Effects of whole-body vibration on bone properties in type 2 diabetes model rats

Objectives: We examined the effects of whole-body vibration (WBV) on bone properties in type 2 diabetes (T2DM) model rats. Methods: Twenty male Hos:ZFDM-Lepr(fa), fa/fa rats (divided into DM and WBV groups, N = 10 each) and 10 Hos: ZFDM-Lepr(fa), fa/+ rats (as the control (CON) group) were used. The WBV group underwent WBV at 45 Hz frequency, with 0.5 g acceleration (15 min/day, 5 days/week) for 8 weeks. Trabecular and cortical bone mass, trabecular bone microstructure (TBMS), and cortical bone geometry (CBG) were analyzed via micro-computed tomography. Bone mechanical strength (maximum load, break point, and stiffness) was also measured. Additionally, bone metabolic and DM-related markers were determined. Results: The bone mechanical strength of the femur improved in the WBV group, although muscle atrophy and bone deterioration were observed in the DM and WBV groups. The serum levels of bone-specific alkaline phosphatase and tartrate-resistant acid phosphatase-5b were significantly higher in the DM and WBV groups than in the CON group. Serum glucose and blood urea nitrogen levels were significantly lower in the WBV group than in the DM group. Conclusions: This study suggests that WBV potentially improves the decrease in the bone mechanical strength of the femur, although it does not prevent the deterioration of bone mineral content, TBMS, and CBG parameters. Further studies are needed to investigate the effective timing and duration of WBV and the conditions that prevent T2DM and deterioration of bone properties and clarify the mechanism underlying WBV effects on bone properties in DM animals.