Effect of Nar on myocardial enzyme levels and cardiac viability in diabetic MI/R rats. Levels of (A) LDH and (B) CK-MB in the coronary effluent were detected using spectrophotometry by commercial assay kits. (C) Cardiac formazan content was measured using an MTT assay. Data are presented as the mean ± SEM (number of repeated measurements: n=3/group). **P<0.01 and ***P<0.001 compared with the STZ-sham group; #P<0.05 and ##P<0.01 compared with the STZ-M/IR group. LDH, lactate dehydrogenase; CK-MB, creatine kinase myocardial band; STZ, streptozotocin; MI/R, myocardial ischemia reperfusion; Nar, naringenin.