| Summary: | 博士 === 中原大學 === 生物醫學工程研究所 === 101 === Diabetes mellitus (DM) is a metabolic disorder that predisposes patients to a high risk of skeletal disorders such as osteoporosis and bone fracture. However, the relationships among DM, bone formation, and bone resorption remain controversial. The promotion or inhibition of cell growth has been shown to be regulated by therapeutic ultrasound in a parameter-dependent manner. Nevertheless, the cellular functions affected by various ultrasound insonifications are not well understood. Therefore, to determine the effects of low-intensity pulsed ultrasound (LIPUS) and high glucose (HG) on bone cells, we investigated the characteristics of transducer and sound fields; the effects of various LIPUS insonifications on the growth of osteoblasts; and the effect of LIPUS insonification on the growth of osteoblasts under normal and HG conditions. We also examined the effect of LIPUS on osteoclastogenesis in RAW264.7 cells.
The results showed that LIPUS insonification enhanced cell viability, alkaline phosphatase (ALP) activity, ALP and osteocalcin (OCN) mRNA expression, and mineralization of osteoblasts in a dose-dependent manner. Cell viability, adenosine triphosphate (ATP), cell migration, and OCN mRNA levels were lower in the high-glucose medium whereas ALP mRNA, osteoprotegerin, and heat shock protein 90 (Hsp90) levels were higher. On the other hand, LIPUS insonification increased cell viability, ATP levels, cell migration, Hsp90 and OCN mRNA levels of osteoblasts in the HG medium. Besides, the insonified osteoclasts had lower levels of tartrate-resistant acid phosphatase (TRAP) activity; pit formation; TRAP, Cathepsin K, receptor-activated nuclear factor-kappa B, and matrix metalloproteinase-9 mRNA. In conclusion, an adequate insonification enhances the growth and differentiation of osteoblasts. LIPUS decreased the inhibitory effect on osteoblasts associated with HG concentration and inhibited the differentiation of osteoclasts from RAW 264.7 cells. These findings may support therapeutic ultrasound, particularly the selection of appropriate parameters and understanding the ultrasonic biological effects of LIPUS on bone cells during bone generation. The biophysical mechanisms underlying the effects of ultrasound on bone cells need to be investigated further to facilitate the development of novel treatments for bone diseases associated with DM.
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