Article

Equine wound healing: influence of low level laser therapy on an equine metacarpal wound healing model

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Abstract

To evaluate the effects of low level laser therapy (LLLT) on healing of full thickness symmetrical skin wounds in horses. LLLT is a therapeutic modality using the application of light, usually a low power laser or light emitting diode in the power range of 1 mW to 12 W that, in practical terms, promotes tissue regeneration as well as reducing inflammation and pain. Experimental study. Healthy horses (n=8). Full thickness, 2.5 cm square skin wounds were created in the mid-metacarpal region on one leg of eight normal horses. LLLT was used on limbs assigned to the experimental group and limbs assigned to the control group were allowed to heal without treatment. LLLT was administered using a line generated optical scanner with a dual diode laser system (model EML; Erchonia Laser Healthcare, McKinney, TX, USA) at a wavelength of 635 nm and an energy output of 17 mW per diode. Wound size was measured for an 80-day period post operatively. Eighty days after surgery incisional biopsies were examined histologically. Wounds treated with LLLT healed faster than the control wounds ( LLLT increased the rate of wound healing.

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... Only two studies using LLLT for the healing of an open wound were identified in equines (see Table 5). In a study conducted by Jann et al., 8 horses received a single 2.5cm square wound on the mid-metacarpal region of one leg [35]. The horses were randomly split into control and laser-treated groups. ...
... The horses were randomly split into control and laser-treated groups. A dual diode laser system with a wavelength of 635 nm and an energy density of 5.1 J/cm 2 was used every other day for five minutes for a total of 80 days [35]. The rate of wound healing and a histological evaluation which consisted of the formation of granulation tissue, ulceration, inflammation, and presence of inflammatory cells were examined. ...
... The rate of wound healing and a histological evaluation which consisted of the formation of granulation tissue, ulceration, inflammation, and presence of inflammatory cells were examined. The rate of wound healing was increased for the laser-treated group in comparison to the control group [35]. A study conducted by Petersen, Botes, Olivier, and Guthrie involved 6 crossbred horses each having a 3 × 3 cm open square wound inflicted on the dorsal metacarpophalangeal joints of both legs, with one leg serving as the control and the other as the laser-treated [36]. ...
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The possibilities that photobiomodulation has brought on to the medical field are ever expanding and the scope it has reached is infinite. Determining how this relatively new treatment technique can be incorporated into the veterinary medical field is of interest to many medical professionals. In this review, we examine the treatment outcomes of low-level-laser therapy (LLLT) in different animal models to pinpoint any similarities between the studies. A search was conducted to identify LLLT studies using different animal models with an open or closed wound. The studies were compared to identify the laser parameters that resulted in positive treatment outcomes. The overall result of the studies examined indicated that daily laser exposure at a wavelength of a 600 or 800 nm range was the most beneficial across the rodent studies regardless of health status or wound type. More studies on rabbit, canine, and equine models are needed to explain the inconsistent results reviewed and find the correct treatment parameters for these species. Further research involving LLLT studies that focus on different factors including health status, treatment interval, wavelength, and energy density is needed to help validate our knowledge about the efficacy of using photobiomodulation in the veterinary medical field.
... Moreover, chronic wounds require intensive standard wound care; however, this is sometimes insufficient to promote healing. At present, photobiomodulation therapy (PBMT) can be used as adjunctive therapy for improving wound healing in veterinary medicine [3,4], dentistry [5], and medicine [6,7]. PBMT involves the use of therapeutic light, including laser, light-emitting diode, and broadband light, in the visible and infrared spectrum [8]. ...
... The use of a 635 nm wavelength with a fluence of 5.1 J/cm 2 gave significantly faster equine wound healing from the epithelialization Available at www.veterinaryworld.org/Vol.14/August-2021/35.pdf result [4]. Recently, applying a simultaneous combination of 850 and 670 nm wavelengths with a fluence of 8 J/cm 2 significantly improved the clinical scar scale in patients with thoracolumbar hemilaminectomy [16]. ...
Article
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Background and aim: Chronic wounds are a clinical problem and require intensive standard wound care. However, this is sometimes insufficient to promote healing. Photobiomodulation therapy (PBMT) can be used as an adjunctive therapy to improve wound healing. Various PBMT devices with different properties and parameter settings as well as different animal species can influence a variety of clinical outcomes. This study aims to assess the use of 830 nm PBMT or simultaneous superpulsed and multiple wavelengths (SPMW; 660, 875, and 905 nm) PBMT on chronic wounds in client-owned dogs. Materials and methods: This study included 21 client-owned dogs with chronic wounds allocated into three groups: (1) Control group (C) treated with irrigated saline and without PBMT (n=7); (2) L1 group treated with irrigated saline together with the radiation of 830 nm PBMT (n=7); and (3) L2 group treated with irrigated saline together with the radiation of simultaneous SPMW-PBMT (n=7). Wound healing was assessed on the basis of wound size reduction as a percentage of wound area every 2nd day for 15 days using image analysis software (ImageJ software®, National Institutes of Health, Rockville, Maryland, USA). Results: A significant difference in the percentage of wound area reduction was noted between the C and PBMT groups (L1 and L2; p<0.05). The average percentages of wound area reduction at the end of the study (15 days) were 42.39±20.58, 56.98±24.82, and 61.81±27.18 in the C, L1, and L2 groups, respectively. A steady decrease in wound size was noted in both PBMT and non-PBMT groups, and coefficients were 7.77, 8.95, and 10.01 in the C, L1, and L2 groups, respectively. The percentage of wound area reduction was found to be significantly different between the PBMT and non-BPMT groups on day 7 (p<0.05). Conclusion: Based on the results of the current study, using either 830 nm PBMT or simultaneous SPMW-PBMT can accelerate the chronic wound healing process in dogs with a significant reduction in wound area. Therefore, it can be used as an adjunctive therapy to improve wound healing in dogs with reduced treatment duration.
... Despite overall inconsistent methodologies in numerous in vitro and in vivo studies evaluating laser therapy, findings indicate that LLLT can improve healing time in mammals [28][29][30]. Specifically, LLLT accelerated wound healing in rats, mice, pigs, horses, dogs, and humans [29,[31][32][33][34][35]. Given the complexities of wound care in captive amphibians, LLLT may represent a valuable noninvasive wound management tool. ...
... LLLT has recently gained popularity in veterinary medicine as an adjunct treatment for a variety of conditions including postoperative pain, soft tissue injury, and dermal wounds. While multiple controlled investigations have found that LLLT can improve healing time in mammals [28][29][30][31][32][33][34], a recent study in domestic dogs found no apparent improvement in acute healing of wounds treated with this modality [36]. Furthermore, very few studies have evaluated the utility of LLLT in nonmammalian species. ...
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Current recommendations for wound management in amphibians are based primarily on clinical experience and on extrapolation from other taxa, whereas controlled clinical studies are lacking. Low-level laser therapy, also termed photobiomodulation, has gained popularity in veterinary medicine and may represent a valuable adjunct therapy for wound care in amphibians, though dosing and safety evaluations have not been previously reported. Silver sulfadiazine (SSD), a topical antimicrobial, is commonly utilized in amphibian medicine but little is known about its effects on wound healing in this class of animals. This pilot study evaluated the effects of repeated treatments of low-level laser therapy or topical SSD on second-intention healing characteristics of surgically induced full-thickness dermal wounds in 33 adult wild-caught marine toads. Toads were anesthetized, and a 6 mm cutaneous biopsy was performed over the right dorsum. They were then randomly assigned to one of three groups: laser therapy (LT) at 5 Hz (905 nm wavelength on a super pulsed sequence), topical SSD (SD), or control sham treatment (CT). Treatments were administered at 24 hrs after biopsy and then every 72 hrs thereafter, concurrent with a visual assessment of the wound. Toads were euthanized at one of five timepoints (day 4, 7, 13, 19, or 28) to permit scoring of histologic criteria, including lymphocytic inflammation, granulomatous inflammation, heterophilic inflammation, granulation tissue, fibrosis, and reepithelialization. Visual assessments and histologic scoring did not identify a benefit of laser therapy or SSD as compared to controls. Laser therapy and SSD, at the doses and dosing schedule utilized in this pilot study, appear to be safe and well-tolerated treatments in marine toads, but may not be warranted for uncomplicated skin wounds in this species.
... Our results are in accordance with most other studies on low-level light treatment of wounds in horses [16][17][18]. However, one non-blinded study on laser treatment in an equine metacarpal wound healing model recorded a positive effect in the late stages of healing [19]. The time for secondary healing of similar sized untreated wounds differs between studies, ranging between 25 ± 3.5 days for wounds on ponies [20] to 44.0± 5.4 days for wounds on the body of horses [21] and 80 days for wounds on horse limbs [19], indicating that the healing time described in the current study was similar to that previously reported. ...
... However, one non-blinded study on laser treatment in an equine metacarpal wound healing model recorded a positive effect in the late stages of healing [19]. The time for secondary healing of similar sized untreated wounds differs between studies, ranging between 25 ± 3.5 days for wounds on ponies [20] to 44.0± 5.4 days for wounds on the body of horses [21] and 80 days for wounds on horse limbs [19], indicating that the healing time described in the current study was similar to that previously reported. ...
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Background: Light-emitting diodes (LEDs) are commonly used for treating a variety of disorders in horses, including wounds. Despite its claim to shorten healing times, there is a lack of scientific documentation regarding its effects. Objectives: To investigate if treatment with pulsating visible red light (λ≈637 nm) and near-infrared (NIR) light (λ≈956 nm) affects wound healing. Study design: Randomised blinded controlled experimental study. Methods: A circular skin wound (Ø=2 cm) was created on each side of the neck in eight healthy horses. One randomly chosen wound received light treatment and the other served as an untreated control. Treatment duration was 4 minutes and 40 seconds (red light 95 seconds, 2.3 mW/cm2; NIR light 185 seconds, 6.4 mW/cm2) and was performed once daily on day 0-4, 7-11, 14-18 and 21-25. The wounds were photographed and evaluated using digital photoplanimetry on day 0, 1, 2, 3, 4, 7, 14, 21, 28 and 35. The degree of swelling was assessed with diagnostic ultrasound on the same days except the last recording was performed on day 36 instead of 35. Days to total healing was recorded. ANOVA was used for statistical analysis (p<0.05). Results: The wound area (p=0.2-0.9) and degree of swelling (p=0.2-1.0) did not differ between treated and control groups on any day. There was a significant difference (p=0.03) in healing time between control (49.0, 95%CI=35.4-62.6 days) and treated wounds (51.8, 95%CI=38.7-64.8 days). Main limitations: The wounds were treated until day 25 and this study does not investigate the effect of a longer treatment period than 25 days. Conclusions: The results of this study do not indicate any clinically relevant positive effect of pulsating visible red light and NIR light on the healing of experimental skin wounds in horses, compared to no treatment.
... Low-level laser therapy is used for treatment of wounds and soft tissue injuries, osteoarthritis, and in attempts to reduce pain (Andris, 2016). Jann et al (2012) observed that superficial metacarpal wounds healed significantly faster with the administration of low level laser therapy compared to control wounds, concluding that low level laser therapy has a positive effect on wound healing (Jann et al., 2012). Along with wound healing properties, the combination of both laser therapy and chiropractic techniques has also been observed to reduce equine musculoskeletal pain more substantially than from the sole practice of one of these techniques (Andris, 2016). ...
... Low-level laser therapy is used for treatment of wounds and soft tissue injuries, osteoarthritis, and in attempts to reduce pain (Andris, 2016). Jann et al (2012) observed that superficial metacarpal wounds healed significantly faster with the administration of low level laser therapy compared to control wounds, concluding that low level laser therapy has a positive effect on wound healing (Jann et al., 2012). Along with wound healing properties, the combination of both laser therapy and chiropractic techniques has also been observed to reduce equine musculoskeletal pain more substantially than from the sole practice of one of these techniques (Andris, 2016). ...
... Despite the numerous accounts of the potential positive effects of laser therapy in various applications for both human and veterinary medicine, exact protocols for various conditions, and tissue healing do not exist. Recent studies in veterinary medicine show the potential benefit of wound healing using PBM induced by laser therapy, including accelerated wound healing in equine distal limb wounds using a wavelength of 635 nm and an energy output of 17 mW per diode for a power density of 5.1 J/cm2 (11). Another recent canine study has shown that surgery in combination with PBM decreases the time to ambulation in dogs with T3-L3 myelopathy secondary to intervertebral disk herniation using a wavelength of 810 nm and an energy output of 200 mW for a power density of 2-8 J/cm2 (4). ...
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Laser therapy is becoming common place in veterinary medicine with little evidence proving efficacy or dosages. This study evaluated surgical wound healing in canines. Twelve Dachshunds underwent thoraco-lumbar hemilaminectomies for intervertebral disc disease (IVDD). Digital photographs were taken of their incisions within 24 h of surgery and 1, 3, 5, 7, and 21 days postoperatively. The first three dogs were used to create a standardized scar scale to score the other dogs' incision healing. The remaining 9 dogs were randomly assigned to either receive 8 J/cm2 laser therapy once a day for 7 days or the non-laser treated control group. Incision healing was scored based on the scar scale from 0 to 5, with zero being a fresh incision and five being completely healed with scar contraction and hair growth. All scar scores significantly improved with increasing time from surgery (<0.001). Good agreement was achieved for inter-rater reliability (p = 0.9). Laser therapy increased the scar scale score, showed improved cosmetic healing, by day seven and continued to be significantly increased on day 21 compared to control dogs (p < 0.001). Daily application of laser therapy at 8J/cm2 hastened wound healing in Dachshunds that received thoracolumbar hemilaminectomies for IVDD. It also improved the cosmetic appearance.
... In their study conducted in New Zealand, Meredith et al. (2001) found that physiotherapy was the second most common method of health promotion in sport horses, and used most often (in 36% of cases) in the jumping horses. The beneficial effect of LLLT on wound healing in horses was confirmed by Jann et al. (2012), who exposed a surgical skin wound of the dorsal surface of the metacarpal region to radiation. Laser radiation of a wavelength of 635 nm was applied at 5.1 J/cm 2 in eight mares. ...
Article
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Laser biostimulation involves applying a laser beam to the tissue to facilitate healing and regenerative processes. Laser therapy is one of the most important physical methods used in human physiotherapy. In veterinary medicine, laser therapy is a new and so far poorly examined method. The results of studies conducted so far are very promising, yet the positive effect of laser light, especially that of class IV, has yet to be confirmed. This article presents an overview of the available literature on the effect of laser treatment on the human and animal organism. Low level laser therapy (LLLT), high intensity laser therapy (HILT), physical therapy
... Despite this, LLLT is emerging as an adjunctive wound therapy in clinical veterinary medicine, although few comparative studies have been reported, and none in dogs. 29,30,[34][35][36] The goal of this study was to document any effect of repeated treatments of LLLT on the healing of acute, full thickness wounds in healthy dogs. The specific objectives were to (1) compare the effect of directly applied LLLT on the healing of open wounds in dogs with non-LLLT treated wounds at distant sites in the same dog and (2) evaluate any systemic effect of LLLT on the healing of open wounds in dogs by comparing the wounds in our experimental model to wounds on dogs (historical controls) that did not receive any laser therapy. ...
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Objective To evaluate the effects of low-level laser therapy (LLLT) on acute, full-thickness wound healing in dogs.Study DesignRandomized block (dog); historical control.AnimalsAdult male Beagles (n = 10).Methods Two 2 × 2 cm2 wounds were surgically created bilaterally on the trunk of each dog. Each side was randomized to receive LLLT (laser, LAS) or standard-of-care management (control, CON), 3 times weekly for 32 days. The LLLT consisted of a dual diode laser (7.5 mW/diode) at 635 nm and total energy density of 1.125 J/cm2. Wound planimetry was performed on the caudal wounds, from which percent contraction and percent epithelialization were calculated. Histologic features were evaluated at 7 time points from cranial wound biopsies. Experimental data were also compared to wounds from a historical female control cohort (historical control, HCON).ResultsThere was no difference between LAS and CON wounds for all parameters, including histology. The HCON wounds had significantly greater contraction and epithelialization compared to LAS and CON wounds. The LAS and CON wounds had significantly less inflammation than HCON wounds early in wound healing, but inflammation was significantly greater in LAS and CON wounds by day 21. Fibroblast infiltration and collagen deposition were significantly less in LAS and CON wounds than HCON wounds.Conclusion There are no apparent beneficial effects of LLLT on the healing of acute wounds in healthy dogs using this LLLT protocol. Gender may influence wound healing in intact dogs.
... 27 In order to administer the energy as evenly as possible with the Mphi vet laser device, considering the size and the shape of the treatment area, the scan modality was chosen. This modality has been already described by other studies, [28][29][30][31][32][33][34] and it is performed by moving the handpiece slowly and evenly over the treatment area following a grid pattern for an established treatment time. The reflection of the laser emission is reduced as a result of the special conformation of the handpiece head, which can be placed directly in contact with the skin. ...
Article
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Objective: The aim of this preliminary study was to investigate the effect of Multiwave Locked System (MLS(®)), a particular model of low-level laser, in the acute phase of collagenase-induced tendon lesions in six adult sheep randomly assigned to two groups. Background data: Tendon injuries are common among human athletes and in sport horses, require a long recovery time, and have a high risk of relapse. Many traditional treatments are not able to repair the injured tendon tissue correctly. In recent years, the use of low-level laser therapy (LLLT) produced interesting results in inflammatory modulation in different musculoskeletal disorders. Methods: Group 1 received 10 treatments of MLS laser therapy at a fluence of 5 J/cm(2) on the left hindlimb. Group 2 received 10 treatments of MLS laser therapy at a fluence of 2.5 J/cm(2) on the left hindlimb. In every subject in both groups, the right hindlimb was considered as the control leg. Results: Clinical follow-up and ultrasonography examinations were performed during the postoperative period, and histological examinations were performed at day 30 after the first application of laser therapy. In particular, results from histological examinations indicate that both treatments induced a statistically significant cell number decrease, although only in the second group did the values return to normal. Moreover, the MLS laser therapy dose of 2.5 J/cm(2) (group 2) caused a significant decrease of vessel area. Conclusions: In this study, clinical and histological evaluation demonstrated that a therapeutic dose <5 J/cm(2) furnished an anti-inflammatory effect, and induced a decrease of fibroblasts and vessel area. Overall, our results suggest that MLS laser therapy was effective in improving collagen fiber organization in the deep digital flexor tendon.
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Purpose of Review The goal of this review is to provide a broad overview of light-based treatments that have shown effectiveness in enhancing various aspects of wound healing, examine the drawbacks that have impeded the translation of some light-based therapies into clinical use, and highlight scenarios where these treatments may confer benefits over current standards in wound care. Recent Findings Several categories of light-based treatments, in particular laser debridement, fractional photothermolysis, and photodynamic therapy, have seen exciting recent clinical results that may justify expanding the use of these modalities in clinical wound care. Antimicrobial blue light is the subject of several ongoing clinical wound trials, the results of which could demonstrate the viability of this technology as a clinical treatment. Photobiomodulation, while conceptually promising, requires more rigorous development and validation before it can become a reliable wound therapy. Summary The technologies underlying light-based therapies are advancing rapidly, and in many cases, their utility in the wound care setting is still being actively explored. We anticipate that as these technologies mature and become optimized for wound applications, their utility in clinical wound care will continue to grow.
Article
Low-level laser therapy has been used clinically to treat musculoskeletal pain; however, there is limited evidence available to support its use in treating back pain in horses. The objective of this study was to evaluate the clinical effectiveness of low-level laser therapy and chiropractic care in treating thoracolumbar pain in competitive western performance horses. The subjects included 61 Quarter Horses actively involved in national western performance competitions judged to have back pain. A randomized, clinical trial was conducted by assigning affected horses to either laser therapy, chiropractic, or combined laser and chiropractic treatment groups. Outcome parameters included a visual analog scale (VAS) of perceived back pain and dysfunction and detailed spinal examinations evaluating pain, muscle tone, and stiffness. Mechanical nociceptive thresholds were measured along the dorsal trunk and values were compared before and after treatment. Repeated measures with post-hoc analysis were used to assess treatment group differences. Low-level laser therapy, as applied in this study, produced significant reductions in back pain, epaxial muscle hypertonicity, and trunk stiffness. Combined laser therapy and chiropractic care produced similar reductions, with additional significant decreases in the severity of epaxial muscle hypertonicity and trunk stiffness. Chiropractic treatment by itself did not produce any significant changes in back pain, muscle hypertonicity, or trunk stiffness; however, there were improvements in trunk and pelvic flexion reflexes. The combination of laser therapy and chiropractic care seemed to provide additive effects in treating back pain and trunk stiffness that were not present with chiropractic treatment alone. The results of this study support the concept that a multimodal approach of laser therapy and chiropractic care is beneficial in treating back pain in horses involved in active competition.
Book
In this book, the authors have provided the latest and most in-depth information on one of clinical medicine's most useful tools: Low-Level Laser Therapy (LLLT). Written by over a dozen experts from five continents, from Jerusalem to Johannesburg and San Diego to Sao Paolo, the breadth of knowledge provided herein expands not only the globe, but many medical fields. LLLT is an inexpensive, easily employed therapeutic strategy that has validated clinical utility in dermatology, oncology, dentistry, veterinary field, wound healing and many other medical arenas. This book provides the most up-to-date information on recent clinical trials as well as catalogs the optimal therapeutic settings for a myriad of disease states. In the past, biochemical mechanisms associated with LLLT therapy have not been well-described; however, this book provides comprehensive and simple biochemical processes pieced together from theories provided by the most recent and reputable publications. The mechanisms involved in the numerous diseases covered by each chapter are also included herein. Low-Level Laser Therapy: History, Mechanisms, and Clinical Uses captures the incredible dynamic usefulness of this simple technology while also listing the therapeutic settings that have been deemed the most effective for dozens of medical ailments. Whether you are a student of medicine or a clinical practitioner, this book will serve as a helpful guide on how LLLT could play a role in the care you or your team provides on a daily basis.
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We used statistical meta-analysis to determine the overall treatment effects of laser phototherapy on tissue repair and pain relief. Low-power laser devices were first used as a form of therapy more than 30 years ago. However, their efficacy in reducing pain or promoting tissue repair remains questionable. Following a literature search, studies meeting our inclusion criteria were identified and coded. Then, the effect size of laser treatment, that is, Cohen's d, was calculated from each study using standard meta-analysis procedures. Thirty-four peer-reviewed papers on tissue repair met our inclusion criteria and were used to calculate 46 treatment effect sizes. Nine peer-reviewed papers on pain control met the inclusion criteria and were used to calculate nine effect sizes. Meta-analysis revealed a positive effect of laser phototherapy on tissue repair (d = +1.81; n = 46) and pain control (d = +1.11; n = 9). The positive effect of treatment on specific indices of tissue repair was evident in the treatment effect sizes determined as follows: collagen formation (d = +2.78), rate of healing (d = +1.57), tensile strength (d = +2.13), time needed for wound closure (d = +0.76), tensile stress (d = +2.65), number and rate of degranulation of mast cells (d = +1.87), and flap survival (d = +1.95). Further, analysis revealed the positive effects of various wavelengths of laser light on tissue repair, with 632.8 nm having the highest treatment effect (d = +2.44) and 780 nm the least (d = 0.60). The overall treatment effect for pain control was positive as well (d = +1.11). The fail-safe number-that is, the number of studies in which laser phototherapy has negative or no effect-needed to nullify the overall outcome of this analysis was 370 for tissue repair and 41 for pain control. These findings mandate the conclusion that laser phototherapy is a highly effective therapeutic armamentarium for tissue repair and pain relief.
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Far red and near infrared (NIR) light promotes wound healing, but the mechanism is poorly understood. Our previous studies using 670 nm light-emitting diode (LED) arrays suggest that cytochrome c oxidase, a photoacceptor in the NIR range, plays an important role in therapeutic photobiomodulation. If this is true, then an irreversible inhibitor of cytochrome c oxidase, potassium cyanide (KCN), should compete with LED and reduce its beneficial effects. This hypothesis was tested on primary cultured neurons. LED treatment partially restored enzyme activity blocked by 10–100 μm KCN. It significantly reduced neuronal cell death induced by 300 μm KCN from 83.6 to 43.5%. However, at 1–100 mm KCN, the protective effects of LED decreased, and neuronal deaths increased. LED significantly restored neuronal ATP content only at 10 μm KCN but not at higher concentrations of KCN tested. Pretreatment with LED enhanced efficacy of LED during exposure to 10 or 100 μm KCN but did not restore enzyme activity to control levels. In contrast, LED was able to completely reverse the detrimental effect of tetrodotoxin, which only indirectly down-regulated enzyme levels. Among the wavelengths tested (670, 728, 770, 830, and 880 nm), the most effective ones (830 nm, 670 nm) paralleled the NIR absorption spectrum of oxidized cytochrome c oxidase, whereas the least effective wavelength, 728 nm, did not. The results are consistent with our hypothesis that the mechanism of photobiomodulation involves the up-regulation of cytochrome c oxidase, leading to increased energy metabolism in neurons functionally inactivated by toxins.
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The aim of this study was to determine the effect of low-energy He-Ne laser treatment on wound healing dynamics (histological and biochemical) in diabetic rats. Low-energy laser photostimulation at certain wavelengths can enhance tissue repair by releasing growth factors from fibroblasts and can facilitate the healing process of diabetic wounds. A circular 4 cm2 excisional wound was created on the dorsum of the experimentally (Alloxan)-induced diabetic rats. In the study group (N = 24) the wound was treated with He-Ne laser (632.8 nm wavelength) at a dose of 4.8 J/cm2 for 5 days a week until the wound healed completely. The control group (N = 24) was sham-irradiated. The results were statistically analyzed by an independent t test for biochemical analysis and the nonparametric Mann-Whitney U test for histopathological parameters. The analysis of the biochemical parameters and histopathological parameters of the wounds showed that the laser-treated group healed faster and better as compared to the control group (p < 0.0001). The laser-treated group healed on average by the 18th day whereas, the control group healed on average by the 59th day. Laser photostimulation promotes the tissue repair process of diabetic wounds.
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Photobiomodulation by light in the red to near infrared range (630-1000 nm) using low energy lasers or light-emitting diode (LED) arrays has been shown to accelerate wound healing, improve recovery from ischemic injury in the heart and attenuate degeneration in the injured optic nerve. Recent evidence indicates that the therapeutic effects of red to near infrared light result, in part, from intracellular signaling mechanisms triggered by the interaction of NIR light with the mitochondrial photoacceptor molecule cytochrome c oxidase. We have demonstrated that NIR-LED photo-irradiation increases the production of cytochrome oxidase in cultured primary neurons and reverses the reduction of cytochrome oxidase activity produced by metabolic inhibitors. We have also shown that NIR-LED treatment prevents the development of oral mucositis in pediatric bone marrow transplant patients. Photobiomodulation improves wound healing in genetically diabetic mice by upregulating genes important in the promotion of wound healing. More recent studies have provided evidence for the therapeutic benefit of NIR-LED treatment in the survival and functional recovery of the retina and optic nerve in vivo after acute injury by the mitochondrial toxin, formic acid generated in the course of methanol intoxication. Gene discovery studies conducted using microarray technology documented a significant upregulation of gene expression in pathways involved in mitochondrial energy production and antioxidant cellular protection. These findings provide a link between the actions of red to near infrared light on mitochondrial oxidative metabolism in vitro and cell injury in vivo. Based on these findings and the strong evidence that mitochondrial dysfunction is involved in the pathogenesis of numerous diseases processes, we propose that NIR-LED photobiomodulation represents an innovative and non-invasive therapeutic approach for the treatment of tissue injury and disease processes in which mitochondrial dysfunction is postulated to play a role including diabetic retinopathy, age-related macular degeneration, Leber's hereditary optic neuropathy and Parkinson's disease.
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In this review, seven studies using photoradiation to treat carpal tunnel syndrome (CTS) are discussed: two controlled studies that observed real laser to have a better effect than sham laser, to treat CTS; three openprotocol studies that observed real laser to have a beneficial effect to treat CTS; and two studies that did not observe real laser to have a better effect than a control condition, to treat CTS. In the five studies that observed beneficial effect from real laser, higher laser dosages (9 Joules, 12-30 Joules, 32 J/cm(2), 225 J/cm(2)) were used at the primary treatment sites (median nerve at the wrist, or cervical neck area), than dosages in the two studies where real laser was not observed to have a better effect than a control condition (1.8 Joules or 6 J/cm(2)). The average success rate across the first five studies was 84% (SD, 8.9; total hands = 171). The average pain duration prior to successful photoradiation was 2 years. Photoradiation is a promising new, conservative treatment for mild/moderate CTS cases (motor latency < 7 msec; needle EMG, normal). It is cost-effective compared to current treatments.
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The first publications about low-power laser therapy (then called laser biostimulation) appeared more than 30 years ago. Since then, approximately 2000 studies have been published on this still controversial topic. In the 1960s and 1970s, doctors in Eastern Europe, and especially in the Soviet Union and Hungary, actively developed laser biostimulation. However, scientists around the world harbored an open skepticism about the credibility of studies stating that low-intensity visible-laser radiation acts directly on an organism at the molecular level. The coherence of laser radiation for achieving stimulative effects on biological objects was more than suspect. Supporters in Western countries, such as Italy, France, and Spain, as well as in Japan and China also adopted and developed this method, but the method was — and still remains — outside mainstream medicine. The controversial points of laser biostimulation, which were topics of great interest at that time, were analyzed in reviews that appeared in the late 1980s.
Article
Introduction The purpose of this Institutional Review Board (IRB)-approved, placebo-controlled, randomized, double-blinded parallel-grouped, multicenter trial was to determine the effectiveness of low-level laser therapy (LLLT) in decreasing patients' postoperative pain 24 hours post breast augmentation surgery. Materials and Methods The Erchonia EML, 630–640 nm, (Erchonia Medicial, Inc., McKinney, Texas) with 2 7-mw laser-emitting diodes was used within 10 minutes of the start of the procedure over each breast for 4 minutes at a distance of 6 inches. This was repeated within 10 minutes of completion of the procedure with the same methodology. One hundred and four (104) patients participated in the study, 50 test subjects and 54 controls. Primary investigator and patient were blinded with respect to treatment group. Results The success criteria for this study using the standardized Visual Analogue Scale (VAS) was a self-reported degree-of-pain rating of less than 30 at 24 hours after the implant procedure. At this time the patient had not taken pain medication for 4 hours. Overall study success criteria were defined as at least 30% difference between treatment groups with respect to proportion of successes. At the 24-hour time interval 37 (74%) of the test subjects and 20 (37%) of the control subjects met the success criteria, a difference of 37% (p<.0002). The amount of pain medication used over the first 7 days post operatively was measured as a covariant. The test subjects used less medication 848 versus 932 total doses (p<.01). Conclusion Low-level laser therapy is effective at significantly decreasing postoperative pain and the amount of pain medication needed after breast augmentation at 1 day and 1 week respectfully. All other covariants studied including, implant type, implant size, incision size, implant location, test site location, amount of swelling measurements, hydration level, and adverse events were found to be neglible.
Article
Differences in wound healing between horses and ponies have provided valuable information about the intrinsic process of wound healing and the complications that are relatively frequently encountered in the equine. Primary intention healing in ponies is less often complicated by wound dehiscence and bone sequestrum formation compared with horses. Second intention healing is faster in ponies than horses due to a stronger initial inflammatory response and greater contribution of wound contraction to wound closure. These differences can to a large extent be explained by differences in the local inflammatory response, which in turn are caused by differences in the functional capacity of the leukocytes. The wound healing process can be divided into several overlapping phases representing the events occurring during healing (eg, the inflammatory phase, formation of granulation tissue, wound contraction and epithelialization) This paper describes the differences between horses and ponies during these phases and reflects the research results on the treatment of equine wounds. Research has resulted in the perception that in clinical practice a maximal effect of treatment will be obtained if a differential approach is chosen, optimizing conditions for each successive phase of the wound healing process.
Article
Four methods of treating granulating wounds on the dorsal aspect of the metacar-pophalangeal and metatarsophalangeal joints of ponies were evaluated. The following treatments were used: Group 1—excision of the granulation tissue with no further treatment; Group 2—cryosurgery; Group 3—excision of the granulation tissue and pressure bandage; and Group 4—excision of the granulation tissue and immobilization of the limb with a plaster cast. The wounds in Group 1 healed fastest, without producing exuberant granulation tissue and with only moderate scar fibrosis. The wounds in Group 2 healed without producing exuberant granulation tissue but with marked scarring. Wounds in Groups 3 and 4 took longer (p < 0.001) to heal compared to wounds in Groups 1 and 2. Wounds in Groups 3 and 4 produced exuberant granulation tissue, but the resultant scars were the least fibrotic.
Article
Background Low levels of laser or non-coherent light, termed low-level light therapy (LLLT) have been reported to accelerate some phases of wound healing, but its clinical use remains controversial.MethodsA full thickness dorsal excisional wound in mice was treated with a single exposure to light of various wavelengths and fluences 30 minutes after wounding. Wound areas were measured until complete healing and immunofluorescence staining of tissue samples was carried out.ResultsWound healing was significantly stimulated in BALB/c and SKH1 hairless mice but not in C57BL/6 mice. Illuminated wounds started to contract while control wounds initially expanded for the first 24 hours. We found a biphasic dose–response curve for fluence of 635-nm light with a maximum positive effect at 2 J/cm2. Eight hundred twenty nanometer was found to be the best wavelength tested compared to 635, 670, and 720 nm. We found no difference between non-coherent 635±15-nm light from a lamp and coherent 633-nm light from a He/Ne laser. LLLT increased the number of α-smooth muscle actin (SMA)-positive cells at the wound edge.ConclusionLLLT stimulates wound contraction in susceptible mouse strains but the mechanism remains uncertain. Lesers Surg. Med. 39:706–715, 2007. © 2007 Wiley-Liss, Inc.
Article
A growing number of laboratory and clinical studies over the past 10 years have shown that low-level laser stimulation (633 or 670 nm) at extremely low power densities (about 0.15 mW/cm(2)), when administered through a particular emission mode, is capable of eliciting significant biological effects. Studies on cell cultures and animal models as well as clinical trials give support to a novel therapeutic modality, which may be referred to as ultra low level laser therapy (ULLLT). In cultured neural cells, pulsed irradiation (670 nm, 0.45 mJ/cm(2)) has shown to stimulate NGF-induced neurite elongation and to protect cells against oxidative stress. In rats, anti-edema and anti-hyperalgesia effects following ULLL irradiation were found. Clinical studies have reported beneficial effects (also revealed through sonography) in the treatment of musculoskeletal disorders. The present paper reviews the existing experimental evidence available on ULLLT. Furthermore, the puzzling issue of the biophysical mechanisms that lie at the basis of the method is explored and some hypotheses are proposed. Besides presenting the state-of-the-art about this novel photobiostimulation therapy, the present paper aims to open up an interdisciplinary discussion and stimulate new research on this subject.
Article
The absorption spectrum of human fibroblast monolayers showed several absorption peaks, among them one at a wave-length of 630 nm. Cultures of these fibroblasts were subjected to He-Ne laser (632.8 nm) irradiation of various energy doses by varying power density and exposure time. On three consecutive days the cell monolayers were irradiated for periods between 0.5 and 10 min. Laser power varied from 0.55 to 5.98 mW. Both cell number and collagen type I production were determined for each irradiation condition within one experiment. Results show that laser power below 2.91 mW could enhance cell proliferation (as determined by cell counting), whereas higher laser power (5.98 mW) had no effect. Stimulatory effects were most pronounced at irradiation times between 0.5 and 2 min. Collagen type I production (as determined by an ELISA) was affected in the opposite direction to cell proliferation: when the cell proliferation was increased, collagen type I production was decreased. From these experiments it is clear that exposure time and power density determine the effects of laser irradiation. Both stimulation and inhibition of the observed cell properties can be obtained with the same laser on the same cells.
Article
Preformed collagen gel was topically applied to cutaneous wounds of the equine dorsal fetlock (thoracic limb) and metatarsal regions to evaluate the effect on exuberant granulation tissue production and wound healing. In 6 horses and 3 ponies (less than 140 cm high at the withers and less than 365 kg), 36 standardized cutaneous limb wounds were surgically induced (4 wounds/animal); 18 wounds were treated topically with collagen gel, and 18 wounds were not treated (controls). Collagen gel was initially applied to the wound at 0, 2, or 7 days after wound formation (groups 1, 2, and 3, respectively). Four measurements were regularly made: amount of wound contraction and the size of the granulation bed, epithelial covering, and total wound. Sequential skin and wound biopsies were evaluated histologically to assess wound healing. Using a computer, data were analyzed for differences in the 4 measurements between treated and control wounds, between fetlock wounds and metatarsal wounds, and among groups 1, 2, and 3. Analyses were performed on days 15 and 45 of wound healing and on the final day of healing. A significant difference (P greater than 0.05) in the production of exuberant granulation tissue, rate of epithelialization, or degree of wound contraction was not detected between the collagen-treated and control wounds. Total healing time and final scar size were similar. Wound healing patterns were significantly different (P less than 0.05) in the fetlock wounds and metatarsal wounds. All wounds enlarged up to day 15 with fetlock wounds enlarging significantly more than did the metatarsal wounds.(ABSTRACT TRUNCATED AT 250 WORDS)
Article
Two 2.5-cm2 full-thickness skin wounds were created surgically over the lateral aspect of the cannon bone of each limb of 6 horses (n = 48 wounds). Dressings evaluated were a nonadherent gauze pad (group 1); a synthetic semiocclusive dressing, (group 2); equine amnion (group 3); and a synthetic fully occlusive dressing (group 4). Wounds were assessed subjectively at each dressing change, and total wound area, area of granulation tissue, and area of epithelium in each wound were determined by computerized digital analysis of photographs of the wounds. Complete healing time (wound covered by epithelium) also was determined for each wound. Statistical comparisons were made, using Kruskal-Wallis analysis and a Mann-Whitney U test. Median time to complete healing was: group 1, 53 days; group 2, 71 days; group 3, 63 days; and group 4, 113 days. Time to complete healing was significantly longer for wounds of group-4 horses than all other groups, and wounds of group-1 horses healed faster than did those of group-2 horses (P < 0.05). Wounds in group-4 horses required significantly (P < or = 0.05) more excisions of granulation tissue (median, 11.5 times) than did those in group-1 (median, 3.5), group-2 (median, 5.5) or group-3 (median, 2.5) horses. Epithelial tissue was detected later in wounds of group-4 horses (median, 27 days) than in wounds of horses in groups 1, 2 or 3 (median, 17 days); however, this difference was not statistically significant.(ABSTRACT TRUNCATED AT 250 WORDS)
Article
To investigate the effects on wound healing of transforming growth factor-beta 1 as a topical treatment to full-thickness, excisional wounds of the distal limb of horses. A randomised block study using four horses, each with wounds assigned to four treatment groups. Four adult Standardbred geldings. Four, 4 cm2, full-thickness wounds were created on the dorsomedial and dorsolateral aspect of the metacarpus or metatarsus of each limb of four horses, giving a total of 64 wounds. For each limb, wounds were randomly assigned to four treatment groups: no treatment (control), carrier (Methyl Cellulose gel), 50 ng/wound rhTGF-beta 1 in carrier, and 500 ng/wound rhTGF-beta 1 in carrier. Wounds were treated on day 0 and day 8. Effects of treatment were evaluated on the basis of the presence of exuberant granulation tissue requiring excision, number of times excision was required, total wound area, area of epithelialisation, area of granulation, and histological evaluation of biopsy samples of wounds on day 8 and excised wounds on day 21. Topical application of TGF-beta 1 at the two concentrations studied had no significant effect on the total area of wounds (P = 0.7), the area of granulation tissue (P = 0.78), the area of epithelialisation (P = 0.92), histological assessment or subjective clinical assessment of wounds. TGF-beta 1 had no beneficial effects on wound healing. Additional trials are needed to test if it has value for wound treatment in horses.
Article
The main objective of current animal and clinical studies was to assess the efficacy of low level laser therapy (LLLT) on wound healing in rabbits and humans. In the initial part of our research we conducted a randomized controlled animal study, where we evaluated the effects of laser irradiation on the healing of surgical wounds on rabbits. The manner of the application of LLLT on the human body are analogous to those of similar physiologic structure in animal tissue, therefore, this study was continued on humans. Clinical study was performed on 74 patients with injuries to the following anatomic locations: ankle and knee, bilaterally, Achilles tendon; epicondylus; shoulder; wrist; interphalangeal joints of hands, unilaterally. All patients had had surgical procedure prior to LLLT. Two types of laser devices were used: infrared diode laser (GaAlAs) 830 nm continuous wave for treatment of trigger points (TPs) and HeNe 632.8 nm combined with diode laser 904-nm pulsed wave for scanning procedure. Both were applied as monotherapy during current clinical study. The results were observed and measured according to the following clinical parameters: redness, heat, pain, swelling and loss of function, and finally postponed to statistical analysis via chi2 test. After comparing the healing process between two groups of patients, we obtained the following results: wound healing was significantly accelerated (25%-35%) in the group of patients treated with LLLT. Pain relief and functional recovery of patients treated with LLLT were significantly improved comparing to untreated patients. In addition to accelerated wound healing, the main advantages of LLLT for postoperative sport- and traffic-related injuries include prevention of side effects of drugs, significantly accelerated functional recovery, earlier return to work, training and sport competition compared to the control group of patients, and cost benefit.
Article
Wound healing is a complex biologic process with initial inflammation, granulation tissue formation, and matrix remodeling. We observed the relation between angiostatic effects and corticosteroid administration time in the rabbit ear chamber. Angiogenesis in the chamber was studied using a microscope-television system. Two experiments were undertaken to represent the systemic and the topical administration of steroids. In experiment 1, 10 mg of triamcinolone acetonide was injected three times intramuscularly (on the day of implantation of the chamber, and the 7th and 14th day after implantation). Vascularization in this group was significantly delayed at the 7th, 14th, and 21st days but no difference from controls was observed in the size and density of vessels after its completion. In experiment 2, 3 mg of triamcinolone acetonide was injected once into the skin adjacent to the chamber on the 10th day after installment of chambers or on the day of installment. In the former group, new vascular growth was delayed until the 21st day after installment. The hemorrhagic zone had narrowed and vascular dilation was observed. In the latter group, endothelial budding was delayed and vascular constriction occurred. New vascular growth was severely delayed and granulation filling of the chamber was not completed. These results suggest not only that the topical administration had the stronger inhibitory effect on neovascularization than the systemic administration but that the effect differed depending on the stage of wound healing. In view of this effect of this steroid, we should pay careful attention to the time when steroids are administered to patients.
Changes in microcirculation during low-intensity He-Ne laser irradiation were studied by measurement of blood vessels and lymphangions' diameter in anesthetized rat mesentery using method of videomicroscopy in vivo. We demonstrated that the red coherent light induced a significant increase in contractility of vessels' smooth muscle cells. The flow decreased in the mesenteric microvessels during H2O2-mediated oxidant stress was restored after He-Ne laser irradiation.
Article
Second-intention repair is faster in ponies than in horses and faster in body wounds than in limb wounds. To a large extent, the differences between horses and ponies can be explained by differences in the local inflammatory response, which are a result of the functional capacity of leukocytes. In ponies, leukocytes produce more inflammatory mediators,resulting in better local defense, faster cellular debridement, and a faster transition to the repair phases, with more wound contraction. In horses,leukocytes produce fewer mediators, initiating a weak inflammatory response, which becomes chronic. This inhibits wound contraction and gives rise to the formation of exuberant granulation tissue. The anatomic environment that influences the inflammatory response and wound contraction most probably determines the differences between body and limb wounds. In body wounds, better perfusion results in faster initiation of the inflammatory phase. The weaker local resistance results in a greater degree of contraction. In limb wounds, particularly of horses, the initial inflammatory response is weak and wound contraction is restricted. Both factors give rise to chronic inflammation, which further inhibits wound contraction and promotes exuberant granulation tissue. The high incidence of exuberant granulation tissue in limb wounds of horses can thus be explained by the chronicity of the inflammatory response as well as by the common use of bandages during treatment. Chronic inflammation is often not recognized as a cause of exuberant granulation tissue. It must be prevented and treated to promote the healing process. Bandages and casts stimulate the formation of exuberant granulation tissue; however, they are advantageous in many respects and play an important role in support of the overall healing process.
Article
Given the recent interest in light-emitting diode (LED) photomodulation and minimally invasive nonablative laser therapies, it is timely to investigate reports that low-level laser therapy (LLLT) may have utility in wound healing. To critically evaluate reported in vitro models and in vivo animal and human studies and to assess the qualitative and quantitative sufficiency of evidence for the efficacy of LLLT in promoting wound healing. Literature review, 1965 to 2003. In examining the effects of LLLT on cell cultures in vitro, some articles report an increase in cell proliferation and collagen production using specific and somewhat arbitrary laser settings with the helium neon (HeNe) and gallium arsenide lasers, but none of the available studies address the mechanism, whether photothermal, photochemical, or photomechanical, whereby LLLT may be exerting its effect. Some studies, especially those using HeNe lasers, report improvements in surgical wound healing in a rodent model; however, these results have not been duplicated in animals such as pigs, which have skin that more closely resembles that of humans. In humans, beneficial effects on superficial wound healing found in small case series have not been replicated in larger studies. To better understand the utility of LLLT in cutaneous wound healing, good clinical studies that correlate cellular effects and biologic processes are needed. Future studies should be well-controlled investigations with rational selection of lasers and treatment parameters. In the absence of such studies, the literature does not appear to support widespread use of LLLT in wound healing at this time. Although applications of high-energy (10-100 W) lasers are well established with significant supportive literature and widespread use, conflicting studies in the literature have limited low-level laser therapy (LLLT) use in the United States to investigational use only. Yet LLLT is used clinically in many other areas, including Canada, Europe, and Asia, for the treatment of various neurologic, chiropractic, dental, and dermatologic disorders. To understand this discrepancy, it is useful to review the studies on LLLT that have, to date, precluded Food and Drug Administration approval of many such technologies in the United States. The fundamental question is whether there is sufficient evidence to support the use of LLLT.
Article
This preliminary laboratory-based study looks at the paracrine release from human skin cells subject to sublethal Q-switched Nd:YAG 532 nm laser irradiation. Human dermal fibroblast and keratinocyte cultures were exposed to sublethal energy using the Nd:YAG 532 nm laser. Altered gene expression was then screened using RT-PCR for a range of paracrine factors known to affect melanogenesis, basic fibroblast growth factor (b-FGF), hepatocyte growth factor (HGF), stem cell factor (SCF), melanocyte stimulating hormone (MSH), endothelin-1 (ET-1), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha) and protease-activated receptor-2 (PAR-2). Enzyme-linked immunosorbent assay (ELISA) was used to confirm protein production. Conditioned medium was used to assess altered melanogenesis in a melanoma cell line. Fibroblasts exposed to sublethal radiation showed upregulation of b-FGF, HGF and SCF. This contrasts with keratinocytes which showed upregulation of IL-6. Elevated protein levels of b-FGF and SCF were confirmed by ELISA assay. Conditioned fibroblast medium was shown to stimulate melanogenesis in a melanoma cell line. This preliminary laboratory study reports, for the first time, specific gene upregulation using the Q-switched Nd:YAG 532 nm laser.
Article
Phototherapy uses monochromatic light in the optical region of 600-1000 nm to treat in a non-destructive and non-thermal fashion various soft-tissue and neurological conditions. This kind of treatment is based on the ability of light red-to-near IR to alter cellular metabolism as a result of its being absorbed by cytochrome c oxidase. To further investigate the involvement of cytochrome c oxidase as a photoacceptor in the alteration of the cellular metabolism, we have aimed our study at, first, recording the absorption spectra of HeLa-cell monolayers in various oxygenation conditions (using fast multichannel recording), secondly, investigating the changes caused in these absorption spectra by radiation at 830 nm (the radiation wavelength often used in phototherapy), and thirdly, comparing between the absorption and action spectra recorded. The absorption measurements have revealed that the 710- to 790-nm spectral region is characteristic of a relatively reduced photoacceptor, while the 650- to 680-nm one characterizes a relatively oxidized photoacceptor. The ratio between the peak intensities at 760 and 665 nm is used to characterize the redox status of cytochrome c oxidase. By this criterion, the irradiation of the cellular monolayers with light at lambda=830 nm (D=6.3 x 10(3)J/m(2)) causes the reduction of the photoacceptor. A similarity is established between the peak positions at 616, 665, 760, 813, and 830 nm in the absorption spectra of the cellular monolayers and the action spectra of the long-term cellular responses (increase in the DNA synthesis rate and cell adhesion to a matrix).
Article
Background and objectives: The vascular extracellular matrix is maintained by a dynamic balance between matrix synthesis and degradation. This equilibrium is disrupted in arterial pathologies such as abdominal aortic aneurysm. Low-level laser irradiation (LLLI) promotes wound healing. However, its effect on smooth muscle cells (SMCs), a central player in these responses, has not been established. The current study was designed to determine the effects of LLLI on arterial SMC proliferation, inflammatory markers, and matrix proteins. Study design/materials and methods: Porcine primary aortic SMCs were irradiated with a 780 nm laser diode (1 and 2 J/cm(2)). Trypan blue exclusion assay, immunofluorescent staining for collagen I and III, Sircol assay, gelatin zymography, and RT-PCR were used to monitor proliferation; collagen trihelix formation; collagen synthesis; matrix metalloproteinase-2 (MMP-2) activity, and gene expression of MMP-1, MMP-2, tissue inhibitor of MMP-1 (TIMP-1), TIMP-2, and IL-1-beta, respectively. Results: LLLI-increased SMC proliferation by 16 and 22% (1 and 2 J/cm(2), respectively) compared to non-irradiated cells (P<0.01 and P<0.0005). Immediately after LLLI, trihelices of collagen I and III appeared as perinuclear fluorescent rings. Collagen synthesis was increased twofold (2 days after LLLI: 14.3+/-3.5 microg, non-irradiated control: 6.6+/-0.7 microg, and TGF-beta stimulated control: 7.1+/-1.2 microg, P<0.05), MMP-2 activity after LLLI was augmented (over non-irradiated control) by 66+/-18% (2 J/cm(2); P<0.05), and MMP-1 gene expression upregulated. However, TIMP-2 was upregulated, and MMP-2 gene expression downregulated. IL-1-beta gene expression was reduced. Conclusions: LLLI stimulates SMC proliferation, stimulates collagen synthesis, modulates the equilibrium between regulatory matrix remodeling enzymes, and inhibits pro-inflammatory IL-1-beta gene expression. These findings may be of therapeutic relevance for arterial diseases such as aneurysm where SMC depletion, weakened extracellular matrix, and an increase in pro-inflammatory markers are major pathologic components.
Irradiation with He-Ne laser increases ATP level in cells cultivated in vitro
  • T Karu
  • L Pyatibrat
  • G Kalendo
Karu T, Pyatibrat L, Kalendo G. Irradiation with He-Ne laser increases ATP level in cells cultivated in vitro. J Photochem Photobiol B 1995;27(3):219 -23.
Mitochondrial membrane potential after low-power laser irradiation
  • R Bortoletto
  • N S Silva
  • Ra
  • M T Pacheco
  • R A Da Matta
  • C Pacheco-Soares
Bortoletto R, Silva NS, Z â ngaro RA, Pacheco MT, Da Matta RA, Pacheco-Soares C. Mitochondrial membrane potential after low-power laser irradiation. Lasers Med Sci 2004;18(4): 204 -6.
Power density and exposure time of He-Ne laser irradiation are more important than total energy dose in photo-biomodulation of human fi broblasts in vitro
  • H H Van Breugel
  • B Pr
van Breugel HH, B ä r PR. Power density and exposure time of He-Ne laser irradiation are more important than total energy dose in photo-biomodulation of human fi broblasts in vitro. Lasers Surg Med 1992;12(5):528 -37.