Effect of mesenchymal stem cell-incorporated hydroxyapatite-collagen scaffold on tissue repair in acute spinal cord injury, and the mechanism involved

Purpose: To study the effect of hydroxyapatite-collagen (HC) scaffold with mesenchymal stem cells (MSCs) on tissue repair in acute spinal cord injury (SCI).Method: Adult female Sprague-Dawley rats weighing 200 - 230 g were randomly divided into two groups implanted either with bone marrow-MSCs (experimental group) or HC scaffold alone (control group). Spinal cord injury was induced using laminectomy, resulting in a 2.0-mm gap at T10 of the spinal cord. The gap was filled in both groups with 2-mm HC scaffold at day 10 of culture. Cellular development, viability, and proliferation inside the scaffold were determined. Angiogenesis was determined by measuring fibronectin (FN) immunofluorescence, von Willebrand factor (vWF), hypoxiainducible factor 1-alpha (HIF-1α) and vascular endothelial growth factor (VEGF).Results: HC scaffold strengthened MSCs. Bone marrow MSCs exhibited no statistically significant difference when compared with cells in culture at day 10 (47.03 ± 3.135 %, p > 0.05). Moreover, on days 5 and 10, FN deposition was higher in MSCs with scaffold than in scaffold-free MSCs. The expressions of FN, vWF, HIF-1α and VEGF were positively correlated, indicating that incorporation of HC scaffold into MSCs significantly improved tissue repair by improving angiogenesis via a differentiation process (p < 0.001).Conclusion: These findings suggest that HC scaffold with MSCs is a potential therapeutic procedure for spinal cord injury. Keywords: Mesenchymal stem cells, Hydroxyapatite-collagen, Spinal cord injury, HC scaffold