Low-Intensity Pulsed Ultrasound Accelerates Osteoblast Differentiation and Promotes Bone Formation in an Osteoporosis Rat Model

Objective: We examined the effects of low-intensity pulsed ultrasound (LIPUS) on cell differentiation, bone mineralized nodule formation and core-binding factor A1 (Cbfa1) expression in a normal human osteoblast (NHOst) cell line and bone formation in an osteoporosis animal model. Methods: NHOst cells were cultured in vitro in medium with or without LIPUS stimulation. The ultrasound stimulation frequency was 1.0 MHz at an intensity of 30 mW/cm(2) for 20 min. Rats were divided into a sham-operated group (Sham) and an ovariectomized group (OVX). The right femur was treated with LIPUS (Sham-LIPUS and OVX-LIPUS) and the left femur was left untreated (Sham-CON and OVX-CON). Results: LIPUS stimulation accelerated bone nodule formation and enhanced alkaline phosphatase activity. The expression levels of Cbfa1 decreased and calcification occurred earlier and more frequently in the LIPUS than in the CON groups. The wet weight of the femur increased in OVX rats with LIPUS stimulation. Morphological images showed an increase in trabecular spongiosa in the OVX-LIPUS group. Conclusion: LIPUS accelerated osteogenesis. Moreover, since LIPUS prevents bone loss, it may be a promising treatment for osteoporosis. Copyright (C) 2009 S. Karger AG, Basel