title: The effect of different mineral frames on ectopic bone formation in mouse hind leg muscles induced by native reindeer bone morphogenetic protein.
abstract: BACKGROUND
  Bone morphogenetic proteins (BMPs) require carrier material for slow release and framing material for osteoconduction.
  
  
  METHODS
  The effect of a frame on early bone formation induced by partially purified native reindeer BMP in composite implants containing 3 mg of BMP, type IV collagen and tricalcium phosphate (TCP/Col/BMP) or hydroxyapatite (HA/Col/BMP) or biphasic tricalcium phosphate-hydroxyapatite (TCP/HA/Col/BMP) or biocoral (NC/Col/BMP) was evaluated using a mouse hind leg muscle pouch model. Collagen with native reindeer BMP (Col/BMP) and corresponding implants without native reindeer BMP served as controls. Evaluation was done by incorporation of 45Ca, radiographically and histologically 3 weeks after the implantation.
  
  
  RESULTS
  None of the implants without native reindeer BMP were able to induce new bone visible on radiographs. The area of new bone formation in the Col/BMP (p=0.026) and TCP/HA/Col/BMP (p=0.012) groups was significantly greater than in the TCP/Col/BMP group. The optical density of the new bone area was significantly greater in the TCP/HA/Col/BMP group than in the TCP/Col/BMP (p=0.036) or Col/BMP (p=0.02) groups. 45Ca incorporation was many times greater in all the groups containing native reindeer BMP than in the corresponding groups without BMP. In the Col/BMP (p=0.046) and TCP/HA/Col/BMP (p=0.046) groups, 45Ca incorporation was significantly greater than in the TCP/Col/BMP group. No significant differences were found in any parameters between HA/Col/BMP and NC/Col/BMP groups and the other BMP-containing groups.
  
  
  CONCLUSIONS
  Hydroxyapatite, biocoral and biphasic tricalciumphosphate-hydroxyapatite are equally good as framing material for native reindeer BMP, while tricalciumphosphate is somewhat worse. Osteoinduction of native reindeer BMP works well with collagen alone.
authors.affiliation: Bone Transplantation Research Group, Aapistie 5, PO Box 5000, 90014, Oulu, Finland.
authors.forename: T
authors.initials: T
authors.lastname: Pekkarinen
authors.forename: T S
authors.initials: TS
authors.lastname: Lindholm
authors.forename: O
authors.initials: O
authors.lastname: Hietala
authors.forename: P
authors.initials: P
authors.lastname: Jalovaara
mesh_terms: D020341:Absorbable Implants; D000818:Animals; D001672:Biocompatible Materials / Q000494:pharmacology; D019485:Bone Morphogenetic Proteins / Q000494:pharmacology*; D002130:Calcium Phosphates / Q000494:pharmacology; D002132:Calcium Radioisotopes / Q000493:pharmacokinetics; D002516:Ceramics / Q000494:pharmacology; D024141:Collagen Type IV / Q000494:pharmacology; D006614:Hindlimb / Q000000981:diagnostic imaging; D006882:Hydroxyapatites / Q000494:pharmacology; D008297:Male; D051379:Mice; D018482:Muscle, Skeletal / Q000601:surgery; D010012:Osteogenesis / Q000187:drug effects*; D011859:Radiography; D012053:Reindeer
chemical_list: D001672:Biocompatible Materials; D019485:Bone Morphogenetic Proteins; D002130:Calcium Phosphates; D002132:Calcium Radioisotopes; D024141:Collagen Type IV; D006882:Hydroxyapatites; C018392:tricalcium phosphate