Background: Volatile anesthetics (VAs) have been shown to enhance myocardia
l recovery during reperfusion, the mechanism of which has not been clarifie
d yet. It has been supposed that this effect of VAs may appear through anti
oxidative mechanisms.
Methods: Thirty guinea pigs were used in the study. There were three groups
with 10 animals in each: I - control, II isoflurane+oxygen and III - oxyge
n. Isoflurane (2.0% v/v) and oxygen (100%) mixture was given to the animals
via a face mask in the isoflurane+oxygen group at the rate of 21 per min f
or 30 min a day for three consecutive days. In the oxygen group, oxygen alo
ne (100%) was given under the same conditions as in the isoflurane+oxygen g
roup. At the end of the experiments, the animals were killed and their hear
ts were removed. In the heart tissues, nitric oxide synthase (NOS) activity
, nitric oxide (NO) pool (NO.+NO2-) and malondialdehyde (MDA) levels were m
easured.
Results: NOS activity was found to be higher and the NO pool lower in the i
soflurane+oxygen group compared with those of control and oxygen groups. In
the oxygen group, MDA level was found to be higher compared to the other g
roups. There was, however, no significant difference between MDA levels of
the control and isoflurane+oxygen groups.
Conclusion: Our results suggest that isoflurane prevents peroxidation react
ions in heart tissue, possibly by scavenging toxic oxygen radicals produced
under hyperoxygenation conditions as occurs with general anesthesia.