Study on the Effects of Low-Intensity Pulsed Ultrasound and Iron Ions for Proliferation and Differentiation of Osteoblasts.

OBJECTIVE

This study involved the proliferation and differentiation of osteoblasts treated with low-intensity pulsed ultrasound (LIPUS) and iron (Fe) ions, respectively. The biological effects of LIPUS and Fe ions on the proliferation and differentiation of osteoblasts were also evaluated.

METHODS

MC3T3-E1 cells were seeded in six-well plates with the medium, which contained different concentrations of Fe (0, 100, 200, 300, 400, 500, 600 and 700 μg L, respectively). LIPUS treatment was directed at the bottom of the plate for 20 min at an intensity of 80 mW cm every day.

RESULTS

Viability results showed that a dose of 400 μg L Fe ions had the best effect at promoting osteogenic proliferation in cell culture. The results of alkaline phosphatase staining and mineralization indicated that the differentiation of osteoblasts was promoted by LIPUS and Fe ions. Fluorescence staining results showed that the number of cell nuclei in the LIPUS, Fe and LIPUS-Fe groups increased by 37.20%, 55.81% and 89.76%, respectively. Migration data indicated that migration and proliferation rates were increased by LIPUS and Fe, and the results of protein expression indicated that LIPUS and Fe may increase the expression of Wnt, β-catenin, and Runx2, hence promoting normal bone regeneration and development.

CONCLUSION

The combination of LIPUS (1.5 MHz, 80 mW cm) and Fe accelerates the proliferation and differentiation of osteoblasts significantly compared with single-factor treatment (stimulated by LIPUS and Fe ions, respectively). This study could establish a foundation for LIPUS-responsive biomaterials in the repair and regeneration of bone tissues.