Objective   To investigate the protective effects of emulsified isoflurane (8% v/v) on myocardial cells after hypoxia/reoxygenation (H/R) in cultured myocardial cells from neonatal rats.    Methods   Myocardial hypoxia/reoxygenation model was established by culturing myocardial cells primarily isolated from neonatal rats. The myocardial cells were divided into 4 groups

the normal group

model group

fat milk treatment group

and mulsified isoflurane treatment group (0.28 mmol/L). Cellular morphologic changes and pulsation frequency were observed under inverted microscope. Cell activity was determined by XTT assay. The activities of plasma superoxide dismutase (SOD) was measured by xanthine oxidase method and the contents of serum malonicaldehyde (MDA) by thiobarbituric acid method. The activities of lactate dehydrogenase (LDH) in the culture medium after H/R injury was measured. Western blot analysis was used to detect caspase-3 protein expression in every group.    Results   Compared with normal group

SOD activity was decreased

and MDA content

LDH activity and the expression of caspase-3 protein were increased in model group (P0.05). Compared with model group

SOD activity was increased

while MDA content

LDH activity and the expression of caspase-3 were decreased (P0.05) after emulsified isoflurane treatment. The morphological and ultrastructural changes of cardiomyocytes were improved after the treatment. Fat milk treatment group showed similar changes

but not significant as emulsified isoflurane treatment did.    Conclusion   Emulcified isoflurane has protective effects on cultured neonatal rat myocardial cells after H/R injury

which may be related to reducement of oxygen free radical and the inhibition of caspase-3 expression.