Low-intensity ultrasound induces angiogenesis by activating endothelial integrin signaling in male mice

Peripheral arterial disease is a medical condition caused by blockages of arteries that provide blood flow to the arms or legs. Pulsed ultrasound (PUS) has been widely used for some therapies such as bone fracture healing. We hypothesized that PUS also affects angiogenesis for ischemia therapy. This study was performed to elucidate the mechanism of PUS therapeutic angiogenesis and evaluate PUS efficacy. Hindlimb ischemic model mice were applied PUS irradiation for 20 min/day for 2 weeks. In consequence, the blood flow rates in hindlimb ischemic model mice treated with PUS improved compared with those in untreated mice. Then we performed a tube formation assay using a human umbilical vein endothelial cell (HUVEC) under conditions of PUS exposure. To elucidate the signal transduction mechanism initiated by PUS stimulation in HUVECs, we evaluated phosphorylation profiles with antibody array analysis. PUS irradiation enhanced tube formation in HUVECs and upregulated phosphorylation of extracellular signal-regulated kinase (ERK) 1/2 through the integrin pathway. Moreover, the blood flow recovery in hindlimb ischemic model mice treated with PUS was completely inhibited in mice administered an anti-integrin blocking antibody. These findings suggested that PUS demonstrated angiogenic effects through the integrin pathway.