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Pellicioli ACA, Martins MD, Dillenburg CS, Marques MM, Squarize CH, Castilho RM. Laser phototherapy accelerates oral keratinocyte migration through the modulation of the mammalian target of rapamycin signaling pathway. JOURNAL OF BIOMEDICAL OPTICS 2014; 19:028002. [PMID: 24531144 DOI: 10.1117/1.jbo.19.2.028002] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Accepted: 01/17/2014] [Indexed: 06/03/2023]
Abstract
Keratinocytes play a central role in wound healing by responding to tissue injury through the activation of cellular proliferation and migration. Current clinical evidence suggests that the laser phototherapy (LPT) accelerates wound healing in a variety of oral diseases; however, the molecular mechanisms involved in response to LPT are not fully understood. Oral keratinocytes (NOK-SI) maintained under nutritional-deficit culture medium (2% fetal bovine serum) were irradiated with InGaAlP laser (660 nm; 40 mW; 0.04 cm2 spot size) in punctual and contact modes. The energy densities used were 4 and 20 J/cm2 corresponding to 4 and 20 s of exposure times and 0.16 and 0.8 J of energy per point, respectively. Three sessions of irradiations were applied with 6-h intervals. Further, the impact of LPT over cellular migration, proliferation, and activation of the mammalian target of rapamycin (mTOR) pathway, known to play a major role in epithelial migration and wound healing, was analyzed. Compared with control cells, the LPT-treated cells showed accelerated cellular migration without any changes in proliferation. Furthermore, LPT resulted in an increase in the phospho-S6 ribosomal protein, indicating activation of the mTOR signaling pathway. Collectively, these findings suggest that the LPT activates mTOR signaling pathway, promotes epithelial cell migration, and accelerates healing of oral mucosa.
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Affiliation(s)
- Ana Carolina Amorim Pellicioli
- Universidade Federal do Rio Grande do Sul, School of Dentistry, Department of Oral Pathology, Porto Alegre, Rio Grande do Sul 90035-003, Brazil
| | - Manoela Domingues Martins
- Universidade Federal do Rio Grande do Sul, School of Dentistry, Department of Oral Pathology, Porto Alegre, Rio Grande do Sul 90035-003, Brazil
| | - Caroline Siviero Dillenburg
- Universidade Federal do Rio Grande do Sul, School of Dentistry, Department of Oral Pathology, Porto Alegre, Rio Grande do Sul 90035-003, Brazil
| | - Márcia Martins Marques
- University of São Paulo, School of Dentistry, Department of Dentistry, São Paulo, São Paulo 05508-000, Brazil
| | - Cristiane H Squarize
- University of Michigan, School of Dentistry, Laboratory of Epithelial Biology, Department of Periodontics and Oral Medicine, Ann Arbor, Michigan 48109-1078
| | - Rogerio M Castilho
- University of Michigan, School of Dentistry, Laboratory of Epithelial Biology, Department of Periodontics and Oral Medicine, Ann Arbor, Michigan 48109-1078
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Wagner VP, Meurer L, Martins MAT, Danilevicz CK, Magnusson AS, Marques MM, Filho MS, Squarize CH, Martins MD. Influence of different energy densities of laser phototherapy on oral wound healing. JOURNAL OF BIOMEDICAL OPTICS 2013; 18:128002. [PMID: 24337496 PMCID: PMC4019369 DOI: 10.1117/1.jbo.18.12.128002] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Revised: 10/04/2013] [Accepted: 11/05/2013] [Indexed: 06/03/2023]
Abstract
The aim of the present prospective study was to evaluate the impact of laser phototherapy (LPT) on the healing of oral ulcers. Different power densities were used on oral wounds in Wistar rats (n=72) randomly divided into three groups: control (0 J/cm2), 4 J/cm2 laser, and 20 J/cm2 laser. Ulcers (3 mm in diameter) were made on the dorsum of the tongue with a punch. Irradiation with an indium-gallium-aluminum-phosphide laser (660 nm; output power: 40 mW; spot size: 0.04 cm2) was performed once a day in close contact with the ulcer for 14 consecutive days. A statistically significant acceleration in healing time was found with wounds treated with 4 J/cm2 LPT. Moreover, striking differences were found in the ulcer area, healing percentage, degree of reepithelialization, and collagen deposition. The most significant changes occurred after 5 days of irradiation. Based on the conditions employed in the present study, LPT is capable of accelerating the oral mucosa wound-healing process. Moreover, faster and more organized reepithelialization and tissue healing of the oral mucosa were achieved with an energy density of 4 J/cm2 in comparison to 20 J/cm2.
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Affiliation(s)
- Vivian Petersen Wagner
- Universidade Federal do Rio Grande do Sul, School of Dentistry, Department of Oral Pathology, Porto Alegre, Rio Grande do Sul, 90035-003, Brazil
| | - Luise Meurer
- Universidade Federal do Rio Grande do Sul, Hospital de Clínicas de Porto Alegre, Department of Pathology, Porto Alegre, Rio Grande do Sul, 90035-903, Brazil
| | - Marco Antonio Trevizani Martins
- Universidade Federal do Rio Grande do Sul, School of Dentistry, Department of Oral Pathology, Porto Alegre, Rio Grande do Sul, 90035-003, Brazil
| | - Chris Krebs Danilevicz
- Universidade Federal do Rio Grande do Sul, School of Dentistry, Department of Oral Pathology, Porto Alegre, Rio Grande do Sul, 90035-003, Brazil
| | - Alessandra Selinger Magnusson
- Universidade Federal do Rio Grande do Sul, School of Dentistry, Department of Oral Pathology, Porto Alegre, Rio Grande do Sul, 90035-003, Brazil
| | - Márcia Martins Marques
- Universidade de São Paulo, School of Dentistry, Department of Dentistry, São Paulo, 05508-000 Brazil
| | - Manoel Sant’Ana Filho
- Universidade Federal do Rio Grande do Sul, School of Dentistry, Department of Oral Pathology, Porto Alegre, Rio Grande do Sul, 90035-003, Brazil
| | - Cristiane Helena Squarize
- University of Michigan School of Dentistry, Laboratory of Epithelial Biology, Department of Periodontics and Oral Medicine, Ann Arbor, Michigan 48109-1078
| | - Manoela Domingues Martins
- Universidade Federal do Rio Grande do Sul, School of Dentistry, Department of Oral Pathology, Porto Alegre, Rio Grande do Sul, 90035-003, Brazil
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Effects of increased low-level diode laser irradiation time on extraction socket healing in rats. Lasers Med Sci 2013; 30:719-26. [DOI: 10.1007/s10103-013-1402-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Accepted: 07/15/2013] [Indexed: 11/30/2022]
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Low-level visible light (LLVL) irradiation promotes proliferation of mesenchymal stem cells. Lasers Med Sci 2012; 28:1113-7. [DOI: 10.1007/s10103-012-1207-z] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Accepted: 09/05/2012] [Indexed: 11/28/2022]
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Lim W, Kim J, Lim C, Kim S, Jeon S, Karna S, Cho M, Choi H, Kim O. Effect of 635 nm light-emitting diode irradiation on intracellular superoxide anion scavenging independent of the cellular enzymatic antioxidant system. Photomed Laser Surg 2012; 30:451-9. [PMID: 22775489 DOI: 10.1089/pho.2011.3199] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
OBJECTIVE The aim of this study was to examine the reactive oxygen species (ROS) that are dissipated by 635 nm irradiation, and the effect of 635 nm irradiation on ROS scavenging system. BACKGROUND DATA Intracellular ROS are produced in the form of superoxide anion by either nicotinamide adenine dinucleotide phosphate (NADPH) oxidase or xanthine oxidase in response to a number of stimuli. Low-level light irradiation decreases the intracellular ROS level and has been used in clinical situations for reducing the level of oxidative stress. METHODS Human epithelial cells were exposed to exogenous and endogenous oxidizing agents that promote the generation of harmful ROS. These were then irradiated with 635 nm LED light, 5 mW/cm(2) for 1 h, 18 J/cm(2) or by 470 nm LED light, also 5 mW/cm(2) for 1 h, 18 J/cm(2) on a 9 cm cell culture dish. After irradiation, the MTT reduction method and malondialdehyde (MDA) colorimetric assay were performed in xanthine/xanthine oxidase (XXO)- or hydrogen peroxide (H(2)O(2))-treated HaCaT cells. The superoxide anion was detected by an electron spin resonance (ESR) spectrometer using 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) as the spin trap and H(2)O(2) was assayed by flow cytometry using 2',7'-dichlorodihydrofluorescein diacetate (H(2)DCF-DA). RESULTS Irradiation at 635 nm enhanced cell viability in the XXO-treated HaCaT cells. Also, irradiation had a much lesser effect on cell viability in the HaCaT cells treated with exogenous H(2)O(2) as compared with that in cells treated with N-acetyl-L-cysteine. The level of the superoxide anion increased in response to XXO treatment, and then decreased after 635 nm irradiation. Irradiation with 635 nm led to a decrease in superoxide anion and lipid peroxidation levels in the presence or absence of diethyldithiocarbamate. CONCLUSIONS These results highlight the potential role of 635 nm irradiation in protection against oxidative stress by scavenging superoxide anions. Also, a pathway that is independent of the activities of intracellular enzymatic ROS scavengers, such as superoxide dismutase, glutathione peroxidase and catalase might be involved in its mechanism of action.
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Affiliation(s)
- WonBong Lim
- Department of Oral Pathology, School of Dentistry, Dental Science Research Institute, Chonnam National University, Bug-Gu, Gwangju, Korea
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Tsai WC, Hsu CC, Pang JHS, Lin MS, Chen YH, Liang FC. Low-level laser irradiation stimulates tenocyte migration with up-regulation of dynamin II expression. PLoS One 2012; 7:e38235. [PMID: 22666495 PMCID: PMC3364209 DOI: 10.1371/journal.pone.0038235] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Accepted: 05/01/2012] [Indexed: 12/12/2022] Open
Abstract
Low-level laser therapy (LLLT) is commonly used to treat sports-related tendinopathy or tendon injury. Tendon healing requires tenocyte migration to the repair site, followed by proliferation and synthesis of the extracellular matrix. This study was designed to determine the effect of laser on tenocyte migration. Furthermore, the correlation between this effect and expression of dynamin 2, a positive regulator of cell motility, was also investigated. Tenocytes intrinsic to rat Achilles tendon were treated with low-level laser (660 nm with energy density at 1.0, 1.5, and 2.0 J/cm2). Tenocyte migration was evaluated by an in vitro wound healing model and by transwell filter migration assay. The messenger RNA (mRNA) and protein expressions of dynamin 2 were determined by reverse transcription/real-time polymerase chain reaction (real-time PCR) and Western blot analysis respectively. Immunofluorescence staining was used to evaluate the dynamin 2 expression in tenocytes. Tenocytes with or without laser irradiation was treated with dynasore, a dynamin competitor and then underwent transwell filter migration assay. In vitro wound model revealed that more tenocytes with laser irradiation migrated across the wound border to the cell-free zone. Transwell filter migration assay confirmed that tenocyte migration was enhanced dose-dependently by laser. Real-time PCR and Western-blot analysis demonstrated that mRNA and protein expressions of dynamin 2 were up-regulated by laser irradiation dose-dependently. Confocal microscopy showed that laser enhanced the expression of dynamin 2 in cytoplasm of tenocytes. The stimulation effect of laser on tenocytes migration was suppressed by dynasore. In conclusion, low-level laser irradiation stimulates tenocyte migration in a process that is mediated by up-regulation of dynamin 2, which can be suppressed by dynasore.
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Affiliation(s)
- Wen-Chung Tsai
- Department of Physical Medicine and Rehabilitation, Chang Gung Memorial Hospital, Taoyuan County, Taiwan
- College of Medicine, Chang Gung University, Taoyuan County, Taiwan
| | - Chih-Chin Hsu
- Department of Physical Medicine and Rehabilitation, Chang Gung Memorial Hospital, Taoyuan County, Taiwan
- College of Medicine, Chang Gung University, Taoyuan County, Taiwan
| | - Jong-Hwei S. Pang
- Graduate Institute of Clinical Medical Sciences, Chang Gung University, Taoyuan County, Taiwan
- * E-mail:
| | - Miao-Sui Lin
- Department of Physical Medicine and Rehabilitation, Chang Gung Memorial Hospital, Taoyuan County, Taiwan
- College of Medicine, Chang Gung University, Taoyuan County, Taiwan
| | - Ying-Hsun Chen
- Department of Physical Medicine and Rehabilitation, Chang Gung Memorial Hospital, Taoyuan County, Taiwan
| | - Fang-Chen Liang
- Department of Physical Medicine and Rehabilitation, Chang Gung Memorial Hospital, Taoyuan County, Taiwan
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Sharma SK, Kharkwal GB, Sajo M, Huang YY, De Taboada L, McCarthy T, Hamblin MR. Dose response effects of 810 nm laser light on mouse primary cortical neurons. Lasers Surg Med 2012; 43:851-9. [PMID: 21956634 DOI: 10.1002/lsm.21100] [Citation(s) in RCA: 349] [Impact Index Per Article: 29.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND AND OBJECTIVES In the past four decades numerous studies have reported the efficacy of low level light (laser) therapy (LLLT) as a treatment for diverse diseases and injuries. Recent studies have shown that LLLT can biomodulate processes in the central nervous system and has been extensively studied as a stroke treatment. However there is still a lack of knowledge on the effects of LLLT at the cellular level in neurons. The present study aimed to study the effect of 810 nm laser on several cellular processes in primary cortical neurons cultured from embryonic mouse brains. STUDY DESIGN/MATERIALS AND METHODS Neurons were irradiated with fluences of 0.03, 0.3, 3, 10, or 30 J/cm(2) of 810-nm laser delivered over varying times at 25 mW/cm(2) and intracellular levels of reactive oxygen species (ROS), nitric oxide and calcium were measured using fluorescent probes within 5 minutes of the end of irradiation. The changes in mitochondrial function in response to light were studied in terms of adenosine triphosphate (ATP) and mitochondrial membrane potential (MMP). RESULTS Light induced a significant increase in calcium, ATP and MMP at lower fluences and a decrease at higher fluences. ROS was significantly induced at low fluences, followed by a decrease and a second larger increase at 30 J/cm(2). Nitric oxide levels showed a similar pattern of a double peak but values were less significant compared to ROS. CONCLUSIONS The results suggest that LLLT at lower fluences is capable of inducing mediators of cell signaling processes which in turn may be responsible for the beneficial stimulatory effects of the low level laser. At higher fluences beneficial mediators are reduced and high levels of Janus-type mediators such as ROS and NO (beneficial at low concentrations and harmful at high concentrations) may be responsible for the damaging effects of high-fluence light and the overall biphasic dose response.
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Affiliation(s)
- Sulbha K Sharma
- Wellman Center for Photomedicine, Massachusetts General Hospital, Department of Dermatology, Harvard Medical School, Boston, Massachusetts 02114, USA
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Meuzelaar H, Heger M, Ariese F, van der Zwan G. No evidence for non-resonant optical frequency-induced effects on the intrinsic fluorescence of adenosine-5′-triphosphate and the kinetics of the firefly luciferin–luciferase reaction. J Photochem Photobiol A Chem 2011. [DOI: 10.1016/j.jphotochem.2011.08.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Low-level laser therapy: a useful technique for enhancing the proliferation of various cultured cells. Lasers Med Sci 2011; 27:237-49. [DOI: 10.1007/s10103-011-0885-2] [Citation(s) in RCA: 282] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2010] [Accepted: 01/05/2011] [Indexed: 12/16/2022]
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ELECTROPHYSICAL AGENTS - Contraindications And Precautions: An Evidence-Based Approach To Clinical Decision Making In Physical Therapy. Physiother Can 2011; 62:1-80. [PMID: 21886384 PMCID: PMC3031347 DOI: 10.3138/ptc.62.5] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Santana-Blank L, Rodríguez-Santana E, Santana-Rodríguez K. Theoretic, experimental, clinical bases of the water oscillator hypothesis in near-infrared photobiomodulation. Photomed Laser Surg 2010; 28 Suppl 1:S41-52. [PMID: 20649429 DOI: 10.1089/pho.2009.2647] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The objective of this review is to propose and document a role for the water oscillator in near-infrared (NIR) photobiomodulation. Greater understanding of the role of the water oscillator may add to a more-coherent description of central effects of NIR light on redox centers and key transmembrane enzymes such as cytochrome c oxidase (CcO). In addition, water provides a complementary pathway for absorption and transportation of NIR energy in photobiomodulation. Because of its unexpected potential, we propose terming it the "water oscillator paradox." Photobiologic mechanisms involved in the treatment of complex diseases are discussed in light of the present state of the art.
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Affiliation(s)
- Luis Santana-Blank
- Fundalas, Foundation Interdisciplinary for Research and Development, Caracas, Venezuela.
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Da Silva NS, Potrich JW. Effect of GaAlAs laser irradiation on enzyme activity. Photomed Laser Surg 2010; 28:431-4. [PMID: 19857051 DOI: 10.1089/pho.2008.2410] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVE The aim of this study was to determine the influence of laser irradiation on enzyme activity. BACKGROUND DATA Enzymes are catalysts of extraordinary efficiency, able to accelerate reactions by manifold. Enzyme laser light activation is currently a fast-growing field and a large number of studies have been produced. MATERIALS AND METHODS Liquid CNPG amylase and control serum (Qualitrol 1H) were used in the experiments. Laboratory analysis of alpha-amylase was performed on two sample groups: (i) E + S and (ii) E + S + L, in six repetitions per irradiation dose. Group 2 was irradiated with gallium-aluminum-arsenide (GaAlAs) 904 nm at doses of 0.01, 0.1, 0.5, and 1 J/cm(2). Enzyme activity was read using a spectrophotometer equipped with a thermostatic chamber capable of precise absorbance measurement at 405 nm. RESULTS The results were analyzed with the Student's t-test, and the percentage of enzyme activity was determined. Photomodulation of alpha-amylase activity by GaAlAs laser was analyzed following irradiation with different doses. Irradiation doses from 0.01 to 1 J/cm(2) led to differences in enzyme activity: 0.01 J/cm(2) (0.10%), 0.1 J/cm(2) (13.44%), 0.5 J/cm(2) (12.57%), and 1 J/cm(2) (-6.10%). CONCLUSION Irradiation doses of 0.1 J/cm(2) and 0.5 J/cm(2) led to statistically significant increases in enzyme activity in comparison to the control. The similar curves of the effects of temperature and pH on enzymatic activity observed in this study suggest that laser irradiation also possess an optimum dose to modulate the enzymatic activity. That is, enzymes have an optimum laser dose (or range) at which their activity is maximal, whereas at higher or lower doses activity decreases.
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Affiliation(s)
- Newton Soares Da Silva
- Laboratório de Biologia Celular & Tecidual, Instituto de Pesquisa & Desenvolvimento, UNIVAP, São José dos Campos, Brazil.
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Absence of 633-nm laser irradiation-induced effects on glucose phosphorylation by hexokinase. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2010; 98:216-22. [DOI: 10.1016/j.jphotobiol.2010.01.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2009] [Revised: 01/05/2010] [Accepted: 01/07/2010] [Indexed: 11/17/2022]
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Sinyakov MS, Zhevelev HM, Avtalion RR. Determinants of Pathology in Light-irradiated Cells. Photochem Photobiol 2010; 86:123-30. [DOI: 10.1111/j.1751-1097.2009.00642.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Abstract
The use of low levels of visible or near infrared light for reducing pain, inflammation and edema, promoting healing of wounds, deeper tissues and nerves, and preventing cell death and tissue damage has been known for over forty years since the invention of lasers. Despite many reports of positive findings from experiments conducted in vitro, in animal models and in randomized controlled clinical trials, LLLT remains controversial in mainstream medicine. The biochemical mechanisms underlying the positive effects are incompletely understood, and the complexity of rationally choosing amongst a large number of illumination parameters such as wavelength, fluence, power density, pulse structure and treatment timing has led to the publication of a number of negative studies as well as many positive ones. A biphasic dose response has been frequently observed where low levels of light have a much better effect on stimulating and repairing tissues than higher levels of light. The so-called Arndt-Schulz curve is frequently used to describe this biphasic dose response. This review will cover the molecular and cellular mechanisms in LLLT, and describe some of our recent results in vitro and in vivo that provide scientific explanations for this biphasic dose response.
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Affiliation(s)
- Ying-Ying Huang
- Wellman Center for Photomedicine, Massachusetts General Hospital, 40 Blossom Street, Boston, MA 02114, USA
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Logg K, Bodvard K, Blomberg A, Käll M. Investigations on light-induced stress in fluorescence microscopy using nuclear localization of the transcription factor Msn2p as a reporter. FEMS Yeast Res 2009; 9:875-84. [DOI: 10.1111/j.1567-1364.2009.00536.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
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Friedmann H, Lipovsky A, Nitzan Y, Lubart R. COMBINED MAGNETIC AND PULSED LASER FIELDS PRODUCE SYNERGISTIC ACCELERATION OF CELLULAR ELECTRON TRANSFER. Laser Ther 2009. [DOI: 10.5978/islsm.18.137] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Lipovsky A, Nitzan Y, Friedmann H, Lubart R. Sensitivity of Staphylococcus aureus strains to broadband visible light. Photochem Photobiol 2008; 85:255-60. [PMID: 18764895 DOI: 10.1111/j.1751-1097.2008.00429.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The phototoxic effect of illumination with broadband visible light on the viability of two Staphylococcus aureus strains was examined in the present study. A difference in the light sensitivity of the two strains was found. Illumination of the tested strains with a fluence rate of 180 J cm(-2) caused a reduction of up to 99.8% in the colony count of one of the strains (the "sensitive" strain). Illumination of the other strain (the "resistant" strain) resulted in a 55.5% reduction in viability. Proliferation of both strains was observed at low fluence rates of light. The phototoxic effect was found to be dependent on oxy radical production. The light-sensitive strain produced higher amounts of hydroxyl and superoxide radicals than the "resistant" strain. Adaptation to oxidative stress was exhibited only by the "resistant" strain. The "sensitive" strain produced ten times more endogenous porphyrins and secreted almost nine times more porphyrins than the resistant strain. Furthermore, the "resistant" strain produced twice as many carotenoids that protect the strain from illumination than the "sensitive" strain. These results indicate that high intensities of visible light cause bacterial photoeradication, a reaction which may assist wound healing by killing the infecting bacteria. On the other hand, low intensities of white light were found to enhance bacterial proliferation and thus prolong wound infection.
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Affiliation(s)
- Anat Lipovsky
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel
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Hawkins DH, Abrahamse H. Time-dependent responses of wounded human skin fibroblasts following phototherapy. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2007; 88:147-55. [PMID: 17728136 DOI: 10.1016/j.jphotobiol.2007.07.003] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2007] [Revised: 07/20/2007] [Accepted: 07/20/2007] [Indexed: 11/15/2022]
Abstract
BACKGROUND AND OBJECTIVE The penetration and distribution of laser light in target tissue is dependent on the wavelength of the light. One problem with most of the published data on laser irradiation is that most studies do not record the duration between the exposure and the evaluation. This study aimed to establish if the dose, wavelength or duration of effect (1h or 24h) influences the biological responses of irradiated fibroblasts. MATERIALS AND METHODS The study established cellular responses of normal and wounded human skin fibroblasts to helium-neon (632.8 nm), diode (830 nm) and Nd:YAG (1064 nm) laser irradiation using one exposure of 5 J/cm(2) or 16 J/cm(2) on day 1 and again on day 4. Cellular responses to laser irradiation were evaluated by measuring changes in cell viability (ATP viability and caspase 3/7 activity) and cell proliferation (ALP enzyme activity and bFGF expression), 1h and 24h post irradiation. RESULTS Wounded cells exposed to 5 J/cm(2) using 632.8 nm showed an increase in ATP viability after 1h, a decrease in caspase 3/7 activity after 24h and an increase in cell proliferation after 24h. The results suggest that changes in parameters such as ATP viability should be observed directly after laser irradiation (1h) whereas other parameters such as caspase 3/7 activity, bFGF expression and ALP enzyme activity should be measured at least 24h after the final exposure. CONCLUSION This study confirms that the duration of effect should be included as one of the main laser parameters when reporting on the effects of laser irradiation. It is important to establish time-dependent responses as the results may provide an understanding of the cellular responses following laser irradiation.
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Affiliation(s)
- Denise H Hawkins
- Laser Research Group, Faculty of Health Sciences, University of Johannesburg, P.O. Box 17011, Doornfontein, Johannesburg 2028, South Africa.
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Chow RT, David MA, Armati PJ. 830 nm laser irradiation induces varicosity formation, reduces mitochondrial membrane potential and blocks fast axonal flow in small and medium diameter rat dorsal root ganglion neurons: implications for the analgesic effects of 830 nm laser. J Peripher Nerv Syst 2007; 12:28-39. [PMID: 17374099 DOI: 10.1111/j.1529-8027.2007.00114.x] [Citation(s) in RCA: 120] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report the formation of 830 nm (cw) laser-induced, reversible axonal varicosities, using immunostaining with beta-tubulin, in small and medium diameter, TRPV-1 positive, cultured rat DRG neurons. Laser also induced a progressive and statistically significant decrease (p<0.005) in MMP in mitochondria in and between static axonal varicosities. In cell bodies of the neuron, the decrease in MMP was also statistically significant (p<0.05), but the decrease occurred more slowly. Importantly we also report for the first time that 830 nm (cw) laser blocked fast axonal flow, imaged in real time using confocal laser microscopy and JC-1 as mitotracker. Control neurons in parallel cultures remained unaffected with no varicosity formation and no change in MMP. Mitochondrial movement was continuous and measured along the axons at a rate of 0.8 microm/s (range 0.5-2 microm/s), consistent with fast axonal flow. Photoacceptors in the mitochondrial membrane absorb laser and mediate the transduction of laser energy into electrochemical changes, initiating a secondary cascade of intracellular events. In neurons, this results in a decrease in MMP with a concurrent decrease in available ATP required for nerve function, including maintenance of microtubules and molecular motors, dyneins and kinesins, responsible for fast axonal flow. Laser-induced neural blockade is a consequence of such changes and provide a mechanism for a neural basis of laser-induced pain relief. The repeated application of laser in a clinical setting modulates nociception and reduces pain. The application of laser therapy for chronic pain may provide a non-drug alternative for the management of chronic pain.
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Affiliation(s)
- Roberta T Chow
- Castle Hill Medical Centre, Discipline of Medicine, The University of Sydney, Sydney, Australia.
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