The influence of suppression of RANKL expression by RNA interference on the function of osteoblast in vitro

Objective:To investigate the change of ligand of receptor activator of NF-κB(RANKL),Osteoprotegerin(OPG) and the function of osteoblast at different times after suppression of the expression RANKL by RNA interference.Methods:Four pairs small interference RNA(siRNA) targeting RANKL were designed and transfected into osteoblast using Lipofectamin2000.RANKL mRNA level was determined by real-time quantitative reverse transcriptase polymerase chain reaction(RT-PCR) to screen the most effective siRNA.Western blot was employed to analyze the expression of RANKL and OPG at 1,2,3,5,7 days after transfecting.Proliferation activity and I type collagen expression of osteoblasts were observed at the same time.Results:The most effective siRNA found out among the 4 candidates.Single dose of this siRNA caused nearly 89% loss of RANKL mRNA.Compared with the control group,RANKL protein in osteoblast decrease to 59.1%、39.5%、26.6%、40.0%、57.3%(P0.05) respectively at 1,2,3,5,7 days after RNAi treatment.The expression rate of OPG protein is lower than the control group at 1,2,3,5, 7 days after transfection,however no statistical difference existed(P0.05).Proliferation activity and I type collagen expression of osteoblasts were similar to the expression profile of OPG(P0.05).Conclusion:These results provided specific siRNA can significantly decrease the expression of RANKL of osteoblast,and the expression of OPG and the major function of osteoblast were not influenced significantly.