Viability values in MLO-y4 osteocyte cell line. Difference of viability (XTT test) expressed in percentage in MLO-y4 osteocytes treated with dexametasone 1 μM (DEX), with or without risedronate (Ris) at different concentrations. In the right side of the figure are also reported the effects on viability of risedronate (Ris) at different concentrations with or without NS-398 COX-2 inhibitor. The addition of NS-398 limited cell viability increased by Ris. This effect was significant at the highest concentration of Ris. The experiments were performed in triplicate.