Hard Tissue Formation by Bone Marrow Stem Cells in Sponge Scaffold with Dextran Coating

Abstract

A scaffold is necessary for bone regeneration, because the structure of hard tissue is three-dimensional. For application in dentistry, it is desirable for the scaffold to be modified the geometry easily according to the defect. Therefore it is thought that a sponge is suitable as a scaffold. A sponge (Polyvinyl formal®: PVF) was purchased for this study. The sponge was made from polyvinyl alcohol (PVA) with formalin preparation. In this study, the PVF sponges were coated with dextran, because dextran may affect cell adhesion. The effect of dextran for hard tissue formation by bone marrow stem cells in the PVF scaffold was examined in vivo. PVF scaffolds (5x5x5 mm) were immersed in each dextran solution of 10 kDa (2 g/dl) and 500 kDa (4 g/dl) and air dried. The coating for the PVF scaffolds by dextran was confirmed by SEM. Rat femur bone marrow cells of 1.107 were seeded in PVF scaffolds. They were implanted for four weeks in rat dorsal subcutaneous tissue. In removed scaffolds, hard tissue formation was examined histologically. Bone formation was conspicuously found in the scaffold coated with 10 kDa of dextran. Value of ALP activity measured biochemically in the scaffold was 58.5 mM/scaffold. By immunochemical examination, it was measured that quantity of osteocalcin in the scaffold was 25.9 ng/scaffold and that of Ca was 129.2 ìg/scaffold. These values showed a significantly higher in comparison with those of the scaffold with 500 kDa dextran coating and without coating. It was suggested in this study that coating of the scaffold with dextran induce increase of quantity of hard tissue formation in PVF scaffold in vivo. It is concluded that 10 kDa dextran coating of PVF scaffolds effectively contribute to adhesion of bone marrow cells in the scaffold.