AIM:To investigate the changes of apelin in blood and myocardium, and the protective mechanisms of ganoderma spores on myocardial ischemia injury induced by isoproterenol in rats. METHODS: The model of myocardial ischemia injury was induced by subcutaneous injection of high dose isoproterenol. Enzyme linked immunosorbent assay (ELISA) was used to measure the apelin contents in blood and myocardium. Semi-quantitative RT-PCR was used to measure the apelin mRNA level in myocardium. Electron microscope was used to observe the pathomorphological changes of myocardium. Ganoderma spores was administered i.g. for 7 weeks. RESULTS: Compared with the normal control group, the apelin contents in blood and myocardium and the apelin mRNA level in myocardium were significantly decreased in the model group (P