Isolation, Identification And Preliminary Functional Analysis Of Genes Related To Transient Myocardial Ischemia/Reperfusion

Brief episodes of myocardial ischemia may result in two phenomena: myocardial stunning and preconditioning. Clarifying the mechanisms of myocardial stunning and preconditioning could improve the prevention and treatment of ischemic heart diseases.A number of genes have been shown up-regulated during myocardial ischemia/reperfusion and playing important roles in myocardial protection, but there are clearly many missing elements to be found. We used suppression subtractive hybridization to construct cDNA libraries enriched for genes up-regulated during transient ischemia/ reperfusion of the rat's hearts. After being confirmed by reverse northern dot blot for differential expression, 85 selected genes were sequenced and searched in Genbank for homology analysis. The differential expression of the genes was further confirmed by RT-PCR and Northern blot analysis. Of 85 selected genes, 31 genes were nuclear- encoded genes, while some of them had been found up-regulated during ischemic preconditioning and participated in cytoprotection in previous literature, others were never found related to myocardial ischemia/reperfusion injury before this study. 18 novel ESTs which may represent new genes have been registered into Genbank with accession numbers .We further used cDNA microarray to analyze myocardial gene expression profile in rats during myocardial ischemia/reperfusion at multiple time points ( 1, 3, 6, 12, 24 hours after reperfusion). Gene expression peaked at 3 hours after reperfusion was lowest at 1 hour after reperfusion. Using self-organizing map (SOM) algorithm, we clustered the genes which changed in expression at two or more time points after reperfusion into twelve clusters and each cluster showed a similar expression pattern. Analysis of gene expression patterns revealed sequential induction of subsets of genes after transient myocardial ischemia/reperfusion that characterize each response. Genes in the same cluster might be regulated in a similar manner.Using bioinformatics analysis and 5′RACE technology, we cloned a new gene Mip1 which was up-regulated after transient...