Abstract
Anoxic depolarization（ AD）, which is caused by ischemia/hypoxia in brain, is known to trigger neuronal
cell death. Energy restoration would be needed for preventing the occurrence of AD and resultant cell
death. Photobiomodulation therapy, in which low-intensity light with a specific wavelength is used for
mitochondria, can enhance energy production in neuronal cells under pathophysiological conditions. In
this study, we examined whether visible （665 nm） or near-infrared （808 nm） laser irradiation can
control the occurrence of AD in rat brain. At both wavelengths, the onset of AD was significantly
delayed in the light-treated hemisphere when compared with that in the non-treated hemisphere （n=8）.
The spreading area of AD was also significantly smaller in the light-treated hemisphere than in the nontreated
hemisphere. These results suggest that photobiomodulation therapy can control AD in the brain,
which is probably due to an increase in ATP by laser irradiation.
