Abstract:

Objective   To investigate the basic regularity and characteristic in the process of wound healing after Ⅲ degree burn, and the relationship with skin grafting and the treatment of transplant bed. Methods   Ⅲ degree burn model was made on the selected adult minipigs and the changes of pathohistology, vascular endothelial cells, basic fibroblast growth factor(bFGF), collagen fibers, and fibroblastic ultrastructure in full-thickness skin burn wound and the junction area were observed dynamically by the techniques of HE staining, immunohistochemical staining, VG staining and transmission electron microscope examination. Results   Vascular endothelial cells and fibroblasts started to proliferate in the junction area in 24-48h postburn. At the 7th day, granulation tissue formed preliminarily and fibroblasts were in a state of active function. In 10-14d postburn, widespread vascularization happened in the junction area and granulation tissue present fibrosis and expansion. After 21 days, granulation tissue revealed and developed into connective tissue with myofibroblast (MFB) visible. The wound shrunk approximately by 14％ and evident edema happened in superficial granulation tissue on 30th day. Proliferation of vascular endothelial cells and expression of bFGF occurred through the whole process of granulation tissue formation. And their cresttimes arrived in 72h-7d and 5-7d. Conclusion   Vascularization happened in the junction after 7-10d postburn and granulation tissue expanded following its regularity. According to situations of the body and the local, autoskin grafting on the superficial hypodermis with improved blood supply should be implemented as soon as possible, which brought exact outcome of high survival rate of grafting and good quality of healing.

Key words: Burn; Granulation tissue; Wound healing; Hypodermis; Skin grafting