Effects of cerium oxide nanoparticles on the proliferation, differentiation, and mineralization function of primary osteoblasts in vitro.

The effects of cerium oxide nanoparticles on the proliferation, differentiation, and mineralization function of primary osteoblasts in vitro were evaluated. The results showed that the cell biological effects of cerium oxide nanoparticles varied with different diameters. The cytotoxicity of cerium oxide nanoparticles on primary osteoblasts varies with the size and incubation time. Sixty-nanometer cerium oxide nanoparticles show significant cytotoxicity on primary osteoblasts at 48 h exposure. Cerium oxide nanoparticles with diameters of 40 nm promoted the differentiation of osteoblasts and the promotion rate was enhanced with increasing concentration. Cerium oxide nanoparticles with diameters of 60 nm promoted the differentiation of osteoblasts at lower concentrations, but turned to inhibit the differentiation at higher concentrations. Cerium oxide nanoparticles promoted the adipogenic transdifferentiation of osteoblasts at all tested concentrations. Moreover, the effects of 60-nm cerium oxide nanoparticles were stronger than that of 40-nm cerium oxide nanoparticles. Cerium oxide nanoparticles promoted the formation of mineralized matrix nodules of osteoblasts at all tested concentrations in a dose-dependent manner and the promotion rate increased with decreasing size. The results showed that cerium oxide nanoparticles had no acute cytotoxic effects on osteoblasts and could promote the osteogenic differentiation and mineralization of osteoblasts. Moreover, the size, concentration, and culture time of nanoparticles have significant influence on the proliferation, differentiation, and mineralization of osteoblasts.