Effects of lanthanum and gadolinium on proliferation and differentiation of primary osteoblasts

The effects of La3+ and Gd3+ on the proliferation, differentiation and adipogenic transdifferentiation of rat calvarial os-teoblast-like cells (ROB cells) were evaluated by MTT method, measuring the activity of alkaline phosphatase (ALP) and Oil red O measurement. Both of La3+ and Gd3+ inhibited the proliferation of ROB cells at all concentrations (1×10−5, 1×10−6 , 1×10−7, 1×10−8, 1×10−9 mol L−1,. La 3+ at concentration of 1×10−5 mol, L−1 significantly increased the alkaline phosphatase activity of ROB cells up to 3 folds, (P<0.01). However, the effects reversed to inhibit at other concentrations. Gd3+ played a negative role in the alkaline phosphatase activity. La 3+ inhibited the adipogenic transdifferentiation of ROB cells at all concentrations in a dose-dependent way. However, Gd3+ promoted the adipogenic transdifferentiation of ROB cells at 1×10−8 and 1×10−9 mol L−1. These findings suggested that the effects of rare earth elements on the proliferation, differentiation and adipogenic transdifferentiation of ROB cells were dependent on their concentrations and species.