The effect of low-intensity pulsed ultrasound on repair of epithelial cell monolayers in vitro

Low intensity pulsed ultrasound (LIPUS) is widely used to accelerate tissue regeneration following injury, but the biological mechanisms of this effect are poorly understood. An in vitro model of epithelial wound healing was used to investigate the effect of LIPUS on the reepithelialization of scrape wounds in normal human urothelial (NHU) cell monolayers. The effects of clinical doses of ultrasound treatment on NHU cell growth and migration were investigated in cells grown under optimal conditions, without growth supplements and in media containing low vs. physiological calcium concentrations. No differences in cell growth or migration were observed. We conclude that there is no direct effect upon uro-epithelial regeneration by therapeutic ultrasound in vitro and suggest that any stimulation of epithelial wound repair in vivo may occur indirectly, for example by modulating the extracellular matrix composition and/or production of paracrine factors by the stroma.