Reindeer BMP extract in the healing of critical-size bone defects in the radius of the rabbit

Abstract

Background Native BMP extracts from reindeer effectively induce ectopic new bone formation in vivo, but their bone healing properties have not yet been evaluated. We investigated the effect of reindeer BMP extracts on the healing of long bone defects.Methods The implants tested contained 5 mg or 10 mg of unsterilized BMP extract from reindeer and 10 mg of gamma-sterilized BMP extract administered with collagen carrier (Lyostypt, B. Braun, Germany). 70 µg of rhBMP-2 with collagen carrier (InductOs; Wyeth Europa) served as positive control, and collagen implants (Lyostypt) and untreated defects served as negative controls. New Zealand White rabbits with 1.5 cm of critical-size radius bone defects were used, with 8 weeks of follow-up.Results Radiographic analysis showed bone formation (BF) to be higher in all groups containing BMPs than in the untreated controls. BF was also higher in the rhBMP-2 group, and marginally higher in the group treated with 10 mg of unsterilized reindeer BMP extract (p = 0.06) as compared to the collagen controls. Bone union (BU) was better in the unsterilized BMP extract groups and rhBMP-2 group than in the untreated controls. BU was also better in the implants with 10 mg of unsterilized reindeer BMP extract and rhBMP-2 than in the collagen-treated implants. The mean area of new bone at the site of the defect proved to be higher in all implants containing BMP than in the untreated defects. It was also higher in the groups with 10 mg of unsterilized reindeer BMP extract and rhBMP-2 than in the collagen-treated controls. Mechanical tests showed torsional stiffness of the bones to be higher in the group with 10 mg of unsterilized BMP extract than in the collagen

Reindeer bone extract can heal the critical-size rat femur defect

“…The 10 mg of bone extract group had significantly higher mean stiffness than the collagen group [9]. Our results confirm previous results, which showed that reindeer bone extract has good osteoconductivity both in [5,6,9]. It is known that the animal and fracture models, delivery systems and route of administration influence the dose response in bone healing studies [16].…”

“…These amounts healed the defect much better than the controls after eight weeks follow-up. The 10 mg of bone extract group had significantly higher mean stiffness than the collagen group [9]. Our results confirm previous results, which showed that reindeer bone extract has good osteoconductivity both in [5,6,9].…”

“…The collagen sponge was soaked in 200 μl sterile water and the sponge with extract was bundled up to form an implant. The doses were chosen according to our previous studies [5,6,9]. The InductOs™ kit (Wyeth Europa, Maidenhead/Berkshire, UK) for the implant contained 12 mg of rhBMP-2 and solvent.…”

“…Radiographs were evaluated with Osiris 4.19 software (Digital Imaging Unit, Geneva, Switzerland). The percentage of orthotopic new BF and the development of union or non-union of the bone (BU) were estimated as previously described [9] according to the scoring system presented in the study of Sciadini et al [14].…”

“…For this reason, animals with segmental long bone defects similar to clinical defects have been used as models for assessing the efficacy of BMPs and carrier materials. The bone healing properties of reindeer bone extract have been previously evaluated in the rabbit radius [9]. However, the time-and dosedependent effects of reindeer bone extract have not been evaluated previously.…”