Different mechanical strain on expression of OPG/ RANKL in osteoblast

Mechanical strain plays a crucial role in bone remodeling during orthodontic tooth movement. Osteoprotegerin(OPG) and receptor activator of NF-kappa B ligand(RANKL)are two major factors involving in this remodeling process .Objective: To study the effects of different magnitude mechanical strain on expression of OPG/ RANKL. Methods:MC3T3-E1 osteoblastic cells were subjected to intermittent tensile stress at 6%,12%, 18% elongation rate simultaneously by strain unit at 6 cycles/min(i.e.5-second elongation and 5-second relaxation)for 24 hours in this experiment.OPG/RANKL mRNA and protein expression were determined by semiquantitative reverse transcriptase-PCR and Western blotting ,respectively. Results: OPG expression were significantly increased with elongation rate increasing , whereas RANKL expression were rarely affected . OPG/RANKL ratio was raised .Conclusion: These results indicate different magnitude mechanical strain can regulate osteblastic expression of OPG/ RANKL and affect osteoclast formation.

*This work was sponsored by the National Natural Science Foundation of China(No.30300393 )