The effect of the configuration of porous cylindrical hydroxyapatite (HA) scaffold and laminin preparation of the scaffold on bone formation was estimated. HA scaffolds with a hollow center of 2 or 4 mm in diameter and those without a hollow center were used. The scaffolds were immersed in laminin solution or in culture medium. Bone marrow cells were obtained from the femora of male Fischer 344 rats. Cell suspension was prepared at 1 x 10(6) cells/mL density. The cells were seeded into HA scaffolds. Each scaffold was implanted in the dorsal subcutis of rats for 4 weeks. Bone formation in scaffolds was observed histologically. The quantity of osteocalcin was measured immunochemically. Many pores containing bone were identified in the laminin-immersed HA scaffold with a hollow center measuring 4 mm in diameter than those without and those with a hollow center measuring 2 mm in diameter. A greater quantity of osteocalcin was detected in the HA scaffold with immersion in laminin than in that without immersion in laminin. However, the results of the immunochemical assay for osteocalcin showed that a hollow center in the scaffold did not contribute to bone formation compared to scaffolds without a hollow center. It is considered that laminin may act as an adhesive for effective cell attachment to the walls of the pores in an HA scaffold.
Although hydroxyapatite is commonly used as a scaffold for bone regeneration, sponges may be suitable because of the adaptability to the defect. To use as a scaffold, the fiber of sponge would be coated with any adhesive to storage stem cells in the sponges. Fiber in the structure of commercially available sponges was coated by immersion in dextran solution and air dried. After seeding of rat bone marrow cells (rBMCs), the sponges were implanted subcutis of rats for estimate osteogenesis in vivo. The level of osteocalcin was 25.28 ± 5.71 ng/scaffold and that of Ca was 129.20 ± 19.69 μg/scaffold. These values were significantly high- er than those in sponges without dextran coating (p < 0.01). It was thought that rBMCs could be stored on the shelf by dextran deposition in the fiber of the sponge. In vivo examination, dextran induced osteogenesis by rBMCs in many spaces in the inner structure of the sponge
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.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.