ABSTRACT
Objective To study the effects of D-Ala2-Leu5-enkephalin(DADLE) preconditioning on rabbit donor heart preservation and protective mechanism.Methods 24 rabbits were randomly divided into 4 groups. In group B, after preconditioning with DADLE(1mg?kg -1 ), the donor hearts were then arrested and preserved with Krebs-Henseleit buffer at 4℃ for 4h,and group A without conditioning as controls. Then the donor hearts were transplanted into the abdomen of recipient rabbits. Recovery situation of contraction of the donor heart was compared. The left ventricular tissues were obtained from the donor hearts after 2h of transplantation.The contents of free radicals and ATPase activity were determined and cardiac ultrastructure were observed.Results After 4h cold storage, the heart undergoing DADLE preconditioning in group B showed better recovery of left ventricular development pressure (LVDP).The activity of sodium-potassium ATPase in group B were higher than that in group A. DADLE increased free radical production 2-fold versus group A. Group B showed slighter injury in transmission electron microscopy observation than that in group A.Conclusion Our study demonstrated opioid preconditioning has protective function to rabbit heart injury caused by long term cold storage. The protective mechanism maybe related to increase of free radical content.