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 osteoblast-like cells (ROB cells) were evaluated by MTT method, measuring the activity of alkaline phosphatase (ALP) and Oil red 0 measurement. Both of La3+ and Gd3+ inhibited the proliferation of ROB cells at all concentrations (1 x 10(-5), 1 x 10(-6), 1 x 10(-7), 1 x 10(-8), 1 x 10(-9) mol.L-1). La3+ at concentration of 1 x 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. La3+ 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 x 10(-8) and 1 x 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.