione peroxidase and
reductase were not changed. There were lethal cases in the groups of
rats exposed to 3 atm O2/2 ~ 3 hrs for 5 days. A lipid-peroxidation
product, malondialdehyde was increased in brains and livers of the rats
exposed to 2 atm O2/2 ~ 3 hrs/5 days and 3 atm O2/1 hr/5 days. The
present results suggest that the pretreatment of hyperbaric oxygenation
can protect the post-ischemic reperfused hearts in association with a
stimulation of the activities of myocardial antioxidant defensive
enzymes, and that the hyperbaric oxygenation of 2 atm O2/1 hr for 5
days would be a safe condition which does not produce any oxygen
toxicity.