Artikel
Treatment of critical size femoral bone defects with 3D plotted calcium phosphate cement and mineralized collagen matrix scaffolds
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Autoren
Veröffentlicht: | 6. November 2018 |
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Gliederung
Text
Objectives: Scaffolds 3D plotted using resorbable pasty calcium phosphate cement (CPC) have high biomechanical stability. Scaffolds plotted using mineralized collagen type I (MCM) have high porosity and good osteoconductive property but a lower biomechanical stability. Our group developed 3D plotted CPC scaffold with pores filled with MCM. Hypothesis of this experiment is improvement of defect healing in group of CPC+MCM scaffold compared to scaffolds made from CPC or MCM alone.
Methods: 48 male Wistar rats were randomized to 4 groups of 12 rats:
- 1.
- control group(empty defect),
- 2.
- CPC,
- 3.
- MCM,
- 4.
- combination of CPC+MCM.
Scaffolds were produced with a three-channel plotting system with diameter about 4 mm, mean pore-size of 500 µm with triangular (60°) geometry. For combined scaffolds, plotted CPC scaffolds were filled with MCM suspension and freeze dried. For the animal experiment a locked plate was placed anterolaterally on femur, a 5-mm defect was created and filled with the group depending scaffold or left empty (control group). After observation period of 8 weeks animals were euthanized and µCT-scans were done to analyze regenerated bone volume (BV) and bone mineral density (BMD). For histomorphological investigations, hematoxylin and eosin staining was done. Degree of defect healing was evaluated according to the score of Huo et. al. Actin staining was applied to count vessels. Osteoclasts in defect area were visualized by tartrate-resistant-acid-phosphatase staining. Descriptive statistics included means and standard deviations. One-way ANOVA was used for statistical analysis between the groups. For post hoc testing unpaired t-tests were applied. Differences were considered significant when p<0.05.
Results and conclusion: Highest BV at the defect site after 8-weeks of follow-up was found for the CPC+MCM group (93,3±15,1 mm³). BMD was higher in the CPC (1165±63 mgHA/mm³) and the CPC + MCM-group (1206±58 mgHA/mm³) than in the control (1027±48 mgHA/mm³) and the MCM-group (1011±63 mgHA/mm³). Histologically highest degree of bone regeneration was found for the CPC+MCM-group. Best vascularization and highest number of osteoclasts were found for CPC+MCM-group.Combination of 3D plotted CPC and MCM showed favorable characteristics for defect regeneration and resulted in highest BV and BMD, vascularization and number of osteoclasts was best for CPC+MCM composite scaffolds. CPC+MCM composite scaffolds are promising materials to produce resorbable patient-specific 3D plotted bone replacement materials with optimal osteoconductive abilities and high biomechanical stability.
Regeneration of a critical size bone defect is improved by combining macroporous 3D plotted CPC with MCM compared to scaffolds made by these materials alone.