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Proceedings Paper

Control of anoxic depolarization in rat brain by near-infrared laser irradiation and its monitoring by intrinsic optical signal imaging
Author(s): Satoko Kawauchi; Shunichi Sato; Yoichi Uozumi; Hiroshi Nawashiro; Miya Ishihara; Hiroshi Ashida
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Paper Abstract

In brain anoxia or ischemia, spreading depolarization is a key event that deterimines brain tissue survival. After onset of anoxia/ischemia, impairment of energy metabolism causes anoxic/ischemic depolarization (AD), which considerably consumes energy, leading to acute neuronal death in the brain. Our previous intrinsic-optical-signal imaging for the rat brains showed that about 2 min after starting hypoxia, AD-related light-scattering waves were focally generated in the bilateral outermost regions in the cortex and spread toward the midline, indicating that AD can be monitored by lightscattering signal. The behaviors of the scattering waves were found to be correlated with the survival of the rats. In the present study, we used the scattering signal-based monitoring method for AD and examined whether near-infrared laser irradiation can control AD in the rat brains. The left hemisphere was irradiated with 808-nm laser transcranially at 7.5 mW/cm2 before (30 min) and during hypoxia. The onset time of the scattering wave (AD) was significantly delayed in the irradiated hemisphere when compared with that in the non-irradiated hemisphere (3.4 s, n=8). The area of AD spreading in the irradiated hemisphere was significantly smaller than that in the non-irradiated hemisphere (27-90% reduction at 10-50 s after AD onset). These results suggest that near-infrared light can delay and reduce anoxic depolarization in the brain, which is probably due to increase in the cerebral ATP by near-infrared laser irradiation.

Paper Details

Date Published: 9 March 2012
PDF: 6 pages
Proc. SPIE 8211, Mechanisms for Low-Light Therapy VII, 82110C (9 March 2012); doi: 10.1117/12.907802
Show Author Affiliations
Satoko Kawauchi, National Defense Medical College Research Institute (Japan)
Shunichi Sato, National Defense Medical College Research Institute (Japan)
Yoichi Uozumi, National Defense Medical College (Japan)
Hiroshi Nawashiro, National Defense Medical College (Japan)
Miya Ishihara, National Defense Medical College (Japan)
Hiroshi Ashida, National Defense Medical College Research Institute (Japan)

Published in SPIE Proceedings Vol. 8211:
Mechanisms for Low-Light Therapy VII
Michael R. Hamblin; Juanita Anders; James D. Carroll, Editor(s)

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