Fractional carbon dioxide laser-induced photothermal activation of mesenchymal stem cell-derived exosomes accelerates diabetic wound healing by enhancing angiogenesis

Figure 9 Schematic illustration showing that low-energy fractional CO₂ laser enhances heat-shock protein 90 expression in adipose-derived mesenchymal stem cells via photothermal effects, thereby improving the biological activity of their derived exosomes. These exosomes derived from CO₂ laser-preconditioned adipose-derived mesenchymal stem cells promote angiogenesis and accelerate diabetic wound healing by activating the sphingosine-1-phosphate receptor/protein kinase B/hypoxia-inducible factor-1α signaling pathway. Ad-MSCs: Adipose-derived mesenchymal stem cells; CO₂ laser-Exos: Exosomes derived from CO₂ laser-preconditioned adipose-derived mesenchymal stem cells; HSP90: Heat-shock protein 90; AKT: Protein kinase B; HIF-1α: Hypoxia-inducible factor-1α; VEGF-A: Vascular endothelial growth factor-A; S1P: Sphingosine-1-phosphate; S1PR: Sphingosine-1-phosphate receptor; HUVECs: Human umbilical vein endothelial cells.