Differentiation of osteoclast-like cells induced by using different concentrations of M-CSF and RANKL

Objective To investigate the effects of macrophage of colony-stimulating factor(M-CSF) and receptor activator of NF-кB ligand(RANKL) on the differentiation and formation of osteoclast-like cells and to lay the foundation for the further study of biology mechanism for tooth movement.Methods The bone marrow mononuclear cells of rats were treated with different concentrations of M-CSF and RANKL.After having been cultured for 1,3,5 and 7 days,the number of tartrate-resistant acid phosphatase(TRAP) positive cells was measured by TRAP staining and pit staining.Results The effects of M-CSF and RANKL on the differentiation of osteoclastlike cells were related to time,the TRAP-positive mononuclear and multinucleated cells were formed on the third day,and the maximum number of TRAP-positive cells appeared on the fifth and seventh day.Without M-CSF,the bone marrow mononuclear cells couldn't differentiate to TRAP-positive cells.When the concentration of RANKL was 50 ng/ml,the number of TRAP-positive cells was related to the concentration of M-CSF;when the concentration of M-CSF exceeded 30 ng/ml,the number of TRAP-positive cells didn't increase significantly;when the concentration of M-CSF was 50 ng/ml,the number of TRAP-positive cells had no relation to the concentration of RANKL.Conclusion With the cooperation of M-CSF,RANKL could induce TRAP-positive osteoclast formation in rat bone marrow culture,and the M-CSF 30 ng/ml,RANKL 50 ng/ml were the most effective.