Cellular Mechanisms of Low Power Laser Therapy: New Questions

Low power laser therapy (photobiomodulation, laser biostimulation) was advanced more than 30 years ago. Since then medical treatment with coherent light sources (lasers) or noncoherent light (Light Emitting Diodes, LED’s) has passed through its childhood and early maturity. The controversial points of laser biostimulation, which were topical at the end of 80ties (reviews [1-3]), are not topical any more. There is no doubt nowadays that low-intensity monochromatic light from lasers of LED’s acts directly on the organism at the molecular level. The photoacceptors, primary physical and chemical reactions in/with photoacceptors, and possible cellular signaling have been already investigated in some extent (reviews [4-7]. It is believed that there excists an universal photobiological mechanism of light action on respiratory chain in both eukaryotic and prokaryotic cells (terminal enzymes of the respiratory chain being the photoacceptors). The specificity of cellular responses appear only during secondary reactions (cellular signaling). The primary and secondary mechanisms on cellular level were also summarized in the first book of the present trilogy [8].