Exosomes isolated from the plasma of remote ischemic conditioning rats improved cardiac function and angiogenesis after myocardial infarction through targeting Hsp70

Remote ischemic conditioning (RIC) is a promising therapeutic strategy to protect heart against ischemic-reperfusion injury. Exosomes have been proved to be an important regulator in many pathological processes. Whether the exosomes derived from RIC could improve cardiac remodeling and function after myocardial infarction (MI) has not been reported. MI animal model was established by ligating the left coronary artery. The bilateral hindlimbs of rats were subjected to RIC treatment using tourniquets. Exosomes were isolated from the plasma of RIC rats and identified by transmission electron microscope. The proliferation, migration, and apoptosis of endothelial cells were measured by CCK8, traswell, and flow cytometry. Western blotting, and qRT-PCR were applied to measure the expression of angiogenesis-related molecules, and immunohistochemistry staining was used to observe the expression of vWF. RIC and RIC exosomes remarkably facilitated cardiac function, cardiac cell remodeling, and angiogenesis. RIC exosomes markedly increased the cell ratio in the G1 phase, cell migration, cell proliferation, tube formation, and inhibited cell apoptosis through Hsp70. The expression of eNOS, iNOS, HIF-1α, Ang-1, and VEGF was markedly increased by RIC exosomes. RIC exosomes significantly improved cardiac function, cardiac remodeling, and angiogenesis after MI, and they accelerated angiogenesis through increasing the levels of angiogenesis-related molecules.