Influence of calcium phosphate crystal morphology on the adhesion, spreading, and growth of bone derived cells

In this study, rat periosteal cells and bone marrow stromal cells (BMSC) were examined when cultured on octacalcium phosphate (OCP) crystals to determine the effects of crystal morphology on their adhesion, spreading, and growth. Three type of OCP crystals with different morphology were prepared by different precipitation methods. OCPI was prepared by homogeneous precipitation; while OCPII and III were prepared by heterogeneous precipitation dripping a calcium ion containing solution into a phosphate ion solution or vice versa, respectively. The effects of crystal morphology on the attachment and spreading of cultured cells on OCP crystals were observed using SEM. The effects of crystal morphology on the growth of periosteal cell or BMSC were evaluated using the MTT assay, while OCP crystal cytotoxicity was determined by measuring lactic dehydrogenase (LDH) released from 2.12 3 105 cells incubated with 60 mg of the different OCPs. BMSCs and periosteal cells attached to or between the crystals of OCPI and the cell number increased over the 17 days of culture. In contrast, cell numbers could not be measured for either periosteal cells or BMSC on OCPII and III. BMSC incubated with OCPII and III showed a higher rate of LDH release, compared with the cells incubated with OCPI. This study demonstrated that the morphology of OCP crystals influenced the attachment, spreading and growth of periosteal cells and BMSC.