JAK2 and myocardial infarction: In our study, pretreatment with Wortmannin (PI-3K inhibitor) or Chelerythrine (PKC inhibitor) or AG490 (JAK2 inhibitor) significantly and almost equally attenuated the Epo preconditioning-induced decrease in myocardial infarct size and release of LDH and CK-MB in the coronary effluent, indicating that Epo simultaneously activates the JAK/STAT, PI-3K and PKC pathways, which play an important role in Epo-preconditioning-induced cardioprotection.