Effects of Bisphosphonates on Bone Cells

Osteoblasts and osteoclasts were stimulated separately with three different BPs: alendronate, risedronate, and ibandronate (all at 10⁻⁵ M). Both types of cells were stimulated with a conditioned medium from 0 to 96 h. During the course of the experiments, a 500-μL sample of the supernatant was collected from both the control and experimental groups for 0 h to 96 h. The collected supernatant was stored at −70°C in an ultrafreezer (New Air, USA) for subsequent analysis of IL-1β, TNF-α, and sRANKL using enzyme-linked immunosorbent assays (ELISAs; R and D Systems, Minneapolis, MN, USA; PeproTech, USA). The absorbance at 450 nm was measured according to the manufacturer's instructions.