Engineered nerve guide conduit enhances peripheral nerve regeneration by modulating the microenvironment through macrophage-triggered cascade reactions

. The polarized macrophages further triggered the cellular cascade reactions, enhancing the pro-healing characteristics of endothelial cells and Schwann cells. In addition, PSM/Gel-SC(IL-4) conduit significantly promoted functional recovery and nerve regeneration in 12-mm rat sciatic nerve defect model, induced pro-healing macrophage polarization at the early stage and accelerated angiogenesis and myelination at the nerve regeneration stage. This study developed a novel immunomodulatory strategy to remodel the regenerative microenvironment, and explored the underlying cellular and molecular mechanism, demonstrating considerable therapeutic potential for long-distance nerve defect.