Attenuation of infarct size in rats and dogs after myocardial infarction by low‐energy laser irradiation

Oron, Uri; Yaakobi, Tali; Oron, Amir; Hayam, Gal; Gepstein, Lior; Rubin, Ofer; Wolf, Tamir; Haim, S

doi:10.1002/lsm.1039

Cited by 121 publications

(104 citation statements)

References 26 publications

(33 reference statements)

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“…Photobiomodulation by light in the red to near-IR range (630-1,000 nm) using low-energy lasers or light-emitting diode (LED) arrays has been shown to accelerate wound healing, improve recovery from ischemic injury in the heart, and attenuate degeneration in the injured optic nerve (19)(20)(21)(22)(23)(24). At the cellular level, photoirradiation at low fluences can generate significant biological effects, including cellular proliferation, collagen synthesis, and the release of growth factors from cells (22,25,26).…”

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confidence: 99%

Therapeutic photobiomodulation for methanol-induced retinal toxicity

Eells

Henry

Summerfelt

et al. 2003

Proc. Natl. Acad. Sci. U.S.A.

346

264

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Methanol intoxication produces toxic injury to the retina and optic nerve, resulting in blindness. The toxic metabolite in methanol intoxication is formic acid, a mitochondrial toxin known to inhibit the essential mitochondrial enzyme, cytochrome oxidase. Photobiomodulation by red to near-IR radiation has been demonstrated to enhance mitochondrial activity and promote cell survival in vitro by stimulation of cytochrome oxidase activity. The present studies were undertaken to test the hypothesis that exposure to monochromatic red radiation from light-emitting diode (LED) arrays would protect the retina against the toxic actions of methanolderived formic acid in a rodent model of methanol toxicity. Using the electroretinogram as a sensitive indicator of retinal function, we demonstrated that three brief (2 min, 24 s) 670-nm LED treatments (4 J͞cm 2 ), delivered at 5, 25, and 50 h of methanol intoxication, attenuated the retinotoxic effects of methanolderived formate. Our studies document a significant recovery of rod-and cone-mediated function in LED-treated, methanol-intoxicated rats. We further show that LED treatment protected the retina from the histopathologic changes induced by methanolderived formate. These findings provide a link between the actions of monochromatic red to near-IR light on mitochondrial oxidative metabolism in vitro and retinoprotection in vivo. They also suggest that photobiomodulation may enhance recovery from retinal injury and other ocular diseases in which mitochondrial dysfunction is postulated to play a role. D ecrements in mitochondrial function have been postulated to be involved in the pathogenesis of numerous retinal and optic nerve diseases, including age-related macular degeneration, diabetic retinopathy, and Leber's hereditary optic neuropathy (1-3). Decrements in mitochondrial function have also been postulated to be involved in the pathogenesis in methanol intoxication (4-7). Methanol intoxication produces toxic injury to the retina and optic nerve, frequently resulting in blindness. A toxic exposure to methanol typically results in the development of formic acidemia, metabolic acidosis, visual toxicity, coma, and, in extreme cases, death (8, 9). Visual disturbances generally develop between 18 and 48 h after methanol ingestion and range from misty or blurred vision to complete blindness. Both acute and chronic methanol exposure have been shown to produce retinal dysfunction and optic nerve damage clinically (8-10) and in experimental animal models (11)(12)(13)(14).Formic acid is the toxic metabolite responsible for the retinal and optic nerve toxicity produced in methanol intoxication (4-7, 15). Formic acid is a mitochondrial toxin that inhibits cytochrome c oxidase, the terminal enzyme of the mitochondrial electron transport chain of all eukaryotes (16,17). Cytochrome oxidase is an important energy-generating enzyme critical for the proper functioning of almost all cells, especially those of highly oxidative organs, including the retina and brain (18). Previous studies in...

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mentioning

confidence: 99%

Therapeutic photobiomodulation for methanol-induced retinal toxicity

Eells

Henry

Summerfelt

et al. 2003

Proc. Natl. Acad. Sci. U.S.A.

346

264

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“…Our results confirm the positive bio-stimulatory effect of LLLT, which depends mainly on the ability of the tissue to respond to light energy. The mechanisms underlying stimulation of bone healing may be multifactorial and include: promotion of angiogenesis [26], collagen production [27], osteogenic cell proliferation and differentiation [28]. Another study in the tibia of rats stated that the improvement of bone repair by LLLT was due to its role in upregulation of cyclooxygenase-2 expression in bone cells [29].…”

Section: Discussionmentioning

confidence: 99%

Effect of Diode Laser on Healing of Tooth Extraction Socket: An Experimental Study in Rabbits

Hamad

Naif

Abdullah

2015

J. Maxillofac. Oral Surg.

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Objectives To evaluate the effect of low-level laser therapy on healing of extracted tooth socket of healthy rabbits. Design The sample of this study was 20 male rabbits of 2-2.5 kg weight with age range of 8-12 months. Right and left lower first premolar teeth were extracted. The extraction sockets of lower right first premolar were irradiated with 0.9 W gallium-aluminum-arsenide (GaAlAs) diode laser for 5 min, immediately after extraction and then every 72 h for the next 12 days. The extraction socket of left side were not exposed to laser and served as a control. The animals were sacrificed after 7, 14, 30 and 45 days and the experimental and control sockets were removed from the harvested mandibles and prepared for haematoxylin and eosin staining and Masson's stain. The prepared slides were examined under light microscope for histological and histomorphometric examination. Results The histological examination showed that diode laser-treated sockets demonstrated early formed new bone with faster maturation of primary bone to secondary bone as compared to non-treated control sockets. Histomorphometric analysis revealed a statistically significant increase in the density and volume of trabecular bone in lasertreated sockets than control sockets. Conclusion Diode laser application to tooth extraction socket has a positive effect on bone formation.

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“…Some authors have cited possible inhibitory effects caused by LLLT (32)(33)(34), and it is not uncommon to find authors who correlated the Arndt-Schulz law with inhibitory or paradoxical responses (35)(36)(37)(38)(39). This law was introduced in the late 19th century by H Schulz, who used potentially harmful chemicals in small doses and observed that they promoted biostimulator effects (39,40).…”

Section: Discussionmentioning

confidence: 99%

Inhibitory effects of low-level laser therapy on skin-flap survival in a rat model

Baldan¹,

Masson²,

Esteves³

et al. 2015

CAN J PLAST SURG

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L ow-level laser therapy (LLLT) has been investigated as a noninvasive and sterile alternative for improvement of microcirculation and, consequently, increasing the viability of ischemic skin flaps (1-13). It is known as an athermal treatment modality due to the relatively low doses and low powers that are unable to promote any change in tissue temperature.Several studies have demonstrated the efficacy of LLLT in accelerating the healing process, the promotion of analgesia, and an increase in microcirculation and capillarity (5,6,11). Skin flaps may progress to necrosis due to intrinsic and extrinsic factors that compromise local microcirculation (14); LLLT has been used to increase skin flap viability.Several parameters must be considered when applying LLLT. These include wavelength, output power, emission mode, spot size and shape of the beam, irradiance, energy density, irradiation time, application technique, energy per point and total energy delivered to the tissue (9). Although all of these parameters appear to be important in modulating physiological and therapeutic responses, wavelength, energy and application time have been suggested by the World Association for Laser Therapy (WALT) as key factors (15). Both infrared (1,2,4,6,11) and red (5,8-10) lasers have been used to increase skin flap viability. Despite the positive results demonstrated with both types of lasers, some studies suggest that lasers with wavelengths in the red spectrum are more effective at increasing skin flap viability (16). The energy used in previous studies assessing the effects of red lasers in dorsal random skin flaps ranged from 0.06 J to 1.44 J per point (3,9,5,10,12). Energies <0.3 J were ineffective (3,9), whereas energies from 0.3 J to 1.44 J (5,10,12) increased skin flap survival. According to Arndt-Schulz' law, very low doses are ineffective, and intense stimuli may result in negative responses in tissue physiology. It appears that energies from 0.3 J to 1.44 J are in the therapeutic window for improving skin flap survival. Nevertheless, to the best of our knowledge, no studies have demonstrated an inhibitory effect on skin flap survival using higher energies of LLLT. Thus, the present study aimed to test an energy greater than those proven to be effective. Accordingly, the objective of the present study was to investigate the inhibitory effect of LLLT (λ=670 nm) on the viability of random skin flaps in rats when irradiated with 2.79 J of energy at each point. METHODS Study designThe present study was approved by the Ethics and Research Committee of Paulista University (São Paulo, Brazil) under protocol number CEP 008/11.The present analysis was an experimental, interventional, randomized study with a blinded assessor. All animals received humane care in strict compliance with the Ethical Guidelines for Animal Experiments, Council for International Organizations of Medical Sciences, Standards of Brazilian Science Society for Laboratory Animals, and current national legislation on Procedures for the Scientific Use of Anima...

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Attenuation of infarct size in rats and dogs after myocardial infarction by low‐energy laser irradiation

Abstract: The results of the present study indicate that delivery of low-energy laser irradiation to infarcted myocardium in rats and dogs has a profound effect on the infarct size after MI.

Cited by 121 publications

References 26 publications

Therapeutic photobiomodulation for methanol-induced retinal toxicity

Therapeutic photobiomodulation for methanol-induced retinal toxicity

Effect of Diode Laser on Healing of Tooth Extraction Socket: An Experimental Study in Rabbits

Inhibitory effects of low-level laser therapy on skin-flap survival in a rat model

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