Exosomes derived from antler stem cell promote regenerative burn healing by the facilitation of angiogenesis and the polarization of M2 macrophages

The underlying mechanisms by which these exosomes facilitate healing in deep burn remain unclear. This study aims to investigate the effect of AnSC-derived exosomes (AnSC-exos) on burn wounds healing and to provide new insights for the clinical treatment of deep burn wounds. AnSC-exos were isolated through ultracentrifugation and subsequently administered to rat models with severe third-degree burn injuries. Wound closure rates, histological analysis, immunohistochemistry results and quantitative real-time PCR analysis were performed. In vitro, we assessed the effects of AnSC-exos on the proliferation and migration of human umbilical vein endothelial cells (HUVEC). Our results convincingly demonstrate that AnSC-exos significantly enhance the speed and quality of healing in burn wounds. At 28 days post-burn injury, we found elevated levels of CD31 and CD163 in the healing tissues, accompanied by a reduction in iNOS levels. Additionally, the relative mRNA expression levels of ColA2/Col3A1 and TGF-β1 were significantly lower than the AnSC-exos group compared to the control group (P<0.001， P<0.0001), while the relative mRNA levels of MMP3 were significantly higher (P<0.05). In vitro, AnSC-exos promotes the proliferation and migration of HUVEC. These results suggest that AnSC-exos facilitate burn wound repair by modulating M2 macrophage polarization, promoting angiogenesis, inhibiting myofibroblast production, and enhancing collagen deposition.