Effect of Alendronate on Osteoclast Generation and Bone Absorbing Function at Different Stages of Differentiation

Objective:To study the effect of alendronate on osteoclast generation and bone absorbing function an different stages of osteoclast differentiation.Methods:Bone marrow mononuclear cells were isolated and underwent preinduction with 30ng/ml M-CSF for 3 days and then the cells were divided into 4 groups.Cells of group A(served as control) was underwent osteoclastogenic induction with 30ng/ml M-CSF and 50ng/ml RANKL.Despite of above osteoclastogenic induction agents,cells of group B,C,D were treated with 0.1uM alendronate at 0-2 day,3-4 day,5-6 day,respectively.Osteoclastogenesis was examined by TRAP staining 6 days after induction and dentin resorption lacunas were verified by scanning electron microscope(SEM).Results:TRAP positive multinuclear cells were observed in all groups of cells and resorption lacunaes were formed in all groups.However,group A showed the most TRAP positive multinuclear cells and the largest resorption lacunaes among 4 groups,followed in turn by group D and group C,while group B had the least TRAP positive multinuclear cells and the smallest resorption lacunaes.Conclusion:The results of the study suggest that earlier alendronate is added during osteoclast differentiation,the more inhibition effects alendronate will exert on osteoclast generation and bone absorbing function.