Effects of ultrasound on Transforming Growth Factor-beta genes in bone cells

Abstract

Therapeutic ultrasound (US) is a widely used form of biophysical stimulation that is increasingly applied to promote fracture healing. Transforming growth factor-beta (TGF-β), which is encoded by three related but different genes, is known to play a major part in bone growth and repair. However, the effects of US on the expression of the TGF-β genes and the physical acoustic mechanisms involved in initiating changes in gene expression in vitro,are not yet known. The present study demonstrates that US had a differential effect on these TGF-β isoforms in a human osteoblast cell line, with the highest dose eliciting the most pronounced up-regulation of both TGF-β1 and TGF-β3 at 1 hour after treatment and thereafter declining. In contrast, US had no effect on TGF-β2 expression. Fluid streaming rather than thermal effects or cavitation was found to be the most likely explanation for the gene responses observed in vitro.

Low-intensity Low-frequency Ultrasound Promotes Proliferation and Differentiation of Odontoblast-like Cells

“…Interestingly, ultrasound also up-regulated the gene expression of key growth factors such as transforming growth factor (TGF-b1) and vascular endothelial growth factor (VEGF), which are thought to be pivotal for tissue repair (9,11). These latter findings are consistent with effects observed in various cell types including bone cells after treatment with megahertz LIPUS (12)(13)(14)(15).…”

Latest Progress of LIPUS in Fracture Healing

“…21,22 In addition, Harle et al claimed that bone osteoblast of MG63 cells ultrasound with intensity <500 mW/cm 2 could cause no cavitation events. 23,24 Tissue properties, such as stiffness and water content, also influence the energy and pressure levels of LIPUS by altering the sound flow and radiation force. 18,24 In patients with dorsally angulated fractures of the distal radius, LIPUS accelerated the healing process in contrast to manipulation and plaster alone (61 AE 3 days versus 98 AE 5 days, P < .0001).…”

“…The thermal effect of LIPUS is very limited due to its low intensity and the biological effect of LIPUS in promoting fracture healing is largely due to the non‐thermal effects of LIPUS (ie, cavitation, acoustic flow, acoustic radiation force) 21,22 . In addition, Harle et al claimed that bone osteoblast of MG63 cells ultrasound with intensity <500 mW/cm 2 could cause no cavitation events 23,24 . Tissue properties, such as stiffness and water content, also influence the energy and pressure levels of LIPUS by altering the sound flow and radiation force 18,24 …”

Landscape of Cellular Bioeffects Triggered by Ultrasound-Induced Sonoporation

“…Until now, chemical and mechanical reactions have been believed to participate in sonoporation-mediated changes in genomic DNA [ 200 , 201 ]. Moreover, the mechanical stimuli provided by US exposure can be transduced and trigger appropriate effector mechanisms, which consequently modulate gene expression [ 202 , 203 ].…”