Low-Intensity Pulsed Ultrasound Enhances BMP-7-Induced Osteogenic Differentiation of Human Fracture Hematoma-Derived Progenitor Cells In Vitro

Abstract

OBJECTIVE: To investigate the effect of the combined application of bone morphogenetic protein-7 (BMP-7) and low-intensity pulsed ultrasound (LIPUS) on human fracture hematoma-derived progenitor cells (HCs). METHODS: HCs were isolated from 6 patients. The cells were then divided into 4 groups and cultured: (1) control group, HCs cultured in growth medium without LIPUS; (2) LIPUS group, HCs cultured in growth medium with LIPUS; (3) BMP-7 group, HCs cultured in osteogenic medium containing BMP-7 without LIPUS; and (4) BMP-7 + LIPUS group, HCs cultured in osteogenic medium with LIPUS. Osteogenic differentiation potential and proliferation of HCs were compared among 4 groups. RESULTS: Alkaline phosphatase activity, the expression of osteogenic genes, and the mineralization of HCs in BMP-7 + LIPUS group were shown to be significantly increased compared with the other groups. However, LIPUS did not affect the proliferation of HCs in the presence or absence of BMP-7. CONCLUSIONS: These findings demonstrated for the first time the significant effect of LIPUS on the osteogenic differentiation of HCs in the presence of BMP-7. This study may provide significant evidence for the clinical combined application of BMP-7 and LIPUS for the treatment of acute bone fractures.