Stromal Vascular Fraction Promotes Viability of Co-grafted Axial Skin Flaps in Rats Model.

ABSTRACT

BACKGROUND: Stromal vascular fraction (SVF) has been proved in promoting the vascularization of fascial flap through cell differentiation and paracrine effect and can be autologous transplanted without culture after isolation in vitro. We intend to establish a novel co-grafted flap model of rats to investigate the efficacy and mechanism of SVF on flaps and skinsin facilitating angiogenesis and immune regulation. METHOD: 60 female Sprague Dawley rats were divided into the SVF group and the control group. A pedicled fascial flap combined with a free skin model was established, and 4×106 CM-DIl labeled SVF cells were transplanted into the fascia flap; the rats were executed on days 1, 2, 3, 7, 10 postoperatively (n = 6). Flow cytometry was carried out to determine the cell proportion and surface marker of SVFs. The therapeutic effects of SVF were evaluated via Doppler blood perfusion imager, flap survival rates, histology, immunohistochemistry and immunofluorescence. The bioinformatic mechanism analysis was achieved by high-throughput RNAseq of mRNA and LncRNA. RESULT: Flow cytometry confirmed SVF contains heterogeneous cellular composition, especially hematopoietic cells. Doppler blood perfusion imager showed SVF significantly improved flap survival with higher blood perfusion and survival rates. Immunohistochemistry of CD31 displayed higher level of angiogenesis in SVF-treated group, and CM-DIL-labeled SVF cells could survive and participate in revascularization, and RNA sequencing results revealed SVF promoted wound healing by facilitating intercellular adhesion, cell migration and positive immune response. CONCLUSION: SVF could reduce skin flap necrosis and activated neovascularization in rats by facilitating intercellular adhesion, cell migration and regulate positive immune response. LEVEL OF EVIDENCE N/A This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.