Effect Of Rare Earth Ions On Proliferation, Differentiation And Mineralization Function Of Osteoblasts In Vitro

Effect of rare earth ions (cerium ion and yttrium ions) on the proliferation, differentiation and mineralization function of primary mouse osteoblasts (OBs) in vitro. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) was used to study the effect of Ln3+ on the growth of OBs, alkaline phosphatase (ALP) activity assay was used to study the effect of Ln3+ on differentiation of OBs, Oil Red 0 assay was used to study the effect on the adipogenic trans-differention of OBs, and ARS dye assay was used to study the effect on the mineralized matrix formation of OBs. The results indicated that Ce3+ and Y3+ at all concentrations (1×10-9,1×10-8, 1×10-7, 1×10-6, 1×10-5, and 1×10-4 mol·L-1) and all incubation time (24h,48h and72h) promoted the proliferation of OBs (P<0.05). There were relatively similar changes affected by Ce3+ and Y3+ in ALP activity. At 24h, the effect of Ce3+ and Y3+ on ALP activity was irregular. At 48h, Ce3+ and Y3+ inhibited the differentiation of OBs at tested concentrations. At 72h, Ce3+ and Y3+ promoted the differentiation of OBs at lower concentrations, but turned to inhibite the differentiation of OBs at higer concentrations. Ce3+ inhibited the adipocytic transdifferentiation of OBs at most tested concentrations on day 9 and day 12. On day 15, Ce3+ promoted the adipocytic transdifferentiation of OBs at all concentrations except 1×10-8 and 1×10-7 mol·L-1. Y3+ promoted the adipocytic transdifferentiation of OBs at most tested concentrations on day 9 and day 12. On day 15, Y3+ promoted the adipocytic transdifferentiation of OBs at lower concentrations, but turned to inhibited at higer concentrations. Ce3+ inhibited the formation of mineralized matrix nodules of OBs at lower concentrations, but promoted the formation of mineralized matrix nodules of OBs at higher concentrations.Y3+ inhibited the formation of mineralized matrix nodules of OBs at concentrations of 1×10-9,1×10-8, and 1×10-6 mol/L, and the effect reversed to improve at other concentrations.These findings suggest that the effects of Ln3+ on the proliferation, differentiation, adipocytic transdifferentiation and mineralization function of primary osteoblasts depend on the concentration, species and incubation time.