The Preliminary Study Of The Mechanism Of GMCSF To Accelerate Wound Repair In Mice Acute Missing Wound

Objective: To investigate the expression characteristic of granulocyte- macrophage colony-stimulating factor (GM-CSF) and its associated effect and mechanism of GM-CSF during the wound healing.Methods: Using mice full-thickness skin injury model.Fifty male mice were obtained and divided randomly into control group (25)and GM-CSF group (25),each group had five time points(5). All mice were received full thickness skin wound (1cm×1cm) through the panniculus carnosus on the midline of back near the neck after anesthesia. Recombinant human granulocyte-macrophage colony stimulating factor (RhGM-CSF)gel (10μg/ cm2) were applicated in GM-CSF group and gel matrix without RhGM-CSF were applicated in control group at days after 3, 5, 7, 10 and 14d post-wounding, the time of wound healing and the percentage of wound closure were observed. The wound specimens were collected to detect the change of wound histopathology;The microvessel number of wound bed was counted by the result of CD31 immunohistochemistry.RT-PCR analyzed the change of GM-CSF,Platelet-derived growth factor(PDGF),Vascular endothelial growth factor (VEGF) and Stromal cell derived factor-1(SDF-1) gene expression.Results: The RT-PCR result showed that the gene expression of GM-CSF reached the peaking in 3d after wound (P<0.01) and kept the high level from 3d to 10d after wound (P< 0.05), following decreased to normal leve at 14d post-wound.the wound healing time was average ahead (2.4±0.27) d than the control mice after rhGM-CSF applicated, and the percentage of wound closure was significant incearsedduring 7～14d post wound (P< 0.05);Compared with that in the control mice, the histology characteristic in GM-CSF group showed that the number of neutrophil was reduced in early stage after wound, and epithelial cell proliferation was obviously in the wound margin, accelerating granulation tissue with quantity of spindle-shaped and oval-shaped cells formation and increasing the number of new vessels. The microvessel density was also incearsed significantly (P<0.05) at 7 to 14d post-wound. Compared to control group, the gene expression of VEGF and SDF-1 were higher significantly after 7d and10d injury(P<0.05),the gene expression of pro-healing factor PDGF was high significantly in every point time(5d,7d,10d,P<0.05;14d,P<0.01)Conclutions: GM-CSF expressed higher in early stage of post- wound,GMCSF promoted wound healing with the mechanism with pro-angiogenic factors and pro-healing growth factors secreted.