Angiogenesis effect of therapeutic ultrasound on ischemic hind limb in mice

Although significant progress in bypass surgery and catheter intervention against peripheral artery disease, the number of severe critical limb ischemia (CLI) patients is increasing. Thus, it is crucial to develop new, non-invasive therapeutic strategies. The purpose of this study was to determine the mechanism of therapeutic ultrasound (TUS) on ischemic angiogenesis using mouse model of hindlimb ischemia and the cellular/molecular mechanisms underlying TUS-related neovascularization. The hindlimb ischemic mice were exposed to extracorporeal TUS for 3, 6, 9 minute per day (1 MHz, 0.3 W/cm(2)) until day 14 after left femoral artery ligation. Increased blood perfusion and capillary density were determined following 9 min of TUS compared with ischemic group. Moreover, TUS treatment increased the protein levels of vascular endothelial growth factor (VEGF), hypoxic inducible factor-1α (HIF-1α), endothelial nitric oxide synthase (eNOS) and p-Akt in vivo. TUS promoted capillary-like tube formation, migration and motility of human umbilical venous endothelial cells (HUVECs). Furthermore, the protein expressions of VEGF, eNOS and p-Akt were increased after TUS treatment. In conclusion, TUS therapy promotes postnatal neovascularization through multiple angiogenic pathways in mice model of ischemic hindlimb.