Abstract: Abstract:Objective To investigate the protective effect   of salvianolic acid B  (Sal B) on myocardium of   myocardial infarction model rats and to clarify the molecular mechanism of Sal B intervention in myocardial infarction.Methods The  SD rats were randomly divided into control group,model group,positive drug experiment (AsA and BHT)  groups and observation drug experiment group(Sal B group).The myocardial infarction models of  rats were set up by  coronary artery ligation.The rats in every experiment groups were administered by intraperitoneal injection with the dose of 120 mg?kg-1,the rats in  model group and control group were injected  with the same dose of distilled water for 7 d.Then  the activities of CK,AST and LDH in serum were detected,and  ELISA assay  was used to analyze the expression levels of IL-1β,IL-6 and TNF-α in serum;and  the apoptotic rate  of cardiocytes  in each group was measured,and the clearance rate of free radical was determined by absorption spectrometry.Results  Compared with control group,the activities of serum CK,AST and LDH in model group were increased   obviously（P<0.01）;compared with model group,the activities of serum CK,AST and LDH  in positive drug and Sal B groups were decreased obviously（P<0.05 or P<0.01）.Compared with control group,the levels of serum IL-1β,IL-6 and TNF-α  in model group were increased  obviously(P<0.01）;compared with model group,the levels of serum IL-1β,IL-6 and TNF-α in Sal B group were decreased significantly (P<0.01）;but there was no marked change in AsA and BHT groups（P>0.05）.Compared with control group,the apoptotic rate  of cardiocytes  in model group was increased obviously（P<0.01）;compared with model group,the apoptotic rate of cardiocytes was decreased significantly  in Sal B group （P<0.01）;there was no marked change in AsA and BHT groups（P>0.05）.Different concentrations of Sal B  increased the clearance rate of DPPH free radical  with statistical difference (P<0.05).The clearance rates of free radical in Sal B group were higher than those in AsA and BHT groups when the concentrations of Sal B were 20-100 mg/L（P<0.05 or P<0.01）.Conclusion Sal B has a protective effect on    experimental myocardial infarction   in rats,and  effectively inhibit apoptosis  of cardiocytes.Its mechanism may be related to suppression of immune and inflammatory factor secretion and  free radical scavenging.

Key words: salvianolic acid B, myocardial infarction, apoptosis, free radical, inflammatory factor