A series of experimental methods including 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H tetrazolium bromide (MTT) test,alkaline phosphatase (ALP) activity measurement,Oil Red O stain and measurement,mineralized function expression and quantitive real time RT-PCR (qRT-PCR) were employed to assess the effect of Nd3+ and Sm3+ on the proliferation,differentiation and mineralization function of primary osteoblasts (OBs) in vitro at cell and molecular levels.The experimental results suggest that concentration,culture time and ion species are pivotal factors for switching the biological effects of rare earth ions from toxicity to activity,from damage to protection,or from down-regulation to up-regulation.
ZHANG JinChaoSHANG MiQinZHANG DaWeiLI YaPingSUN JingCHEN Hang
This study has investigated the effects of gold nanoparticles (Au NPs) on the proliferation, differentiation, and mineralization of a murine preosteoblast cell line MC3T3-E1 in vitro. The results show that Au NPs with diameters of both 20 and 40 nm promoted the proliferation, differentiation, and mineralization of MC3T3-E1 cells in a time- and dose-dependent manner at the concentra-tions of 1.5×10-5, 3.0×10-5, and 1.5×10-4 μmol/L. The reverse transcriptase polymerase chain reaction (RT-PCR) indicates that the expressions of runt-related transcription factor 2 (Runx2), bone morphogenetic protein 2 (BMP-2), alkaline phosphatase (ALP), and osteocalcin (OCN) genes increased after the 20 and 40 nm Au NP treatments, and the expression levels were higher than those of the NaF group. The above results suggest that Au NPs have the potential to promote the osteogenic differentiation and miner- alization of MC3T3-E1 cells and the particle size plays a significant role in the process. Runx2, BMP-2, ALP, and OCN genes may interact with each other, further stimulating the osteogenic differentiation of MC3T3-E1 cells.
The effects of cerium ion(Ce3+) on the proliferation,differentiation,adipocytic transdifferentiation and mineralization function of primary mouse osteoblasts(OBs) were investigated.The results indicated that Ce3+ at all concentrations(1×10-9,1×10-8,1×10-7,1×10-6,1×10-5,and 1×10-4 mol/L) promoted the proliferation of osteoblasts(OBs).On day 1 and 3,Ce3+ promoted the differentiation of OBs at concentrations of 1×10-9,1×10-7,and 1×10-6 mol/L,but inhibited the differentiation of OBs at higher concentrations.On day 2,Ce3+ inhibited the differentiation of OBs at tested concentrations.On day 9 and 12,Ce3+ inhibited the adipocytic transdifferentiation of OBs at most concentrations.On day 15,Ce3+ promoted the adipocytic transdifferentiation of OBs at concentrations of 1×10-9,1×10-6,1×10-5,and 1×10-4 mol/L,but had no effects at other concentrations.Ce3+ inhibited the formation of mineralized matrix nodules of OBs at concentrations of 1×10-9,1×10-8 and 1×10-7 mol/L,and promoted the formation of mineralized matrix nodules of OBs at other concentrations.These findings suggested that the effects of Ce3+ on the proliferation,differentiation,adipocytic transdifferentiation and mineralization function of primary OBs depended on the concentration and culture time;moreover,they were pivotal factors for switching the biological effects of Ce3+ from toxicity to activity,from damage to protection,or from down-regulation to up-regulation.
