S0201-1-5 リン酸オクタカルシウム(OCP)の溶解性と細胞吸収性(骨再生と骨再建のためのバイオマテリアル(1),社会変革を技術で廻す機械工学)

抄録

Synthetic octacalcium phosphate (OCP) exhibits biodegradable characteristics if implanted in various bone defects. OCP tends to convert to hydroxyapatite (HA) both in vitro at physiologic pH and in the implanted sites. This conversion is accompanied by calcium ion consumption from and phosphate ion release into the surrounding solution. When OCP is incubated in culture medium, this tendency is more distinct as the dose of OCP increased. The equilibrium is attained to approach to the saturation with respect to OCP but slightly to higher degree of supersaturation beyond OCP. The growth of mouse bone marrow stromal ST-2 cells on OCP crystals is inhibited in the initial stage of incubation while osteoblastic differentiation is facilitated at the later stage more than that by HA crystals. The slight advancement of OCP hydrolysis into HA inhibits the appearance of osteoclastic cells around the OCP-implant in rat tibia bone marrow spaces. The results suggests that the characteristics of OCP which tend to convert to HA is a factor that stimulates not only osteoblastic cellular activity but also osteoclastic cellular response induced by OCP crystals.