MC3T3-E1 and RAW264.7 cell response to hydroxyapatite and alpha-type alumina adsorbed with bovine serum albumin

Initial cell responses following implantation are important for inducing osteoconductivity. We investigated cell adhesion, spreading, and proliferation in response to native and bovine serum albumin (BSA)-adsorbed disc of hydroxyapatite (HA) or alpha-type alumina (α-Al₂O₃) using mouse MC3T3-E1 osteoblastic cells and mouse RAW264.7 macrophages. The adsorbed BSA inhibited adhesion and spreading of MC3T3-E1 cells, but did not affect MC3T3-E1 cell proliferation on HA and α-Al₂O₃ substrates. Thus, MC3T3-E1 cells quickly adhere to original HA before cell binding is impeded by adsorption of BSA in quantities sufficient to inhibit the adhesion of MC3T3-E1 cells. The adsorbed BSA inhibits adhesion of RAW264.7 cells to α-Al₂O₃, but not to HA. BSA adsorption does not affect RAW264.7 cell spreading and proliferation on both HA and α-Al ₂O₃ substrates. Thus, BSA adsorbed on HA stimulates a different cell response than α-Al₂O_3. Moreover, quick adherence of osteoblast cells and monocyte-macrophage lineage cells plays a role in HA osteoconductivity.