The effects of transcutaneous low-level laser therapy on the skin healing process: an experimental model (original) (raw)
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Photomedicine and Laser Surgery, 2007
Objective: This study evaluated the action of low-level laser therapy (LLLT) on the modulation of inflammatory reactions during wound healing in comparison with meloxicam. Background Data: LLLT has been recommended for the postoperative period because of its ability to speed healing of wounds. However, data in the literature are in disagreement about its anti-inflammatory action. Methods: Standardized circular wounds were made on the backs of 64 Wistar rats. The animals were divided into four groups according to the selected postoperative therapy: group A-control; group B-administration of meloxicam; and groups C and D-irradiation with red (؍ 685 nm) and infrared (؍ 830 nm) laser energy, respectively. The animals were killed at 12, 36, and 72 h and 7 days after the procedure. Results: Microscopic analysis revealed significant vascular activation of irradiated sites in the first 36 h. Only group B showed decreases in the intensity of polymorphonuclear infiltrates and edema. Group D showed a higher degree of organization and maturation of collagen fibers than the other groups at 72 h. The animals in group C showed the best healing pattern at 7 days. The anti-inflammatory action of meloxicam was confirmed by the results obtained in this research. The quantification of interleukin-1 (IL-1) mRNA by real-time polymerase chain reaction (PCR) did not show any reduction in the inflammatory process in the irradiated groups when compared to the other groups. Conclusions: LLLT improves the quality of histologic repair and is useful during wound healing. However, with the methods used in this study the laser energy did not minimize tissue inflammatory reactions.
Lasers in Medical Science, 2014
The wound-healing process plays an essential role in the protective response to epidermal injury by tissue regeneration. In the elderly, skin functions deteriorate as a consequence of morphological and structural changes. This study aimed to evaluate and compare the effect of low-level laser therapy (LLLT) in cutaneous wound healing in young and aged rats. A total of 60 male rats comprising 30 young (±30 days) and 30 aged (±500 days) was used. The animals were divided into four experimental groups and underwent skin wound and/or treatment with LLLT (660 nm, 30 mW, 1.07 W/cm 2 , 0.028 cm 2 , 72 J/cm 2 , and 2 J). Analyses were conducted to verify the effects of LLLT in the tissue repair process, in the gene expression, and protein expression of TNF-α, IL-1β, and IL-10, obtained in skin wound model. Results showed that there were significant differences between the young control group and the aged control group and their respective treated groups (LLLT young and LLLT aged). We conclude that LLLT has shown to be effective in the treatment of skin wounds in young and aged animals at different stages of the tissue repair process, which suggests that different LLLT dosimetry should be considered in treatment of subjects of different ages. Further clinical trials are needed to confirm these findings in clinical settings.
Journal of Photochemistry and Photobiology B-biology, 2007
Background: Low intensity laser therapy has been recommended to support the cutaneous repair; however, so far studies do not have evaluated the tissue response following a single laser treatment. This study investigated the effect of a single laser irradiation on the healing of full-thickness skin lesions in rats. Methods: Forty-eight male rats were randomly divided into three groups. One surgical lesion was created on the back of rats using a punch of 8 mm in diameter. One group was not submitted to any treatment after surgery and it was used as control. Two energy doses from an 830-nm near-infrared diode laser were used immediately post-wounding: 1.3 J cm À2 and 3 J cm À2 . The laser intensity 53 mW cm À2 was kept for both groups. Biometrical and histological analyses were accomplished at days 3, 7 and 14 post-wounding. Results: Irradiated lesions presented a more advanced healing process than control group. The dose of 1.3 J cm À2 leaded to better results. Lesions of the group irradiated with 1.3 J cm À2 presented faster lesion contraction showing quicker re-epithelization and reformed connective tissue with more organized collagen fibers. Conclusions: Low-intensity laser therapy may accelerate cutaneous wound healing in a rat model even if a single laser treatment is performed. This finding might broaden current treatment regimens.
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.
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.
Lasers in Medical Science, 2013
This study aims to investigate the effect of different energy densities provided by low-level laser therapy (LLLT) on the morphology of scar tissue and the oxidative response in the healing of secondary intention skin wounds in rats. Twenty-four male adult Wistar rats were used. Skin wounds were made on the backs of the animals, which were randomized into three groups of eight animals each as follows, 0.9% saline (control); laser GaAsAl 30 J/cm 2 (L30); laser GaAsAl 90 J/cm 2 (L90). The experiment lasted 21 days. Every 7 days, the wound contraction index (WCI) was calculated and tissue from different wounds was removed to assess the proportion of cells and blood vessels, collagen maturation index (CMI), thiobarbituric acid reactive substance (TBARS) levels and catalase activity (CAT). On the 7th and 14th days, the WCI and the proportion of cells were significantly higher in groups L30 and L90 compared to the control (p<0.05). At all the time points analyzed, there was a greater proportion of blood vessels and a higher CMI in group L90 compared to the other groups (p<0.05). On the 7th and 14th days, lower TBARS levels and increased CAT activity were found in the L90 group compared to the control (p<0.05). On the 7th day, a moderately negative correlation was found between TBARS levels and WCI, CMI and CAT in all the groups. LLLT may modulate the oxidative status of wounded tissue, constituting a possible mechanism through which the LLLT exerts its effects in the initial phases of tissue repair.
Microscopy research and technique, 2016
Burns are injuries caused by direct or indirect contact to chemical, physical, or biological agents. Low-level laser therapy (LLLT) is a promising treatment since it is low-cost, non-invasive, and induces cell proliferation. This study aimed to investigate the effects of LLLT (660 nm) at two different fluences (12.5 J/cm(2) and 25 J/cm(2) ) per point of application on third-degree burns in rats. Thirty rats (Wistar) divided into GC, GL12.5, and GL25 were used in the study, and submitted to burn injury through a soldering iron at 150°C, pressed on their back for 10 s. LLLT was applied immediately, and 2, 4, 6, and 8 days after wound induction. Histological analysis revealed a decreased inflammatory infiltrate in the group treated with 25 J/cm(2) , and intense inflammatory infiltrate in the control group and in the group treated with 12.5 J/cm(2) . The immunostaining of COX-2 was more intense in the control groups and in the group treated with 12.5 J/cm(2) than in the group treated wi...
The Effect of Low Level Laser Therapy on Surgical Wound Healing
2010
Surgical wounds are superficial or deep wounds on skin or mucous membranes due to a surgical intervention using a scalpel to cut through skin or mucosa and the underlying tissue. The wound treatment costs in terms of finance and time are relatively high; the complete wound healing lasts 3 weeks. To reduce this period of healing of surgical wound and avoid complications, therapeutic methods and drug are used in postoperative period. One of these methods is Low Level Laser Therapy. This method has been used for treatment of wounds for over two decades in many medical facilities of the world. However, despite such wide clinical usage, there is still controversy regarding the efficacy of Low Level Laser Therapy in the treatment of wounds. Many laser systems, different laser parameters and irradiation conditions, and a great variety of treatment protocols lead to these conclusions. The goal of this paper is to present our evaluation of Low Level Laser Therapy role in surgical aseptic wou...
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.