Regulation of neurite outgrowth on PC12 cells by visible light

Control over neurite outgrowth is fundamentally important not only in biophysics and neuroscience application, but also for the preparation of neurite circuits in vitro (development of neuron-computers) as well as for in vivo nerve regeneration. The effect of neurite outgrowth of PC12 cells on collagen-coated glass plates under intermittent light irradiation at 525 nm and 0.4 mW/cm² of intensity was investigated in this study. Neurite outgrowth of PC12 cells was significantly suppressed when PC12 cells were cultivated under intermittent light irradiation with a total irradiation time of more than 2 min per hour. No temperature increase was observed in the culture medium under either continuous or intermittent light irradiation. Therefore, suppression of neurite outgrowth under light irradiation was not due to the increase of temperature in the culture medium, but rather the effect of light on the PC12 cells; especially the signal transmittance of light to PC12 cells. The light irradiation interval also affected the neurite outgrowth of PC12 cells when the total irradiation time was constant.