This study aimed to determine the in vitro effect of cadmium on the differentiation of duck embryonic bone marrow cells into osteoclasts. Bone marrow cells were harvested from 23-day old Gaoyou duck embryos and were cultured with either 50 nmol/L cadmium alone or different cadmium concentrations (0, 5, 10, 20 and 50 nmol/L) in combination with macrophage colony stimulating factor (M-CSF) and receptor activator of nuclear factor κB ligand (RANKL). Tartrate-resistant acid phosphatase (TRAP) staining, pit formation assay with bovine cortical bone slices, and co-staining with tetramethyl rhodamine isothiocyanate (TRITC)-conjugated phalloidin and Hoechst 33258 were performed to determine the number of TRAP-positive cells and bone resorption activity. Cadmium at a concentration ⩾ 10 nmol/L in the presence of M-CSF and RANKL significantly increased in a concentration-dependent manner both the number of TRAP-positive cells (35-160%) and bone resorption activity (36-261%) (P<0.05). High cadmium concentrations in the presence of M-CSF and RANKL markedly promoted the formation of filamentous (F)-actin rings in differentiated osteoclasts. In conclusion, cadmium promotes in vitro the differentiation of duck embryonic osteoclasts in the presence of M-CSF and RANKL.
Keywords: Bone marrow cell; Cadmium; Duck; Embryo; Osteoclast.
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