Abstract:

BACKGROUND: There have been few studies regarding low frequency vibration stimulating osteogenic differentiation of bone marrow stromal cells in vivo.
OBJECTIVE: To investigate the effects of different frequencies of vibration on receptor activator of nuclear factor-kappa B (RANK)/ receptor activator of nuclear factor kappa-B ligand (RANKL)/osteoprotegerin (OPG) pathway and preliminarily investigate the underlying mechanism. 
METHODS: Eighty New Zealand rabbits of bone defects were established. After transplantation of complex of New Zealand bone marrow stromal stem cells and decalcified bone matrix into bone defect region, rat models were randomly divided into a control group and four vibration groups according to different vibration frequencies (12.5, 25, 50, 100 Hz). The vibration group received different frequencies of vibration for 5 weeks from day 7. After vibration, OPG mRNA and RANKL mRNA expression was detected.
RESULTS AND CONCLUSION: Compared with the control group, OPG and RANKL mRNA expression was significantly up regulated in each vibration group (P < 0.05), in particular in 25 and 50 Hz vibration groups (P < 0.01), but the expression was significantly down regulated in the 100 Hz vibration group (P < 0.05). This suggests that vibration at a certain frequency can stimulate bone marrow stromal cells to repair bone defects, which occurs possibly because vibration can promote the up regulation of OPG mRNA expression, with the ideal vibration frequency of 25 and 50 Hz.