In VitroEffects of Low-Intensity Pulsed Ultrasound Stimulation on the Osteogenic Differentiation of Human Alveolar Bone-Derived Mesenchymal Stem Cells for Tooth Tissue Engineering

Abstract

Ultrasound stimulation produces significant multifunctional effects that are directly relevant to alveolar bone formation, which is necessary for periodontal healing and regeneration. We focused to find out effects of specific duty cycles and the percentage of time that ultrasound is being generated over one on/off pulse period, under ultrasound stimulation. Low-intensity pulsed ultrasound ((LIPUS) 1 MHz) with duty cycles of 20% and 50% was used in this study, and human alveolar bone-derived mesenchymal stem cells (hABMSCs) were treated with an intensity of 50 mW/cm2 and exposure time of 10 min/day. hABMSCs exposed at duty cycles of 20% and 50% had similar cell viability (O.D.), which was higher (*P < 0.05) than that of control cells. The alkaline phosphatase (ALP) was significantly enhanced at 1 week with LIPUS treatment in osteogenic cultures as compared to control. Gene expressions showed significantly higher expression levels of CD29, CD44, COL1, and OCN in the hABMSCs under LIPUS treatment when compared to control after two weeks of treatment. The effects were partially controlled by LIPUS treatment, indicating that modulation of osteogenesis in hABMSCs was related to the specific stimulation. Furthermore, mineralized nodule formation was markedly increased after LIPUS treatment than that seen in untreated cells. Through simple staining methods such as Alizarin red and von Kossa staining, calcium deposits generated their highest levels at about 3 weeks. These results suggest that LIPUS could enhance the cell viability and osteogenic differentiation of hABMSCs, and could be part of effective treatment methods for clinical applications.

On the Behaviour of Living Cells under the Influence of Ultrasound

“…Claims have been made about pain relief with the aid of ultrasound equipment, but these are not supported by scientific evidence [6,7]. Several studies have suggested increased tissue repair owing to ultrasound exposure [8,9], which has led to the increased use of ultrasound equipment when treating bone fracture [10]. However, the acoustic setups of these [8][9][10] and other [11][12][13][14] tissue-repair studies have been such that thermal effects could not be ruled out.…”

Focused Low-Intensity Pulsed Ultrasound Enhances Bone Regeneration in Rat Calvarial Bone Defect through Enhancement of Cell Proliferation

“…Some studies have proposed that ultrasound treatment enhances the repair of fractured bone (Hasuike et al 2011;Ishihara et al 2014;Lim et al 2013;Yang and Park 2001); however, the energy from non-targeted exposure to ultrasound can diffuse, resulting in a decrease in positive effects. Therefore, in this study we investigated focused ultrasound (FUS), which can deliver highly focused acoustic energy to specific areas of biological tissues as small as a few millimeters in diameter .…”

Acoustic Therapy as Mechanical Stimulation of Osteogenesis

“…Reports have shown that acoustic loading increases expression of SDF-1 and CXCR4, thereby resulting in mesenchymal stem cells migration to the fracture site. In spite of that, more investigation is needed to clarify the exact cascade of reactions triggered by SFD-1/ CXCR4 [56,[87][88][89].…”