Objective To compare the myocardial protective effects of post-treatment with sevoflurane and isoflurane on myocardial ischemia-reperfusion injury(MIRI) in adult rats.Methods Twenty-four adult male SD rats were divided into four groups (n =6) by using the random number table,control group (C),isehemia-reperfusion group (R),sevoflurane post-treatment (S) and isoflurane post-treatment group(I).The Langendorff isolated heart perfusion model was established.The heart rate(HR),left ventricular end-diastolic pressure(LLVEDP),left ventricular developed pressure(LVDP),maximum rate of rise of left ventricular pressure(LV+-dp/dtmax),and maximum rate of decrease of left ventricular pressure(LV-dp/dtmax) were recorded at the end of equilibrium perfusion,and at 30,90 min of reperfusion,respectively.At the end of infusion,1 mm3.of apical myocardial tissue was removed for observing mitochondrial structure under electron microscopy and scoring.The myocardial infarct size(MIS) in the remaining heart tissue was measured by TTC staining.Results Compared with the R group,the S and I groups showed improved cardiac function indicators,decreased MIS,and reduced mitochondrial damage after reperfusion(P＜0.05).Compared with the S group,the I group showed worse heart function,increased MIS,and more severe mitochondrial damage after reperfusion(P＜0.05).Conclusion Post-treatment with sevoflurane and isoflurane has a protective effect on MIRI in adult rats.Post-treatment with sevoflurane has a better cardioprotective effect than that with isoflurane.