title: The effect of an octacalcium phosphate co-precipitated gelatin composite on the repair of critical-sized rat calvarial defects.
abstract: This study was designed to investigate the extent to which an octacalcium phosphate/gelatin (OCP/Gel) composite can repair rat calvarial critical-sized defects (CSD). OCP crystals were grown with various concentrations of gelatin molecules and the OCP/Gel composites were characterized by chemical analysis, X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), selected area electron diffraction (SAED) and mercury intrusion porosimetry. The OCP/Gel composite disks received vacuum dehydrothermal treatment, were implanted in Wistar rat calvarial CSD for 4, 8 and 16 weeks, and then subjected to radiologic, histologic, histomorphometric and histochemical assessment. The attachment of mouse bone marrow stromal ST-2 cells on the disks of the OCP/Gel composites was also examined after 1 day of incubation. OCP/Gel composites containing 24 wt.%, 31 wt.% and 40 wt.% of OCP and with approximate pore sizes of 10-500 μm were obtained. Plate-like crystals were observed closely associated with the Gel matrices. TEM, XRD, FTIR and SAED confirmed that the plate-like crystals were identical to those of the OCP phase, but contained a small amount of sphere-like amorphous material adjacent to the OCP crystals. The OCP (40 wt.%)/Gel composite repaired 71% of the CSD in conjunction with material degradation by osteoclastic cells, which reduced the percentage of the remaining implant to less than 3% within 16 weeks. Of the seeded ST-2 cells, 60-70% were able to migrate and attach to the OCP/Gel composites after 1 day of incubation, regardless of the OCP content. These results indicate that an OCP/Gel composite can repair rat calvarial CSD very efficiently and has favorable biodegradation characteristics. Therefore, it is hypothesized that host osteoblastic cells can easily migrate into an OCP/Gel composite.
authors.affiliation: Division of Oral Surgery, Tohoku University Graduate School of Dentistry, Sendai, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Handa
authors.forename: T
authors.initials: T
authors.lastname: Anada
authors.forename: Y
authors.initials: Y
authors.lastname: Honda
authors.forename: H
authors.initials: H
authors.lastname: Yamazaki
authors.forename: K
authors.initials: K
authors.lastname: Kobayashi
authors.forename: N
authors.initials: N
authors.lastname: Kanda
authors.forename: S
authors.initials: S
authors.lastname: Kamakura
authors.forename: S
authors.initials: S
authors.lastname: Echigo
authors.forename: O
authors.initials: O
authors.lastname: Suzuki
mesh_terms: D020341:Absorbable Implants; D000818:Animals; D001854:Bone Marrow Cells / Q000378:metabolism / Q000473:pathology; D018786:Bone Substitutes / Q000737:chemistry / Q000494:pharmacology*; D002130:Calcium Phosphates / Q000737:chemistry / Q000494:pharmacology*; D002460:Cell Line; D005780:Gelatin / Q000737:chemistry / Q000494:pharmacology*; D008297:Male; D008422:Materials Testing; D051379:Mice; D046529:Microscopy, Electron, Transmission; D051381:Rats; D017208:Rats, Wistar; D012886:Skull / Q000293:injuries* / Q000378:metabolism / Q000473:pathology; D012887:Skull Fractures / Q000378:metabolism / Q000473:pathology / Q000628:therapy*; D017550:Spectroscopy, Fourier Transform Infrared; D017154:Stromal Cells / Q000378:metabolism / Q000473:pathology
chemical_list: D018786:Bone Substitutes; D002130:Calcium Phosphates; C022045:octacalcium phosphate; D005780:Gelatin