J Korean Orthop Assoc.  2011 Feb;46(1):18-27. 10.4055/jkoa.2011.46.1.18.

New Bone Formation Following Transplantation of Stem Cells and Nanoscale Hydroxyapatite Scaffold Materials into Rabbit Long Bone Defects

• Kang NW
• Kim HT
• Kang JH
• Lee JS
• Ahn TY
• Jun ES
• Chang HK
• Jang SP
• Lee JK

• KMID: 2106567
• DOI: http://doi.org/10.4055/jkoa.2011.46.1.18

Abstract

PURPOSE
We observed new bone formation following the transplantation of allogenic periosteum-derived stem cells and different sizes of hydroxyapatite (HA) scaffold materials into rabbit long-bone defects.
MATERIALS AND METHODS
Thirty-two white rabbits were grouped according to the material transplanted into their tibial bone defects: group 1 (microscale HA only); group 2 (nanoscale HA only); group 3 (microscale HA plus stem cells); and group 4 (nanoscale HA plus stem cells). Viscosity was controlled by the relative amounts of HA and agar. After surgery, radiologic, microscopic, and biochemical observations were performed weekly for 8 weeks.
RESULTS
Nanoscale HA (groups 2 and 4) provided better bone formation than microscale HA (groups 1 and 3). The rabbits that had been transplanted with nanoscale HA plus stem cells (group 4) had more homogeneous bone formation during the natural repair process than the other groups.
CONCLUSION
Further study is required using nanoscale HA plus organic substance and stem cells, which are more similar to human bone structure, for better bone formation.

Keyword

bone defect; stem cell; nanoscale hydroxyapatite

MeSH Terms

Agar
Durapatite
Humans
Osteogenesis
Rabbits
Stem Cells
Transplants
Viscosity
Agar
Durapatite

Figure

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  Figure 1 An external fixation device was applied to the rabbit tibia (A). After exposure of the tibia (B), an 1.5 cm section of the tibia was excised (C). A mixture of agar, hydroxyapatite powder, and stem cells was inserted into the bone defect (D).

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  Figure 2 XRD patterns of micro-sized (A) and nano-sized (B) HA powders.

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  Figure 3 TEM micrographs of micro-sized (A) and nano-sized (B) HA powders.

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  Figure 4 (A) HA nanoparticles attached on the surface of periosteum-derived stem cell. (B) The effect of particle volume fraction on the ratio of the viscosity of agar based nanofluid to that of base fluid.

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  Figure 5 Serial radiographs of groups 1 through 4. In group 1 (A), diffuse bone formation was seen at 3 weeks and consolidation was complete after 8 weeks, but only in the lateral portion of the defect. In groups 2 (B), 3 (C), and 4 (D), bone formation and consolidation were seen as time passed. More abundant bone formation was seen in the groups transplanted with stem cells (C, D).

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  Figure 6 Microscopic findings of new bone at 8 weeks after transplantation (H-E, ×100). (A) In group 1, cartilaginous components were predominant. (B) In group 2, well-formed lamellar bone was observed. (C) In group 3, defects showed mostly loose connective tissue, with scant amounts of woven and lamellar bones. (D) In group 4, the tibial defects were almost filled with inflammatory cells, with conspicuous bone formation.

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  Figure 7 Biweekly changes in optical density of alkaline phosphatase (ALP) for groups 1 through 4. Optical density of ALP was measured at 405nm. Control values were measured 1 day before surgery; values for control through 6 weeks are the means obtained from 5 rabbits.

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  Figure 8 Biweekly changes in optical density of osteocalcin (OC) for groups 1 through 4. Optical density of OC was measured at 450nm. Control values were measured 1 day before surgery; values for control through 6 weeks are the means obtained from 5 rabbits.

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