Extracorporeal shockwave therapy rescued mouse critical limb ischemia via upregulating GPR120 against inflammation and promoting angiogenesis for restoring the blood flow in ischemic zone-experimental study.

Abstract

Background: This study tested the hypothesis that extracorporeal shockwave therapy (ECSWT) effectively rescues critical limb ischemia (CLI) in mice through the upregulation of GPR120, which protects against inflammation and angiogenesis to restore blood flow in the ischemic area.

Methods and results: Compared with the control, ECSWT-induced GPR120-mediated anti-inflammatory effects significantly suppressed the expression of inflammatory signaling biomarkers (TAK1/MAPK family/NF-κB/IL-1β/IL-6/TNF-α/MCP-1) in HUVECs, and these effects were abolished by silencing GPR120 or by the GPR120 antagonist AH7614 (all P < 0.001). C57BL/6 mice ( n = 40) were equally categorized into Groups 1 (sham-operated control), 2 (CLI), 3 (CLI + ECSWT), and 4 (CLI + ECSWT + AH7614). By Days 7, 14, and 28 just prior to harvesting the quadriceps muscle, the laser Doppler results showed that the ratio of ischemia to normal blood flow (INBF) in the CLI area was highest in Group 1, lowest in Group 2, and significantly greater in Group 3 than in Group 4 (all P < 0.0001). Endothelial cell markers (CD31/vWF) and GPR120 + cells exhibited identical patterns of INBF among the groups, whereas angiogenesis biomarkers (CXCR4/SDF-1/VEGF/VEGFR2) were significantly and progressively upregulated from Groups 1 to 4 (all P < 0.0001). The protein levels of inflammation (MMP-9, IL-6, and TNF-α) and oxidative stress (NOX-1 and NOX-2) and the cellular levels of inflammation (CD68+)/DNA damage (γ-H2AX+) displayed opposite patterns, whereas the small vessel density in the CLI area displayed an identical pattern of INBF among the groups (all P < 0.0001).

Conclusions: ECSWT rescued CLI by increasing GPR120-mediated suppression of inflammation and enhancing angiogenesis via activation of VEGFR2.