| Background: In plastic and reconstructive surgery, tissue expansion technique isa basic skill. Due to the limited ability of skin regeneration,4-6months are alwaysneeded to achieve expected area. Only the regenenration ability is improved, the largearea skin could be harvested. Till now, to find a way of enhancing the skinregeneration ability is still a difficulty to be solved for plastic surgerons. The skintissue expansion process produces a microenvironment that is similar to trauma.Adipose tissue derived stem cells (ADSCs) transplantation has been demonstrated tobe much effective in promoting wound healing.Objective: To explore if ADSCs transplantation could promote regeneration ofexpanded skin, and the mechanisms were also explored.Methods:(1) The conditioned medium of ADSCs (ADSC-CM) was harvested,and its influence on FB migration, proliferation and collagen secretion was detected;(2) The tissue expansion model was built on the back of rats. According to thedifferent cell injection, the rats were divided into3groups, they are ADSCs group, FBgroup and control group. Tissue expansion was carried out twice a week for4weeks,and maintained the pressure at60mmHg. The expansion volume and area as well asretraction ratio were measured to make further statistical analysis at the end of tissueexpansion;(3) The expanded skin at1w,2w and4w was harvested, and the skinthickness, the number of proliferating cells, collagen content, neovascularizationdegree and the density of macrophages and myofibroblasts were detected.(4) ADSCswere induced towards endothelial cells and epithelial cells by lineage specificinduction. ADSCs were labeled with10μM BrdU for48hours. Then,BrdU-labeled-ADSCs were transplanted into expanded skin for4weeks to observe their survival and distribution.(5) The gene and protein expression of vascularendothelial growth factor (VEGF), epidermal growth factor (EGF) and basicfibroblast growth factor (bFGF) in ADSCs and fibroblasts as well as in expanded skinin the3groups was detected.Results:(1) ADSC-CM could enhance the migration, proliferation and collagen Igene expression of dermal fibroblasts, and the roles presented a dose-dependent way.(2) After cell transplantation, the ADSCs group exhibited accelerated expansion withhigher inflation volume, and a larger expansion area than did both the FB group andthe control group. The retraction ration was reduced in ADSCs group.(3) Comparedwith the FB group and the control group, the skin in the ADSC group was muchthicker. At the same time, the thickness of the epidermal layer, as well as thethickness of the dermal layer and the subcutaneous tissue was also thicker in theADSCs group than that in the other two groups. There were no differences among thethree groups in regard to the thickness of the fibrous capsule. The percentage ofproliferating cells was significantly higher in the ADSCs group than the FB group andthe control group. Anti-PCNA staining showed that the proliferating cells wereprimarily observed at the stratum basale and hair follicles. The collagen in the ADSCgroup deposited more and lined tighter than the other two groups. The hydroxyprolinecontent increased significantly in the ADSC group. The capillary density in the ADSCgroup was clearly increased. There was no difference about the density ofmacrophages and myofibroblasts among the3groups.(4) After induction for7days,the ADSCs could differentiate into endothelial cells and epidermal cells. Theengrafted BrdU-labeled-ADSCs were transplanted and tracked. The results showedthat the cells appeared mainly in subcutaneous tissue for4weeks. Some of thetransplanted cells appeared in hair follicles and blood vessels.(5) The higherexpression of VEGF and EGF gene and protein mainly emerged in ADSCs andADSCs-treated expanded skin.Conclusion: The transplantation of ADSCs could enhance the regeneration ofexpanded skin by participating in skin structures and up-regulating the secretion ofepidermal growth factor and vascular endothelial growth factor. |
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