ELISA analysis of TNF-α and IL-1β produced by BMSCs cultured on titanium surface after 6, 12, 24, 48 and 72 h treatments (a, b). Real-time PCR analysis of inflammatory genes TNF-α and IL-1β in BMSCs cultured on titanium disks after 6, 12, 24, 48 and 72 h treatments (c, d). The results were represented as relative ratio to control (control = 1) at the first time point. Data were expressed as mean ± SD from three independent cultures with triplicates, *P < 0.05