title: Ectopic osteoinduction and early degradation of recombinant human bone morphogenetic protein-2-loaded porous beta-tricalcium phosphate in mice.
abstract: The present study investigated the ectopic osteoinduction and early degradation of recombinant human bone morphogenetic protein-2 (rhBMP-2)-loaded porous beta-tricalcium phosphate (beta-TCP) in mice. The porous beta-TCP with 50 microg of rhBMP-2 (n = 25) and porous beta-TCP (control group, n = 25) were implanted into muscle pouches in the right and left thigh of 28-day-old mice (n = 25), respectively. At every time point (3, 7, 14, 21 and 28 days after implantation), five mice were euthanized and the histological examinations of implantation sites were performed. In addition, the alkaline phosphatase (ALP) activity was also quantitatively analyzed. For the rhBMP-2-loaded group, blood vessel formation and immature cartilage was observed within the porous beta-TCP 3 days after implantation. Mature cartilage was observed 7 days after implantation of rhBMP-2-loaded porous beta-TCP. Newly formed woven bone, lamellar bone as well as marrow were observed 14 and 21 days after implantation of the rhBMP-2-loaded porous beta-TCP. Lamellar bone and marrow were observed 28 days after implantation of the rhBMP-2-loaded porous beta-TCP. For the control group, no bone or cartilage was observed at all time points. However, multinucleated giant cells and fibrous tissues were observed in the control group at 7 and 28 days after implantation, respectively. At 21 and 28 days after implantation, porous beta-TCP was observed to fragment indicating early degradation of the porous beta-TCP in both groups. In addition, ALP was observed to be significantly higher in the rhBMP-2-loaded beta-TCP as compared to the control beta-TCP. It was concluded from this study that the rhBMP-2-loaded porous beta-TCP induced blood vessel and ectopic bone formation.
authors.affiliation: Department of Orthopedic Surgery, Navy General Hospital, Beijing 100037, China.
authors.forename: Ge
authors.initials: G
authors.lastname: Liang
authors.forename: Yunzhi
authors.initials: Y
authors.lastname: Yang
authors.forename: Sunho
authors.initials: S
authors.lastname: Oh
authors.forename: Joo L
authors.initials: JL
authors.lastname: Ong
authors.forename: Changqiong
authors.initials: C
authors.lastname: Zheng
authors.forename: Junguo
authors.initials: J
authors.lastname: Ran
authors.forename: Guangfu
authors.initials: G
authors.lastname: Yin
authors.forename: Dali
authors.initials: D
authors.lastname: Zhou
mesh_terms: D020341:Absorbable Implants; D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins / Q000008:administration & dosage*; D018786:Bone Substitutes / Q000737:chemistry*; D002130:Calcium Phosphates / Q000737:chemistry*; D002454:Cell Differentiation / Q000187:drug effects; D002828:Choristoma / Q000473:pathology / Q000503:physiopathology; D004343:Drug Implants / Q000008:administration & dosage*; D008297:Male; D008422:Materials Testing; D051379:Mice; D010006:Osteoblasts / Q000187:drug effects / Q000473:pathology* / Q000502:physiology; D010012:Osteogenesis / Q000187:drug effects*; D016062:Porosity; D016212:Transforming Growth Factor beta / Q000008:administration & dosage*
chemical_list: C525718:BMP2 protein, human; D001672:Biocompatible Materials; C525719:Bmp2 protein, mouse; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; D018786:Bone Substitutes; D002130:Calcium Phosphates; D004343:Drug Implants; D016212:Transforming Growth Factor beta; C485817:beta-tricalcium phosphate