Vascular endothelial growth pattern of endochondral bone graft in the presence of demineralized intramembranous bone matrix - Quantitative analysis

Objective: To determine the timely ingrowth of new blood vessels of composite endochondral (EC) bone and demineralized bone matrix (DBM) prepared from intramembranous (IM) origin (EC-DBMIM) and to compare it with EC bone graft alone. Design: Thirty-two rabbits with 32 critical-size (10 x 5 mm), full-thickness bony defects in rabbit parietal bone were divided into two groups: composite EC-DBMIM group-implanted with composite autogenous EC bone and DBMIM; EC bone group-implanted with EC bone alone. Two rabbits from each group were sacrificed 1, 2, 3, 4, 5, 6, 7, and 14 days after grafting. Neovascularization was assessed by immunohistochemical staining with antihuman angiogenesis-related endothelial cell antibodies (EN 7/44). Quantitative analysis of neovascularization, represented by percentage area of positive immunohistochemical staining, was performed on 320 sections of the experimental groups by a computer-assisted image analyzer. Results: Positive immunohistochemical staining was first identified on day 2 post grafting for the composite EC-DBMIM group in comparison with day 4 in the EC bone graft group. The composite EC-DBMIM bone graft group showed earlier and almost 100% more neovascularization when compared with the EC bone graft group. Conclusion: DBMIM enhances healing and integration of EC bone graft by enhancing vascularization as well as increasing the amount of new blood vessels formed. In clinical cases in which EC autogenous bone is used to graft a large defect such as in cleft palate and craniofacial surgery, DBMIM should allow better integration and healing of the EC bone graft to the host bone.