Abstract
BackgroundLow-intensity pulsed ultrasound (LIPUS) has been highlighted as a potential therapy for tissue repair and regeneration. However, little is known about LIPUS effects on neuromodulation. This research was conducted to study LIPUS effect on the proliferation of human neural stem cells.Materials and methodsThe human SH-SY5Y neuroblastoma cell line was used as a neural stem cell model. The well-documented SH-SY5Y neurogenic protocol, which involves treatment with all trans-retinoic acid (ATRA) for 5 days and then brain-derived neurotrophic factor (BDNF) for 7 days, was used to synchronise the growth cell cycle to G1 phase of the cell cycle before proliferation testing. Subsequently, the neural stem cells were then treated with single or triple 20-min LIPUS exposures (Intensity ISATA: 60 mW/cm2, frequency: 1.5 MHz, pulse repetition: 100 Hz, and duty cycle: 20%). Cell proliferation was analysed using cell counting of beta-tubulin and neurofilament medium-positive neural stem cells, Ki67-cell proliferation marker and metabolic-based assays (cell counting kit-8 and alamarBlue). The involvement of ERK signalling was investigated by quantification of phospho-ERK1/2 levels and cell proliferation with and without MEK/ERK inhibitor (U0126).ResultsThe results show that LIPUS exposure(s) induced cell proliferation, as evidenced by an increase in the numbers of neural stem cells. ERK signalling is involved in LIPUS-induced neural stem cell proliferation, as evidenced by concurrent inhibition of LIPUS-induced phospho-ERK levels and cell proliferation in the presence of the MEK/ERK inhibitor.ConclusionThis study provides original evidence that LIPUS can stimulate neural stem/progenitor cell proliferation. LIPUS may be suggested as a sole or an adjunct therapeutic application to promote the neural stem cell pool in stem cell therapies and tissue engineering approaches for nerve repair and regeneration for the management of traumatic nerve injuries and regenerative endodontic treatment.
Low-intensity pulsed ultrasound (LIPUS) stimulates proliferation of SH-SY5Y-derived neural stem cells. Single LIPUS exposure produced significant neural stem cell numbers, but triple LIPUS exposures resulted in greater neural stem cell numbers than the single LIPUS exposure, albeit the difference was not statistically significant. ERK signalling plays a role in the induction of the cell proliferation induced by LIPUS. image