Evaluation of the osteoinductive effect of PDGF-BB associated with different carriers for bone regeneration in surgical created defects

Abstract

Extensive bone defects in maxillofacial region can be corrected with autogenous grafts; otherwise, the disadvantages of the therapeutics modality take the research for new bone substitutes. Considering this, the use of osteoinductive factors, platelet derived growth factor (PDGF-BB) have been an alternative. Otherwise, carriers and scaffolds are essential to maintain the osteoinduction capacity of PDGF-BB. Therefore, the present project has the aim to evaluate the biological role of different PDGF-BB carriers (beta-tricalcium phosphate matrix, hydroxiapatite ceramic matrix and bovine bone mineral matrix) in the process of bone repair in surgically created cavities in rats 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 beta-tricalcium phosphate matrix (Cerasorb®M, Curassan Ltd,Germany) plus PDGF-BB (R&D Systems, Inc., Minneapolis, MN, USA) and the B defect will be filled with beta-tricalcium phosphate matrix; in Group III, the A defect will be filled with hydroxiapatite ceramic matrix (Endobon®, Biomet 3i Ltda, Belgium) plus PDGF-BB and The B defect will be filled with the hydroxiapatite ceramic matrix; in Group IV, the A defect will be filled with bovine bone mineral matrix (Bio-Oss®, Geistlich Pharma Group Ltd, Switzerland )plus PDGF-BB and the B defect will be filled with bovine bone mineral matrix. The animals will be sacrificed at 15 and 30 pos operative days. The analysis of biologic mechanisms involved in the bone repair process will be obtained by histomorphometric and immunohistochemistry analysis through the expression of Runx2, alkaline phosphatase, osteopontin, osteocalcin, TRAP and Type I collagen proteins, that are involved in osteoinductive, mineralization and bone resorption process. (AU)