Evaluation of ceramics composed of different hydroxyapatite to tricalcium phosphate ratios as carriers for rhBMP-2.
We have investigated pellet-shaped implants prepared from biphasic calcium phosphate (BCP) ceramics with five different ratios of hydroxyapatite (HAP) to beta tricalcium phosphate (beta-TCP). The purpose of this study was to evaluate these BCP ceramics as carriers for rhBMP-2. BCP ceramics impregnated with the different doses of recombinant human bone morphogenetic protein 2 (rhBMP-2) (1, 5 and 10g) were used for the experimental purpose and the ceramics without rhBMP-2 were used as control. The pellets were placed into subcutaneous pockets on the dorsum of 4-week-old male Wistar rats. The animals were sacrificed 2 and 4 weeks after implantation. Bone induction was estimated by alkaline phosphatase (ALP) activity measured at 2 weeks after implantation. Pellets were also examined radiologically, histologically and histomorphometrically. The results showed that all experimental pellets exhibited new bone formation whereas the control pellets produced only fibrous connective tissue. Here, 100% HAP ceramic showed most amount of bone formation, whereas 25% HAP to 75% TCP ceramic produced the bone least in amount among different BCP ceramics at the end of 4 weeks. This study indicates that formation of new bone depends on the ceramic content with high HAP-TCP ratio and high dose of rhBMP-2.
Alam
M I
MI
Oral Surgery Department of Oral Restitution, Tokyo Medical and Dental University Graduate School, Japan.
Asahina
I
I
Ohmamiuda
K
K
Takahashi
K
K
Yokota
S
S
Enomoto
S
S
D000469:Alkaline Phosphatase / Q000032:analysis*; D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry*; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins / Q000008:administration & dosage* / Q000494:pharmacology*; D002130:Calcium Phosphates / Q000032:analysis / Q000737:chemistry*; D002516:Ceramics / Q000737:chemistry*; D003238:Connective Tissue / Q000502:physiology; D003239:Connective Tissue Cells / Q000166:cytology / Q000187:drug effects; D003692:Delayed-Action Preparations; D004337:Drug Carriers; D004343:Drug Implants; D017886:Durapatite / Q000032:analysis / Q000737:chemistry*; D006801:Humans; D008297:Male; D008422:Materials Testing / Q000379:methods; D008855:Microscopy, Electron, Scanning; D010006:Osteoblasts / Q000166:cytology* / Q000187:drug effects; D010011:Osteocytes / Q000166:cytology* / Q000187:drug effects; D010012:Osteogenesis / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D011994:Recombinant Proteins / Q000008:administration & dosage / Q000494:pharmacology; D016212:Transforming Growth Factor beta
C525718:BMP2 protein, human; D001672:Biocompatible Materials; C525720:Bmp2 protein, rat; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; D002130:Calcium Phosphates; D003692:Delayed-Action Preparations; D004337:Drug Carriers; D004343:Drug Implants; D011994:Recombinant Proteins; D016212:Transforming Growth Factor beta; C485817:beta-tricalcium phosphate; C499469:recombinant human bone morphogenetic protein-2; D017886:Durapatite; D000469:Alkaline Phosphatase; C018392:tricalcium phosphate