Recovery Course of Full-Thickness Skin Defects With Exposed Bone: An Evaluation by a Quantitative Examination of New Blood Vessels

BackgroundFull-thickness skin defects with exposed bone are often hard to heal. The lack or delayed re-vascularization is considered one of the major causes, and the periosteum is also suggested to have an important role in tissue regeneration.Materials and methodsFull-thickness skin defect wounds with exposed bone were made in the parietal region of Wister rats. The periosteum of the exposed parietal bone was removed in the periosteum-lacking group, but maintained in the control group (periosteum-intact group). The wound was covered by an artificial dermis made of collagen. The wound healing process was histologically compared. Double immunostaining of α-smooth muscle actin (SMA) and von Willebrand factor (vWF) was used for re-vascularization examination, and the blood vessel density in the artificial dermis was quantified.ResultsThe density of the blood vessels in the uninjured parietal tissue was approximately 80 vessels/mm2. To reach this density, 7 and 21 days were required for the control (periosteum-intact) and the periosteum-lacking groups, respectively. This coincided with complete revascularization, fibroblast migration and the reentry of blood vessels to the upper layer of the wound were observed.ConclusionThe described results support the importance of the periosteum in the full-thickness skin defect healing process.