In the present study, it was demonstrated that pharmacological postconditioning with tanshinone IIA, one of the active ingredients in the Chinese medicine Danshen, protects the myocardium from ischemia-reperfusion injury by activating the PI3K/Akt-eNOS pathway, and the blockage of mPTP opening may be involved in this cardioprotective effect. The gene discussed is NOS3; the disease is ischemia reperfusion injury.