Comparison of the Effectiveness of Methods for Obtaining and Application the Stromal-Vascular Fraction of Adipose Tissue in an Experimental Model of a Donor Wound in Burns

Introduction . The optimal method of obtaining and application a stromal-vascular fraction (SVF) of adipose tissue in the treatment of donor wounds in burned patients has not been determined. Objective — to compare the effectiveness of the stromal-vascular fraction of adipose tissue in the treatment of donor wounds, depending on the method of obtaining (mechanical and enzymatic) and the injection (subdermal, intradermal) into the tissue. Material and methods . Wistar rats (n = 30) were divided into 2 investigated groups: in the first group (eSVF) enzymatic processing of adipose tissue (n = 10) was used, in the second group (mSVF) mechanical processing was used (n = 10). Another 10 rats were used as adipose tissue donors’ group. A deep burn was created in all animals, and after 4 days two more donor wounds were created by taking a split thickness skin autograft: the stromal-vascular fraction was injected intradermally into one of the wounds, subdermally into the other. After 14 days, the area of epithelialization, the microcirculation index and the histological microstructure of the skin were evaluated. Results . The proportion of completely epithelized donor wounds in the eSVF-group was 85 %, in the mSVF-group — 55 % (p < 0.05). The index of microcirculation significantly decreased after intradermal injections in the eSVF-group (p < 0.01), and after subdermal injections — in the mSVF-group (p < 0.05). According to histomorphometry, with intradermal injections of eSVF, the thickness of the epidermis and the layer of granulation tissue is less than in the mSVF group (p < 0.01). At the same time, the relative density of collagen fibers in the granulation tissue was significantly higher after the injections of eSVF than after mSVF (p < 0.01). Comparison of injections of the stromal-vascular fraction showed: no significant differences were found when using eSVF; when using mSVF, the subdermal injections are preferable, since it was accompanied by a significantly lower thickness of granulation tissue (p < 0.01). Conclusions . The enzymatically obtained stromal-vascular fraction of adipose tissue has advantages over the mechanically obtained one: the efficiency of eSVF is equally high when used with intradermally and subdermally injections, which are confirmed by the structure and blood circulation in the newly formed skin. When using mSVF, intradermal injections are the least effective, and subdermal injections are accompanied by a moderately pronounced positive dynamic in the microstructure of the skin of donor wounds.