Research On Light Therapy for Chronic Wounds

Articles and Abstracts on Chronic Wound Research

Photobiomodulation of surgical wound dehiscence in a diabetic individual by low-level laser therapy following median sternotomy.

Dixit S, Maiya A, Umakanth S, Borkar S

Abstract
In this single case study, we attempt to outline the possible effect of low-level laser therapy (LLLT) on delayed wound healing and pain in chronic dehiscent sternotomy of a diabetic individual. The methods that were employed to evaluate changes pre and post irradiation were wound photography, wound area measurement, pressure ulcer scale of healing (PUSH), and visual analogue scale (VAS) for pain. After irradiation, proliferation of healthy granulation tissue was observed with decrease in scores of PUSH for sternal dehiscence and VAS for bilateral shoulders and sternal dehiscence. We found that LLLT irradiation could be a novel method of treatment for chronic sternal dehiscence following coronary artery bypass grafting, as it augments wound healing with an early closure of the wound deficit. Hence, this might be translated into an early functional rehabilitation and decreased pain perception of an individual following surgical complication.

Source
Indian J Palliat Care 2013 Jan 19(1) 71-5

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http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=23766600

 

The effects of low-level laser therapy on palatal mucoperiosteal wound healing and oxidative stress status in experimental diabetic rats.

Firat ET, Dag A, Gunay A, Kaya B, Karadede MI, Kanay BE, Ketani A, Evliyaoglu O, Uysal E

Abstract Objective 
The biostimulation effects of low-level laser therapy (LLLT) have recently been demonstrated. In this study, we aimed to investigate the effects of LLLT on palatal mucoperiostal wound healing and oxidative stress status in experimental diabetic rats. Materials and methods: Forty-two male Wistar rats that weighed 250-300 g were used in this study. Experimental diabetes was induced in all of the rats using streptozotocin. A standardized full thickness wound was made in the mucoperiosteum of the hard palates of the rats using a 3 mm biopsy punch. The rats were divided into groups: 1 (control group, non- irradiated), and 2 (experimental group, irradiated). Treatment using a GaAlAs laser at a wavelength of 940 nm and at dose of 10 J/cm(2) began after surgery, and was repeated on the 2nd, 4th, and 6th days post-surgery. Seven animals from each group were killed on the 7th, 14th, and 21st day after surgery. Biopsies were performed for the histological analysis and blood samples were collected by cardiac puncture for biochemical analysis. Results: The histopathological findings revealed reduced numbers of inflammatory cells, and increased mitotic activity of fibroblasts, collagen synthesis, and vascularization in rats in group 2. The total oxidative status was significantly decreased in the laser-treated group on the 21st day. Conclusions: LLLT elicits a positive healing effect on palatal mucoperiostal wounds, and modulates the oxidative status in experimental diabetic rats.

Source
Photomed Laser Surg 2013 Jul 31(7) 315-21

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http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=23789588

 

Efficacy of Low Level Laser Therapy on Scar Tissue.

Freitas CP, Melo C, Alexandrino AM, Noites A

Abstract Background 
Physiotherapy has a very important role for the maintenance of the integumentary system integrity. Very few evidence exists in humans. Nevertheless, there are some studies about tissue regeneration using low level laser therapy (LLLT). Aim: To analyse the effectiveness of LLLT on scar tissue. Methods: Seventeen volunteer subjects were stratified by age of their scars, and then randomly assigned to an experimental group (EG) – n= 9 -, and a placebo group (PG) – n= 8. Fifteen sessions were applied to both groups 3 times a week. However in the PG the laser device was switched off. Scars’ thickness, length, width, macroscopic aspect, pain threshold, pain perception and itching were measured. Results: After 5 weeks there were no statistically significant differences in any variable between both groups. Therefore, analysing independently each group, EG showed a significantly improvement in macroscopic aspect (p=0,003) using LLLT. Taking into account scars’ age, LLLT showed in EG a tendency to decrease older scars’ thickness. Conclusion: The intervention with LLLT appears to have a positive effect on the macroscopic scars’ appearance, and on old scars’ thickness, in the studied sample. However, it cannot be said for sure that LLLT has influence on scar tissue.

Source
J Cosmet Laser Ther 2013 Apr 22

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http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=23607736

 

Effect of red and near-infrared wavelengths on low-level laser (light) therapy-induced healing of partial-thickness dermal abrasion in mice.

Gupta A, Dai T, Hamblin MR

Summary
Low-level laser (light) therapy (LLLT) promotes wound healing, reduces pain and inflammation, and prevents tissue death. Studies have explored the effects of various radiant exposures on the effect of LLLT; however, studies of wavelength dependency in in vivo models are less common. In the present study, the healing effects of LLLT mediated by different wavelengths of light in the red and near-infrared (NIR) wavelength regions (635, 730, 810, and 980 nm) delivered at constant fluence (4 J/cm2) and fluence rate (10 mW/cm2) were evaluated in a mouse model of partial-thickness dermal abrasion. Wavelengths of 635 and 810 nm were found to be effective in promoting the healing of dermal abrasions. However, treatment using 730- and 980-nm wavelengths showed no sign of stimulated healing. Healing was maximally augmented in mice treated with an 810-nm wavelength, as evidenced by significant wound area reduction (p < 0.05), enhanced collagen accumulation, and complete re-epithelialization as compared to other wavelengths and non-illuminated controls. Significant acceleration of re-epithelialization and cellular proliferation revealed by immunofluorescence staining for cytokeratin-14 and proliferating cell nuclear antigen (p < 0.05) was evident in the 810-nm wavelength compared with other groups. Photobiomodulation mediated by red (635 nm) and NIR (810 nm) light suggests that the biological response of the wound tissue depends on the wavelength employed. The effectiveness of 810-nm wavelength agrees with previous publications and, together with the partial effectiveness of 635 nm and the ineffectiveness of 730 and 980 nm wavelengths, can be explained by the absorption spectrum of cytochrome c oxidase, the candidate mitochondrial chromophore in LLLT.

Source
Lasers Med Sci 2013 Apr 26

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http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=23619627

 

Conventional systemic treatments associated with therapeutic sites of local lesions of secondary syphilis in the oral cavity in patients with AIDS.

Giovani EM, de Paula Neto ER, Vieira BC, de Andrade DM

Summary
Patients with HIV infection may develop common diseases with atypical clinical features. HIV infection can change the classic clinical course of syphilis and increase the incidence of malignant syphilis. Malignant syphilis is a rare subtype of secondary syphilis that presents special clinical and histological features and has been associated with several processes characterized by variable degrees of immunosuppression. It is necessary to consider the possibility of this entity in the differential diagnoses in HIV-infected patients with cutaneous lesions. The dental surgeon (or oral surgeon) is vital to the medical team for promoting the health and improving the quality of life of syphilis patients. A patient with HIV infection was referred to us for complaints of a white patch on the tongue, stinging and burning sensation on the tongue, loss of taste, and dryness of the mouth. On clinical examination, the patient was found to have a tabetic gait (the Prussian soldier gait) associated with Charcot arthropathy. We also identified bilateral lesions with ulceration and exposure of the tissue that were tender, characterized by discrete necrosis. The treatment that was initiated at that time involved cleaning the area with gauze to remove all the white patches, followed by rinsing with bicarbonate in water (one teaspoon of baking soda dissolved in half a glass of water) four times a day. Additionally, fluconazole (100 mg/day for 7 days) was prescribed. We diagnosed secondary malignant syphilis of approximately 5 days duration. As an adjunctive therapy, we performed low-intensity laser treatment using a GaAsAl (gallium-aluminum arsenide) laser at 790 nm. With this treatment there was progressive resolution of the lesions.

Source
Indian J Dent Res 2012 Sep 23(5) 670-3

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http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=23422616

 

Advancement in the research of effect of low level laser therapy on wound healing

Mao HS, Yao M, Fang Y

Summary
Low level laser therapy (LLLT) is a therapeutic method which regulates the biological behavior of cells with light. The effects of LLLT consist of promotion of tissue repair, inhibition of inflammation, and relief of pain by promoting or inhibiting the cell proliferation, increasing or decreasing the release of some bioactive substances. Therefore, LLLT is also known as photomodulation. At present, there are many relevant experimental studies of LLLT abroad, and they are also used clinically. This article reviews the effect of LLLT on wound healing.

Source
Zhonghua Shao Shang Za Zhi 2012 Dec 28(6) 462-4

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http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=23327917

 

Mechanisms of action for light therapy: a review of molecular interactions

Prindeze NJ, Moffatt LT, Shupp JW

Summary
Five decades after the first documented use of a laser for wound healing, research in light therapy has yet to elucidate the underlying biochemical pathways causing its effects. The aim of this review is to summarize the current research into the biochemical mechanisms of light therapy in order to better direct future studies. The implication of cytochrome c oxidase as the photoacceptor modulating light therapy is reviewed, as are the predominant hypotheses of the biochemical pathways involved in the stimulation of wound healing, cellular proliferation, production of transcription factors and other reported stimulatory effects.

Source
Exp Biol Med (Maywood) 2012 Nov 1 237(11) 1241-8

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http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=23239434

 

Clinical Trial Abstracts on Chronic Wound Research

Photobiomodulation by helium neon and diode lasers in an excisional wound model: A single blinded trial.


Dixit S, Maiya A, Rao L, Rao MA, Shastry BA, Ramachandra L

Abstract
BACKGROUND: Application of different kinds of lasers in clinical and experimental studies causes photobiomodulation that works at localized cellular and humoral level on various biological systems. Increased numbers of fibroblasts, myofibroblast, and degranulation of mast cells have been the observed benefits post-irradiation. OBJECTIVE: Was to find out the effect of irradiation with energy densities of 3.38 J/cm(2), 8 J/cm(2), and 18 J/cm(2) on animal tissue (albino wistar rats) in an excisional wound model and to assess changes in biochemical (hydroxyproline) and histopathological levels in excisional wound model.

MATERIALS AND METHODS: The animals were divided into 4 groups, which were labeled as L1, diode laser (18 J/cm(2)), L2 Helium-neon (He-Ne, 8 J/cm(2)), L3 diode laser (3.38 J/cm(2)), and sham treatment for control was depicted by C, respectively. Histological and hydroxyproline analysis was performed on 7, 14, 21 days of post-wounding. One-way analysis of variance, ANOVA and Bonferroni’s multiple comparison tests were done for tissue hydroxyproline levels.

RESULTS: There was no significant increase in the hydroxyproline content (P < 0.005) when observed in study group and compared to controls. Whereas significant epithelizations was seen in group treated with He-Ne laser of intensity of 8 J/cm(2).

CONCLUSION: The experimental observations suggest that low intensity helium-neon laser of 8 J/cm(2) intensity facilitated photo stimulation by tissue repair, but failed to show significant tissue hydroxyproline levels in excisional wound model.

Source
Adv Biomed Res 2012 1 38

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http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=23326769

 

Effects of pulsed infra-red low level-laser irradiation on mast cells number and degranulation in open skin wound healing of healthy and streptozotocin-induced diabetic rats

Fathabadie FF, Bayat M, Amini A, Bayat M, Rezaie F

Introduction 
Low-level laser therapy (LLLT) has been reported to be capable of changing mast cell numbers and degranulation in experimental wounds. Objective: We conducted a study on the influence of pulsed LLLT on mast cells in wounds of non-diabetic and diabetic rats. Methods: Thirty-six rats were randomly divided into non-diabetic and diabetic groups. Type 1 diabetes milletes (DM) was induced in rats of the diabetic group by administration of streptozotocin (STZ). We inflicted two wounds in each rat. The first wound in both non-diabetic and diabetic groups was treated with an 890-nm laser, having pulse frequency of 80 Hz and energy density of 0.2 J/cm2. Mast cell numbers and degranulation of all subgroups were assessed at 4, 7, and 15 days after the infliction of the wounds. Results and conclusion: According to the paired t-test, the total number of laser-treated mast cells was significantly higher than that of the placebos in the non-diabetic groups on days 4 and 15. The total number of laser-treated mast cells was significantly higher than that of the placebos in the diabetic groups on days 4 and 15. The number of granulated mast cells was significantly higher than that of degranulated mast cells for all laser-treated mast cells and placebo mast cells of the non-diabetic and diabetic groups.

Source
J Cosmet Laser Ther 2013 Mar 6

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http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=23463989

 

Wound-healing effects of low-level laser therapy in diabetic rats involve the modulation of MMP-2 and MMP-9 and the redistribution of collagen types I and III

Aparecida Da Silva A, Leal-Junior EC, Alves AC, Rambo CS, Dos Santos SA, Vieira RP, De Carvalho PD

Abstract
The present study aimed to determine if LLLT restores the balance between mRNA expression of matrix metalloproteinases (MMP-2 and MMP-9) and also the balance between collagen types I and III during the healing process of diabetic wounds. One hundred and twenty male Wistar rats were distributed in Control (untreated non-diabetic rats: UND); Laser (laser treated in non-diabetic rats: LTND); Diabetic (diabetic rats non-laser treated rats: UD); and Diabetic+ Laser (diabetic rats laser treated: DLT) groups. The diabetes model using streptozotocin efficiently induced diabetes, as demonstrated through increased levels of blood glucose. Diode laser (50 mW, 660 nm, 4 J/cm2, 80 s) was applied a single time after scare induction. Twenty-four hours after LLLT application, rats were euthanized, the scarred areas were collected for MMP-2 and MMP-9 mRNA analysis and also for histological analysis (inflammation and types I and III collagen). The results demonstrated that scare in untreated diabetic rats significantly increased the MMP-2 and MMP-9 expression compared with that in non-diabetic rats (p < 0.05), while LLLT significantly reduced MMP-2 and MMP-9 expression compared with that in untreated diabetic rats (p < 0.05). To conclude, the results also showed that LLLT was able to alter the expression of MMP-9 as well as accelerate the production of collagen and increase the total percentage of collagen type III in diabetic animals.

Source
J Cosmet Laser Ther 2013 Mar 6

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http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=23463906

 

Laser photostimulation (660 nm) of wound healing in diabetic mice is not brought about by ameliorating diabetes

Peplow PV, Chung TY, Baxter GD.

BACKGROUND AND OBJECTIVES:
We have used a 660-nm laser diode in genetic diabetic mice to stimulate the healing of wounds covered with a Tegaderm HP dressing that causes a retardation of contraction (splinted wounds). It is possible that the stimulation of healing could be due to possible diabetes-modifying properties of laser light. This has been examined by using the 660 nm laser to irradiate non-wounded diabetic mice with the same dose and at same location as for wounded diabetic mice.

MATERIALS AND METHODS:
Twenty-two diabetic mice were used and divided into two equal groups. Body weight and water intake of mice were measured daily for 7 days prior to the start of treatment (Day 0). The left flank of mice in the experimental group was irradiated with 660 nm laser, 100 mW, 20 seconds/day, 7 days; for mice in the control group, the left flank was sham-treated with the laser power supply not switched on. Body weight and water intake of mice were measured to Day 14. On Day 14, the mice were fasted for 4 hours, anaesthetized with sodium pentobarbitone (i.p.) and blood collected by cardiac puncture into heparinized tubes. The plasma was assayed for glucose and glycated hemoglobin A1c.

RESULTS:
There were no significant differences in body weight and water intake over 22 days between mice in the experimental group and control group. On day 14, the mean blood plasma glucose level was not significantly different between the two groups; glycated hemoglobin A1c was not detected in the samples.

CONCLUSION:
Irradiation of the left flank in diabetic mice with 660 nm laser system does not have a significant hypoglycemic effect, and the laser-stimulated healing of wounds in diabetic mice is due to cellular and biochemical changes in the immediate wound environment.

Source
Photomed Laser Surg. 2007 Jun;25(3):159-69.

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http://www.ncbi.nlm.nih.gov/pubmed/22109569

 

Influence of broad-spectrum and infrared light in combination with laser irradiation on the proliferation of wounded skin fibroblasts

Hawkins D, Abrahamse H.

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.

Source
PMID: 17603855 [PubMed - indexed for MEDLINE]

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http://www.ncbi.nlm.nih.gov/pubmed/17603855

 

Phototherapy improves healing of chronic venous ulcers

Caetano KS, Frade MA, Minatel DG, Santana LA, Enwemeka CS.

OBJECTIVE:
We tested the hypothesis that LED phototherapy with combined 660-nm and 890-nm light will promote healing of venous ulcers that failed to respond to other forms of treatment.

BACKGROUND DATA:
A variety of dressings, growth factors, and adjunct therapies are used to treat venous ulcers, but none seems to yield satisfactory results.

MATERIALS AND METHODS:
We used a randomized placebo-controlled double-blind study to compare a total of 20 patients divided with 32 chronic ulcers into three groups. In group 1 the ulcers were cleaned, dressed with 1% silver sulfadiazine (SDZ) cream, and treated with placebo phototherapy (<.03 J/cm(-3)) using a Dynatron Solaris 705 phototherapy research device. In group 2 the ulcers were treated similarly but received real phototherapy (3 J/cm(-2)) instead of placebo. In group 3 (controls), the ulcers were simply cleaned and dressed with SDZ without phototherapy. The ulcers were evaluated with digital photography and computer image analysis over 90 d or until full healing was attained.

RESULTS:
Ulcers treated with phototherapy healed significantly faster than controls when compared at day 30 (p +/- 0.01), day 60 (p +/- 0.05), and day 90 (p +/- 0.001), and similarly healed faster than the placebo-treated ulcers at days 30 and 90 (p +/- 0.01), but not at day 60. The beneficial effect of phototherapy was more pronounced when the confounding effect of small-sized ulcers was removed from the analysis. Medium- and large-sized ulcers healed significantly faster with treatment (>or=40% rate of healing per month) than placebo or control ulcers (p +/- 0.05).

CONCLUSION:
Phototherapy promotes healing of chronic venous ulcers, particularly large recalcitrant ulcers that do not respond to conventional treatment.

Source
Photomed Laser Surg. 2009 Feb;27(1):111-8. doi: 10.1089/pho.2008.2398.

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http://www.ncbi.nlm.nih.gov/pubmed/19196110

 

Low-level light stimulates excisional wound healing in mice

Demidova-Rice TN, Salomatina EV, Yaroslavsky AN, Herman IM, Hamblin MR.

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.

METHODS:
A 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.

RESULTS:
Wound 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/cm(2). 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 alpha-smooth muscle actin (SMA)-positive cells at the wound edge.

CONCLUSION:
LLLT stimulates wound contraction in susceptible mouse strains but the mechanism remains uncertain.

Source
Lasers Surg Med. 2007 Oct;39(9):706-15.

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http://www.ncbi.nlm.nih.gov/pubmed/17960752

 

Effect of LED phototherapy (λ700 ± 20 nm) on TGF-β expression during wound healing: an immunohistochemical study in a rodent model

de Sousa AP, de Aguiar Valença Neto Ade A, Marchionni AM, de Araújo Ramos M, dos Reis Júnior JA, Pereira MC, Cangussú MC, de Almeida Reis SR, Pinheiro AL.

OBJECTIVE:
The aim of the present investigation was to evaluate transforming growth factor β (TGF-β) expression on cutaneous wounds in rodents treated or not treated with LED light.

BACKGROUND:
TGF-β is a multifunctional cytokine that presents a central action during tissue repair. Although several studies both in vitro and in vivo have shown that LED phototherapy influences tissue repair, a full understanding of the mechanisms involved in its usage, such as in the modulation of some growth factors, remains unclear.

MATERIALS AND METHODS:
Under general anesthesia, 24 young adult male Wistar rats weighing 200-250 g had one excisional wound created on the dorsum of each, and were randomly distributed into two groups: G0 (Control) and G1 (LED, λ700 ± 20 nm, 16 mW, SAEF = 5 J/cm(2), Illuminated Area = 2 cm(2), 8 mWcm(2), 626 s) Each group was subdivided into three subgroups according to the animal death timing (2, 4, and 6 days). LED phototherapy started immediately after surgery and was repeated every other day during the experimental time. Following animal death, specimens were removed, routinely processed to wax, cut and immunomarked with polyclonal anti-TGF-β, and underwent histological analysis by light microscopy. The mean area of expression of each group was calculated. The data were statistically analyzed using ANOVA and Tukey's test.

RESULTS:
The area of the expression of TGF-β on LED-irradiated animals was significantly smaller than on controls at day 2 (p = 0.013). No significant difference was found at later times. It is concluded that the use of LED light, at these specific parameters, caused an inhibition of the expression of TGF-β at an early stage of the healing process.

Source
Photomed Laser Surg. 2011 Sep;29(9):605-11.

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http://www.ncbi.nlm.nih.gov/pubmed/21595552

 

Effect of LED phototherapy of three distinct wavelengths on fibroblasts on wound healing: a histological study in a rodent model

de Sousa AP, Santos JN, Dos Reis JA Jr, Ramos TA, de Souza J, Cangussú MC, Pinheiro AL.

AIM:
The aim of the present investigation was to evaluate histologically fibroblastic proliferation on dorsal cutaneous wounds in a rodent model treated or not with light-emitting diodes (LEDs) of three wavelengths.

BACKGROUND:
Fibroblasts secrete substances essential for wound healing. There are few reports of LED phototherapy on fibroblast proliferation, mainly in vivo.

ANIMALS AND METHODS:
Following approval by the Animal Experimentation Committee of the School of Dentistry of the Federal University of Bahia, we obtained 16 young adult male Wistar rats weighing between 200 and 250 g. Under general anesthesia, one excisional wound was created on the dorsum of each animal; they were then randomly distributed into four groups of four animals each: G0, untreated control; G1, red LED (700 +/- 20 nm, 15 mW, 10 J/cm(2)); G2, green LED (530 +/- 20 nm, 8 mW, 10 J/cm(2)); and G3, blue LED (460 +/- 20 nm, 22 mW, 10 J/cm(2)). The irradiation started immediately after surgery and was repeated every other day for 7 days. Animals were killed 8 days after surgery. The specimens were removed, routinely processed to wax, cut, and stained with hematoxylin/eosin (HE). Fibroblasts were scored by measuring the percentage of these cells occupying the area corresponding to wound healing on stained sections.

RESULTS:
The quantitative results showed that red LED (700 +/- 20 nm) and green LED (530 +/- 20 nm) showed a significant increase in fibroblast numbers (p < 0.01 and p = 0.02) when compared with the control group.

CONCLUSION:
The use of green and red LED light is effective in increasing fibroblastic proliferation on rodents.

Source
Photomed Laser Surg. 2010 Aug;28(4):547-52. doi: 10.1089/pho.2009.2605.

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http://www.ncbi.nlm.nih.gov/pubmed/20001321

 

Effect of multiple exposures of low-level laser therapy on the cellular responses of wounded human skin fibroblasts

Hawkins D, Abrahamse H.

OBJECTIVE:
This study aimed to establish the behavior of wounded human skin fibroblasts (HSF) after heliumneon (HeNe) (632.8 nm) laser irradiation using one, two, or three exposures of different doses, namely, 2.5, 5.0, or 16.0 J/cm(2) on each day for 2 consecutive days.

BACKGROUND DATA:
Low-level laser therapy (LLLT) is a form of phototherapy used to promote wound healing in different clinical conditions. LLLT at than adequate wavelength, intensity, and dose can accelerate tissue repair. However, there is still conflicting information about the effect of multiple irradiations on the cellular responses of wounded cells.

METHODS:
Cellular responses to HeNe laser irradiation were evaluated by measuring changes in cell morphology, cell viability, cell proliferation, and damage caused by multiple irradiations.

RESULTS:
A single dose of 5.0 J/cm(2), and two or three doses of 2.5 J/cm(2) had a stimulatory or positive effect on wounded fibroblasts with an increase in cell migration and cell proliferation while maintaining cell viability, but without causing additional stress or damage to the cells. Multiple exposures at higher doses (16 J/cm(2)) caused additional stress, which reduces cell migration, cell viability, and ATP activity, and inhibits cell proliferation.

CONCLUSION:
The results show that the correct energy density or fluence (J/cm(2)) and number of exposures can stimulate cellular responses of wounded fibroblasts and promote cell migration and cell proliferation by stimulating mitochondrial activity and maintaining viability without causing additional stress or damage to the wounded cells. Results indicate that the cumulative effect of lower doses (2.5 or 5 J/cm(2)) determines the stimulatory effect, while multiple exposures at higher doses (16 J/cm(2)) result in an inhibitory effect with more damage.

Source
Photomed Laser Surg. 2006 Dec;24(6):705-14.

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http://www.ncbi.nlm.nih.gov/pubmed/17199470

 

 

This website is intended for healthcare professionals and clinical researchers only. All of the treatments using LED phototherapy devices that are discussed on this website are in various stages of investigation and have not been approved by the FDA except where specifically stated.

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