Bone Repair by Culture-Expanded Fetal Calvarium-Derived Osteoprogenitor Cells in Rat Tibial Defects: Percutaneous Grafting Versus Cell-Calcium Hydroxyapatite Ceramic Composite Grafting

Abstract

We investigated the role of calvarium-derived osteoprogenitor cells reconstituted porous calcium hydroxyapatite ceramic(CHAC) blocks in enhancing healing of an 8mm tibial diaphyseal defect fixed with external fixator. Forty-eigth Sprague-Dawley female rats weighing 250-300gm were divide into four groups; group I, no treatment in the defect as a control; group II, osteoprogenitor cells injected into the defect; group III, porous CHAC blocks alone introduced into the defect; group IV, composite graft of porous CHAC blocks combined with osteoprogenitor cells introduced into the defect. Radiological and histological studies were done on the animals killed at one week, and thereafterevery four weeks up to thirteen weeks. In groups I and II, massive fibrous tissues interposed in the defects throughout the study periods. In group III, scanty new bone formation occurred along with significant fibrous interposition in the defect. By contrast, in group IV, progressiw enchondral bone formation occurred with time in isolated pore regions from fiw weeks on after implantation, although the defect was not completely replaced by new bone until thirteen weeks. Our results indicated that composite graft of porous CHAC blocks combined with osteoprogenitor cells enhances bone healing by osteoinduction.