Effect of Alendronate on Cytoplasmic Spreading of Osteoclast in Vitro

Objective:Using cytoplasmic spreading area of osteoclast as osteoclastic function index to investigate the effect of alendronate on osteoclast in vitro.Methods:Bone marrow cells were obtained from neonatal rat,and seeded in 35 mm dishes at the density of 1×10 5/ml.1 dish was control,the other 3 were experimental dishes with 10 -11 M,10 -10 M,and 10 -9 M alendronate respectively.6 osteoclasts in each dish were selected randomly,observed at regular time,microphotos were analysed by computer assisted photo analysis system to quantify cytoplasmic spreading area of osteoclast.Results:10 -11 M alendronate had no effect on cytoplasmic spreading( P 0.05),10 -10 M?10 -9 M alendronate decreased spreading area( P 0.01).Cytoplasmic spreading area decreased much more with 10 -9 M alendronate than with 10 -10 M( P 0.01).Conclusion:Cytoplasmic spreading area of osteoclast is osteoclastic function index,which is easier and more promptly to be observed.10 -10 M or above alendronate inhibited osteoclastic function,the effect was augmented with increasing of alendronate concentration.