BMP-2 and bFGF in an irradiated bone model.
BACKGROUND
Basic fibroblast growth factor (bFGF) is considered to enhance angiogenesis and to support bone formation in the presence of vital bone cells. Bone morphogenetic protein-2 (rhBMP-2) is known to induce bone formation. The aim of this study was to analyze the effect of bFGF and rhBMP-2 in the irradiated mandible.


METHODS
The right mandibles of 24 rats were irradiated with a single dose of 20 Gy at a high-dose-rate (HDR) after loading machine (bio effective equivalent dose to ca. 45 x 2 Gy). After 12 weeks 100 microg rhBMP-2 (n=6 animals, group 1), 100 microg bFGF (n=6 animals, group 2) and 100 microg rhBMP-2 plus 100 microg bFGF (n=6 animals, group 3) were injected along the right mandible (left mandible: no irradiation, no growth factor). Another 6 animals (group 4) remained untreated after the irradiation. After another 7 weeks the specimens were examined by non-decalcified histology.


RESULTS
Bone apposition of the experimental versus control sides was not statistically significantly different when one of the growth factors was applied alone (rhBMP-2: p=0.917; bFGF: p=0.345). Average bone apposition was significantly decreased on the experimental sides of group 3 (rhBMP-2+bFGF: p=0.046) and group 4 (p=0.008). Average bone densities were unaffected in all settings (for all p>0.1).


CONCLUSIONS
The application of bFGF and the application of rhBMP-2 alone did result in predictable bone generation in the irradiated mandible with the bone apposition being equal to that of the non-irradiated side. The application of both growth factors together or none at all after irradiation results in significantly reduced bone apposition.
Springer
Ingo N G
IN
Department of Oral and Maxillofacial Surgery, University of Kiel, Germany. springer@mkg.uni-kiel.de
Niehoff
Peter
P
Açil
Yahya
Y
Marget
Matthias
M
Lange
Arne
A
Warnke
Patrick H
PH
Pielenz
Helge
H
Roldán
J Camilo
JC
Wiltfang
Jörg
J
D000818:Animals; D015519:Bone Density / Q000187:drug effects / Q000528:radiation effects; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins / Q000494:pharmacology*; D001861:Bone Regeneration / Q000187:drug effects / Q000528:radiation effects; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology*; D006801:Humans; D008334:Mandible / Q000187:drug effects* / Q000528:radiation effects*; D023421:Models, Animal; D010025:Osteoradionecrosis / Q000503:physiopathology; D011882:Radiotherapy, High-Energy / Q000009:adverse effects*; D051381:Rats; D011916:Rats, Inbred F344; D011917:Rats, Inbred Lew; D011921:Rats, Inbred WKY; D011994:Recombinant Proteins / Q000494:pharmacology; D018709:Statistics, Nonparametric; D016212:Transforming Growth Factor beta / Q000494:pharmacology*
C525718:BMP2 protein, human; C525720:Bmp2 protein, rat; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; D011994:Recombinant Proteins; D016212:Transforming Growth Factor beta; D016222:Fibroblast Growth Factor 2