Abstract: Objective  To explore the feasibility of deep second-degree burn skin (DBS) as dermal substitute for constructing model of complex skin transplanting in repairing wounds. Methods  A total of 20 Wistar rats were randomly divided into the deep second-degree burn dermal matrix (DBDM) transplanting group (experimental group) and acellular dermal matrix (ADM) transplanting group (control group), 10 rats in each group. After a second-degree scald, the skin of two rats in experimental group was treated with enzyme digestion to remove cells to prepare DBDM. The back skin of newborn rats was integrally taken and the subcutaneous and dermal tissues were removed. The thin skin overlapped with mesh DBDM were transplanted into the back skin wound of full-thickness in size of 2cm×2cm or so. After 14 days, the situatioin of composite skin growth was observed. ADM was prepared by normal skin in control group, and other experiment steps were the same as the experimental group. Results  The freshly prepared DBDM was yellow-white, less soft in texture of flexibility and extensibility compared with ADM. Collagen fibers of DBDM were thickened unevenly with hyaline changing and arranging in disorder. No cellular, blood vessels, hair follicles and other components were observed in DBDM under light microscope. Fourteen days after the composite skin transplantation experiments, the survival rate of rats and transplants in the two groups had significant difference (P<0.05). The bilayer composite skin and subcutaneous tissue connected closely. The deep DBDM or ADM was pink. The skin after operation had no significant swelling or inflammation. Infiltration of inflammatory cells and ingrowth of fibroblast and capillary appeared more earlier in DBDM group compared with those in ADM group. Inflammatory cells were mainly neutrophils and macrophages. New collagen deposition was rapid and collagen fibers arranged in a regular and dense state. Conclusion  Sources of DBDM is wide and preparation method is simple. Biocompatibility of transplants is good and burn toxin-like effect is weak. DBDM can act as dermal substitute of autologous split thickness skin. The experiment may provide new ideas for clinical transformation and utilization of DBS.

Key words: Dermal matrix, Deep second-degree burn, Composite skin, Rats