Neural stem cells influenced by ultrasound: Frequency and energy density dependencies

Therapeutic ultrasound is a widely used application in clinics. The response to ultrasound is tissue specific and the parameters of ultrasonic treatments are decisive. Here, the responses of primary enteric (ENS) and central nervous system (CNS) neural stem cells were investigated to different frequency – energy density – combination treatments between 510 kHz–3 W s/cm² and 4.36 MHz–25 W s/cm². Responses to ultrasonic treatments were both frequency and energy density dependent. Ultrasound enhanced the expansion and showed enlarged neurospheres for both ENS and CNS neural stem cell cultures. Differentiation was not impaired in regard to neuronal and glial cell number as well as neurite and glial fiber outgrowth. Ultrasound is a promising tool to expand neural stem cells in vitro neither influencing neurogenesis nor gliogenesis by applying specific frequency – energy density – combinations.