Evaluation of the effectiveness of 3D bone matrices osteoinduction by using in vitro and in vivo models.

Due to some accidents and illnesses, it is possible that bones are damaged and require repair, or it may be that bone need to be formed in jaw before dental implant. In some cases, medical intervention is required as the body cannot heal itself. Many approaches are used to repair bone defects in reconstructive medicine, with one of the most popular being the use of allograft bone. Surgeons have a variety of bone allograft structures and shapes to choose from in order to fill in a defect.

The aim of this study is to evaluate the increase in bone regeneration caused by different 3D bone matrix allografts, and asses this effectiveness by in vitro and in vivo models. In the laboratory phase, bone allografts of different shapes and sizes were seeded with mesenchymal stem cells for three weeks. Cell seeding on bone allografts, safety and cell proliferation were evaluated. To investigate the osteoinduction properties of allografts, the expression of osteogenic genes based on selective housekeeping genes using Real–Time PCR was assessed. The alkaline phosphatase enzyme activity in cells was measured by ELISA. In the dentistry phase, focus was made on the use of different size and shape of bone allografts for the treatment of sinus lift in humans. Radiographic evidence was used to evaluate the new bone formation after sinus lift and bone repairing was evaluated by CT scanning. Results showed all products have cell seeding capability. MTT assay tests revealed that none of the allografts exerted cytotoxic properties on Mesenchymal stem cells. Scanning electron microscopy images showed the appropriate pore size for stem cell seeding. The qualitative result of Alizarin red staining test indicates that mineral bone allografts of different structures, such as; cube product and bone powder size of 500- 1000 μm, have the highest mineralization. The expression of osteogenic-related genes increased significantly compared to the negative control group. ATP5B and RPL13A genes were selected as the best reference genes. The results show successful bone formation of allografts as extracellular matrix scaffolds both in vitro and in vivo conditions which have the necessary characteristics for stem cell proliferation and differentiation. This study can help the surgeon to choose suitable bone allograft based on their requirements.