Allografts such as nondecalcified bone allograft (MBM), decalcified bone allograft (DBM), bone (HABM) or synthetic hydroxyapatite (HA) acting as a scaffold have been used in humans to fill maxillary sinuses and bone defects in conjunction with dental implants; however, such scaffolds have not always stimulated bone formation. Our recent in vivo studies revealed that while MBM and DBM scaffolds are bioactive the HABM is not. Our objective: was to evaluate the cell-matrix interaction of bone derived matrices, in vitro. The experimental methods: consisted of bone matrices rings of 3-4 mm in diameter and 2-3 mm in height, were cut from the cortex of DA rats diaphysis and treated chemically to achieve bone matrices of three types, MBM, DBM or HABM. The bone matrices rings were placed on a glass bottomed culture dish filled with DMEM supplemented with 1% bovine serum; C2C12 were inoculated inside the well created by the matrix rings. To evaluate cell adhesion and morphology, time-lapse video microscopy was performed under incubator environment. Results: show that in the DBM and MBM matrices rings, the cells are very motile attaching and detaching from the matrix surface. They spread and elongate significantly, presenting shapes of differentiated functional fibroblast-like cells with well-developed processes. Cells in the HABM rings are more round and remain smaller; very few develop extended processes and motility is limited. Interestingly, many of these cells suddenly disrupt and died few hours after plating, while in the MBM and DBM rings most of the cells survive the 10 hr-time of experimental observation .
In conclusion: these findings suggest that bone matrices which include the organic matrix are attractant to the C2C12 cells and provide molecular signals that affect normal function of cells, while bone mineral proper lack this properties.