VASCULAR ENDOTHELIAL GROWTH-PATTERN DURING DEMINERALIZED BONE-MATRIX INDUCED OSTEOGENESIS

The purpose of the current study was to determine the timely ingrowth of blood vessels associated with demineralized bone matrix (DBM) induc ed osteogenesis. Critical-size (10 x 5mm), full thickness bony defects in rabbit parietal bone were implanted with DBM. Histological and ult rastructural changes were examined 1, 2, 3, 4, 5, 6, 7 and 14 days lat er. Neovascularization was assessed by immunohistochemical staining fo r factor VIII antigen (marker for vascular endothelium) and also confi rmed by staining using pan-endothelial antibody (CD31) (a marker for e ndothelium). Immunohistochemical evaluation revealed a positive staini ng for CD31 and Factor VIII expressed by endothelial cells by day 3 po st grafting. By day 4, small blood vessels were first seen budding fro m host bed towards the grafted DBM. Ultrastructural identification of cells in the early stages of healing revealed the presence of macropha ges. The monocyte-derived macrophage appears to play a central role in the repair process using DBM. Results of this study demonstrated a ra pid vascularization during the DBM induced osteogenesis. This rapid va scularization is vital to the healing and bone induction ability of th e DBM.