Lack of repair of rat skull critical size defect treated with bovine morphometric protein bound to microgranular bioabsorbable hydroxyapatite.
The ability of a pool of bovine bone morphogenetic proteins bound to synthetic microgranular hydroxyapatite (BMPb-HA) to stimulate bone repair was determined in rat critical size defects. An 8-mm diameter defect was created in the calvaria of 25 rats. In 15 rats, the defects were filled with BMPb-HA homogenized with blood (experimental group), and in 10 rats the defects were filled only with blood clots (control). The calvariae of experimental rats were collected 1, 3 and 6 months after surgery and of the control rats at the end of surgery and 6 months thereafter. The morphometric results obtained in the radiographs showed an absence of new bone formation at 1 and 3 months post-surgery and, histologically, the defects were filled with fibrous connective tissue and numerous foci of a foreign body-type granulomatous reaction around hydroxyapatite agglomerates. At the end of 6 months, the number and size of the granulomatous foci decreased and the area of the defects was reduced by 22% compared to the 0-hour control due to the formation of new bone at their borders, although the mean area was similar to the 6-month control. We conclude that the use of BMPb-HA in the treatment of critical size bone defects of the rat skull leads to the formation of a foreign body-type granulomatous reaction that markedly inhibits new bone formation, suggesting that synthetic microgranular hydroxyapatite does not represent a good carrier for BMP-induced bone formation.
Ferreira
Gabriel Ramalho
GR
Department of Biological Sciences, Faculty of Dentistry of Bauru, University of São Paulo, Bauru, SP, Brazil.
Cestari
Tania Mary
TM
Granjeiro
José Mauro
JM
Taga
Rumio
R
D020341:Absorbable Implants; D000818:Animals; D001672:Biocompatible Materials / Q000009:adverse effects / Q000627:therapeutic use*; D001769:Blood; D001847:Bone Diseases / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D019485:Bone Morphogenetic Proteins / Q000627:therapeutic use*; D018786:Bone Substitutes / Q000009:adverse effects / Q000627:therapeutic use*; D002417:Cattle; D003238:Connective Tissue / Q000473:pathology; D004337:Drug Carriers; D017886:Durapatite / Q000009:adverse effects / Q000627:therapeutic use*; D005347:Fibroblasts / Q000473:pathology; D015745:Granuloma, Foreign-Body / Q000139:chemically induced / Q000473:pathology; D007963:Leukocytes, Mononuclear / Q000473:pathology; D008264:Macrophages / Q000473:pathology; D008297:Male; D010012:Osteogenesis / Q000187:drug effects; D011859:Radiography; D051381:Rats; D012886:Skull / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D013997:Time Factors
D001672:Biocompatible Materials; D019485:Bone Morphogenetic Proteins; D018786:Bone Substitutes; D004337:Drug Carriers; D017886:Durapatite