Efficacy of three different laser wavelengths for in vitro wound healing (original) (raw)
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Biophotonic Effects of Low-Level Laser Therapy at Different Wavelengths for Potential Wound Healing
Photonics
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 observ...
Estimation of the optimal wavelengths for laser-induced wound healing
Lasers in Surgery and Medicine, 2010
Background and objectives: According to earlier in vitro low level laser therapy (LLLT) studies, wavelengths in the red and near infrared range, that are absorbed by cytochrome oxidase, stimulate cell growth and hence wound healing. Wavelengths in the blue region that are absorbed by flavins were found to exert a bactericidal effect that is very important for treating infected wounds. However, as far as therapeutic application of light is concerned, penetration into the tissue must be considered. For this purpose we estimated the penetration depth as a function of the relevant wavelengths, using the formulae of the photon migration model for skin tissue. Methods: We use the photon diffusion model, which is an analytical model for describing light transfer in biological tissues. We refer to the most common chromophores in human tissue and evaluate their volume fraction and concentration in skin cells. These empirically estimated mean wavelength-dependent absorption coefficients are then substituted in the theoretical expressions for the optical penetration depth in the tissue. The wavelengths, for which the penetration depth is the highest, are the optimal wavelengths to be used in wound healing treatments. Results: Our model suggests that the optimal wavelengths for therapeutic treatments are in the red region with a local maximum at 730 nm. As to the blue region, a local maximum at 480 nm was found. Conclusion: Light at 480 nm should be used for treating infected wounds followed by 730 nm light for enhancing wound closure.
Photomedicine and Laser Surgery, 2004
Objective: The objective of the present investigation was to assess the histological effects of different wavelengths and intensities on the healing process of cutaneous wounds. Background Data: Tissue repair is a dynamic interactive process which involves mediators, cells and extra-cellular matrix. Several reports on the use of laser therapy have shown that the healing process is positively affected when the correct parameters are used. Methods: Eighteen standardized wounds were surgically created on the dorsum of male and female Wistar rats, which were subsequently divided into two experimental groups according to wavelength used .670 or 685 nm) for lasertherapy (LLLT). Each group was divided into three subgroups of three animals according to the intensity of the applied irradiation (2, 15, or 25 mW). Twelve animals were used as untreated controls and were not irradiated. The irradiation was carried out during seven consecutive days. The animals were sacrificed eight days after surgery. The specimens were removed, kept in 4% formaldehyde for 24 h, routinely prepared to wax, stained with H&E, and analyzed under light microscopy. Results: For both groups, light microscopy showed a substitution repair process; however, when LLLT was used, a positive biomodulatory effect was detectable, chiefly associated with shorter wavelength and low intensity. Conclusions: The results of the present study indicate that LLLT improved cutaneous wound repair and that the effect is a result of an inversely proportional relationship between wavelength and intensity, with treatment more effective when combining higher intensity with short wavelength or lower intensity with higher wavelength. 513 518
Laser Photons and Pharmacological Treatments in Wound Healing
The exploitation of photobiology in medicine has been of great interest to mankind. There is a growing interest in the use of lasers for treatment purposes because of the photochemical alterations induced in biomolecules by light energy. In this paper we present our data on laser biostimulation, the combination of pharmacological treatments Solcoseryl TM (SS) and Polygen TM (PG) with light therapy using in-vitro and in-vivo models. In-vitro experiments indicate the ability of laser photons and pharmacological agents SS or PG to augment or abate the cloning efficiency of various cell lines. In-vivo studies focused on the dosimetry of various laser wavelengths and the use of wound healing drugs and 632.8nm laser in wound healing. The application of pharmacological treatments combined with laser therapy reveals the utility of light-drug treatment combinations. Given the ever-increasing cost of medical care, the burden incurred on patients, caregivers and society, this line of research fulfills the increasing need to develop treatment methods that enhance wound healing, especially in situations involving resistance to healing.
Photomedicine and Laser Surgery, 2005
Objective: This study aimed to describe, through morphologic and cytochemical analysis, the healing process of wounds submitted (or not) to laser therapy (λ685 nm) or polarized light (λ400-2000 nm). Background Data: There are many reports on different effects of several types of phototherapies on the treatment of distinct conditions, amongst them, on wound healing. Laser therapy and the use of polarized light are still controversial despite successive reports on their positive effects on several biological processes. Methods: Thirty male Wistar rats, approximately 4 months old, were used, and standardized excisional wounds were created on their dorsum. The wounds were irradiated in four equidistant points with laser light or illuminated with polarized light, both with doses of 20 or 40 J/cm2. Group 1 acted as untreated controls. Animals were irradiated every 48 h during 7 days, starting immediately after surgery, and were humanely killed on the 8th post-operative day. Specimens were taken and routinely processed and stained with H&E, and for descriptive analysis of myofibroblasts and collagen fibers, the specimens were imunnomarked by smooth muscle α-actin and picrosirius stain. Results: Control specimens showed the presence of ulceration, hyperemia, discrete edema, intense, and diffuse inflammation, collagen deposition was irregular, and myofibroblasts were seen parallel to the wound margins. Wounds treated by laser therapy with a dose of 20 J/cm2 showed mild hyperemia, inflammation varied from moderate to intense, the number of fibroblasts was large, and the distribution of collagen fibers was more regular. Increasing the dose to 40 J/cm2 evidenced exuberant neovascularization, severe hyperemia, moderate to severe inflammation, large collagen deposition, and fewer myofibroblasts. On subjects illuminated with polarized light with a dose of 20 J/cm2, mild to moderate hyperemia was detectable, and collagen matrix was expressive and unevenly distributed; a larger number of myofibroblasts was present and no re-epithelialization was seen. Increasing the dose resulted in mild to moderate hyperemia, no reepithelialization was seen, edema was discrete, and inflammation was moderate. Conclusion: The use of 685-nm laser light or polarized light with a dose of 20 J/cm2 resulted in increased collagen deposition and better organization on healing wounds, and the number of myofibroblast was increased when polarized light is used.
Analysis of the Systemic Effect of Red and Infrared Laser Therapy on Wound Repair
… and Laser Surgery, 2009
Objective: To evaluate, using histological analysis, the systemic action and repair process of wounds produced on the back of rats and treated with red, infrared, or both lasers applied directly or indirectly to the wounds. Background Data: Skin tissue repair and wound healing are complex processes that involve a series of dynamic events. Many benefits are associated with biomodulation uisng laser therapy. Methods: Thirty-six male Wistar rats were divided into four groups: control (without laser), red laser (aluminium gallium indium phosphide (AlGaInP); λ = 685 nm; λ = 0.0314 cm 2 ; CW; P = 30 mW; D = 20 J, time of irradiation = 667 sec), infrared laser (gallium-aluminum-arsenide (GaAlAs): λ = 830 nm; λ = 0.0314 cm 2 ; CW; P = 50 mW; D = 20 J, time of irradiation = 401 sec), and both lasers (infrared laser: GaAlAs; λ = 830 nm; λ = 0.0314 cm 2 ; CW; P = 50 mW; D = 10 J, time of irradiation = 201 sec + red laser: AlGaInP; λ = 685 nm; λ = 0.0314 cm 2 ; CW; P = 30 mW; D = 10 J, time of irradiation = 334 sec; total dose = 20 J). Three subgroups were formed according to observation time points. Three wounds were produced on the back of each animal. Only the wound closest to the head was irradiated in the experimental groups. For the evaluation of skin reaction and wound healing, three animals of each group were killed at 3, 5, and 7 days postoperatively. The irradiation protocol established 48-hour intervals between applications, with the first application immediately after the surgical procedure. Results: In the red and infrared laser group, healing was more advanced in the wound located furthest from the point of laser application. The most effective healing of a proximal wound was verified in the control group on the 7th postoperative day. Conclusion: The combined application of red and infrared lasers resulted in the most evident systemic effect on the repair of skin wounds produced in rats.
Laser Therapy for Wound Healing: A Review of Current Techniques and Mechanisms of Action
Biosciences Biotechnology Research Asia
Along with conventional medications, different techniques have been used for wound healing such as ultrasound, electric field, magnetic field, pressure relieving beds, cushions, etc. These methods are usually utilized for prevention and healing of pressure wounds. One of these methods with great potential is LASER (Light Amplification by Stimulated Emission of Radiation) therapy. Different parameters can affect the efficiency of laser therapy. Several studies have attempted to develop this technique in different medical applications. This paper aims to provide a review of the LASER techniques for wound healing, sketch their background, determine the biological effects that support the use of LASER sources in the treatment of wounds and as well as the optimal light parameters such as wavelength and dose for wound healing Keywords : Laser, Wound Healing, Mechanism of Action
Laboratory methods for evaluating the effect of low level laser therapy (LLLT) in wound healing
African Journal of Biomedical Research, 2006
The basic tenet of laser therapy is that laser radiation has a wavelength dependent capability to alter cellular behaviour in the absence of significant heating. Low intensity radiation can inhibit as well as stimulate cellular activity. Laser therapy typically involves the delivery of 1-4J/cm 2 to treatments sites with lasers having output powers between 10mW and 90mW. There are two major areas of laser therapy research: the laboratory and the clinic. The laboratory presents the least ambiguous results. Here, although unsupported results do appear, the vast majority of published work finds clear evidence that laser irradiation alters cellular processes in a nonthermal, wavelength-dependent manner. Low energy laser irradiation alters t he cellular function by effecting protein synthesis, cell growth and differentiation, cell motility, membrane potential and binding affinities, neurotransmitter release, ATP synthesis and prostaglandin synthesis. Laboratory findings provide scientific rati onale of laser therapy and the effect of laser therapy on cellular processes. This review outlines some of the current methods employed in the laboratory to measure the effect of low level laser therapy (LLLT) on cellular and molecular processes in the cell. This review briefly explains the different structural, cellular and molecular parameters and highlights some of the basic principles and protocols including specialized equipment requirements.
Photomedicine and Laser Surgery, 2007
Objective: This study aimed to establish if broad-spectrum or infrared (IR) light in combination with laser therapy can assist phototherapy and accelerate cell proliferation to improve the rate of wound healing. Background Data: The effect of laser light may be partly or completely reduced by broad-spectrum light. There are few studies that investigate the benefit or detriment of combining laser irradiation with broad-spectrum or IR light. Methods: Wounded human skin fibroblasts were irradiated with a dose of 5 J/cm 2 using a heliumneon laser, a diode laser, or a Nd:YAG laser in the dark, in the light, or in IR. Changes in cell proliferation were evaluated using optical density at 540 nm, alkaline phosphatase (ALP) enzyme activity, cytokine expression, and basic fibroblast growth factor (bFGF) expression. Results: The optical density and ALP enzyme activity indicate that 5 J/cm 2 using 1064 nm in the light is more effective in increasing cell proliferation or cell growth than 830 nm in the light, but not as effective as 632.8 nm in the light. bFGF expression shows that the response of wounded cells exposed to 5 J/cm 2 in IR light is far less than the biological response of wounded cells exposed to 5 J/cm 2 in the dark or light. The results indicate that wounded cells exposed to 5 J/cm 2 using 632.8 nm in the dark results in a greater increase in IL-6 when compared to cells exposed to 5 J/cm 2 in the light or in IR. Conclusion: Results indicate that 5 J/cm 2 (using 632.8 nm in the dark or 830 nm in the light) is the most effective dose to stimulate cell proliferation, which may ultimately accelerate or improve the rate of wound healing.