Conditioned media suppressed ALP activity in osteoblasts
(A) TRAP staining for RAW264.7 after Ti particles stimulation 24 h (scale bar = 200 μm). (B) ALP activity after stimulation 6 h. (C) ALP activity after stimulation 12 h. (D) ALP activity after stimulation 24 h. Ti 1:10 means the number of Ti particles is ten times to cells (*P<0.05, **P<0.01, and ***P<0.001).