Prompted by a study of traumatic brain injury (TBI) in a model system of cultured astrocytes, we discovered that low level laser illumination (LLL) at 660nm elevates the level of intracellular Ca²⁺. The coherence of the illumination was not essential since incoherent red light also worked. For cells bathed in low Ca²⁺ saline so that influx was suppressed, the Ca²⁺ level rose with no significant latency following illumination and consistent with a slow leak of Ca²⁺ from storage such as from the endoplasmic reticulum and/or mitochondria. When the cells were bathed in normal Ca²⁺ saline, the internal Ca²⁺ rose, but with a latency of about 17 seconds from the beginning of illumination. Pharmacologic studies with ryanodine inhibited the light effect. Testing the cells with fluid shear stress as used in the TBI model showed that mechanically induced elevation of cell Ca²⁺ was unaffected by illumination.

Date Published: 23 March 2016
PDF: 10 pages
Proc. SPIE 9695, Mechanisms of Photobiomodulation Therapy XI, 969509 (23 March 2016); doi: 10.1117/12.2222222

Published in SPIE Proceedings Vol. 9695:
Mechanisms of Photobiomodulation Therapy XI
Michael R. Hamblin; James D. Carroll; Praveen Arany, Editor(s)