Aim To investigate the dynamic changes of the expression of HCN2 and HCN4 mRNA and protein in infarcted border zones of post-AMI heart. Methods AMI model induced by the left anterior descending coronary artery(LAD) ligation in Sprague-Dawley rats,were randomly divided into 24 hours group,1-week group,2-week group,4-week group.Accordingly,the sham-operation group was established.Left ventricular infarcted border zone myocardial tissues were harvested at each time,meanwhile,corresponding myocardial tissues in sham-operated rats were harvested too.HCN2 and HCN4 mRNA and protein expression were measured by RT-PCR,immunohistochemistry and Western blotting. Results The expression of HCN2 and HCN4 mRNA and protein were detected in sham-operated rats.The expression of HCN2 and HCN4 mRNA and protein underwent a dynamic change process.The expression of two of them exhibited an ascending tendency at 24 hours after AMI,reached peak value at 1 week after AMI,decreased gradually after that.But the expression of HCN2 channel was also increased compared with sham-operated group at 4 week after AMI,while there was no significant difference in HCN4. Conclusion Expression of HCN2 and HCN4 mRNA and protein in infarcted border zone myocardial tissues underwent a dynamic change process and reached peak value at 1 week after AMI.