Granulocyte-colony stimulating factor mediates neovascularization in acellular dermal matrix-transplanted areas by promoting endothelial progenitor cell homing

Acellular dermal matrix (ADM) is an ideal material for tissue engineering skin construc-tion. Accelerating the vascularization of ADM is of great significance for improving the survival of skin transplantation. The purpose of this study is to investigate the function of granulocyte-colony stimulating factor (G-CSF) in endothelial progenitor cells (EPCs)-mediated neovascularization in ADM-transplanted skin area. Male Kunming mice were subcutaneous injected with 10 & mu;g/kg G-CSF at 5 days before skin in situ replantation or porcine ADM transplantation. The surrounding tissues of implanted skin or venous blood was collected from the mice before the operation, and after the operation for 48 h, 72 h, 1 week, and 2 weeks, respectively. Cells co-expressing EPC mark-ers, CD133, CD34, and Flk-1 were detected by flow cytometry. Immunohistochemistry of BrdU was performed to evaluate neovascularization in ADM-transplanted skin area. The results showed that G-CSF treatment increased the number of CD133+-CD34+ cells and CD133+-Flk-1+ cells in ADM-implanted area as well as the number of CD34+-Flk-1+ cells in peripheral blood. Likewise, G-CSF also increased the number of capillaries in ADM-transplanted areas. To sum up, G-CSF mobilizes EPC migration from bone marrow to peripheral blood and homing to wound sites, thus inducing neovascularization in ADM-transplanted areas.