RESUMO
BACKGROUND: Although stromal vascular fraction (SVF) cells and adipose-derived stem cells have well-defined antiaging effects on skin, certain disadvantages have limited their clinical application. OBJECTIVES: The aim of this study was to evaluate the effects of microfat, nanofat, and SVF-gel in improving ultraviolet (UV)-induced photoaged skin injury in nude mice. METHODS: After successfully establishing a photoaging model by UVA and UVB irradiation in nude mice, the back of each mouse was divided into 2 regions and randomly injected under the dermis with 0.5 mL of microfat, nanofat, SVF-gel, and phosphate-buffered saline. Inflammatory infiltration, dermis thickness, hydroxyproline content, Type I/Type III collagen ratio, elastic fiber morphology, skin cell proliferation, and adipocyte viability were measured. The overall structure of the skin was also observed by scanning electron microscopy. RESULTS: In the microfat group, the grafts survived well, with intact structure and viable adipocytes and little infiltration of inflammatory cells. Microfat promoted skin cell proliferation, collagen content increased, the ratio of Type I and III collagen reversed, and new oxytalan fibers formed, which to some extent improved the photoaging skin. In the nanofat and SVF-gel groups, a large amount of inflammatory cell infiltration and foam cell deposition in the grafts and dermis led to fibrosis and proliferation of skin tissue. Although the skin thickness and collagen content were also increased, these factors did not improve the photoaging skin. CONCLUSIONS: Microfat survives well, and improves photoaged skin injury in nude mice by promoting skin tissue regeneration and supplementing the capacity of subcutaneous adipose tissue.
