How does SpectraVET Laser Therapy Work?
The effects of all light and laser therapies are primarily photochemical; not thermal - at least, not on a macro-scale – and result from a chain of mechanisms initiated by photon absorption:
Primary: Absorption of photons by photo-receptive molecules (chromophores such as e.g. cytochromes, porphyrins, etc.) and the transduction of photon energy to induce chemical changes (i.e., photochemistry)
Secondary: Modulation of ATP production (dose dependent), Nitric Oxide release, and the formation of Reactive Oxygen Species (ROS);
Tertiary: The products of secondary mechanisms then produce effects such as gene transcription, inter-cellular signaling, and vasodilation; and,
Quaternary: Vasodilation increases perfusion, facilitating improved oxygenation and recruitment of macrophages, neutrophils and lymphocytes to areas undergoing repair and/or infection as well as further re-vascularization and proliferation of cells to aid healing. Improved perfusion will also facilitate clearance of inflammatory cells, fluids and debris (i.e. lymphatic drainage) more efficiently.
Russian researcher Prof. Tiina Karu identified cytochrome c oxidase in the mitochondrial respiratory chain as a primary chromophore for photobiomodulation, and suggested that the activation of a retrograde-type cellular signaling pathway could explain how a single relatively brief exposure to light can have effects that last for hours, days or even weeks. Any source of light, whether laser, LED, or even filtered white light, has the potential to be absorbed by e.g. cytochrome c oxidase and, therefore, to affect mitochondrial respiration and elicit downstream effects, if the wavelength, intensity and irradiation duration are appropriate.
A number of the effects of laser irradiation, however, are unique, and due to the speckle field that is created when coherent laser radiation is reflected, refracted and scattered. The speckle field is not simply a phenomenon created at and limited to the tissue surface, however, the depth within the tissue at which speckles can still be created from transdermal irradiation is a topic of some debate.
Laser speckles formed in the tissue create temperature and pressure gradients across cell membranes, increasing the rate of diffusion across those membranes. Further, photons within each speckle are highly polarized, leading to an increased probability of photon absorption (one possible reason for why laser therapy has been shown to consistently out-perform other non-coherent light sources, especially for deeper tissue treatments).