Analysis of different BMP2 carriers in the bone repair process in surgically created cavities: an histomorphometric, immunohistochemical and fluorochrome evaluation in rats calvaria

• Grant number: 08/03291-8
• Support Opportunities: Regular Research Grants
• Start date: August 01, 2008
• End date: July 31, 2010
• Field of knowledge: Health Sciences - Dentistry - Oral and Maxillofacial Surgery
• Principal Investigator: Tetuo Okamoto
• Grantee: Tetuo Okamoto
• Host Institution: Faculdade de Odontologia (FOA). Universidade Estadual Paulista (UNESP). Campus de Araçatuba. Araçatuba , SP, Brazil

Abstract

Extensive bone defects in facial maxilo region can be corrected with autogenous grafts, otherwise, the desadvantages of the therapeutics modality take the research for new bone substitutes. Considering this, the use of osteoinductor factors, as bone morphogenetic proteins (BMPs), have been an alternative. Otherwise, carriers and frameworks are essential to maintain the osteoinduction capacity of BMPs. Therefore, the present project has the aim to evaluate the biological role of different BMP2 carriers (demineralized bone matrix gel, calcium phosphate ciment and polilatic and poliglicolic copolymer) in the process of bone repair in surgically created cavities in rat's calvaria. Two critical size defects (A and B), with 5 mm diameter, will be prepared with trefine and slow rotation motor over intense irrigation for each animal. The animals will be divided in 4 groups; in Group I, the A defect will be filled with blood clot and the B defect will be filled with particulated autogenous bone; in Group II, the A defect will be filled with demineralized bone matrix gel plus BMP2 and the B defect will be filled with demineralized bone matrix gel; in Group III, the A defect will be filled with calcium phosphate cement plus BMP2 and The B defect will be filled with the calcium phosphate ciment; in Group IV, the A defect will be filled with polilatic and poliglicolic acid copolymers plus BMP2 and the B defect will be filled with polylactic polyglicolic acid copolymer. The animals will be sacrificed at 5, 15 and 30 pos operative days. The analysis of biologic mechanisms involved in the bone repair process will be obtained by hystomorphommetric use of fluorochromes and immunohistochemistry through the expression of Runx2, alkaline phosphatase, osteopontin, osteocalcin, TRAP and Type I collagen proteins, that are involved in the process of osteoinduction, mineralization and bone resorption. (AU)