Abstract: This study evaluated the cardioprotective effects of liquiritigenin on ischemia/reperfusion (I/R) injury using an isolated Langendorff rat heart model.Adult SD rats were randomly divided into five groups:control group,model group,low dose pretreatment group (0.1 μg/mL),middle dose pretreatment group (0.5 μg/mL) and high dose pretreatment group (0.1 μg/mL).The left ventricular developed pressure (LVDP) and the maximum up/down rate of the left ventricular pressure (dp/dtmax) were documented as the indices of myocardial function by a physiological recorder.TTC staining was performed to assess infarct size.Coronary effluent was analyzed for lactate dehydrogenase (LDH) and creatine kinase (CK) release to assess the degree of cardiac injury.Superoxide dismutase (SOD) activity and malondialdehyde (MDA) level were analyzed to determine the oxidative stress status of myocardial tissue.The levels of tumor necrosis factor(TNF-α) and interleukin6 (IL-6) were analyzed to determine the inflammation status of myocardial tissue.Cardiomyocyte apoptosis analysis was performed using an TUNEL Kit.The proteins levels of Bax and Bcl-2 were measured by Western blot.The results showed that liquiritigenin (0.5 and 1.0 μg/mL) pretreatment decreased CK and LDH levels in coronary flow,and attenuated myocardial infarct size.This pretreatment with liquiritigenin also increased SOD activity,but decreased MDA,TNF-α and IL-6 activities.The cell apoptosis in the hearts from the liquiritigenintreated group were lower than those in the hearts from the model group.Meanwhile,the expression levels of Bcl-2 expression was upregulated,the expression levels of bax was downregulated.Therefore,the cardioprotective effects of liquiritigenin may be attributed to its antioxidant,anti-inflammatory and anti-apoptosis activities.

Key words: Liquiritigenin, cardioprotective, antioxidant, anti-inflammatory, anti-apoptosis