Far-infrared ray radiation promotes neurite outgrowth of neuron-like PC12 cells through AKT1 signaling

Abstract

Background/purpose: Far-infrared (FIR) therapy is a safe and noninvasive source for medical applications. Animal study has shown the effects of FIR in promoting nerve repair. However, the cellular mechanism is not well known. Nerve growth factor (NGF) treated neuron-like PC12 cells for neurite outgrowth have been widely employed as the in vitro model for neural regeneration. Methods: In this study, we tried to evaluate the potential of FIR in promoting neurite outgrowth and related mechanism by using NGF-treated neuron-like PC12 cells as a cellular model. We found that FIR could promote neurites outgrowth of neuron-like PC12 cells at earlier culture period. Results: The neurite outgrowth-enhancing effect of FIR irradiation was more obvious when lower NGF concentration (1 ng/ml and 10 ng/ml) was added into the medium. We also found that FIR had no thermal effects on culture medium. The effects of FIR in promoting neurite outgrowth were dose dependent, and higher power density of FIR provided more effects for improving neurite outgrowth. The mechanism of FIR in promoting neurite outgrowth was through AKT1 pathway. Conclusion: The effects of FIR irradiation on promoting neurite outgrowth and neural regeneration of NGF-treated neuron-like PC12 cells are dose dependent and through activation of AKT1 phosphorylation. This study provided important information for understanding the cellular mechanism of FIR in promoting neurite outgrowth and possible neural regeneration for further clinical applications. Keywords: Far-infrared, Neurite outgrowth, Neural regeneration, Neuron-like PC12 cells