Effect of Hydroxyethyl Starch on Myeloperoxidase and Endothelin-1 in Rabbits with Myocardial Ischemia-Reperfusion Injury

Objective To observe the effect of hydroxyethyl starch on myeloperoxidase( MPO) and endothelin-1( ET-1) in rabbits with myocardial ischemia-reperfusion( MI/R) injury. Methods Thirty-six New Zealand rabbits were randomly divided into three groups: Lactated Ringer's group( group A,n = 12),albumin group( group B,n = 12) and hydroxyethyl starch group( group C,n = 12). The rabbits in group A,B,C were infused with Lactated Ringer's solution( 6 ml/kg),5% human albumin( 6 ml/kg),6% hydroxyethyl starch( 6 ml/kg),respectively,through internal jugular vein 15 minutes before reperfusion,and were infused with compound sodium lactate[10 ml /( kg·h) ]through ear vein during observation period. Blood samples were obtained before occlusion,30 minutes after occlusion,60 and 180 minutes after reperfusion,respectively,to determine the levles of serum lactate dehydrogenase( LDH),creatine phosphokinase( CPK),interleukin-8( IL-8) and ET-1. The changes of myocardial infarction( MI) and MPO activity were examined following the rabbits had been killed 180 minutes after reperfusion. Results The activities of serum LDH,CPK,IL-8 and ET-1 in the three groups increased gradually with increasing reperfusion time,but the increase in group C was significantly lower than that in group A,group B( P 0. 05). The activity of MPO in ischemic areas increased significantly compared with that in the non-ischemic areas in the three groups,which was the highest in group A but the lowest in group C( P 0. 05).Myocardial infarct size in group C was significantly smaller than that in group A or group B,which was smaller in group B in contrast with that in group A( all P 0. 05). Conclusion Hydroxyethyl starch may reduce the activity of MPO in ischemic areas by preventing the production and release of IL-8 and ET-1,it can protect myocardium from ischemiareperfusion injury.