Mineral apposition rates provide significant information on long-term effects in BMP-induced bone regeneration.
In this study, a CaP biomaterial was used as a carrier for rhBMP-2. Biomaterials were investigated in calvarial and femoral defects using a rabbit animal model, with unloaded biomaterials serving as control. Fluorochrome labels were administered at days 14 and 70. Specimens were retrieved after 12 weeks for histological analysis. When area fractions were assessed by conventional histomorphometry, no significant effect of rhBMP-2 on the amounts of regenerated bone and residual biomaterial were seen by 12 weeks. After mineral appositional rate (MAR) measurement using double labels, calculation yielded significantly higher MARs for defects at both implantation sites, when compared with surrounding bone, whether or not biomaterials were loaded with rhBMP-2. Analyzing the effect of rhBMP-2, both defect sites showed significantly higher MARs in the rhBMP-2 group. MARs of bone surrounding the defects had also been elevated significantly by rhBMP-2 at calvarial and femoral implantation sites. It is concluded that MAR measurement is suitable to identify long-term effects of rhBMP-2 on bone formation at a time when conventional histomorphometry using fractional area determination is inadequate. Also, by MAR assessment, effects of rhBMP-2 on surrounding bone can be documented.
Schopper
Christian
C
Hospital of Cranio-Maxillofacial and Oral Surgery, Medical University of Vienna, Austria. christian.schopper@meduniwien.ac.at
Moser
Doris
D
Spassova-Tzekova
Else
E
Russmueller
Guenter
G
Goriwoda
Walter
W
Lagogiannis
Georgios
G
Ewers
Rolf
R
Redl
Heinz
H
D000818:Animals; D001672:Biocompatible Materials / Q000494:pharmacology; D055396:Bone Morphogenetic Protein 2 / Q000494:pharmacology*; D001861:Bone Regeneration / Q000187:drug effects*; D001842:Bone and Bones / Q000166:cytology / Q000187:drug effects; D006801:Humans; D008903:Minerals / Q000378:metabolism*; D011817:Rabbits; D013997:Time Factors; D014945:Wound Healing / Q000187:drug effects
D001672:Biocompatible Materials; D055396:Bone Morphogenetic Protein 2; D008903:Minerals