Chitosan/Dicarboxilic Acid Scaffolds for Mineralized Tissues Regeneration

Objectives: Limited self-regenerating ability of human bone makes the reconstruction of critical size bone defect as a clinical challenge. A novel chitosan/dicarboxylic acid scaffold (CS/DA scaffold) has been developed and proven to be an excellent candidate material in bone tissue engineering. This study was designed to evaluate the potential of a CS/DA scaffold with and without seeded primary human periodontal ligament cells (hPDLCs) to regenerate bone in critical-size mouse calvarial defect model.
Methods: Periodontal ligament cells were obtained from healthy individuals. Osteogenic differentiation was analyzed by bone nodule formation assay and gene expression. In vivo bone regeneration was performed in C57BL/6Mlac mouse calvarial defects. Eighteen mice were divided into 3 groups of 6 each. Four-millimeter calvarial defects were created on both side of parietal bone and implanted with either CS/DA scaffold or CS/DA scaffold with hPDLCs. The empty bony defects were kept as control. New bone formation was assessed using microcomputed tomography and histological analyses 6 and 12 weeks after surgery.
Results: CS/DA scaffold significantly promote osteoblast-related gene expression when cultured in vitro. In vivo bone regeneration at 6 and 12 weeks was significantly enhanced by CS/DA scaffold alone and CS/DA scaffold implanted with hPDLCs (P <0.05). Histological staining confirmed these findings. An abundant new bone formation was observed in CS/DA scaffold and CS/DA scaffold with hPDLCs compared with control. Moreover, CS/DA could also be served as a scaffold to carry osteoinductive drug such as Triclostatin A (TSA), a histone deacetylase inhibitor. CS/DA scaffold incorporated with TSA exhibited prominence bone induction capability.

Conclusions: Our study proposes CS/DA scaffold could represent as a novel bone regenerative material with good osteoinductive/osteoconductive properties.