Effects of Laminin For Osteogenesis in Porous Hydroxyapatite

Summery: As a tooth is composed of hard tissue covering pulp, it may be suitable for tooth regeneration to use porous cylindrical hydroxyapatite (HA) scaffolds with a hollow center. Generally, in vivo examination, bone marrow cell suspension for osteogenesis in cell/HA composite scaffold without subculture is prepared at a density of 1 × 10⁷ cells/ml or higher. In dentistry, stem cells would be obtained from tooth pulp. For dentine formation, a smaller number of stem cells must be used. In this study, a suspension of rat bone marrow cells at 1 × 10⁶ cells/ml of density was prepared to estimate the adhesive effect of laminin. After immersion of HA scaffold in laminin solution, bone marrow cells were seeded in the pores of the HA scaffolds by immersion in the cell suspension for preparing the cell/HA composite scaffolds. The specimens were respectively implanted in the dorsal subcutis of 7-week-old male Fischer 344 rats for 4 weeks for histological examination. Comparing with the results of in vivo examination, alkaline phosphatase activity of bone marrow cells on laminin-coated plate with and without dexamethasone cultured for 2 weeks was measured in vitro. It was considered that laminin contributed to bone formation in pores of a scaffold.