Comparative study of biphasic calcium phosphate with beta-tricalcium phosphate in rat cranial defects--A molecular-biological and histological study.
The aim of this study was to evaluate the in vivo biocompatibility of a biphasic calcium phosphate (BCP) bone graft substitute consisting of 60% hydroxyapatite and 40% β-tricalcium phosphate (β-TCP) in comparison to a pure β-TCP of identical shape and porosity. The materials were evaluated using an established rat cranial defect model in 24 animals. One bone defect with a diameter of 5mm was created per animal. The defects were filled with either BCP or β-TCP and left to heal for 4 weeks. Twelve samples (6 per material) were processed for histological evaluation and immunohistochemistry. The remaining 12 samples were processed for mRNA expression analysis. No signs of inflammation or adverse material reactions were detected. New bone formation in the former defect site did not differ between the two groups (BCP: 49.2%; β-TCP: 52.4%). Osteoblast-like and TRAP-positive osteoclast-like cells were found at the surface of the bone graft substitute granules. The β-TCP group showed significantly higher mRNA levels for the bone resorption marker Acp5 and osteogenic differentiation marker Runx2. The expression of IGF1, IGF2, VEGF, Phex, Alpl, Col1, Col2, Bglap and MMP8 did not differ between the groups. The in vivo biocompatibility of BCP is to a large part identical to those of TCP. Within the limitation of the animal model, the implantation study shows that BCP can be used as bone graft substitute, due to the fact that the material integrates into tissue, remains stable in the implantation bed and serves as an osteoconductive scaffold.
Department of Orthodontics, Carl Gustav Carus Campus, Technische Universität Dresden, Germany. Electronic address: christiane.kunert-keil@uniklinikum-dresden.de.
Christiane
C
Kunert-Keil
Department of Orthodontics, Carl Gustav Carus Campus, Technische Universität Dresden, Germany.
Franziska
F
Scholz
Department of Orthodontics, Carl Gustav Carus Campus, Technische Universität Dresden, Germany.
Tomasz
T
Gedrange
Department of Orthodontics, Carl Gustav Carus Campus, Technische Universität Dresden, Germany.
Tomasz
T
Gredes
D000818:Animals; D001672:Biocompatible Materials; D015415:Biomarkers / Q000032:analysis; D001846:Bone Development / Q000187:drug effects; D001862:Bone Resorption / Q000473:pathology; D018786:Bone Substitutes; D002130:Calcium Phosphates / Q000494:pharmacology*; D017886:Durapatite; D005260:Female; D008297:Male; D008422:Materials Testing; D010006:Osteoblasts / Q000187:drug effects; D010010:Osteoclasts / Q000187:drug effects; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D051381:Rats; D011917:Rats, Inbred Lew; D012886:Skull / Q000002:abnormalities* / Q000187:drug effects*; D054457:Tissue Scaffolds; D014945:Wound Healing
D001672:Biocompatible Materials; D015415:Biomarkers; D018786:Bone Substitutes; D002130:Calcium Phosphates; D012333:RNA, Messenger; C485817:beta-tricalcium phosphate; D017886:Durapatite
BCP; Biphasic calcium phosphate; Bone regeneration; Histology; RT-PCR; TCP; Tricalcium phosphate