LIPUS Enhance Elongation of Neurites in Rat Cortical Neurons through Inhibition of GSK-3β

ObjectiveLow-intensity pulsed ultrasound (LIPUS) has been reported to enhance proliferation and to alter protein production in various kinds of cells. In the present study, we measured the neurites length after LIPUS treatment to define the effectiveness of LIPUS stimulation on neurons, and then we examined the acticity of GSK-3β to study the intracellular mechanism of neurite's outgrowth.MethodsLIPUS was applied to cultured primary rat cortical neurons for 5 minutes every day with spatial- and temporal average intensities (SATA) of 10 mW/cm2, a pulse width of 200 microseconds, a repetition rate of 1.5 KHz, and an operation frequency of 1 MHz. Neurons were photographed on the third day after LIPUS treatment and harvested at third, seventh, and tenth days for immunoblot and semi-quantitative RT-PCR analysis.ResultsMorphology change showed that neurite extension was enhanced by LIPUS. There was also a remarkable decrease of proteins, including p-Akt, p-GSK-3β, and p-CRMP-2, observed on the seventh and tenth days, and of GSK-3β mRNA expression, observed on the seventh day, in neurons treated with LIPUS.ConclusionLIPUS can enhance elongation of neurites and it is possible through the decreased expression of GSK-3β.