Derm substitute is the foundation of constructing tissue engineering skin.OBJECTIVE:
To construct the living derm substitute and to perform the in vivo and in vitro relevant experiments.METHODS:
Collagen gel and fibroblasts were mixed to construct the living derm substitute and then histological observation was performed in vitro. Living derm substitutes were transplanted onto the back wounds of BALB/c nude mice with full-thickness skin defects, and the histological observation was performed after 4 weeks.RESULTS AND CONCLUSION:
①In vitro experiment: With the cultured time gone, the diameter of the living derm substitute reduced gradually, and the toughness increased. Up to 14 days, the diameter decreased to the original diameter of 18.2%, which was not broken under clamping and lifting. Fibroblasts grew well in the collagen gel and maintained secretory activity. Type I collagen, fibronectin and vascular endothelial growth factor were all positively expressed in the collagen gel. ②In vivo experiment: At 4 weeks after living derm substitute transplanted onto the wounds, the living derm substitutes were covered by epidermis with clear stratification that was thicker than normal skin. Fibroblasts in the dermis were alive and worked, and the collagen fibers arranged orderly which were homogeneous and non-hierarchical. Rare inflammatory cells could be seen in the dermis, mature blood vessels could be seen, and there lack of hair follicles and sebaceous. Living derm substitute could be constructed by fibroblasts in three-dimensional type I collagen gel culturing, which could promote the epithelialization after transplanted onto the wound.