Alendronate affects osteoprotegerin/receptor of activator of nuclear factor κB-ligand expression in human marrow stroma cells in vitro

Objective To evaluate the effect of alendronate on osteoprotegerin(OPG)and receptor of activator of nuclear factor κB-ligand(RANKL)expression in human marrow stroma cells(hMSCs)in vitro.Methods hMSCs were isolated from human marrow,cultured in vitro,and randomly divided into two groups:alendronate group,hMSCs culture fluid containing 1×10-7mol/L alendronate;control group,no special treatment but culturing hMSCs in DMEM.Two weeks after treatment,the expressions of OPG and RANKL were evaluated by RT-PCR and Western blot.Results hMSCs became uniform spindle-shaped fibroblasts.As cells proliferated,they formed colonies and showed whirlpool arrangement.After one week's treatment,hMSCs in alendronate group had reduced processes and gradually showed disc shape,which did not happen in control group but kept fibroblast shape and just increased in density.In RT-PCR,the ratio of OPG/RANKL in alendronate group and control group was 8.77±1.16 and 4.58±1.27,respectively.In Western blot,the ratio of OPG/RANKL in alendronate group and control group was 2.58±0.47 and 1.52±0.32,respectively.The ratio of OPG/RANKL was higher in alendronate group than in control group(P<0.01).Conclusion Alendronate enhances OPG expression and inhibits RANKL expression of hMSCs in vitro.