ArticleLiterature Review

Effect of NASA Light-Emitting Diode Irradiation on Wound Healing

January 2002
Journal of Clinical Laser Medicine & Surgery 19(6):305-14

DOI:10.1089/104454701753342758

Source
PubMed

Authors:

Harry Whelan

Medical College of Wisconsin

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The purpose of this study was to assess the effects of hyperbaric oxygen (HBO) and near-infrared light therapy on wound healing. Light-emitting diodes (LED), originally developed for NASA plant growth experiments in space show promise for delivering light deep into tissues of the body to promote wound healing and human tissue growth. In this paper, we review and present our new data of LED treatment on cells grown in culture, on ischemic and diabetic wounds in rat models, and on acute and chronic wounds in humans. In vitro and in vivo (animal and human) studies utilized a variety of LED wavelength, power intensity, and energy density parameters to begin to identify conditions for each biological tissue that are optimal for biostimulation. Results: LED produced in vitro increases of cell growth of 140-200% in mouse-derived fibroblasts, rat-derived osteoblasts, and rat-derived skeletal muscle cells, and increases in growth of 155-171% of normal human epithelial cells. Wound size decreased up to 36% in conjunction with HBO in ischemic rat models. LED produced improvement of greater than 40% in musculoskeletal training injuries in Navy SEAL team members, and decreased wound healing time in crew members aboard a U.S. Naval submarine. LED produced a 47% reduction in pain of children suffering from oral mucositis. We believe that the use of NASA LED for light therapy alone, and in conjunction with hyperbaric oxygen, will greatly enhance the natural wound healing process, and more quickly return the patient to a preinjury/illness level of activity. This work is supported and managed through the NASA Marshall Space Flight Center-SBIR Program.

Phototherapy as a Treatment for Dermatological Diseases, Cancer, Aesthetic Dermatologic Conditions and Allergenic Rhinitis in Adult and Paediatric Medicine

Article

Full-text available

Jan 2023

Roy Kennedy

The development of light-emitting diodes (LEDs) has led to an increase in the use of lighting regimes within medicine particularly as a treatment for dermatological conditions. New devices have demonstrated significant results for the treatment of medical conditions, including mild-to-moderate acne vulgaris, wound healing, psoriasis, squamous cell carcinoma in situ (Bowen’s disease), basal cell carcinoma, actinic keratosis, and cosmetic applications. The three wavelengths of light that have demonstrated several therapeutic applications are blue (415 nm), red (633 nm), and near-infrared (830 nm). This review shows their potential for treating dermatological conditions. Phototherapy has also been shown to be an effective treatment for allergenic rhinitis in children and adults. In a double-anonymized randomized study it was found that there was 70% improvement of clinical symptoms of allergic rhinitis after intranasal illumination by low-energy narrow-band phototherapy at a wavelength of 660 nm three times a day for 14 consecutive days. Improvement of oedema in many patients with an age range of 7–17 were also observed. These light treatments can now be self-administered by sufferers using devices such as the Allergy Reliever phototherapy device. The device emits visible light (mUV/VIS) and infra-red light (660 nm and 940 nm) wavelengths directly on to the skin in the nasal cavity for a 3 min period. Several phototherapy devices emitting a range of wavelengths have recently become available for use and which give good outcomes for some dermatological conditions.

Combination of photodynamic therapy and phototherapy for the treatment of cutaneous open wounds in dogs - case reports

Article

Full-text available

Nov 2021

The evolution of cutaneous open wounds was evaluated in five client-owned dogs treated with photodynamic therapy (PDT), mediated by methylene blue and phototherapy with light-emitting diodes (LED) as the light source. On the first day of treatment, the wound was irrigated with sterile 0.9% sodium chloride solution, the surface was dried, and 3% solution of hydrogen peroxide soaked for 1 minute. The hydrogen peroxide was mechanically removed and, immediately after, 0.01% methylene blue was used in the wound for five minutes, after which a cluster of red LEDs (650 - 670 nm wavelength, 350 mW power, and irradiance of 200 mW/cm2) was used. Subsequently, single phototherapy sessions, every 48 hours or more, were applied until wound healing. In general, 24J was used for PDT and 12J for phototherapy. In all cases, the cutaneous open wounds treated with PDT associated with phototherapy healed without complications, and it may be considered as a treatment option, especially for extensive lesions.

Non Invasive Phisical Physical Regenerative Therapies: Laser therapy, Mechanism of Action and Results

Article

Full-text available

Jan 2021

Low-level laser therapy (LLLT) and high-intensity laser therapy (HILT) have emerged as a therapeutic alternative suitable for a wide range of medical conditions. The main advantage of high-intensity laser over LLLT is its ability to deliver a much higher dose in a shorter time while achieving deeper penetration into the affected tissue and producing a thermal effect. Although HILT, provides very satisfactory clinical results, more clinical research is require to justify its massive use. Keywords: Low-level laser therapy, High-level laser therapy, Biostimulation, Phototherapy.

Biophotonic Effects of Low-Level Laser Therapy at Different Wavelengths for Potential Wound Healing

Article

Full-text available

Aug 2022

Our objective was to assess the effect of low-level laser therapy (LLLT) administered using a diode laser on the growth processes of human fibroblast cells involved in wound healing. Initially, studies were conducted using a diode laser at wavelengths of 633, 520, and 450 nm with an irradiance of 3 mW/cm2. The distance between the light source and culture plate was 3 cm. The mechanism(s) of action of the diode laser illumination on human fibroblast cells were studied by examining different wavelengths to determine the relevant light parameters for optimal treatment. In addition, the percentages of fibroblast-mediated procollagen and matrix metallopeptidase (MMP)-1, -2, and -9 production were compared. In the clinical study, the changes in basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF), and fibroblast collagen production were assessed in 60 patients with complicated wounds who received LLLT (633 nm). No statistically significant difference was observed between red light versus green and blue light in the viability analysis. In addition, the effects of LLLT on the cell cultures of fibroblast cells in vitro demonstrated a decrease in the relative expression of MMP-1, -2, and -9 while using light with a wavelength of 633 nm. In the clinical study, 633 nm diode laser LLLT at 2–8 J/cm2 was administered to 60 patients with complicated wounds; all patients showed increased levels of bFGF and VEGF and the occurrence of collagen synthesis. Our studies demonstrated that LLLT might affect fibroblast cell growth processes involved in wound healing.

Mechanisms of PhotoBioModulation (PBM) focused on oral mucositis prevention and treatment: a scoping review

Article

Full-text available

Apr 2021
BMC Oral Health

Background Oral mucositis (OM) is a severe complication cancer patients undergo when treated with chemoradiotherapy. Photobiomodulation (PBM) therapy also known as low-level laser therapy has been increasingly used for the treatment of such oral toxicity. The aim of this review is to discuss the mechanisms of photobiomodulation (PBM) regarding OM prevention and treatment, and more precisely to focus on the effect of PBM on tumor and healthy cells. Methods MEDLINE/PubMed, and google scholar were searched electronically. Selected studies were focusing on PBM effects on tumor and healthy cells. Results PBM interactions with the tissue and additional mechanism in OM therapy were detailed in this review. Moreover, this review highlighted a controversy about the carcinogenic effect of PBM. Indeed, Many studies reported that PBM could enhance malignant cell proliferation; suggesting that PBM would have no protective effect. In addition to acting on cancer cells, PBM may damage healthy cells. Conclusion More prospective studies are needed to assess the effect of PBM on cancer cells in order to improve its use for OM prevention and treatment.

Low-level laser or LED photobiomodulation on oral mucositis in pediatric patients under high doses of methotrexate: prospective, randomized, controlled trial

Article

Full-text available

Nov 2021
SUPPORT CARE CANCER

Purpose The objective of the present study was to compare the efficacy of photobiomodulation with low-level laser therapy (LLLT) or light-emitting diode therapy (LEDT) devices for the prevention and treatment of oral mucositis in pediatric patients diagnosed with acute lymphoblastic leukemia undergoing chemotherapy with high doses of methotrexate (MTX). Methods Eighty patients were randomly divided into two groups: LLLT and LEDT. Both protocols were applied with the same energy and radiant exposure. The protocols started in the beginning of high doses MTX and finished when the patients were discharged from the hospital or there was oral mucositis resolution. The oral mucositis was assessed during each session in accordance to the World Health Organization (WHO) score. The patients’ self-assessed pain was scored on a visual analog scale (VAS). Results The incidence of oral mucositis was similar to LLLT and LEDT, 10% and 12.5%, respectively. Both groups required the same number of days to reach score of zero for mucositis and pain (p > 0. 05), and there was no significant difference in mean VAS between the groups. Conclusions These findings suggest that LEDT has similar effects to LLLT to avoid and treat oral mucositis. Brazilian Clinical Trial Registry with #U1111-1221-5943

Photobiomodulation: A review of the molecular evidence for low level light therapy

Article

Dec 2020
J PLAST RECONSTR AES

Graeme E Glass

Light energy is harnessed for therapeutic use in a number of ways, most recently by way of photobiomodulation. This phenomenon is a cascade of physiological events induced by the non-thermal exposure of tissue to light at the near infrared end of the visible spectrum. Therapeutic photobiomodulation has become a highly commercialized interest, marketed for everything from facial rejuvenation to fat loss and diode-based devices are popular in both the clinic setting and for use at home. The lack of regulatory standards makes it difficult to draw clear conclusions about efficacy and safety but it is crucial that we understand the theoretical basis for photobiomodulation so that we can engage in honest dialogue with our patients and design better clinical studies to put claims of efficacy to the test. This article presents a summary of the science of photobiomodulation and examines the differences between laser light, on which much of the preclinical evidence is based and light from diodes which are typically used in a clinical setting.

Effects of Intermittent Irradiation with Low-Level LED Light on Osteoblast-Like Cells Derived from Rat Bone Marrow

Article

Jan 2023

Recently, low level laser therapy (LLLT) has been reported to promote wound healing of fractures, tooth extraction sockets and bone-dental implants osseointegration. In this study, we investigated the effects of LLLT on cell proliferation, differentiation and calcification of rat bone marrow-derived osteoblast-like cells using blue LED light irradiation at a wavelength of 455 nm. The irradiation conditions were as follows; LED with a wavelength of 455 nm, 510 mW output power (measured value in the irradiated field: 100 mW/cm²), distance: 20.8 mm, and irradiation for 14 seconds every 1.5 hours at an energy of 5.6 joules/cm² (up to 4.5 hours). The experimental groups were divided into 4 groups; control group, LED light-irradiation group, FGF-containing media group and LED light-irradiation and FGF-containing media group (n=3). The cell proliferative ability was determined using Cell Counting Kit-8 immediately after the first LED irradiation, after 1.5, 3.0, 4.5 and 12 hours by ELISA. Lab assay ALP was used to search for cell differentiation potential, and ALP activity levels in the samples were determined after 3 and 7 days. And the ALP staining was also performed after 7 days, and the ALP staining positive was determined by analyzing the percentage of stained area in each well. For the search of cellular calcification activity, Alizarin Red staining was used to determine its positivity rate by analyzing the stained area fraction of each well after 14 and 28 days. In all the searched results, both the cell proliferation and differentiation abilities were highest in the LED group. And the calcification ability was significantly higher in the LED, FGF and LED▪FGF groups than that in the control group. The results of this study suggested that LLLT with blue LED light irradiation was useful for bone tissue regeneration.

A comparative study : The Effect of The Red Laser Irradiation, Collagen Cream, The Red Laser-Collagen, and Gentamicine Cream on The Cutaneous Wound Healing in Rabbits

Article

Full-text available

Dec 2022

The present study used 24 adult rabbits divided into 4 group, each group had 6 rabbits, all group were incised on dorsal surface (rabbits back), first group were treated by Gentamicin cream as a control group while second group were treated by collagen cream, third group were treated by laser therapy while fourth group were treated by collagen-laser therapy. 2 nd and 3 rd groups were showed significant results compare with 1 st group while 4 th group also excellent significant result, this method can applicant safely and simply and can applicant with other injury .

Photobiomodulation for modulation of neuropathic pain and improvement of scar tissue

Article

Full-text available

Oct 2022

Background This case-report explores the effects of photobiomodulation therapy (PBMT) on the healing of scar tissue. The patient was a 32-year old female two years post cholecystectomy resulting in a 15 cm linear scar that was causing severe pain. Methods Treatment was initiated using the BIOFLEX® therapist device which consists of LED arrays and laser probes of a specific wavelength, power and frequency applied directly on the skin overlying the scar. The frequency and duration of treatment was every other day for six weeks in a clinic setting, followed by three times a week for two months at home. Then the patient continued to use the BIOFLEX® therapist home device on an as-needed basis. Findings The final result of this patient's treatment was significant flattening and decreased redness of her scar. Her self-reported pain decreased to a 6/10. At the one year follow up, the patient reported that she stopped taking her opioids, antidepressant and sleeping pills and that her pain decreased to a 4/10. At the last review her pain score was 1/10; and she had returned to work and took Tylenol (acetaminophen) occasionally for breakthrough pain. Conclusions We attribute the patient's improvement in scar appearance and pain symptoms to PBMT. Since pain is often associated with depressed mood and sleep disturbances, it cannot be determined whether PBMT was the direct or indirect cause of this patient's improved mood. For future studies, we propose the use of control subjects with similar scars treated with sham treatment compared to those who will receive the PBMT and observed for the same duration of time and compare the overall results. Lay Summary Dermatological applications, especially wound healing; are accepted indications for photobiomodulation therapy (PBMT). The expansion into other clinical applications, particularly neurological ones show potential benefit. We present a case of a patient with a hypertrophic scar associated with severe neuropathic pain and concurrent depression, all of which improved directly or indirectly with PBMT. Although the original focus of treatment was dermatological the improvement in pain plus the discontinuation of therapy (opioids, antidepressants and benzodiazepines) were considered to be due to the PBMT.

Light Emitting Diodes Irradiation Regulates miRNA-877-3p to Promote Cardiomyocyte Proliferation

Article

Full-text available

Jul 2022
Int J Med Sci

Mammalian cardiomyocytes (CMs) maintain a low capacity for self-renewal in adulthood, therefore the induction of CMs cycle re-entry is an important approach to promote myocardial repair after injury. Recently, photobiomodulation (PBM) has been used to manipulate physiological activities of various tissues and organs by non-invasive means. Here, we demonstrate that conditioned PBM using light-emitting diodes with a wavelength of 630 nm (LED-Red) was capable of promoting the proliferation of neonatal CMs. Further studies showed that low-power LED-Red affected the expression of miR-877-3p and promoted the proliferation of CMs. In contrast, silencing of miR-877-3p partially abolished the pro-proliferative actions of LED-Red irradiation on CMs. Mechanistically, GADD45g was identified as a downstream target gene of miR-877-3p. Conditioned LED-Red irradiation also inhibited the expression of GADD45g in neonatal CMs. Moreover, GADD45g siRNA reversed the positive effect of LED-Red on the proliferation of neonatal CMs. Taken together, conditioned LED-Red irradiation increased miR-877-3p expression and promoted the proliferation of neonatal CMs by targeting GADD45g. This finding provides a new insight into the role of LED-Red irradiation in neonatal CMs biology and suggests its potential application in myocardial injury repair.

Photobiomodulation Improves Serum Cytokine Response in Mild to Moderate COVID-19: The First Randomized, Double-Blind, Placebo Controlled, Pilot Study

Article

Full-text available

Jul 2022

Background Because the major event in COVID-19 is the release of pre- and inflammatory cytokines, finding a reliable therapeutic strategy to inhibit this release, help patients manage organ damage and avoid ICU admission or severe disease progression is of paramount importance. Photobiomodulation (PBM), based on numerous studies, may help in this regard, and the present study sought to evaluate the effects of said technology on cytokine reduction. Methods This study was conducted in the 2nd half of 2021. The current study included 52 mild-to-moderately ill COVID-19, hospitalized patients. They were divided in two groups: a Placebo group and a PBM group, treated with PBM (620-635 nm light via 8 LEDs that provide an energy density of 45.40 J/cm ² and a power density of 0.12 W/cm ² ), twice daily for three days, along with classical approved treatment. 28 patients were in Placebo group and 24 in PBM group. In both groups, blood samples were taken four times in three days and serum IL-6, IL-8, IL-10, and TNF-α levels were determined. Results During the study period, in PBM group, there was a significant decrease in serum levels of IL-6 (-82.5% +/- 4, P<0.001), IL-8 (-54.4% ± 8, P<0.001), and TNF-α (-82.4% ± 8, P<0.001), although we did not detect a significant change in IL-10 during the study. The IL-6/IL-10 Ratio also improved in PBM group. The Placebo group showed no decrease or even an increase in these parameters. There were no reported complications or sequelae due to PBM therapy throughout the study. Conclusion The major cytokines in COVID-19 pathophysiology, including IL-6, IL-8, and TNF-α, responded positively to PBM therapy and opened a new window for inhibiting and managing a cytokine storm within only 3-10 days.

Photobiomodulation Drives MiR-136-5p Expression to Promote Injury Repair after Myocardial Infarction

Article

Full-text available

Apr 2022
INT J BIOL SCI

Photobiomodulation (PBM) has emerged as an alternative therapy involved in modulating a variety of biological effects. In this study, we verified whether PBM can affect cardiac physiological activity in mice through noninvasive irradiation using light-emitting diodes at a wavelength of 630 nm (LED-Red). We found that the PBM involved in regulating the repair of injured myocardium is wavelength-limited. LED-Red caused cardiomyocytes (CMs) that had exited the cell cycle to divide and proliferate again, and the cell proliferation ratio increased significantly with the accumulation of intracellular photopower. In addition, LED-Red promoted myocardial revascularization and myocardial regeneration, reduced the area of fibrosis in mice with myocardial infarction (MI), and thus improved cardiac contractile function. In regard to the mechanism, miRNA sequencing analysis showed that low-power LED-Red irradiation could induce differential changes in miRNAs in CMs. Among them, miR-136-5p was identified as a cardiac photo-sensitive miRNA and was obviously inhibited after stimulation, which produced a proliferation-promoting effect on CMs. Subsequent luciferase reporter assays confirmed the involvement of Ino80 as a binding target of miR-136-5p in the regulatory process of CM proliferation. Similarly, LED-Red irradiation elevated intracellular Ino80 expression. After knockdown of Ino80, the proliferation-promoting effect of LED-Red on CMs was inhibited. Collectively, this study demonstrates that LED-Red can promote CM proliferation by inhibiting cardiac photo-sensitive miRNA- miR-136-5p expression through targeting Ino80. The findings provided a new potential strategy for the treatment of ischemic cardiomyopathy (ICD).

Light Signaling and Myopia Development: A Review

Article

Full-text available

Mar 2022

Introduction: The aim of this article was to comprehensively review the relationship between light exposure and myopia with a focus on the effects of the light wavelength, illuminance, and contrast on the occurrence and progression of myopia. Methods: This review was performed by searching PubMed data sets including research articles and reviews utilizing the terms "light", "myopia", "refractive error", and "illuminance", and the review was concluded in November 2021. Myopia onset and progression were closely linked with emmetropization and hyperopia. To better elucidate the mechanism of myopia, some of the articles that focused on this topic were included. This article is based on previously conducted studies and does not contain any new studies with human participants or animals performed by any of the authors. Results: The pathogenesis and prevention of myopia are not completely clear. Studies have provided evidence supporting the idea that light could affect eye growth in three ways. Changing the corresponding conditions will cause changes in the growth rate and mode of the eyes, and preliminary results have shown that FR/NIR (far red/near-infrared) light is effective for myopia in juveniles. Conclusion: This review discusses the results of studies on the effects of light exposure on myopia with the aims of providing clues and a theoretical basis for the use of light to control the development of myopia and offering new ideas for subsequent studies.

Neuroaffective Embodied Self Therapy (NEST):An Integrative Approach to Case Formulation and EMDR Treatment Planning for Complex Cases

Article

Full-text available

Jan 2018

Sandra Paulsen

Neuroaffective Embodied Self Therapy (NEST): An Integrative Approach to Case Formulation and EMDR Treatment Planning for Complex Cases

Comparative study on Photobiomodulation between 630 nm and 810 nm LED in diabetic wound healing both in vitro and in vivo

Article

Full-text available

Mar 2022

Photobiomodulation (PBM) promoting wound healing has been demonstrated by many studies. Currently, 630 nm and 810 nm light-emitting diodes (LEDs), as light sources, are frequently used in the treatment of diabetic foot ulcers (DFUs) in clinics. However, the dose–effect relationship of LED-mediated PBM is not fully understood. Furthermore, among the 630[Formula: see text]nm and 810[Formula: see text]nm LEDs, which one gets a better effect on accelerating the wound healing of diabetic ulcers is not clear. The aim of this study is to evaluate and compare the effects of 630[Formula: see text]nm and 810[Formula: see text]nm LED-mediated PBM in wound healing both in vitro and in vivo. Our results showed that both 630[Formula: see text]nm and 810[Formula: see text]nm LED irradiation significantly promoted the proliferation of mouse fibroblast cells (L929) at different light irradiances (1, 5, and 10[Formula: see text]mW/cm[Formula: see text]. The cell proliferation rate increased with the extension of irradiation time (100, 200, and 500[Formula: see text]s), but it decreased when the irradiation time was over 500[Formula: see text]s. Both 630[Formula: see text]nm and 810[Formula: see text]nm LED irradiation (5[Formula: see text]mW/cm[Formula: see text] significantly improved the migration capability of L929 cells. No difference between 630[Formula: see text]nm and 810[Formula: see text]nm LED-mediated PBM in promoting cell proliferation and migration was detected. In vivo results presented that both 630[Formula: see text]nm and 810[Formula: see text]nm LED irradiation promoted the wound healing and the expression of the vascular endothelial growth factor (VEGF) and transforming growth factor (TGF) in the wounded skin of type 2 diabetic mice. Overall, these results suggested that LED-mediated PBM promotes wound healing of diabetic mice through promoting fibroblast cell proliferation, migration, and the expression of growth factors in the wounded skin. LEDs (630[Formula: see text]nm and 810[Formula: see text]nm) have a similar outcome in promoting wound healing of type 2 diabetic mice.

Effect of low-level laser therapy on the membrane induced by the Masquelet technique at an orthotopic site in rabbits

Article

Full-text available

Nov 2021
ACTA CIR BRAS

Purpose: To evaluate the low-level laser therapy (LLLT) on the membrane induced by the Masquelet technique in rabbits. Methods: Twelve Norfolk rabbits at approximately 3 months of age were used. A 1-cm segmental defect was induced in both radii, which were filled with polymethylmethacrylate cylinder. LLLT was used postoperatively in the bone defect of one of the forelimbs every 48 hours for 15 days. Six rabbits were euthanatized on third and sixth postoperative weeks. Results: In both forelimbs, radiographs showed new bone growth from radius cut ends on the third postoperative week and more advanced stage on the sixth postoperative week. Ultrasound showed induced membrane one week after the surgery. Histologically, there were no significant differences in the semi-quantitative score of inflammation intensity, total number of blood vessels, bone metaplasia, and collagen. The average thicknesses were 2,050.17 and 1,451.96 μm for control membranes and 2,724.26 and 2,081.03 μm for irradiated membranes, respectively, on third and sixth postoperative weeks. Vascular endothelial growth factor A (VEGF-A) and platelet derived growth factor (PDGF) expression were present in the induced membranes of control and irradiated forelimbs, but there was no significant difference. Conclusions: Based on assessment methods, it was not possible to demonstrate the effect of LLLT on the induced membrane.

Diode Laser Biostimulatory Effect on Dental Implant Inserted into Narrows Mandibular Ridges: Clinico-Radiographic Evaluation

Article

Sep 2021

The Effect of 630 nm Photobiomodulation on the Anti-Inflammatory Effect of Human Gingival Fibroblasts

Article

Full-text available

Aug 2021

Periodontal disease is the most common oral chronic inflammatory disease in humans. Recent studies have indicated that red light Photobiomodulation (PBM) could inhibit cell inflammation effectively, but the effect of different doses of PBM on the treatment of inflammation has to be improved. Thus, this study was aimed to investigate the effects of various doses of PBM (630 ± 30 nm, (1) 5 mW/cm2, 1 J/cm2, 200 s; (2) 5 mW/cm2, 3 J/cm2, 600 s; (3) 5 mW/cm2, 9 J/cm2, 1800 s; (4) 5 mW/cm2, 18 J/cm2, 3600 s; (5) 5 mW/cm2,36 J/cm2, 7200 s) on the anti-inflammatory response of human gingival fibroblasts. Our results suggested that PBM (630 ± 30 nm) with doses of 18 J/cm2 and 36 J/cm2 could significantly inhibit the production of inflammatory cytokines such as Prostaglandin E2 (PGE2) and IL-8, presumably due to the fact that a high dose of PBM treatment could reduce intracellular Reactive oxygen species (ROS) in human gingival fibroblasts, thus reducing the expression of COX-2 enzyme. In addition, it was found that treatment with different doses of PBM (630 ± 30 nm) did not result in reduced mitochondrial membrane potential and mitochondrial dysfunction in human gingival fibroblasts. Our study provides a theoretical reference for the selection of PBM parameters and the application of PBM in the clinical treatment of periodontitis.

Light Emitting Diode Mediated Photobiomodulation Therapy in Orthodontics - A Review of Contemporary Literature

Article

Aug 2021

BACKGROUND Photobiomodulation is an emerging area of medical and dental science that has gained attention in numerous clinical fields with the advent of new generational light - emitting diodes (LEDs), as evident in the extent of published scientific literature in recent years. The rationale behind LED - mediated photobiomodulation therapy (LPT) is that at certain biologically active wavelengths, LEDs have shown to have therapeutic effects at the cellular and subcellular levels and are an efficient alternative photon source after lasers, along with their numerous benefits. Subsequent to favourable in-vitro, animal and recently human clinical trials, considerable attention has been garnered towards the promising applications and the integration of LPT with traditional therapeutic protocols, including in orthodontics. Originally started and accepted as a modality in acceleration of tooth movement, pain management and increasing the bone remodelling rate and quality, the advancements in this therapeutic technology have created new avenues in the treatment of temporomandibular disorders, root resorption, bone consolidation during maxillary expansion and distraction osteogenesis, as well as for improvement in miniscrew stability. Since it is non-invasive, easy to perform and user friendly with reported efficacy, an established consensus of wavelengths and parameters with respect to guidance for clinical use will go a long way in enabling the successful achievement of numerous objectives. This review article of published research intends to evaluate the adjunctive applications of LPT within orthodontic treatment at several levels along with the underlying mechanism, parameters and reported outcomes. KEY WORDS Photobiomodulation Therapy, Light Emitting Diodes, LED - Mediated Phototherapy, Low Level Light Therapy, NIR-LED, Light Accelerated Orthodontics

Fluorescent Light Energy and Chronic Lesions: A Winning Association

Article

Full-text available

Jul 2021

Background: Chronic ulcers represent a challenge for healthcare professionals and a large expense for national health care systems for their difficulty in achieving complete healing and for their high incidence of recurrence. With the progressive aging of the general population, the incidence of these injuries will only increase, further affecting the public health budget, hence the need to find new strategies for their management. The purpose of this study was to share the experience of the Complex Operational Unit of Plastic Surgery of the University Hospital of Padua with fluorescent light energy therapy, outlining its role in the treatment of chronic ulcers in the daily use outside the previous EUREKA study. Methods: In this case series study, we enrolled 15 patients with chronic ulcers of any etiology between January 2018 and July 2019 and we treated them using fluorescence light energy. We evaluated efficacy and safety endpoints reporting data in excel files completed by medical staff during the study. Results: The study confirms the effectiveness of fluorescent light energy inducing chronic ulcer healing, regardless of etiology, or at least preparing the lesions for a skin graft closure surgery. The system showed a low rate of complications established by patient adherence to treatment. Patients also reported a reduction in pain both at home and during outpatient dressings. Conclusion: Based on our experience, fluorescent light energy shows an excellent safety and efficacy profile in chronic ulcers no more responsive to traditional dressings and/or surgery.

Enhancing the Therapeutic Potential of Mesenchymal Stem Cells with Light-Emitting Diode: Implications and Molecular Mechanisms

Article

Full-text available

Feb 2021
OXID MED CELL LONGEV

This study evaluated the effects of light-emitting diode (LED) on mesenchymal stem cells (MSCs). An electronic search was conducted in PubMed/MEDLINE, Scopus, and Web of Science database for articles published from 1980 to February 2020. Ten articles met the search criteria and were included in this review. The risk of bias was evaluated to report quality, safety, and environmental standards. MSCs were derived from adipose tissue, bone marrow, dental pulp, gingiva, and umbilical cord. Protocols for cellular irradiation used red and blue light spectrum with variations of the parameters. The LED has been shown to induce greater cellular viability, proliferation, differentiation, and secretion of growth factors. The set of information available leads to proposing a complex signaling cascade for the action of photobiomodulation, including angiogenic factors, singlet oxygen, mitogen-activated protein kinase/extracellular signal-regulated protein kinase, Janus kinase/signal transducer, and reactive oxygen species. In conclusion, although our results suggest that LED can boost MSCs, a nonuniformity in the experimental protocol, bias, and the limited number of studies reduces the power of systematic review. Further research is essential to find the optimal LED irradiation parameters to boost MSCs function and evaluate its impact in the clinical setting.

Photobiomodulation: The Clinical Applications of Low-Level Light Therapy

Article

Jan 2021

Graeme E Glass

Background Low level light therapy is a recent aaddition to the pantheon of light-based therapeutic interventions. Termed “photobiomodulation”, the absorption of red/near infrared light energy induces enhancement of mitochondrial ATP production, cell signaling and growth factor synthesis and attenuates oxidative stress. Photobiomodulation is highly commercialized with devices marketed directly to the consumer. In the grey area between the commercial and therapeutic sectors, harnessing the clinical potential in reproducible and scientifically measurable ways remains challenging. Objectives This article presents a summary of the clinical evidence for photobiomodulation and discusses the regulatory framework for low level light therapy Methods A review of the clinical literature pertaining to the use of low level light therapy for skin rejuvenation (facial rhytids and dyschromias), acne vulgaris, wound healing, body contouring and androgenic alopecia was performed. Results A reasonable body of clinical trial evidence exists in support of the role of low energy red/near infrared light as a safe and effective method of skin rejuvenation, treatment of acne vulgaris, alopecia and, especially, body contouring. Methodological flaws, small patient cohorts and industry funding mean there is ample scope to improve the quality of evidence. It remains unclear if LED-based light sources induces physiologic effects of the nature and magnitude of laser-based systems which were used in most of the higher quality studies. Conclusions Low level light therapy is here to stay. However, its ubiquity and commercial success has outpaced the empirical approach on which solid clinical evidence is established. Thus, the challenge is to prove its therapeutic utility in retrospect. Well-designed, adequately powered, independent clinical trials will help us answer some of the unresolved questions and enable the potential of this therapy to be realized.

Development of a Patch-Type Sensor for Skin Using Laser Irradiation Based on Tissue Impedance for Diagnosis and Treatment of Pressure Ulcer

Article

Full-text available

Dec 2020

Pressure ulcer is a disease that has been increasing rapidly worldwide in recent years following the growing elderly population. However, its diagnoses and treatments still depend on the naked eye and traditional drug treatments, respectively. In this study, we examined the effects of the pressure ulcer-induced regions based on impedance measurements and skin electrical signals, and its treatment efficacy was verified using photobiomodulation therapy. The light used in this therapy was a light emitting diode light (660 nm), and it was verified to enhance antioxidant capacity in the enzyme-based antioxidation process. An examination of the angiogenesis efficacy based on wound healing activity and tube formation activation at the cell level confirmed that photobiomodulation therapy accelerated wound healing and angiogenesis. When the treatment effect of the therapy was evaluated with a rat animal model of pressure ulcer, the region affected by the pressure ulcer and the infiltration of inflammatory cells were significantly reduced by photobiomodulation therapy. The diagnosis using skin impedance measurement showed differences in the region affected by the pressure ulcer. The results of this study confirmed the diagnosis based on the impedance and treatment efficacy of photobiomodulation therapy and the treatment of pressure ulcer. The use of photobiomodulation therapy in conjunction with the existing treatment methods is expected to improve the efficiency of the pressure ulcer treatment.

Verification of the Effects of Red Light-emitting Diode Therapy on Acute Lung Injury in a Sepsis Model in Rats

Article

Full-text available

Oct 2020
BRAZ ARCH BIOL TECHN

The aim of this study was to evaluate the in vivo response of red light-emitting diode (LED) on acute lung injury (ALI) in a sepsis model in rats. Twenty rats were randomly allocated into two experimental groups (n=10): Control Sepsis Group (CS); sepsis and red LED group (SRL). The anterior region of the trachea and ventral regions of the chest (below the ribs), bilaterally were irradiated daily for two consecutive days, starting immediately after the surgery using red (630 nm) LED. The histological results showed that in red LED treated group presented a modulation of the lung inflammatory process, less intense alveolar septum thickening and decrease of the inflammatory cells. Moreover, LED significantly reduced the lung injury score and increased interleukin type 10 (IL-10) protein expression compared SG. These results suggest that LED was efficient in attenuating ALI in a sepsis model in rats by reducing inflammatory cells into lung tissue and enhancing the anti-inflammatory cytokine production.

A Holistic Perspective on How Photobiomodulation May Influence Fatigue, Pain, and Depression in Inflammatory Bowel Disease: Beyond Molecular Mechanisms

Article

Full-text available

May 2023

Background: Numerous mechanisms, mostly molecular, have been tested and proposed for photobiomodulation. Photobiomodulation is finding a niche in the treatment of conditions that have no gold-standard treatment or only partially effective pharmacological treatment. Many chronic conditions are characterised by symptoms for which there is no cure or control and for which pharmaceuticals may add to the disease burden through side effects. To add quality to life, alternate methods of symptom management need to be identified. Objective: To demonstrate how photobiomodulation, through its numerous mechanisms, may offer an adjunctive therapy in inflammatory bowel disease. Rather than considering only molecular mechanisms, we take an overarching biopsychosocial approach to propose how existing evidence gleaned from other studies may underpin a treatment strategy of potential benefit to people with Crohn's disease and ulcerative colitis. Main findings: In this paper, the authors have proposed the perspective that photobiomodulation, through an integrated effect on the neuroimmune and microbiome-gut-brain axis, has the potential to be effective in managing the fatigue, pain, and depressive symptoms of people with inflammatory bowel disease.

Integrative Medicine in Zoological Species

Chapter

Jan 2023

Optimization of green LED light intensity for accelerating wound healing in olive flounder Paralichthys olivaceus (Temminck et Schlegel)

Article

Feb 2023
AQUACULTURE

Recent studies showed that green wavelength light-emitting diodes (LEDs) were effective for wound healing in various animal models, including olive flounder. However, determining the optimal light intensity for phototherapy is very important for accelerating wound healing and safety. Therefore, the purpose of this study was to investigate the optimal intensity of green LEDs (520 nm) for accelerating wound healing using olive flounder Paralichthys olivaceus (Temminck et Schlegel). In vitro studies, A Paralichthys olivaceus-derived embryo cell line (Hirame natural embryo cells; HINAE) was used to verify the proliferative effects of various intensities (20, 40, 80, and 120 μmol·m−2·s−1) of green LED (520 nm) light in 24-h light for seven days. In vivo studies, artificial wounds (4 mm in diameter) were made in flounders using a biopsy punch, and the wounds were exposed to green LED (520 nm) light at 20, 40, and 60 μmol·m−2·s−1, as well as ambient light as a control, in 12-h light/ dark cycles for 28 days. The results showed that 520 nm LED treatment at 40 μmol·m−2·s−1 significantly stimulated HINAE cell proliferation relative to ambient light (3±1 μmol·m-2·s-1) and the 20, 80 and 120 μmol·m−2·s−1 LED intensity groups. The relative wound healing rate of fish exposed to 40 μmol·m−2·s−1 of green LED (520 nm) light was significantly higher than that of the other groups and showed a high expression of wound healing-related genes such as matrix metalloproteinase (mmp)-9, mmp-13, epidermal growth factor (egf), and vascular endothelial growth factor (vegf)-. After the injuries, the survival rate of fish exposed to 520 nm LED light at an intensity of 60 μmol·m−2·s−1 was markedly lower (82%) than those of the control and 20 and 40 μmol·m−2·s−1-treated groups (over 95%). Stress-related factors such as catalase and superoxide dismutase (SOD) in the fish wound areas and serum glucose levels were significantly increased in the 60 μmol·m−2·s−1 exposure group, showing that prolonged exposure to strong light intensity could negatively affect physiology and wound healing. Therefore, the results showed that 40 μmol·m−2·s−1 intensity green LED (520 nm) light was the most effective light condition for accelerating wound healing in olive flounder.

Blue Light Inhibits Proliferation of Metastatic Cancer Cells by Regulating Translational Initiation: A Synergistic Property with Anticancer Drugs

Article

Feb 2023
PHOTOCHEM PHOTOBIOL

The aim of this study was to examine the inhibitory effect of blue light (BL) on the proliferation of metastatic cancer cells and synergistic properties with chemo‐drugs. BL significantly inhibited the proliferation of B cell lymphoma (A20 and RAMOS) cells in a dose‐dependent manner. Anti‐proliferative effect of BL irradiation was identified to be associated with the inhibition of proliferating‐cell nuclear antigen expression and cell cycle by decreasing S‐phase cells. Consistent with its inhibitory effects, BL irradiation at 20 J/cm2 daily for 10 days inhibited metastasis of cancer cells which were distributed and invaded to other organs including bone marrow, liver, kidney, etc., and induced paraplegia, thereby leading to an increased survival rate of tumor‐bearing mice. Anti‐proliferative activity of BL was expanded in solid tumor cells including pancreatic carcinoma (Mia PaCa‐2, PANC‐1), lung carcinoma A549, and colorectal carcinoma HCT116 cells. Additionally, combination with chemo‐drugs such as 5‐FU and gemcitabine resulted in an increase in the anti‐proliferative activity after BL irradiation accompanied by regulating mRNA translational process via inhibition of p70S6K, 4EBP‐1, and eIF4E phosphorylation during cellular proliferation. These results indicate the anti‐metastatic and photo‐biogoverning abilities of BL irradiation as a potent therapeutic potential for repressing the progression of tumor cells.

Acute and Chronic Wound Management: Assessment, Therapy and Monitoring Strategies

Chapter

Jan 2023

The dynamic nature of the wound healing is a well-studied process. With the rapid evolution of healthcare science, efforts are being made to design newer therapies, along with advancement in the available technologies. In this regard, a detailed knowledge about the molecular mechanisms underlying the healing process is necessary to develop a more effective and targeted therapeutic method. In addition to improve the therapeutic techniques, various wound healing models also need to be designed and studied for understanding the associated molecular intricacies of each phase of the healing process. Novel technologies are being combined with the long-practiced traditional therapeutic methods with the object of achieving a synergistic effect for faster healing with minimal scarring. With technological development, non-invasive wound assessment methods are being implemented by utilizing various imaging techniques and electromagnetic radiations, to minimize painful invasive wound analysis. Smart devices are also been developed with an aim to monitor the healing process in real time, which provides the ability to modulate treatment procedures according to the rate of healing. This chapter aims to give a brief overview on the emerging therapeutic methods which are being developed to aid in wound management strategies. An overview of the different invasive and non-invasive wound assessment and monitoring methods along with mathematically designed wound assessment models is also discussed in a nutshell. This would provide an idea about the possible areas for development on the currently available strategies for improving the healthcare and well-being of individuals.

The Effects of Visible and Near Infrared Light in Humans

Chapter

Sep 2007

Joan E. Roberts

In an era of global warming knowledge of the effects of solar radiation on humans is of great importance and the latest discoveries in environmental photobiology are presented in this book. The Editor has brought together a wide range of world class contributors to provide the reader with information on the clinical effects of solar radiation, such as inflammation, pigmentation, immune-suppression, cancer and aging, with emphasis on the ethnic or genetic background. The book also offers updates on the biochemical mechanisms involved in the generation of damage to DNA, lipids and proteins and on their removal. Each chapter has been written to provide a "historical" description of the phenomenology followed by the description of the state of the art. In this way, non-specialized and specialised readers alike can be updated in the essential aspects of the field. Key topics include: - Damages from acute versus chronic sun exposure - Skin Color, Melanin, Race/Ethnicity and UV-Induced DNA Damage - The effects of solar radiation on the immune response in humans - Genetic background and UV-induced skin cancer - The photochemistry of indirect damages: Lipid and Protein Damage provoked by UV radiation - DNA repair therapy This title will become an indispensable resource for students and professional at all levels working in fields relating to photochemistry, environmental science, biochemistry and biotechnology.

Multifunctional optical sensing applications of luminescent ions doped perovskite structured LaGaO3 phosphors in near-infrared spectroscopy

Article

Oct 2022

Near-infrared (NIR) phosphor have attracted great attention due to its promising applications in bioimaging, night vision, medical diagnosis and food safety. However, the development of NIR phosphors with excellent sensing properties still remains a challenge. In this study, NIR phosphor LaGaO3: Nd/Cr has been successfully synthesized. Excitation at 460 nm the phosphor can exhibit excellent temperature sensing performance with the maximum absolute sensitivity 0.6043% K⁻¹. The NIR phosphor also displays distinguished anti-thermal quenching performance with the emission intensity at 573 K retaining 78.34% of that at room temperature. In addition, there is a linear fitting relationship between the luminescence intensity ratio and applying stress. More importantly, NIR phosphor-converted light-emitting diode (pc-LED) has been fabricated by combining LaGaO3: Nd/Cr phosphors with blue LED chips, which shows a NIR output power of 979 mW and a photoelectric conversion efficiency up to 7.79% at 280 mA. Utilizing the prepared NIR pc-LED as a light source, the distribution of blood vessels and bones in human palms can be clearly observed with the assistance of infrared camera. These results indicate that the produced NIR phosphors have a wide range of optical sensing applications.

Photobiomodulation in 3D tissue engineering

Article

Full-text available

Sep 2022

Significance: The method of photobiomodulation (PBM) has been used in medicine for a long time to promote anti-inflammation and pain-resolving processes in different organs and tissues. PBM triggers numerous cellular pathways including stimulation of the mitochondrial respiratory chain, alteration of the cytoskeleton, cell death prevention, increasing proliferative activity, and directing cell differentiation. The most effective wavelengths for PBM are found within the optical window (750 to 1100 nm), in which light can permeate tissues and other water-containing structures to depths of up to a few cm. PBM already finds its applications in the developing fields of tissue engineering and regenerative medicine. However, the diversity of three-dimensional (3D) systems, irradiation sources, and protocols intricate the PBM applications. Aim: We aim to discuss the PBM and 3D tissue engineered constructs to define the fields of interest for PBM applications in tissue engineering. Approach: First, we provide a brief overview of PBM and the timeline of its development. Then, we discuss the optical properties of 3D cultivation systems and important points of light dosimetry. Finally, we analyze the cellular pathways induced by PBM and outcomes observed in various 3D tissue-engineered constructs: hydrogels, scaffolds, spheroids, cell sheets, bioprinted structures, and organoids. Results: Our summarized results demonstrate the great potential of PBM in the stimulation of the cell survival and viability in 3D conditions. The strategies to achieve different cell physiology states with particular PBM parameters are outlined. Conclusions: PBM has already proved itself as a convenient and effective tool to prevent drastic cellular events in the stress conditions. Because of the poor viability of cells in scaffolds and the convenience of PBM devices, 3D tissue engineering is a perspective field for PBM applications.

Superweak biophoton emission: possible biological significance and ways of practical use

Article

Full-text available

Feb 2022

Vladimir A Kostyuk

Widespread in nature ability of biological objects to emit photons (biophotons) made it possible to create devices for non-invasive and continuous monitoring of the metabolism of organs and tissues, used as a powerful clinical diagnostic tool, as well as for visualisation and spatio-temporal analysis of functioning organs and, in particular, the brain. Numerous experimental data indicating the participation of biophotons in the processes of inter- and intracellular communication served as a theoretical basis for the medical use of low-intensity light therapy for the effective treatment of a wide range of diseases, including delayed wound healing, pain in arthritis, and acute stroke.

Comparative analysis of Laser and LED phototherapies pain control after insertion of elastomeric separators in orthodontics patients: Clinical trial

Article

May 2022
J PHOTOCH PHOTOBIO B

The aim of this study was to evaluate the effectiveness of pain modulation following Laser or LED phototherapies during the process of tooth separation. This was a longitudinal randomized controlled clinical trial in four observational times carried out in 60 patients (15 males, 45 females, average 24.1 years old) who were randomly divided into three groups: G1 (LED, AsGaAl, λ850 ± 10 nm, 150 mW, 17 J/cm², 57 s per session), G2 (Laser, AsGaAl, λ780 nm, 70 mW, 20.0 J/cm², 240 s per session) and G3 (Non-irradiated Control). All patients were submitted to tooth separation using elastomeric separators. The pain level was measured by using a visual analogue scale (VAS) immediately after insertion (T1) of the elastic, at 48 (T2), 96 (T3) hours and 6 days (T4). It was observed an increase of the pain on the Control group from T1 to T2, with statistical significance. Pain levels in the LED and Laser groups were always significantly lower (<0.001), except for T1. According with the results of the present study it may be concluded that, either LED or Laser phototherapies, were effective in reducing the pain level after dental separation process when compared to the control group.

Safety and Feasibility of Low Fluence Intense Pulsed Light for Treating Pediatric Patients with Moderate-to-Severe Blepharitis

Article

Full-text available

May 2022

To explore the safety and feasibility of low fluence intense pulsed light (IPL) for treating pediatric patients with moderate-to-severe blepharitis and to analyze potential factors associated with the recovery of meibomian glands (MG) dropout, a retrospective, noncomparative study, including 17 blepharitis patients (33 eyes) aged between 5 and 16 years old was conducted. All of the participants were given 4 continuous sessions of low-fluence (9–12 J/cm2) IPL at 3–4 week intervals. Corneal fluorescein staining (CFS), tear breakup time (BUT), inferior tear meniscus height, Demodex presence, and MG morphology were examined before and after the treatment. Results indicated that CFS, BUT and MG morphology (central/total gland area ratio and gland signal index) had significantly improved (p < 0.05). Symptoms and signs such as severe corneal neovascularization, limbal pannus and conjunctival congestion also subsided. Among age, gender, presence of Demodex and interval before diagnosis, age initiating the formal treatment was confirmed as a negatively correlated factor of the recovery of MG dropout (p = 0.032, B = −1.755). No notable adverse events were reported. In conclusion, low fluence IPL seems to be a safe and effective alternative for moderate-to-severe pediatric blepharitis, and MG dropout is prone to recover in younger patients.

Efficacy of Intense Pulsed Light Treatment in Patients with Sjögren’s Syndrome Associated with Meibomian Gland Dysfunction

Article

Dec 2021

Purpose: To investigate the efficacy of intense pulsed light (IPL) treatment in patients with meibomian gland dysfunction (MGD) associated with Sjögren’s syndrome.Methods: This study included 43 patients with MGD and Sjögren’s syndrome. Patients received either IPL with meibomian gland expression (IPL/MGX) (n = 22) or MGX only (n = 21). Treatments were administered three times at a 3-week interval. Patients were followed up 6 weeks after the end of the treatment. Ocular Surface Disease Index (OSDI), tear film breakup time with fluorescein dye (FBUT), non-invasive tear breakup time, tear meniscus height (TMH), Schirmer test, SICCA ocular surface staining score, meibum quality score (MQS), and meibum expression score (MES) were evaluated at each visit. Meibomian gland dropouts (meiboscore) and tear film lipid layer grade were measured using keratography.Results: OSDI, FBUT, corneal surface staining score, MQS, meiboscore, and tear film lipid layer grade improved after IPL/MGX treatment (p < 0.05). In both treatment groups, MES significantly improved (p < 0.01 and p < 0.05 for IPL/MGX and MGX groups, respectively). The Schirmer test score, conjunctival surface staining score, and TMH after treatment were not significantly different between the groups. After treatment, the IPL/MGX group had significantly lower OSDI, FBUT, corneal staining score, MQS, and MES, but higher FBUT, compared with the MGX group (p < 0.05).Conclusions: IPL treatment effectively improved tear film, ocular surface parameters, meibomian gland function, and lipid layer grade in patients with Sjögren’s syndrome and MGD.

Simultaneous Exposure to Intracellular and Extracellular Photosensitizers for the Treatment of Staphylococcus aureus Infections

Article

Sep 2021

Staphylococcus aureus is a serious threat to public health due to the rise of antibiotic resistance in this organism, which can prolong or exacerbate skin and soft tissue infections (SSTIs). Methicillin-resistant S. aureus is a Gram-positive bacterium and a leading cause of SSTIs. As such, many efforts are underway to develop therapies that target essential biological processes in S. aureus . Antimicrobial photodynamic therapy is effective alternative to antibiotics, therefore we developed an approach to simultaneously expose S. aureus to intracellular and extracellular photoactivators. A near infrared photosensitizer was conjugated to human monoclonal antibodies (mAbs) that target the S. aureus Isd heme acquisition proteins. Additionally, the compound VU0038882 was developed to increase photoactivatable porphyrins within the cell. Combinatorial PDT treatment of drug-resistant S. aureus exposed to VU0038882 and conjugated anti-Isd mAbs proved to be an effective antibacterial strategy in vitro and in a murine model of SSTIs.

GAGG:Cr3+ Phosphors for Far-Infrared Light Emitting Diodes

Article

Aug 2021

Recently, Far-infrared Light Emitting Diodes have attracted considerable interest in the research field worldwide. Emerging light therapy requires effective red/far-infrared light resources in clinical and plant photomorphogenesis to target or promote the interaction of light with living organisms. Here, Gd 3 Al 4 GaO 12 :Cr ³⁺ (hereinafter referred to as: GAGG:Cr ³⁺ ) phosphor was synthesized by high-temperature solid-phase method, and the crystal structure, morphology, and luminescence properties of this series of phosphor samples were studied. Through X-ray powder diffraction to obtain pure phase GAGG:Cr ³⁺ series phosphor. Under the excitation of 420nm blue light, a broad band emission from 640 to 850nm is obtained, which is the result of the transition of Cr ³⁺ ⁴ T 2 → ⁴ A 2 level. A sharp emission peak at 693nm is the R line belonging to Cr ³⁺ in Gd 3 Al 4 GaO 12 garnet. R line is assigned to the spin-forbidden ² E→ ⁴ A 2 transitions of Cr ³⁺ ions that occupy the ideal octahedral sites. As the Cr ³⁺ doping concentration increases, the luminous intensity of the sample increases first and then decreases. When the doping concentration of Cr ³⁺ is 0.1mol phosphor,the luminous intensity is strongest at one single broad peak at about 712nm. At 440k, the R sharp line (693nm) and broad band (712nm) emission intensity maintained 78.6% and 71.8% , compared to room temperature intensity, respectively. The change of fluorescence lifetime at different temperatures gives the mechanism of fluorescence change with temperature. The current exploration will pave a promising way to engineer GAGG:Cr ³⁺ activated optoelectronic devices for all kinds of photobiological applications.

Application of Narrow-band Optical Radiation and Kinesiotaping in Posterior Cervical Sympathetic Syndrome

Article

Apr 2021

Aim. To substantiate the application of the infrared range narrow-band optical radiation and kinesiotaping combined effect in the complex treatment of patients with posterior cervical sympathetic syndrome on the basis of clinical studies. Material and methods. The dynamics of complaints for dizziness in 60 patients of two groups were evaluated using the DHI (Dizziness Handicap Inventory) and VRBQ (Vestibular Rehabilitation Benefit Questionnaire) scales, headache and pain in the neck using the visual analog scale (VAS), tinnitus, visual defocusing, nausea, vomiting, palpitations, decreased concentration and attention using the International Classification of Functioning, Disability and Health (ICF). To assess the posture, the shoulder Aksenova index was used. A duplex scan of the brachycephalic arteries and an assessment of anxiety and depression on the Sheehan and Beck scales, respectively, were used to assess blood flow through the vertebral arteries. Results. Statistically reliable data (p <0.05) for reducing dizziness, headache, pain in the cervical region, reducing the severity of tinnitus, defocusing vision, nausea, and decreasing concentration and attention were obtained in the group using the combined effects of narrow-band infrared optical radiation and kinesiotherapy in comparison with the control group. Statistically reliable data (p <0.05) for improving linear velocity of blood flow Vm, Vps for the left vertebral artery at the extracranial level and statistically reliable data (p<0.05) for improving linear velocity of blood flow Vm, Vps for vertebral arteries were obtained at the intracranial level. Statistically reliable data (p<0.05) on the effectiveness of kinesiotaping for the correction of the upper cross syndrome were obtained. Conclusion. The application of the narrow-band infrared range optical radiation and kinesioteping combined exposure can be recommended in the complex treatment of patients with posterior cervical sympathetic syndrome as well as to increase the linear velocity of blood flow in the vertebral arteries, the use of kinesiotaping can be recommended for the correction of biomechanical disorders, correction of the upper cross syndrome.

The effect of LED photobiomodulation on the proliferation and osteoblastic differentiation of periodontal ligament stem cells: in vitro

Article

Apr 2021

Background The aim of this study was to investigate the influence of three different light-emitting diode (LED) wavelengths on the proliferation and osteoblastic differentiation of periodontal ligament stem cells (PDLSCs) in vitro. Methods PDLSCs seeded on 96- and 24-well plates, for proliferation and osteoblastic differentiation, respectively, were irradiated daily by LED light with peak emission wavelengths of 630, 680, and 830 nm at constant energy densities of 3.5 J/cm². Cultures were grown for 8 days for the proliferation assay, 10 days for the alkaline phosphatase (ALP) assay, and 28 days for Alizarin red staining. Mitochondrial activity, ALP enzyme level, and the ability to form calcium phosphate deposits were measured and compared across cultures. Results Results obtained from statistical analysis of the experimental data indicated that the rate of proliferation (P < 0.05) in 830-nm irradiated cultures were significantly higher than the control samples at day 6 and 8; whereas, for the 630- and 680-nm groups, test results showed lower proliferation rates at day 8. For osteoblastic differentiation, significantly greater mineralization than the control samples was detected in the red-light groups (630 and 680 nm) during the late differentiation period (P < 0.001), which was supported by a higher ALP activity of the 630- and 680-nm groups in the early stage (P < 0.01). Conclusion The results of this study demonstrate that the PDLSCs responded differently to specific LED wavelengths. For enhancing cellular proliferation, 830-nm LED irradiation was more effective. On the other hand, the wavelengths of 630 and 680 nm were better for stimulating osteoblastic differentiation.

Effect of Irradiation with Visible Light (Green, Red, Blue) on Inhibition of Melanin Biosynthesis

Article

Mar 2021

Kyung-Run Ko

Photobiomodulation effects of pulsed-NIR laser (810 nm) and LED (808 ± 3 nm) with identical treatment regimen on burn wound healing: A quantitative label-free global proteomic approach

Article

Full-text available

Mar 2021

Photobiomodulation (PBM) has evolved as a rapidly growing therapeutic biophysical non-invasive approach for the acceleration of tissue repair, mitigation of pain, inflammation and restoration of cellular functions. This study compares the PBM effect of pulsed-mode (10 Hz) of NIR laser (810 nm) and LED (808 ± 3 nm) with identical treatment regimen (average power 70 mW; average irradiance 40 mW/cm²; total fluence 24 J/cm², duty cycle 50%; pulse duration 50 msec; peak irradiance 80 mW/cm²; 10 min exposure once daily for 7 days) on full-thickness, third-degree burn wound in rat using comprehensive analysis of quantitative label-free global proteomics, followed by validation of the proteomics data by various biophysical, biochemical, molecular, histological and immunohistochemical (IHC) assays. The proteomic analysis clearly revealed the common biological processes indicated by modulation of similar biological pathways (known for tissue repair process) associated with neuronal (4), metabolic (10), vascular (3), inflammation (4) and cell signaling (12) in both laser and LED treated groups. Validation of proteomic analysis using various healing markers demonstrated attenuated inflammatory response like decreased TNF-α, IL-1β, IL-6, COX-2 levels (ELISA), enhanced cellular proliferation (PCNA, TGF-β2), collagen, ECM accumulation (biochemical, H&E, Masson's trichrome staining, IHC assays), wound contraction and cytoprotection (TUNEL assay) in both laser and LED-treated groups as compared to the control. Collectively, the proteomics data revealed previously know molecules along with novel identified molecules post-PBM treatment, which broaden the understanding of tissue repair mechanisms. This study profoundly signifies that both laser and LED in 810 nm wavelength range at pulsed-mode (10 Hz) are equally effective for PBM-mediated potential treatment to accelerate burn wound healing.

Role of Photo-Biomodulation Therapy in Facial Rejuvenation and Facial Plastic Surgery

Article

Feb 2021
FACIAL PLAST SURG

Jose A De Cordova

Photo-biomodulation (PBM) also known as low-level laser therapy is a rising technology with multiple potential uses in medicine and recently in the cosmetic field for the treatment of skin conditions and skin rejuvenation. Due to its wound healing and anti-inflammatory properties, there is an increase in popularity in its use as adjunctive treatment before and after surgical procedures in the face and neck.

Lactobacillus bulgaricus and Lactobacillus plantarum improve diabetic wound healing through modulating inflammatory factors

Article

Nov 2020

Probiotics are nonpathogenic bacterial strains that exert beneficial effects on the host. Previous studies have shown that topical use of some strains of probiotic bacteria have good effects on the healing of cutaneous wounds. In the current study, the wound healing potentials of bacterial probiotics on diabetic cutaneous wounds were evaluated. The effects of probiotics on migration, the viability of fibroblasts, and macrophage proliferation were measured through using wound healing assay, methylthiazol tetrazolium assay, and bromodeoxyuridine, respectively. In this regard, in vivo diabetic wound healing experiments in Wistar rats following treatment with nontoxic concentrations of Lactobacillus bulgaricus and Lactobacillus plantarum were conducted. The histopathological and gene expression analyses were performed following removal of wound sites 3, 7, and 14 days postwounding. Results showed that treatment with probiotics accelerated the healing process of diabetic wounds and modulated the inflammatory cells in wound sites during a 14‐day period postwounding. The altered mRNA levels of inflammatory cytokines were observed in wound sites following treatment with probiotics. The findings of the current study reveal that L. bulgaricus and L. plantarum could improve the healing of diabetic wounds via regulation of inflammation. Treatment with L. bulgaricus and L. plantarum accelerated the wound healing process in the diabetic Wistar rats.

Low-Level Laser-Assisted Liposuction: A Multicenter Side-by-Side Comparison Study

Article

Jun 2003

Introduction Liposuction has undergone many revisions since 1980, the most notable being the introduction of the tumescent technique of local anesthesia by Jeffery Klein, MD. Since then, in an effort to improve the aesthetics of the technique and the ease and safety of the procedure, other techniques have been introduced. These include superficial liposuction, UAL, external ultrasonic liposuction, mechanically assisted liposuction, and, most recently, laser-assisted liposuction. Materials and Methods Four centers in the United States, operating under an 1RB protocol, performed liposuction with the tumescent technique of local anesthesia on specified cosmetic units of the body. One side was exposed to 635-nm laser therapy after tumescence was achieved, whereas the contralateral side was not. Observations were recorded during surgery and at 2 weeks postoperatively. Results Observations of intraoperative technique did not show an advantage to laser-assisted liposuction. Observations of the postoperative course were equivocal, though there was evidence of reduction of edema in certain patients. Discussion The addition of laser therapy to liposuction technique is based on years of experience demonstrating improved wound healing using a technique of low-level laser therapy. Although the recorded observations did not support an advantage to the addition of laser therapy, there was a paradoxical difference of opinion among patients and surgeons who participated in the study. These individuals believed that, compared with patients not treated with low-level laser therapy, there was at least a reduction in degree and duration of postoperative pain and induration. As low-level laser therapy may have systemic effects on wound healing, comparing treated and untreated contralateral sides may not be valid because both sides experienced improvements in postoperative course. Laser-assisted liposuction has a potential advantage, not supported by this study, in the intraoperative and postoperative course of liposuction surgery. New studies using double-blind techniques will need to be conducted.

Kienbock’s Disease: A Case Study

Article

Jan 2020

Skin Health

Chapter

Jul 2006

4. Regenerative Medicine of Skin, Hair, Dental Tissues, and Cornea

Chapter

Dec 2006

David Stocum

Chronic wounds are characterized by a failure to re-epithelialize and by defective production as well as remodeling of extracellular matrix (ECM). Acute incisional and excisional skin wounds account for over 4.5 million medical procedures per year in the US. Therapies that accelerate normal skin repair and production of stronger scar tissue are desirable, because they lead to quicker recovery from burns and surgical operations, particularly in older individuals. Therapies that heal chronic wounds save tissue that might otherwise be lost to necrosis and infection as well as save the life of the patient in some cases. Deep incisions are repaired by stitching the wound edges together, resulting in a thin line of scar tissue on the surface of the skin. To increase the area that can be covered by a skin autograft, surgeons use meshed split-thickness skin grafts (MSTSGs). A wide variety of topical agents have been employed to accelerate the normal repair process and produce stronger scar tissue in acute wounds of normal skin. Application of healing accelerants as early as possible after wounding is desirable, because of the cascade affects that carry through to later stages of healing. No dental restorative materials have the same physical and chemical characteristics of natural tooth tissues. The current technique to restore periodontal tissue is guided by tissue regeneration, which does not produce predictably good outcomes. Cornea is unable to regenerate if limbal tissue that provides the stem cells for regeneration is compromised. If a part of the limbus in either eye remains undamaged, pieces of this tissue can be removed and cultured on human amniotic membrane to form a larger sheet. Pieces of this epithelial sheet can then be transplanted as an autogeneic sectorial or a ring graft to regenerate and maintain the damaged cornea.

Noninvasive Brain Stimulation & Space Exploration: Opportunities and Challenges

Article

Sep 2020

As NASA prepares for longer space missions aiming for the Moon and Mars, astronauts' health and performance are becoming a central concern due to the threats associated with galactic cosmic radiation, unnatural gravity fields, and life in extreme environments. In space, the human brain undergoes functional and structural changes related to fluid shift and intracranial pressure. Behavioral abnormalities, such as cognitive deficits, sleep disruption, and visuomotor difficulties, as well as psychological effects, are also a concern. We discuss opportunities and challenges of noninvasive brain stimulation (NiBS) methods - including transcranial magnetic stimulation (TMS) and transcranial electrical stimulation (tES) - to support space exploration in several ways. NiBS includes safe and portable techniques already applied in a wide range of cognitive and motor domains, as well as therapeutically. NiBS could be used to enhance in-flight performance, supporting astronauts during pre-flight Earth-based training, as well as to identify biomarkers of post-flight brain changes for optimization of rehabilitation/compensatory strategies. We review these NiBS techniques and their effects on brain physiology, psychology, and cognition.

Light-emitting Diodes as a Light Source for Intraoperative Photodynamic Therapy

Article

Full-text available

Mar 1996

The NASA light-emitting diode medical program-progress in space flight and terrestrial applications

Article

Full-text available

Jan 2000

This work is supported and managed through the NASA Marshall Space Flight Center-SBIR Program. Studies on cells exposed to microgravity and hypergravity indicate that human cells need gravity to stimulate cell growth. As the gravitational force increases or decreases, the cell function responds in a linear fashion. This poses significant health risks for astronauts in long termspace flight. LED-technology developed for NASA plant growth experiments in space shows promise for delivering light deep into tissues of the body to promote wound healing and human tissue growth. This LED-technology is also biologically optimal for photodynamic therapy of cancer. .

Effect of a diode laser on cell proliferation, alkaline phosphatase activity, and osteopontin mRNA in proliferating and differentiating osteoblastic cells.

Article

Full-text available

Aug 2004

Different types of osteoblast behavior result from external stimulation in the early and in the late stages of cell differentiation. The purpose of this study was to investigate the influence of a diode laser on osteoblasts and to compare any effects between the proliferating and the differentiating phases. In the proliferating phases, the numbers of cells greatly increased in the laser irradiated group as compared with that of the control group. The increases in the numbers of cells in the differentiating phase were no greater than were those in the proliferating phase. The alkaline phosphatase activity of cells in the proliferating phase was highest 5 days after the laser irradiation, however, the activity in the differentiating phase increased day by day. Although osteopontin mRNA levels in the proliferating phase increased in the first 3 days of culture and then decreased in both groups, this decrease of osteopontin mRNA was small in the irradiated group. In contrast, osteopontin mRNA expression in the differentiating phase increased at day 1 and then decreased in the control group, while osteopontin mRNA levels in the irradiated group did not decrease.

Medical applications of space light-emitting diode technology—space station and beyond

Article

Full-text available

Jan 1999

Space light-emitting diode (LED) technology has provided medicine with a new tool capable of delivering light deep into tissues of the body, at wavelengths which are biologically optimal for cancer treatment and wound healing. This LED technology has already flown on Space Shuttle missions, and shows promise for wound healing applications of benefit to Space Station astronauts.

Laser and light-emitting diode effects on pre-osteoblast growth and differentiation

Article

Full-text available

Nov 2012
LASER MED SCI

The acceleration of bone regeneration by low-intensity laser irradiation may hold potential benefits in clinical therapy in orthopedics and dentistry. The purpose of this study is to compare the effects of light-emitting diode (LED) and laser on pre-osteoblast MC3T3 proliferation and differentiation. Cells were irradiated with red, infrared, and LED (3 and 5 J/cm(2)). Lasers had a power density of 1 W/cm(2) and irradiation time of 2 and 5 s. LED had a power density of 60 mW/cm(2) and irradiation time of 50 and 83 s. Control group did not receive irradiation. Cell growth was assessed by a colorimetric test (MTT) (24, 48, 72, and 96 h), and cell differentiation was evaluated by alkaline phosphatase (ALP) quantification after growth in osteogenic medium (72 and 96 h and 7 and 14 days). At 24 h, the cell growth was enhanced 3.6 times by LED (5 J/cm(2)), 6.8 times by red laser (3 J/cm(2)), and 10.1 times by red laser (5 J/cm(2)) in relation to control group (p < 0.05). At the other periods, there was no influence of irradiation on cell growth (p > 0.05). The production of ALP was not influenced by irradiation at any period of time (p > 0.05). Low-intensity laser and LED have similar effects on stimulation of cell growth, but no effect on cell differentiation.

Effect of laser and LED phototherapies on the healing of cutaneous wound on healthy and iron-deficient Wistar rats and their impact on fibroblastic activity during wound healing

Article

Full-text available

Jul 2012
LASER MED SCI

Iron deficiency impairs the formation of hemoglobin, red blood cells, as well the transport of oxygen. The wound healing process involves numerous functions, many of which are dependent on the presence of oxygen. Laser has been shown to improve angiogenesis, increases blood supply, cell proliferation and function. We aimed to study the effect of λ660 nm laser and λ700 nm light-emitting diode (LED) on fibroblastic proliferation on cutaneous wounds on iron-deficient rodents. Induction of iron anemia was carried out by feeding 105 newborn rats with a special iron-free diet. A 1 × 1 cm wound was created on the dorsum of each animal that were randomly distributed into seven groups: I, control anemic; II, anemic no treatment; III, anemic + L; IV, anemic + LED; V, healthy no treatment; VI, healthy + laser; VII, healthy + LED (n = 15 each). Phototherapy was carried out using either a diode laser (λ660 nm, 40 mW, 10 J/cm(2)) or a prototype LED device (λ700 ± 20 nm, 15 mW, 10 J/cm(2)). Treatment started immediately after surgery and was repeated at 48-h interval during 7, 14, and 21 days. After animal death, specimens were taken, routinely processed, cut, stained with hematoxylin-eosin, and underwent histological analysis and fibroblast counting. Significant difference between healthy and anemic subjects on regards the number of fibroblast between treatments was seen (p < 0.008, p < 0.001). On healthy animals, significant higher count was seen when laser was used (p < 0.008). Anemic subjects irradiated with LED showed significantly higher count (p < 0.001). It is concluded that the use of LED light caused a significant positive biomodulation of fibroblastic proliferation on anemic animals and laser was more effective on increasing proliferation on non-anemics.

Near-Infrared Photobiomodulation in an Animal Model of Traumatic Brain Injury: Improvements at the Behavioral and Biochemical Levels

Article

Full-text available

Jul 2012
PHOTOMED LASER SURG

The purpose of this was to evaluate the neuroprotective effects of near-infrared (NIR) light using an in-vivo rodent model of traumatic brain injury (TBI), controlled cortical impact (CCI), and to characterize changes at the behavioral and biochemical levels. NIR upregulates mitochondrial function, and decreases oxidative stress. Mitochondrial oxidative stress and apoptosis are important in TBI. NIR enhanced cell viability and mitochondrial function in previous in-vitro TBI models, supporting potential NIR in-vivo benefits. Sprague-Dawley rats were divided into three groups: severe TBI, sham surgery, and anesthetization only (behavioral response only). Cohorts in each group were administered either no NIR or NIR. They received two 670 nm LED treatments (5 min, 50 mW/cm(2), 15 J/cm(2)) per day for 72 h (chemical analysis) or 10 days (behavioral). During the recovery period, animals were tested for locomotor and behavioral activities using a TruScan device. Frozen brain tissue was obtained at 72 h and evaluated for apoptotic markers and reduced glutathione (GSH) levels. Significant differences were seen in the TBI plus and minus NIR (TBI+/-) and sham plus and minus NIR (S+/-) comparisons for some of the TruScan nose poke parameters. A statistically significant decrease was found in the Bax pro-apoptotic marker attributable to NIR exposure, along with lesser increases in Bcl-2 anti-apoptotic marker and GSH levels. These results show statistically significant, preclinical outcomes that support the use of NIR treatment after TBI in effecting changes at the behavioral, cellular, and chemical levels.

Effect of 635 nm Light-Emitting Diode Irradiation on Intracellular Superoxide Anion Scavenging Independent of the Cellular Enzymatic Antioxidant System

Article

Full-text available

Jul 2012
PHOTOMED LASER SURG

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. 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. 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). 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. 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.

Effects of Photostimulation on Wound Healing in Diabetic Mice

Article

Full-text available

Jan 1997
LASER SURG MED

Background and Objective Low-level laser irradiation at certain fluences and wavelengths can enhance the release of growth factors from fibroblasts and stimulate cell proliferation in vitro. We evaluated whether low-level laser irradiation can improve wound healing in diabetes mellitus.Study Design/Materials and Methods Genetically diabetic mice (C57BL/Ksj/db/db) were used as the animal model for this wound healing study. The experimental animals were divided among four groups: negative control, positive control (topical basic fibroblast growth factor [bFGF] on wound), laser therapy group; and a combination group of laser therapy and topical bFGF. An argon dye laser (Lexel Auora Model 600) at a wavelength of 630 nm and an output of 20 mW/cm2 was used as the light source. The speed of wound closure and histological evaluation were used to analyze the experimental results.ResultsLaser irradiation enhanced the percentage of wound closure over time as compared to the negative control group (58.4 ± 2.6 vs. 40.8 ± 3.4 at day 10 and 95.7 ± 2 vs. 82.3 ± 3.6 at day 20, P < .01). Histological evaluation showed that laser irradiation improved wound epithelialization, cellular content, granulation tissue formation, and collagen deposition in laser-treated wounds as compared to the negative control group (6.4 ± 0.16 vs. 3.8 ± 0.13 at day 10 and 12 ± 0.21 vs. 8.2 ± 0.31, P < .01).Conclusion This study of laser biostimulation on wound healing in diabetic mice suggests that such therapy may be of great benefit in the treatment of chronic wounds that occur as a complication of diabetes mellitus. Lasers Surg Med 20:56–63, 1997. © 1997 Wiley-Liss, Inc.

Comparative study of laser and LED systems of low intensity applied to tendon healing

Article

Full-text available

Sep 2009

The aim of this study was to compare the effects of Low-intensity Laser Therapy (LILT) and Light Emitting Diode Therapy (LEDT) of low intensity on the treatment of lesioned Achilles tendon of rats. The experimental model consisted of a partial mechanical lesion on the right Achilles tendon deep portion of 90 rats. One hour after the lesion, the injured animals received applications of laser/LED (685, 830/630, 880 nm), and the same procedure was repeated at 24-h intervals, for 10 days. The healing process and deposition of collagen were evaluated based on a polarization microscopy analysis of the alignment and organization of collagen bundles, through the birefringence (optical retardation-OR). The results showed a real efficiency of treatments based on LEDT and confirmed that LILT seems to be effective on healing process. Although absence of coherence of LED light, tendon healing treatment with this feature was satisfactory and can certainly replace treatments based on laser light applications. Applications of infrared laser at 830 nm and LED 880 nm were more efficient when the aim is a good organization, aggregation, and alignment of the collagen bundles on tendon healing. However, more research is needed for a safety and more efficient determination of a protocol with LED.

LED Phototherapy Improves Healing of Nipple Trauma: A Pilot Study

Article

Full-text available

Mar 2012
PHOTOMED LASER SURG

The purpose of this study was to evaluate the clinical effectiveness of a LED phototherapy prototype apparatus in the healing of nipple trauma in breastfeeding women. There is no scientific evidence of an effective treatment for nipple trauma. The experimental group was treated with orientation on nipple care and adequate breastfeeding techniques in addition to active LED phototherapy. The control group was treated with orientation on nipple care and adequate breastfeeding techniques in addition to placebo LED phototherapy. Participants were treated twice a week, for a total of eight sessions. Healing of the nipple lesions was measured by a reduction in their area, and decrease in pain intensity was measured in accordance with an 11-point Pain Intensity Numerical Rating Scale and a standard 7-point patient global impression of change. Statistically significant reductions in measured nipple lesion area (p<0.001) were observed for both the experimental and control groups with an increase in the number of treatment sessions. A significant difference between the experimental and control groups was observed for the healing of nipple lesions (p<0.001). The pain intensity was significantly reduced only in the experimental group (p<0.001). Preliminary results demonstrated the prototype apparatus for LED phototherapy to be an effective tool in accelerating the healing of nipple trauma.

Does LED phototherapy influence the repair of bone defects grafted with MTA, bone morphogenetic proteins, and guided bone regeneration? A description of the repair process on rodents

Article

Full-text available

Dec 2011
LASER MED SCI

This work carried out a histological analysis on bone defects grafted (MTA) treated or not with LED, BMPs, and membrane (GBR). Benefits of their isolated or combined usage on bone repair were reported, but not their association. Ninety rats were divided into ten groups and each subdivided into three. Defects on G II and I were filled with the blood clot. G II was further LED irradiated. G III and IV were filled with MTA; G IV was further LED irradiated. In G V and VI, the defects were filled with MTA and covered with a membrane (GBR). G VI was further LED irradiated. In G VII and VIII, BMPs were added to the MTA and group VIII was further LED irradiated. In G IX and X, the MTA + BMP graft was covered with a membrane (GBR). G X was further LED irradiated. LED was applied over the defect at 48-h intervals and repeated for 15 days. Specimens were processed, cut, and stained with H&E and Sirius red and underwent histological analysis. The use of LED light alone dramatically reduced inflammation. However, its use on MTA associated with BMP and/or GBR increased the severity of the inflammatory reaction. Regarding bone reabsorption, the poorest result was seen when the LED light was associated with the MTA + BMP graft. In the groups Clot and MTA + GBR, no bone reabsorption was detectable. Increased collagen deposition was observed when the LED light was associated with the use of the MTA associated with BMP and/or GBR. Increased new bone formation was observed when the LED light was used alone or associated with the use of MTA + GBR, MTA + BMP, on association of MTA + BMP + GBR and when BMP was added to the MTA. Our results indicate that the use of LED light alone or in association with MTA, MTA + BMP, MTA + GBR, and MTA + BMP + GBR caused less inflammation, and an increase of both collagen deposition and bone deposition as seen on both histological and morphometric analysis.

Radiant Near Infrared Light Emitting Diode Exposure as Skin Preparation to Enhance Photodynamic Therapy Inflammatory Type Acne Treatment Outcome

Article

Full-text available

Feb 2010
LASER SURG MED

An alternative approach in the treatment of acne vulgaris is photodynamic therapy (PDT) that uses light and aminolevulinic acid (ALA)-induced protoporphyrin IX (PpIX) production to eradicate Propionibacterium acnes found in acne lesions. PpIX formation is dependent on ALA percutaneaous penetration. In this study, to enhance ALA penetration and subsequent accumulation of PpIX, skin temperature was increased with radiant infrared (IR) prior to ALA-PDT application and compared to ALA-PDT alone in the treatment of inflammatory acne. Ten patients exhibiting inflammatory acne with a lesion count of > or =10 were assigned to a split face or split back group. One side was pre-treated for 15 minutes with radiant IR light emitting diode (LED) (970 nm), while the other side was used as control. ALA was then applied after which PDT LED (630 nm) was performed on the entire face or back surface. Blinded lesion counts and clinical global assessment of severity were performed based on digital photographs before and 4 weeks after the PDT procedure. This randomized, controlled, and rater-blinded trial revealed a significant difference in median reduction of inflammatory lesions on the IR pre-treated (73%, 95% confidence interval (CI) 51-81%) versus the control side (38%, 95% CI 8-55%) 1 month after PDT (P<0.0001). Clinical assessment of severity was also significantly lower on the IR-treated side than on the control side (median 1, 95% CI 0.74-1.34 vs. 2, 95% CI 1.17-1.72). No unusual treatment-related adverse effects were observed. The reported therapeutic effects may be due to enhanced induction of alterations in transcutaneous diffusion kinetics of the photosensitizer at higher skin temperature and/or conversion of ALA to PpIX. Pre-PDT radiant IR LED exposure appears to be a promising method to enhance PDT efficacy for the treatment of acne lesions.

Biostimulation of wound healing by low-energy laser irradiation A review

Article

May 1996
J CLIN PERIODONTOL

This paper reviews studies on the basic principles of biostimulation of wound healing by various low-energy lasers. It looks at the mechanism of action of biostimulation as well as the lasers effect on cell proliferation, collagen synthesis, and would healing.

Experimental Imunological Study with Radiological Application of Low Power Laser

Chapter

Jan 1998

Aim of the study was to compare different wavelength laser immunological reactions.

Laser acceleration of open skin wound closure in rats and its dosimetric dependence

Article

Jan 1997

Farouk A H Al-Watban

The Effect of Laser Radiation on Wound Healing and Collagen Synthesis

Article

Jan 1973

The mechanism of wound healing was studied with 35S, 14C labelled amino acids during the early proliferative phase, following artificial incision. The measurements show that 4 joule laser energy applied at the earliest time favourably influences wound healing; the production of collagen in the cicatricial tissue treated with laser exceeds that of the control by about 30-50 per cent.

In Vitro Comparison of Light-Emitting Diodes and Carnosic Acid Effects on Keratinocyte Proliferation and Wound Healing

Article

Mar 2012

Introduction: Light-emitting diode (LED) therapy uses different wavelengths of light and has been reported to accelerate cutaneous wound healing. Carnosic acid is an antioxidant that is also thought to be photoprotective. We designed an in vitro study to examine the effects of LED and carnosic acid on the proliferation and migration of human keratinocytes. Materials and Methods: Clinically normal human keratinocytes were cultured and exposed to two wavelengths: 620 nm and 660 nm LED at different ß uences. In the second part of this study, a different batch of human keratinocytes was grown in culture, and different concentrations of carnosic acid were added. Results: At the two wavelengths that were used, LED did not appear to have any therapeutic effect and was not effective in stimulating keratinocyte proliferation. Exposure to greater energy levels (increased fluence) produced increased cell damage that was directly proportional to the increase in energy. On the other hand, treatment of the cell cultures with the antioxidant carnosic acid resulted in an increase of keratinocyte cell proliferation, and this increase was also proportional to the concentration of carnosic acid. Conclusions: This study did not support the hypothesis that LED treatment results in keratinocyte proliferation; however, carnosic acid, a potent antioxidant, stimulated keratinocyte production and could be implicated in wound healing and rejuvenation.

Stretchable Light-Emitting Electrochemical Cells Using an Elastomeric Emissive Material

Data

Mar 2014

Magnetoledtherapy in comprehensive pediatric rehabilitation

Article

Aug 2012

IntroductionLED light therapy with magnetostimulation (magnetoledtherapy) has a vast range of applications in the treatment of neurological, rheumatic and orthopedic illnesses. In some cases it serves as an alternative procedure to pharmacological treatment, in particular to nonsteroidal anti-inflammatory drugs.AimThe aim of this study was to discuss the use of magnetoledtherapy in the rehabilitation of children.Materials and methodsThis article is a review of selected literature and other available source materials.DiscussionDue to biological hysteresis, therapeutic outcomes of magnetoledtherapy appear later than in the case of other physical therapy methods; they last longer, even up to several months after the exposure, thus leading to more beneficial treatment effects. Therapeutic methods available for very young people are limited due to various contraindications. When exposure conditions are carefully considered and accounted for, magnetoledtherapy can be applied even in infants, serving as a beneficial complement to kinesiotherapy. Children willingly participate in such treatment because magnetoledtherapy produces few side effects and has a positive effect on a patient's well-being following the application. Selected indications for the use of this method in children include neuralgias, juvenile rheumatoid arthritis, collagenoses, aseptic necrosis, osteoporosis, tendinitis, tendovaginitis, bursitis, injuries without a disruption in tissue continuity including sprains, bruises and fractures, improvement in the quality and time of healing, burns, effects of exposure to sunlight and laser light, neonatal physiological jaundice, dermatoses including dermatitises, acne, herpes, vitiligo, psoriasis, central nervous system lesions, dental periapical lesions, cerebral palsy, peripheral nerve lesions, especially perinatal brachial plexus palsy, polyneuropathies, amyotrophic lateral sclerosis, spinal muscular atrophy, muscular dystrophies, congenital bone deformations, neuroses, sleep disorders, stress, Attention Deficit Hyperactivity Disorder (ADHD), speech impairment therapy and therapy for children with Down's syndrome. Therefore, this therapy is widely applicable. In the treatment of children, it is indispensible to strictly follow application parameters and observe specifications concerning the size of the area that is exposed to treatment.Conclusions Magnetoledtherapy is a valuable complement to the comprehensive rehabilitation of children and should be recommended for a wider application.

Irradiation with HeNe laser can influence the cytotoxic response of HeLa cells to ionizing radiation

Article

Nov 1996
Proceedings of SPIE

A monolayer of HeLa cells in plateau-phase of growth was exposed to He-Ne laser radiation either 5 min, 60 min or 180 min before (gamma) -irradiation. It has been shown that in the case of a 5-min interval between the two types of irradiations the survival curve was practically identical to the survival curve of the cells after (gamma) -irradiation only. In the case of He-Ne laser exposure 60 min before (gamma) -irradiation with doses of over 5 Gy, a fraction of more resistant cells was revealed: their D0 was twice as high as the D0 of the min population. A preexposure of cells to He-Ne laser 60 or 180 min before (gamma) - irradiation also changed the shape of the growth curves as compared to (gamma) -irradiated cells. It is proposed that the preexposure of cells to He-Ne laser radiation activates, in a subpopulation of cells, processes which speed up the repair of (gamma) -radiation damage. The possibility that the described phenomenon is an adaptive response of cells is discussed.

A Successfully Treated Diabetic Ulcer by Xenon Ray Irradiation

Article

Apr 2006

We report a 59-year-old Japanese male with diabetic ulcer successfully treated with xenon ray irradiation. The patient, having diabetes mellitus and heart disease, presented with a 1-month history of an unhealed cutaneous ulcer on his left foot. No treatment with topical application was effective. Therefore, xenon ray irradiation was administered. After irradiation was performed with a total dose of 142.7 J/cm2 over a treatment course of 10 weeks, the cutaneous ulcer improved. Xenon ray irradiation has a light source ranging from an ultra-violet wavelength to a near-infrared ray with a peak at 800-900 nm. Xenon ray treatment cutting off the ultra-violet wavelength has been introduced for the control of pain and the rehabilitation of patients with motor disturbances. Near-infrared irradiation is used to promote wound healing. This result indicates that xenon ray irradiation can be valuable for the treatment of cutaneous ulcer in patients with diabetes mellitus.

NASA light emitting diode medical applications from deep space to deep sea

Article

Feb 2001

This work is supported and managed through the NASA Marshall Space Flight Center-SBIR Program. LED-technology developed for NASA plant growth experiments in space shows promise for delivering light deep into tissues of the body to promote wound healing and human tissue growth. We present the results of LED-treatment of cells grown in culture and the effects of LEDs on patients’ chronic and acute wounds. LED-technology is also biologically optimal for photodynamic therapy of cancer and we discuss our successes using LEDs in conjunction with light-activated chemotherapeutic drugs.

The influence of insulator properties on the electro-optical performance of flexible ZnS:ErF 3 alternating current thin film electroluminescent devices

Article

Dec 2006
THIN SOLID FILMS

We have developed flexible ZnS:ErF3 alternating current thin film electroluminescent devices on molybdenum foils, and quantified the effect of insulator properties for the case of alumina (Al2O3) and barium tantalate (BaTa2O6) on the device electrical characteristics, and infrared emission. The inverted, full-stack structures could be flexed in tension and compression without mechanical failure or deterioration of optical output, and flex radii of a few centimeters are routinely achieved. Thus, the feasibility of a flexible, inorganic, large area electroluminescent emitter has been demonstrated. Compared to the Al2O3 devices, the numbers for structures employing BaTa2O6 represent a 29% increase in flux density at 980 nm, a 36% increase at 1540 nm, an 18% increase in conduction charge, a 10% increase in phosphor field and a 14% increase in threshold voltage. Our interpretation of the data is as follows: in the case of BaTa2O6, the interface states from which electrons are sourced into the phosphor are deeper, requiring a higher voltage for field emission. As a consequence, electrons are injected into the phosphor when the phosphor field is higher, resulting in better excitation efficiency and improved optical generation. The increase in conduction charge is interpreted as a higher density of interface states, which appear to have a narrower energy distribution based on the more abrupt threshold behavior observed.

Comparison of light-emitting diode wavelength on activity and migration of rabbit ACL cells

Article

Apr 2013
LASER MED SCI

The purpose of this study was to evaluate the biological response and gene expression of New Zealand White Rabbit anterior cruciate ligament (ACL) fibroblasts for different wave lengths of light-emitting diode (LED) irradiation. In other words, this study was undertaken to evaluate the effects of different wavelengths of LED irradiation on cell growth, expression of extracellular matrix and growth factors, migration, and expression of actin and integrin. Proliferation assay showed that red (630 nm, 9.5 J/cm(2)) and green LED (530 nm, 9.8 J/cm(2)) irradiated cells were more increased than control group but there was no difference between the control group and the blue LED (460 nm, 27 J/cm(2)) irradiated group. Moreover, the expression of insulin-like growth factor, transforming growth factor-beta (TGF-β1), and collagen I were significantly increased in the red and green LED-irradiated group, but the expression of collagen was decreased in the blue LED-irradiated group. The results of staining showed that collagen and TGF-β1 were weaker in the control group and blue LED-irradiated cells, but stronger in the red and green LED-irradiated cells. Also, in the red and green LED-irradiated group, the expression of actin and integrin was not changed compared to the control group, but the expression of actin and integrin was decreased in the blue irradiated group. This study revealed that irradiation with a wavelength of 460 nm (blue LED) is cytotoxic to ACL cells, but irradiation with nontoxic fluencies of 530 (green LED) and 630 nm (red LED) wavelengths induced cell growth in cultured ACL cells.

Efficacy of Light-Emitting Diode Photomodulation in Reducing Erythema After Fractional Carbon Dioxide Laser Resurfacing: A Pilot Study

Article

Apr 2013
DERMATOL SURG

Background: The most common side effects of fractional carbon dioxide (CO2 ) laser resurfacing are erythema and edema of the treated skin. Light-emitting diode (LED) devices have been shown to stimulate fibroblast activity and hasten wound healing. The current study was designed to evaluate the efficacy of such LED devices in treating post-laser therapy erythema. Objectives: To evaluate the clinical efficacy of LED photomodulation in reducing erythema resulting from ablative fractional CO2 laser resurfacing. Materials and methods: Randomly selected facial halves of 10 Korean subjects (Fitzpatrick skin type III-IV) were treated using a 635-nm wavelength LED array immediately after full-face fractional laser skin resurfacing. Each participant was subsequently treated with LED daily for the following 7 days. Clinical photographs, subjective physician assessment, and chromometer erythema index were used to track the results, with clinical improvement assessed using a 5-point grading scale. Results: The postlaser erythema resolved faster on the experimental side than the control side, with improvements noted according to physician assessment and chromometer erythema index. Statistically significant improvements between the two sides were first noted on day 4. Conclusion: Treatment using a 635-nm-wavelength LED array decreases the intensity and duration of post-fractional CO2 laser treatment erythema.

The activation of directional stem cell motility by green light-emitting diode irradiation

Article

Dec 2012

Laser and LED phototherapies on angiogenesis

Article

Aug 2012
LASER MED SCI

Angiogenesis is a key process for wound healing. There are few reports of LED phototherapy on angiogenesis, mainly in vivo. The aim of the present investigation was to evaluate histologically the angiogenesis on dorsal cutaneous wounds treated with laser (660 and 790 nm) or LEDs (700, 530, and 460 nm) in a rodent model. Twenty-four young adult male Wistar rats weighting between 200 and 250 g were used on the present study. Under general anesthesia, one excisional wound was created on the dorsum of each animal that were then randomly distributed into six groups with four animals each: G0-control; G1-laser λ660 nm (60 mW, ϕ ∼2 mm, 10 J/cm(2)); G2-laser λ790 nm (50 mW, ϕ ∼2 mm, 10 J/cm(2)); G3-LED λ700 ± 20 nm (15 mW, ϕ ∼16 mm, 10 J/cm(2)); G4-LED λ530 ± 20 nm (8 mW, ϕ ∼16 mm, 10 J/cm(2)); G5-LED λ460 ± 20 nm (22 mW, ϕ ∼16 mm, 10 J/cm(2)). Irradiation started immediately after surgery and was repeated every other day for 7 days. Animal death occurred at the eighth day after surgery. The specimens were removed, routinely processed to wax, cut and stained with HE. Angiogenesis was scored by blood vessel counting in the wounded area. Quantitative results showed that green LED (λ530 ± 20 nm), red LED (λ700 ± 20 nm), λ790 nm laser and λ660 nm laser caused significant increased angiogenesis when compared to the control group. It is concluded that both laser and LED light are capable of stimulating angiogenesis in vivo on cutaneous wounds and that coherence was not decisive on the outcome of the treatment.

Modulation of Lipopolysaccharide-Induced NF-κB Signaling Pathway by 635 nm Irradiation via Heat Shock Protein 27 in Human Gingival Fibroblast Cells

Article

Aug 2012

Near infrared light protects cardiomyocytes from hypoxia and reoxygenation injury by a nitric oxide dependent mechanism

Article

Jan 2009
J MOL CELL CARDIOL

Photobiomodulation with near infrared light (NIR) provides cellular protection in various disease models. Previously, infrared light emitted by a low-energy laser has been shown to significantly improve recovery from ischemic injury of the canine heart. The goal of this investigation was to test the hypothesis that NIR (670 nm) from light emitting diodes produces cellular protection against hypoxia and reoxygenation-induced cardiomyocyte injury. Additionally, nitric oxide (NO) was investigated as a potential cellular mediator of NIR. Our results demonstrate that exposure to NIR at the time of reoxygenation protects neonatal rat cardiomyocytes and HL-1 cells from injury, as assessed by lactate dehydrogenase release and MTT assay. Similarly, indices of apoptosis, including caspase 3 activity, annexin binding and the release of cytochrome c from mitochondria into the cytosol, were decreased after NIR treatment. NIR increased NO in cardiomyocytes, and the protective effect of NIR was completely reversed by the NO scavengers carboxy-PTIO and oxyhemoglobin, but only partially blocked by the NO synthase (NOS) inhibitor L-NMMA. Mitochondrial metabolism, measured by ATP synthase activity, was increased by NIR, and NO-induced inhibition of oxygen consumption with substrates for complex I or complex IV was reversed by exposure to NIR. Taken together these data provide evidence for protection against hypoxia and reoxygenation injury in cardiomyocytes by NIR in a manner that is dependent upon NO derived from NOS and non-NOS sources.

Regeneration in denervated toad (Bufo viridis) gastrocnemius muscle and promotion of the process by low energy laser irradiation

Article

Jan 1995
Anat Rec

Background: It is known that while denervated skeletal muscles have the ability to regenerate, maturation of regenerated myofibres does not take place under these conditions. Denervation also causes elevation of "invasive" and satellite cells, but the role of these cells in the regeneration process after injury to the denervated muscle is still unknown. Low energy lasers have recently been found to modulate and accelerate physiological processes in cells. The aim of the present study was to compare regeneration in denervated and innervated amphibian muscles and to investigate whether this process in denervated muscles can be stimulated by low energy laser irradiation prior to injury in these muscles. Methods: Denervated gastrocnemius muscles of toads were irradiated with He-Ne laser (6.0 mW, 31.2 J/cm2) 7 days postdenervation (control muscle received red light irradiation at the same wavelength). Nine days after denervation cold injury was performed on the site of irradiation of both groups of muscles. At 14 days postinjury all muscles were removed and processed for histology and histomorphometric analysis of mononucleated cells, myotubes, and young myofibres in the regenerated zone. Results: The volume fraction (percent of total injured zone) of the various histological structures in the injured zones 14 days after cold injury in the denervated (9 days prior to injury) muscles did not differ from innervated injured muscles at the same time interval postinjury. The mononucleated cells and myotubes in the laser irradiated muscles comprised 49 +/- 4% and 6 +/- 1% of the injured area, respectively, which was significantly lower than their volume fraction (67 +/- 2% and 11 +/- 2%, respectively) in the control muscles. The young myofibres populated 34 +/- 4% of the total injured area in the denervated and laser irradiated muscles which was significantly higher than their volume fraction (12 +/- 2%) in control denervated muscles. Conclusions: It is concluded that initial stages of regeneration can also take place in skeletal denervated and injured muscles of amphibians. The kinetics of the regeneration process are identical in denervated and innervated muscles. The process of regeneration in denervated muscles can be markedly enhanced if the muscle is irradiated by low energy laser prior to injury, probably by activation (stimulation of proliferation and/or differentiation) cells in the muscles that are "recruited" and participate in the process of regeneration.

The anti‐inflammatory mechanism of 635 nm light‐emitting‐diode irradiation compared with existing COX inhibitors

Article

Aug 2007
LASER SURG MED

Background and Objectives Inhibition of cyclooxygenase (COX) and prostaglandin E2 (PGE2) protects cells against cell injury in specific pathophysiological situations: inflammation and oxidative stress. Although the anti-inflammatory effects have been reported in clinical fields for specific wavelength irradiation during wound healing, the physiological mechanism has not been clarified yet. The aim of the present study is to investigate the anti-inflammatory mechanism of 635 nm light-emitting-diode (LED) irradiation compared with existing COX inhibitors.Study Design/Materials and Methods The present study investigated anti-inflammatory effects of 635 nm irradiation on PGE2 release, COX and phospholipase A2 (PLA2) expression, and reactive oxygen species (ROS) dissociation in arachidonic acid (AA)-treated human gingival fibroblast (hGF). These results were compared with their existing COX inhibitors: indomethacin and ibuprofen. The PGE2 release was measured by enzyme immunoassay, the COX expression was measured by western blot and reverse transcriptase polymerase chain reaction (RT-PCR), and ROS level was measured by flow cytometry, laser scanning confocal microscope and RT-PCR.ResultsResults showed that 635 nm irradiation and existing COX inhibitors inhibit expression of COX and PGE2 release. Unlike indomethacin and ibuprofen, 635 nm irradiation leads to a decrease of ROS levels and mRNA expression of cytosolic phospholipase A2 (cPLA2) and secretary phospholipase A2 (sPLA2).Conclusion Taken together, 635 nm irradiation, unlike indomethacin and ibuprofen, can directly dissociate the ROS. This inhibits cPLA2, sPLA2, and COX expression, and results in the inhibition of PGE2 release. Thus, we suggest that 635 nm irradiation inhibits PGE2 synthesis like COX inhibitor and appears to be useful as an anti-inflammatory tool. Lesers Surg. Med. 39:614–621, 2007. © 2007 Wiley-Liss, Inc.

Article

May 2012

Effect of 710 nm visible light irradiation on neurite outgrowth in primary rat cortical neurons following ischemic insult

Article

May 2012
BIOCHEM BIOPH RES CO

We previously reported that 710 nm Light-emitting Diode (LED) has a protective effect through cellular immunity activation in the stroke animal model. However, whether LED directly protects neurons suffering from neurodegeneration was entirely unknown. Therefore, we sought to determine the effects of 710 nm visible light irradiation on neuronal protection and neuronal outgrowth in an in vitro stroke model. Primary cultured rat cortical neurons were exposed to oxygen-glucose deprivation (OGD) and reoxygenation and normal conditions. An LED array with a peak wavelength of 710 nm was placed beneath the covered culture dishes with the room light turned off and were irradiated accordingly. LED treatments (4 min at 4 J/cm(2) and 50 mW/cm(2)) were given once to four times within 8h at 2h intervals for 7 days. Mean neurite density, mean neurite diameter, and total fiber length were also measured after microtubule associated protein 2 (MAP2) immunostaining using the Axio Vision program. Synaptic marker expression and MAPK activation were confirmed by Western blotting. Images captured after MAP2 immunocytochemistry showed significant (p<0.05) enhancement of post-ischemic neurite outgrowth with LED treatment once and twice a day. MAPK activation was enhanced by LED treatment in both OGD-exposed and normal cells. The levels of synaptic markers such as PSD 95, GAP 43, and synaptophysin significantly increased with LED treatment in both OGD-exposed and normal cells (p<0.05). Our data suggest that LED treatment may promote synaptogenesis through MAPK activation and subsequently protect cell death in the in vitro stroke model.

Time-resolved spectroscopy of hemoglobin and myoglobin in resting and ischemic muscle

Article

Jan 1988
ANAL BIOCHEM

Difficulties of quantitation of hemoglobin/myoglobin absorption changes in muscle have led to the development of a new approach using short pulses of light. This method uses input light pulses sufficiently short so that the time course of travel of light through the brain can be precisely measured. The time of arrival of light at the detector gives the optical path length, given the velocity of light in tissues. The intensity profile of photon migration in tissues permits determination of the path length that the exiting photons have traveled and the concentration change of the pigments. A cavity-dumped liquid dye laser illuminates the tissue with 130-ps pulses detected as 600-ps duration at a half height at 3.0-cm distance from the input point. The decay of intensity from the 50% point onward to 0.1% follows a logarithmic function of slope μ which is attributed to the total absorption coefficient of the tissue. Increments of μ due to deoxyhemoglobin absorption at 760 and 630 nm are used to calculate the concentration change. This permits the calculation of the path length for continuous light measurements of 2 cm for a particular geometry. Variation of the wavelength of the laser affords determination of a spectrum of changes in the tissue.

Light-Induced Vasodilation of Coronary Arteries and Its Possible Clinical Implication

Article

Feb 2012

Christian Plass

Effect of NASA Light-Emitting Diode Irradiation on Wound Healing

Abstract

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