Elementary Processes in Cells after Light Absorption Do Not Depend on the Degree of Polarization: Implications for the Mechanisms of Laser Phototherapy

Karu, Tiina I.; Pyatibrat, Ludmila V.; Moskvin, S V; Andreev, S. A.; Letokhov, V. S.

doi:10.1089/pho.2007.2134

Cited by 27 publications

(21 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…14,15 As discussed below, it is a remarkable finding that in mammalian tissues, the photosensitivity of certain chromophores conserves physiologic significance, in spite of their adaptation to naturally function without external photons. 16 A distinctive property of chromophores is that they absorb particular wavelengths and reflect others, thus conferring specific colors to molecules. For example the porphyrin ring in chlorophyll a has peaks of absorption at 430 nm and 662 nm.…”

Section: Hormetic Effects Of Llltmentioning

confidence: 99%

Low-level light therapy of the eye and brain

Rojas¹,

González-Lima²

2011

117

View full text Add to dashboard Cite

Low-level light therapy (LLLT) using red to near-infrared light energy has gained attention in recent years as a new scientific approach with therapeutic applications in ophthalmology, neurology, and psychiatry. The ongoing therapeutic revolution spearheaded by LLLT is largely propelled by progress in the basic science fields of photobiology and bioenergetics. This paper describes the mechanisms of action of LLLT at the molecular, cellular, and nervous tissue levels. Photoneuromodulation of cytochrome oxidase activity is the most important primary mechanism of action of LLLT. Cytochrome oxidase is the primary photoacceptor of light in the red to near-infrared region of the electromagnetic spectrum. It is also a key mitochondrial enzyme for cellular bioenergetics, especially for nerve cells in the retina and the brain. Evidence shows that LLLT can secondarily enhance neural metabolism by regulating mitochondrial function, intraneuronal signaling systems, and redox states. Current knowledge about LLLT dosimetry relevant for its hormetic effects on nervous tissue, including noninvasive in vivo retinal and transcranial effects, is also presented. Recent research is reviewed that supports LLLT potential benefits in retinal disease, stroke, neurotrauma, neurodegeneration, and memory and mood disorders. Since mitochondrial dysfunction plays a key role in neurodegeneration, LLLT has potential significant applications against retinal and brain damage by counteracting the consequences of mitochondrial failure. Upon transcranial delivery in vivo, LLLT induces brain metabolic and antioxidant beneficial effects, as measured by increases in cytochrome oxidase and superoxide dismutase activities. Increases in cerebral blood flow and cognitive functions induced by LLLT have also been observed in humans. Importantly, LLLT given at energy densities that exert beneficial effects does not induce adverse effects. This highlights the value of LLLT as a novel paradigm to treat visual, neurological, and psychological conditions, and supports that neuronal energy metabolism could constitute a major target for neurotherapeutics of the eye and brain.

show abstract

Section: Hormetic Effects Of Llltmentioning

confidence: 99%

Low-level light therapy of the eye and brain

Rojas¹,

González-Lima²

2011

117

View full text Add to dashboard Cite

show abstract

“…Laser biostimulation can obtain different intracellular biological reactions to stimulate regenerative abilities, without undesired adverse effects, reducing also the pharmacological support and its possible invasiveness. Besides explaining many controversies in the field of low-power laser effects (i.e., the diversity of effects, the variable magnitude or absence of effects in certain studies), the proposed redox-regulation mechanism may be a fundamental explanation for some clinical effects of irradiation, for example the positive results achieved in treating wounds, chronic inflammation, and ischemia, all characterized by acidosis and hypoxia [7].…”

Section: Introductionmentioning

confidence: 99%

Clinical evaluation of the efficiency of low-level laser therapy for oral lichen planus: a prospective case series

et al. 2013

View full text Add to dashboard Cite

This is an author version of the contribution published on:Questa è la versione dell 'autore dell'opera: Lasers Med Sci. 2014 Jan;29(1):185-90. doi: 10.1007/s10103-013-1313 The definitive version is available at:La versione definitiva è disponibile alla URL: http://link.springer.com/article/10.1007URL: http://link.springer.com/article/10. /s10103-013-1313 Clinical evaluation of the efficiency of low-level laser therapy for oral lichen planus: a prospective case series. Eighty-two lesions were treated. We reported significant reduction in clinical scores of the treated lesions and in reported pain. No detailed complications or therapy side effects were observed during the study. AdrianaAs previously reported by our group with a preliminary report, this study suggests that LLLT could be a possible treatment choice for patients with unresponsive symptomatic OLP, also reducing the possible invasiveness correlated with other therapies.

show abstract

“…21,22 Karu et al showed in an in vitro study that the basic processes of LLLT occurring in HeLa cells were light absorption and photochemistry but that the incident characteristics of photons, such as degree of light polarization, did not affect the biological reactions in LLLT. 23 However, scattering of photons in vivo depends on the microstructure of tissue, and light propagation into biological tissue would therefore change the healing property. For instance, Ribeiro et al investigated the repair of skin burns in rats with a linearly polarized He-Ne laser beam, which was parallel or perpendicular to the direction of the spinal column, at the same laser dose.…”

Section: Introductionmentioning

confidence: 99%

Low-level laser therapy for spinal cord injury in rats: effects of polarization

et al. 2013

View full text Add to dashboard Cite

Abstract. The effects of laser polarization on the efficacy of near-infrared low-level laser therapy for spinal cord injury (SCI) are presented. Rat spinal cords were injured with a weight-drop device, and the lesion sites were directly irradiated with a linearly polarized 808-nm diode laser positioned either perpendicular or parallel to the spine immediately after the injury and daily for five consecutive days. Functional recovery was assessed daily by an open-field test. Regardless of the polarization direction, functional scores of SCI rats that were treated with the 808-nm laser irradiation were significantly higher than those of SCI alone group (Group 1) from day 5 after injury. The locomotive function of SCI rats irradiated parallel to the spinal column (Group 3) was significantly improved from day 10 after injury, compared to SCI rats treated with the linear polarization perpendicular to the spinal column (Group 2). There were no significant differences in ATP contents in the injured tissue among the three groups. We speculate that the higher efficacy with parallel irradiation is attributable to the deeper light penetration into tissue with anisotropic scattering. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

show abstract

Elementary Processes in Cells after Light Absorption Do Not Depend on the Degree of Polarization: Implications for the Mechanisms of Laser Phototherapy

Cited by 27 publications

References 22 publications

Low-level light therapy of the eye and brain

Low-level light therapy of the eye and brain

Clinical evaluation of the efficiency of low-level laser therapy for oral lichen planus: a prospective case series

Low-level laser therapy for spinal cord injury in rats: effects of polarization

Contact Info

Product

Resources

About