Prolonged myocardial protection of 11,12-epoxyeicosatrienoic on immature isolated rabbit hearts

Objective To observe the protective effect of 11,12-epoxyeicosatrienoic acid(11,12-EET)on immature isolated rabbit hearts.Methods Forty-eight isolated immature rabbit hearts were randomly assigned to two groups: Control group,the hearts were arrested with St.Thomas No.2 solution and stored in the same solution ( n =24);EET group,the hearts were arrested with St.Thomas No.2 plus 11,12-EET solution and stored in the same solution ( n =24). All rabbit hearts were stored for 8,16 and 24 h with 4 ℃ hypothetmia, and underwent 30 min reperfusion ( 37 ℃ ). On the Langendorff perfusion apparatus,left ventricle developed pressure (LVDP),left ventricle end-diastolic pressure (LVEDP),+dp/pt max ,coronary blood effluent (CBE) and arrhythmias score were measured before and after ischemia. Myocardial water content,the value of creatine kinase (CK) and lactic dehydrogenase (LDH) were also measured,and myocardial ultrastructure observed. Results Postischemic recovery of myocardial function and myocardial edema were significantly better in EET group at different time points. The changes of arrhythmias score,CK,LDH and myocardial ultrastructure in EET group were superior to those in control group. After the hearts were preserved for 16 h ,the recovery of myocardial function and arrhythmias score in EET group were basically close to the measured values before heart preservation,while those in control group were significantly decreased. After the hearts were stored for 24 h ,all hearts in EET group beated again during reperfusion,but 5 hearts in control group could not beat anymore.Conclusion Addition of 11,12-EET into the St.Thomas No.2 cardioplegic solution could prolong the storage time and enhance the myocardial protective effect to the isolated immature hearts.