A FGFR1, β-Klotho, PI3K p110, Akt1, or control siRNA was directly injected to the left ventricular anterior wall of FGF21−/− mice by the 6-injection approach, myocardial ischemia/reperfusion injury was induced 3 days following siRNA administration, and the fraction of myocardial infarcts was measured and analyzed at 5 days following myocardial injury. The gene discussed is KLB; the disease is myocardial infarction.