Healing of segmental bone defects in rats induced by a beta-TCP-MCPM cement combined with rhBMP-2.
A beta-tricalcium phosphate-monocalcium phosphate monohydrate (beta-TCP-MCPM) cement was evaluated as an effective carrier of recombinant human bone morphogenetic protein-2 (rhBMP-2) in rat femoral critical-size defects. Hard cement cylinders (4 x 5 mm) impregnated with two different doses of rhBMP-2 (1.26 or 6.28 microg) were implanted into each defect, and the results were compared with those in rats that had implantations of cylinders only. Implantation of the 6.28 microg dose of rhBMP-2 caused a large bone shell to form around the defect, resulting in osseous union in all cases within 3 weeks. Except for beta-TCP granules, the cement was resorbed and replaced by bone tissue at 6 weeks. A torsion test at 9 weeks showed that the failure torque and bone stiffness had recovered 99% and 141%, respectively, compared with the intact contralateral femur. The defects that received 1.26 microg of rhBMP-2 resulted in 40% union and 41% of the failure torque at 9 weeks. However, no instances of union were observed in the defects implanted with cylinders only. In conclusion, the beta-TCP-MCPM cement was shown to be effective as a rhBMP-2 carrier. Combined with rhBMP-2, this cement was rapidly resorbed and completely healed the defects.
Department of Orthopaedic Surgery, Kinki University School of Medicine, 377-2, Ohno-Higashi, Osaka-Sayama, Osaka 589-8511, Japan.
K
K
Ohura
C
C
Hamanishi
S
S
Tanaka
N
N
Matsuda
D000818:Animals; D001696:Biomechanical Phenomena; D001843:Bone Cements; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins / Q000008:administration & dosage*; D001858:Bone Nails; D001860:Bone Plates; D002130:Calcium Phosphates; D004337:Drug Carriers; D005264:Femoral Fractures / Q000188:drug therapy / Q000473:pathology / Q000601:surgery; D017102:Fracture Healing / Q000187:drug effects*; D006801:Humans; D008297:Male; D008422:Materials Testing; D051381:Rats; D017207:Rats, Sprague-Dawley; D011994:Recombinant Proteins / Q000008:administration & dosage; D016212:Transforming Growth Factor beta
C525718:BMP2 protein, human; C525720:Bmp2 protein, rat; D001843:Bone Cements; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; D002130:Calcium Phosphates; D004337:Drug Carriers; D011994:Recombinant Proteins; D016212:Transforming Growth Factor beta; C103718:beta-tricalcium phosphate-monocalcium phosphate monohydrate-calcium sulfate hemihydrate mixture; C499469:recombinant human bone morphogenetic protein-2