Photobiomodulation Improves Cutaneous Wound Healing in an Animal Model of Type II Diabetes

Physical Treatments and Therapies for Androgenetic Alopecia

Androgenetic alopecia, the most common cause of hair loss affecting both men and women, is typically treated using pharmaceutical options, such as minoxidil and finasteride. While these medications work for many individuals, they are not suitable options for all. To date, the only non-pharmaceutical option that the United States Food and Drug Administration has cleared as a treatment for androgenetic alopecia is low-level laser therapy (LLLT). Numerous clinical trials utilizing LLLT devices of various types are available. However, a myriad of other physical treatments for this form of hair loss have been reported in the literature. This review evaluated the effectiveness of microneedling, pulsed electromagnetic field (PEMF) therapy, low-level laser therapy (LLLT), fractional laser therapy, and nonablative laser therapy for the treatment of androgenetic alopecia (AGA). It also explores the potential of multimodal treatments combining these physical therapies. The majority of evidence in the literature supports LLLT as a physical therapy for androgenetic alopecia. However, other physical treatments, such as nonablative laser treatments, and multimodal approaches, such as PEMF-LLLT, seem to have the potential to be equally or more promising and merit further exploration.

Effect of a portable light emitting diode device on wound healing in a rat model

Light-emitting diode (LED) lights produce a variety of wavelengths that have demonstrable efficacy in therapeutic and aesthetic fields. However, a repetitive treatment regimen is required to produce treatment outcomes, which has created a need for portable LED devices. In this study, we aimed to develop a portable therapeutic LED device and investigate its healing effect on excisional wounds in a rat model. The 35 × 35 mm-sized LED device was used on a total of 30 rats with full-thickness wounds that were divided into two groups depending on radiation intensity (11.1 and 22.2 mW/cm2 group). LED irradiation was performed every 24 h for 30 min, over 14 days, in direct contact with the wound. Percentage wound closure was measured by photographic quantification and was assessed histologically using haematoxylin and eosin (H&E) and Masson's Trichrome staining, and immunohistochemistry for Vascular endothelial growth factor (VEGF) and CD31. Percentage wound closure was significantly higher in 22.2 mW/cm2 irradiated wounds than that in the control wounds on days 7 and 10. The area of collagen deposition was remarkably larger in 22.2 mW/cm2 irradiated wounds than that in the control, with more horizontally organized fibres. CD31 immunostaining confirmed a significant increase in the number of microvessels in 22.2 mW/cm2 irradiated wounds than that in the control wounds, although there was no difference in VEGF immunostaining. Our novel portable LED device accelerates wound healing in a rat model, raising the possibility that portable LED devices can combine convenience with accessibility to play an innovative role in wound dressing.

Efficacy of one-hour negative pressure wound therapy and magnetic field energy in wound healing

OBJECTIVE

Wound healing is an important aspect of health but needs further research to identify the effects and interactions of different treatment approaches on healing. The aims of this study were to investigate the effectiveness of one-hour negative pressure wound therapy (NPWT) and compare histological differences between one-hour NPWT and magnetic field energy (MFE) in rats on early-stage wound healing, wound size and angiogenesis.

METHOD

Standardised wounds were created on Wistar rats that were allocated and divided into NPWT, MFE and control groups. Both treatments were applied for 1 hour/day for 10 days. Wound size, histological changes and wound area blood flow were assessed.

RESULTS

The wound size of all groups was similar on days 0, 2 and 10. The MFE group's wound size was smaller than the NPWT group on days 4, 6 and 8 (p<0.05). Development of the granulation tissue in both the one-hour NPWT and MFE groups was greater than in the control group. Additionally, the inflammatory phase was shorter, and wounds entered the proliferative stage faster in the MFE group than both of the other groups.

CONCLUSION

Treatment with MFE may be more effective in terms of early stage wound closure and angiogenesis. On the other hand, the NPWT group's wound area blood flow was significantly greater than the other two groups. MFE is superior to one-hour NPWT in terms of wound area and angiogenesis. Furthermore, it is worthwhile to note that one-hour NPWT increases bloodflow in the wound area, which stimulates healing.

Novel Insights about Synergistic Effect of Zamzam Water with SGL2 Inhibitors on Wound Healing in STZ-Induced Diabetic Rats: The Role of anti-Inflammatory and Proangiogenic Effects

Background: Hyperglycemia usually impairs wound healing by dysregulating the inflammatory response and angiogenesis. This study aimed to examine the synergistic effect of dapagliflozin and Zamzam water (ZW) on the healing of diabetic wounds and to explore their anti-inflammatory and proangiogenic effects.Materials and methods: A full-thickness excisional wound was made on the backs of all groups after two weeks of diabetes induction. Forty rats were divided into five groups, with eight rats per group; Group 1: Control non-diabetic rats; Group II: Untreated diabetic rats; Group III: Diabetic rats drinking ZW; Group IV: Diabetic rats receiving an oral dose of 1 mg/kg dapagliflozin; and Group V: Received both dapagliflozin and ZW. The healing of diabetic wounds was assessed by measuring wound closure, oxidative stress markers, immunohistochemical staining of NF-βB, VEGF, CD34, CD45, Ki-67, and eNOS, gene expression of MMP-9, TGF-β1, EGF-b1, FGF, and Col1A1, protein levels of TNFα, IL-1β, IL6, Ang II, and HIF-1α by ELISA assay, and histological examination with H & E and Masson's trichrome. Combined treatment with dapagliflozin and ZW significantly (p < 0.05) enhanced the wound closure and antioxidant enzyme level, with apparent histological improvement, and shortened the inflammatory stage of the diabetic wound by decreasing the level of inflammatory markers NF-κB, TNF-α, IL-1β, IL6, and CD45. Therefore, it improved angiogenesis markers VEGF, CD34, eNOS, EGF-β1, FGF, Ang II, and HIF-1α, increasing Ki-67 cellular proliferation. Moreover, it enhanced the remodeling stage by increasing MMP-2, TGF-β1, and Col1A1 levels compared to diabetic rats.

Electromechanical therapy in diabetic foot ulcers patients: A systematic review and meta-analysis

Purpose

Diabetic foot ulcer (DFU) is one of the most devastating and troublesome consequences of diabetes. The current therapies are not always effective because of the complicated aetiology and interactions of local and systemic components in DFU. However, adjunctive therapy (electromechanical therapy) has become the latest modality in recent years, although there is a lack of significant research to support its utilization as a treatment standard. The purpose of this systematic research was to review the literature on the application of electromechanical therapies in the healing of DFUs.

Methods

For this systematic review, we searched PubMed, Medline, EmBase, the Cochrane library, and Google Scholar for the most current research (1990-2022) on electromechanical therapies for DFUs. We used the PICO method (where P is population, I is intervention, C is comparator/control, and O is outcome for our study) to establish research question with the terms [Electromechanical therapy OR Laser therapy OR photo therapy OR Ultrasound therapy OR Shockwave therapy] AND [diabetic foot ulcers OR diabetes] were used as search criteria. Searches were restricted to English language articles only. Whereas, Cochrane handbook of "Systematic Reviews of Interventions" with critical appraisal for medical and health sciences checklist for systematic review was used for risk of bias assessment. There were 39 publications in this study that were deemed to be acceptable. All the suitably selected studies include 1779 patients.

Results

The meta-analysis of 15 included research articles showed the overall effect was significant (P = 0.0002) thus supporting experimental groups have improvement in the DFUs healing in comparison to the control group.

Conclusion

This systematic review and meta-analysis revealed electromechanical treatments are significantly viable options for patients with DFUs. Electromechanical therapy can considerably reduce treatment ineffectiveness, accelerate healing, and minimize the time it takes for complete ulcer healing.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40200-023-01240-2.

Invitro impact of a combination of red and infrared LEDs, infrared laser and magnetic field on biomarkers of oxidative stress and hemolysis of erythrocytes sampled from healthy individuals and diabetes patients

AIMS

Low-intensity infrared laser irradiation with output emissions of the laser and LED for in vitro irradiation of plasma and erythrocyte samples collected from healthy individuals and diabetes mellitus (DM) patients was used in the current study.

METHODS

The generated emission was in the range 0.85-0.89 nm with pulse duration near 130 ns and repetition rates of pulses 50, 150, 600, and 1500 Hz, average power 0, 50, or 100 mW, in the range of 1-9 min for different 30 variants of irradiation. The levels of 2-thiobarbituric-acid reactive substances (TBARS), aldehydic and ketonic derivatives of oxidatively modified proteins (OMP), total antioxidant capacity (TAC), acid-induced resistance of erythrocytes, and activities of the main antioxidant enzymes were assessed in erythrocyte and plasma samples after irradiation.

RESULTS

The low-intensity infrared laser irradiation and low-intensity light emitted by a red LED decreased the lipid peroxidation levels in the erythrocytes of both healthy individuals and DM patients. A statistically significant decrease in TBARS and OMP levels and an increase in the TAC level were observed at the irradiation energy of 34.39 and 68.79 J/cm² for samples collected from both healthy individuals and DM patients. The effects of the irradiation were accompanied by a statistically significant decrease in catalase activity of both healthy individuals and DM patients.

CONCLUSIONS

In many variants of the laser irradiation and low-intensity light emitted by a red LED used in our study, a decrease in the percent of hemolyzed erythrocytes was observed, suggesting that laser therapy protocols should take into account fluencies, frequencies, and wavelengths of the laser before the beginning of treatment, especially in DM patients.

Quantitative Assessment of Low-Dose Photodynamic Therapy Effects on Diabetic Wound Healing Using Raman Spectroscopy

One of challenges that faces diabetes is the wound healing process. The delayed diabetic wound healing is caused by a complicated molecular mechanism involving numerous physiological variables. Low-dose photodynamic therapy (LDPDT) provides excellent results in rejuvenation and wound healing. In this study, the LDPDT effect on diabetic wounds in mice was studied using two photosensitizers, 5-aminolevulinic acid and methylene blue, and two laser dose expositions of 1 J/cm² and 4 J/cm² by Raman spectroscopy (RS). The latter was used as a noninvasive method, providing specific information about tissue state based on the fundamental vibrational modes of its molecular components. RS allows high spatial resolution acquisition of biochemical and structural information through the generation of point spectra or spectral images. An approach to in vivo quantitative assessment of diabetic wound healing state was developed. This approach is based on an application of the principal component analysis combined with the Mahalanobis metrics to skin Raman spectra, in particular, intensities of the amide I and CH₂ bands.

Recombinant Expression of Human IL-33 Protein and Its Effect on Skin Wound Healing in Diabetic Mice

Chronic refractory wounds are one of the complications of diabetes mellitus that require effective therapy. The dermal-wound-healing property of IL-33 in diabetics is little understood. Therefore, this study aimed to express recombinant humanized mature IL-33 (rhmatIL-33) in Escherichia coli BL21 (DE3) and demonstrate its efficacy on dermal wounds in streptozotocin (STZ)-induced diabetic and nondiabetic mice by the dorsal incisional skin wound model. Results revealed that the rhmatIL-33 accelerated the scratch-healing of keratinocytes and fibroblasts at the cellular level. The wounds of diabetic mice (DM) showed more severe ulceration and inflammation than wild-type mice (WT), and the exogenous administration of rhmatIL-33 increased wound healing in both diabetic and wild-type mice. Compared with the up-regulation of endogenous IL-33 mRNA after injury in WT mice, the IL-33 mRNA decreased after injury in DM mice. Exogenous IL-33 administration increased the endogenous IL-33 mRNA in the DM group but decreased the IL-33 mRNA expression level of the WT group, indicating that IL-33 plays a balancing role in wound healing. IL-33 administration also elevated ILC2 cells in the wounds of diabetic and non-diabetic mice and improve the transcript levels of YM1, a marker of M2 macrophages. In conclusion, Hyperglycemia in diabetic mice inhibited the expression of IL-33 in the dermal wound. Exogenous addition of recombinant IL-33 promoted wound healing in diabetic mice by effectively increasing the level of IL-33 in wound tissue, increasing ILC2 cells, and accelerating the transformation of macrophage M1 to M2 phenotype.

Impact of photobiomodulation on macrophages and their polarization during diabetic wound healing: a systematic review

This review aims to providing essential information and the current knowledge about the potential role of macrophages, especially their M2 subtypes in different diabetic wounds both in clinical and pre-clinical models under the influence of photobiomodulation (PBM). The long-term goal is to advance the macrophage-based therapies to accelerate healing of diabetic foot ulcers. We reviewed all databases provided by PubMed, Google Scholar, Scopus, Web of Science, and Cochrane precisely from their dates of inception to 25/10/2021. The keywords of Diabetes mellitus diseases, wound healing, macrophage, and photobiomodulation or low-level laser therapy were used in this systematic review.A total of 438 articles were initially identified in pubmed.ncbi.nlm.nih.gov (15 articles), Google scholar (398 articles), Scopus (18 articles), and Web of Science (7 articles). Four hundred sixteen articles that remained after duplicate studies (22 articles) were excluded. After screening abstracts and full texts, 14 articles were included in our analysis. Among them, 4 articles were about the effect of PBM on macrophages in type 2 diabetes and also found 10 articles about the impact of PBM on macrophages in type 1 diabetes. The obtained data from most of the reviewed studies affirmed that the PBM alone or combined with other agents (e.g., stem cells) could moderate the inflammatory response and accelerate the wound healing process in pre-clinical diabetic wound models. However, only very few studies conducted the detailed functions of polarized macrophages and M2 subtypes in wound healing of diabetic models under the influence of PBM. Further pre-clinical and clinical investigations are still needed to investigate the role of M2 macrophages, especially its M2c subtype, in the healing processes of diabetic foot ulcers in clinical and preclinical settings.

Pulsed low-intensity laser treatment stimulates wound healing without enhancing biofilm development in vitro

OBJECTIVES

Treating infected or chronic wounds burdened with biofilms still is a major challenge in medical care. Healing-stimulating factors lose their efficacy due to bacterial degradation, and antimicrobial substances negatively affect dermal cells. Therefore, alternative treatment approaches like the pulsed low intensity laser therapy (LILT) require consideration.

METHODS

The effect of pulsed LILT (904 nm, in three frequencies) on relevant human cells of the wound healing process (fibroblasts (BJ), keratinocytes (HaCaT), endothelial cells (HMEC), monocytes (THP-1)) were investigated in in-vitro and ex-vivo wound models with respect to viability, proliferation and migration. Antimicrobial efficacy of the most efficient frequency in cell biological analyses of LILT (3200 Hz) was determined in a human biofilm model (lhBIOM). Quantification of bacterial load was evaluated by suspension method and qualitative visualization was performed by scanning electron microscopy (SEM).

RESULTS

Pulsed LILT at 904 nm at 3200 Hz ± 50% showed the most positive effects on metabolic activity and proliferation of human wound cells in vitro (after 72 h - BJ: BPT 0.97 ± 0.05 vs. 0.75 ± 0.04 (p = 0.0283); HaCaT: BPT 0.79 ± 0.04 vs. 0.59 ± 0.02 (p = 0.0106); HMEC: 0.74 ± 0.02 vs. 0.52 ± 0.04 (p = 0.009); THP-1: 0.58 ± 0.01 vs. 0.64 ± 0.01 (p > 0.05) and ex vivo. Interestingly, re-epithelialization was stimulated in a frequency-independent manner. The inhibition of metabolic activity after TNF-α application was abolished after laser treatment. No impact of LILT on monocytes was detected. Likewise, the tested LILT regimens showed no growth rate reducing effects on three bacterial strains (after 72 h - PA: -1.03%; SA: -0.02%; EF: -1,89%) and one fungal (-2.06%) biofilm producing species compared to the respective untreated control. Accordingly, no significant morphological changes of the biofilms were observed after LILT treatment in the SEM.

CONCLUSIONS

Frequent application of LILT (904 nm, 3200 Hz) seems to be beneficial for the metabolism of human dermal cells during wound healing. Considering this, the lack of disturbance of the behavior of the immune cells and no growth-inducing effect on bacteria and fungi in the biofilm can be assigned as rather positive. Based on this combined mode of action, LILT may be an option for hard to heal wounds infected with persistent biofilms.

The In Vivo Quantitative Assessment of the Effectiveness of Low-Dose Photodynamic Therapy on Wound Healing Using Optical Coherence Tomography

The effect of low-dose photodynamic therapy on in vivo wound healing was investigated using optical coherence tomography. This work aims to develop an approach to quantitative assessment of the wound's state during wound healing including the effect of low-dose photodynamic therapy using topical application of two different photosensitizers, 5-aminolevulinic acid and methylene blue, and two laser doses of 1 J/cm2 and 4 J/cm2. It was concluded that the laser dose of 4 J/cm2 was better compared to 1 J/cm2 and allowed the wound healing process to accelerate.

In Vivo Quantification of the Effectiveness of Topical Low-Dose Photodynamic Therapy in Wound Healing Using Two-Photon Microscopy

The effect of low-dose photodynamic therapy on in vivo wound healing with topical application of 5-aminolevulinic acid and methylene blue was investigated using an animal model for two laser radiation doses (1 and 4 J/cm2). A second-harmonic-generation-to-auto-fluorescence aging index of the dermis (SAAID) was analyzed by two-photon microscopy. SAAID measured at 60-80 μm depths was shown to be a suitable quantitative parameter to monitor wound healing. A comparison of SAAID in healthy and wound tissues during phototherapy showed that both light doses were effective for wound healing; however, healing was better at a dose of 4 J/cm2.

Photobiomodulation at Different Wavelengths Boosts Mitochondrial Redox Metabolism and Hemoglobin Oxygenation: Lasers vs. Light-Emitting Diodes In Vivo

Our group previously examined 8 min photobiomodulation (PBM) by 1064 nm laser on the human forearm in vivo to determine its significant effects on vascular hemodynamics and cytochrome c oxidase redox activity. Since PBM uses a wide array of wavelengths, in this paper, we investigated (i) whether different wavelengths of lasers induced different PBM effects, and (ii) if a light-emitting diode (LED) at a similar wavelength to a laser could induce similar PBM effects. A broadband near-infrared spectroscopy (bbNIRS) system was utilized to assess concentration changes in oxygenated hemoglobin (Δ[HbO]) and oxidized cytochrome c oxidase (Δ[oxCCO]) during and after PBM with lasers at 800 nm, 850 nm, and 1064 nm, as well as a LED at 810 nm. Two groups of 10 healthy participants were measured before, during, and after active and sham PBM on their forearms. All results were tested for significance using repeated measures ANOVA. Our results showed that (i) lasers at all three wavelengths enabled significant increases in Δ[HbO] and Δ[oxCCO] of the human forearm while the 1064 nm laser sustained the increases longer, and that (ii) the 810-nm LED with a moderate irradiance (≈135 mW/cm²) induced measurable and significant rises in Δ[HbO] and Δ[oxCCO] with respect to the sham stimulation on the human forearm.

Photobiomodulation Therapy to Promote Angiogenesis in Diabetic Mice with Hindlimb Ischemia

Objective: To assess whether photobiomodulation therapy (PBMT) induces angiogenesis in diabetic mice with hindlimb ischemia (HLI). Background: Patients with diabetes mellitus (DM) are at high risk of developing peripheral arterial disease (PAD) in the lower extremities. PBMT has been shown to promote angiogenesis both in vitro and in vivo and could be a treatment for DM patients with PAD. Methods: Femoral artery ligation/excision in mice was performed to induce HLI as an animal model of PAD. PBMT at a dose of 660 nm and 1.91 J/cm² was delivered for 10 min on 5 consecutive days after the HLI surgery. Control mice received HLI only. Mice in the DM group were injected with streptozocin to induce diabetes before HLI surgery. Mice in the laser and DM+ laser groups received both HLI and PBMT, and the latter group had induced DM. After the laser treatment, lower limb blood flow was evaluated by laser Doppler. The capillary density and CD31 were analyzed by immunofluorescence staining, and protein levels of vascular endothelial growth factor (VEGF)-A, hypoxia-inducible factor-1α (HIF-1α), inducible nitric oxide synthase (iNOS), endothelial nitric oxide synthase (eNOS), and extracellular signal-regulated kinases (ERK) were measured by Western blotting of tissue samples. Results: Compared with the control and DM mice, the laser and DM+ laser groups had more than double the capillary density and blood perfusion rate. Levels of CD31 and VEGF-A proteins in groups that received laser were increased by 1.9- to 3.2-fold compared with groups that did not undergo laser treatment. Animals treated with PBMT exhibited significantly increased HIF-1α expression and ERK phosphorylation compared with animals that did not receive this treatment, and the amount of phospho-eNOS and iNOS increased and decreased, respectively. Conclusions: PBMT can induce therapeutic angiogenesis, indicating that low intensity laser could be a novel treatment for PAD patients.

Photobiomodulation in diabetic wound healing: A review of red and near-infrared wavelength applications

The development of a painless, non-invasive, and faster way to diabetic wound healing is at the forefront of research. The complexity associated with diabetic wounds makes it a cause for concern amongst diabetic patients and the world at large. Irradiation of cells generates a photobiomodulatory response on cells and tissues, directly causing alteration of cellular processes and inducing diabetic wound repair. Photobiomodulation therapy (PBMT) using red and near-infrared (NIR) wavelengths is being considered as a promising technique for speeding up the rate of diabetic wound healing, eradication of pain and reduction of inflammation through the alteration of diverse cellular and molecular processes. This review presents the extent to which the potential of red and NIR wavelengths have been harnessed in PBMT for diabetic wound healing. Important research challenges and gaps are identified and discussed, and future directions mapped out. This review thus provides useful insights and strategies into improvement of PBMT, including its acceptance within the global medical research community.

Improvement of full-thickness rat skin wounds by photobiomodulation therapy (PBMT): A dosimetric study

Basic dosimetric studies are necessary to support the use of photobiomodulation therapy (PBMT), since the great variety of laser parameters that are reported in the literature have created an obstacle to identifying reproducible results. Thus, the present study evaluates the process of tissue repair after the photobiomodulation therapy, taking into consideration the dose, frequency and the mode of energy delivery used. For this, 6 mm diameter wounds were created on dorsal skin of Wistar rats, and the animals were divided in control and irradiated groups, where L1 and L4 (irradiated with 1 point of 10 J/cm2), L2 and L5 (5 points of 10 J/cm2), L3 and L6 (1 point of 50 J/cm2), respectively for one or multiple days of irradiations. A diode laser, λ 660 nm, 40 mW of power and 0.028 cm2 of spot area was used. Our data showed that the group receiving multiple treatments over the first week post wounding, applied at 10 J/cm2 at each of 5 points on and around the wound (group L5) presented the best improvement of wound closure, higher cytokeratin 10, lower macrophage infiltration, and greater tissue resistance to rupture. We conclude that PBMT improves the skin wound healing process, and the outcomes were directly related to the chosen laser parameters and irradiation mode.

Efficacy of Biophysical Energies on Healing of Diabetic Skin Wounds in Cell Studies and Animal Experimental Models: A Systematic Review

We have systematically assessed published cell studies and animal experimental reports on the efficacy of selected biophysical energies (BPEs) in the treatment of diabetic foot ulcers. These BPEs include electrical stimulation (ES), pulsed electromagnetic field (PEMF), extracorporeal shockwave (ECSW), photo energies and ultrasound (US). Databases searched included CINAHL, MEDLINE and PubMed from 1966 to 2018. Studies reviewed include animal and cell studies on treatment with BPEs compared with sham, control or other BPEs. Information regarding the objective measures of tissue healing and data was extracted. Eighty-two studies were eventually selected for the critical appraisal: five on PEMF, four each on ES and ECSW, sixty-six for photo energies, and three about US. Based on the percentage of original wound size affected by the BPEs, both PEMF and low-level laser therapy (LLL) demonstrated a significant clinical benefit compared to the control or sham treatment, whereas the effect of US did not reveal a significance. Our results indicate potential benefits of selected BPEs in diabetic wound management. However, due to the heterogeneity of the current clinical trials, comprehensive studies using well-designed trials are warranted to confirm the results.

Efficacy of low-level light therapy for treatment of diabetic foot ulcer: A systematic review and meta-analysis of randomized controlled trials

AIMS

The goal of this systematic review and meta-analysis based on seven Randomized control trials (RCTs) is to examine whether Low-level light therapy (LLLT) is effective at healing diabetic foot ulcer (DFU) and to provide evidence-based recommendations and clinical guidelines for the future clinical treatment of DFUs.

METHODS

Medline, Embase, Scopus, Cochrane Library, and Web of Science databases were searched for studies published up to June 30, 2017, without language or data restrictions. RCTs that investigated the use of LLLT for DFU treatment were included. Standard methods of meta-analysis were performed to evaluate outcomes of LLLT on the healing of DFU.

RESULTS

Seven RCTs involving 194 participants were eligible for this systematic review and meta-analysis. The results of meta-analysis showed that LLLT has emerged as a potential noninvasive treatment for DFUs, as LLLT was found to effectively reduce the ulcer area [weighted mean difference (WMD) 34.18, 95% confidence intervals (CI) 19.38-48.99, P < 0.00001], improve the complete healing rate [odds ratio (OR) 6.72, 95% CI 1.99-22.64, P = 0.002]. Qualitative analysis of the included RCTs found that LLLT also played a role in the treatment of DFUs through promoting rapid granulation formation and shortening ulcer closure time, as well as alleviating foot ulcer pain. None of the treatment-related adverse event was reported.

CONCLUSIONS

LLLT was recognized as a potential method in the comprehensive treatment of DFUs. Further well designed and high-quality studies are required to confirm the role of LLLT in the management of DFUs.

Low level laser therapy induces increased viability and proliferation in isolated cancer cells

OBJECTIVES

Low level laser therapy (LLLT), which stimulates natural biological processes in the application region, is frequently used in dental treatments. The aim of our study was to evaluate the effects of LLLT which could activate precancerous cells or increase existing cancerous tissue in case of clinically undetectable situations.

MATERIALS AND METHODS

Saos-2 osteoblast-like osteosarcoma cells and A549 human lung carcinoma cells were used. Twenty-four hours after preparation of cell culture plates, laser irradiation was performed 1, 2 and 3 times according to the test groups using Nd:YAG laser with the power output 0.5, 1, 2 and 3 W. Cell proliferation analysis was performed by MTT assay at the 24th hour following the last laser applications.

RESULTS

Generally, it was observed that the proliferation rates increased as the number of applications increased, when compared to the controls, especially in those cases in which the irradiation was performed 2 or 3 times more.

CONCLUSION

The findings of this study have led to the conclusion that LLLT increases cancer cell proliferation, depending on the power output level of the laser and the number of applications. In addition to the proliferation and mitotic activity of the cancer tissue cells, we concluded that LLLT, which is frequently used in dental practice, could activate precancerous cells or increase existing cancerous tissue.

The effect of combined photobiomodulation and metformin on open skin wound healing in a non-genetic model of type II diabetes

This study intended to examine the combined influences of photobiomodulation (PBM) and metformin on the microbial flora and biomechanical parameters of wounds in a non-genetic model of type II diabetes mellitus (TII DM). We induced a non-genetic model of TII DM in 20 rats by feeding them a 10% fructose solution for 2weeks followed by an injection of streptozotocin (STZ, 40mg/kg). After 21days from the injection of STZ, we induced one full-thickness skin wound in each of the diabetic rats. We randomly divided the rats into four groups: i) placebo; ii) pulsed wave laser (890nm, 80Hz, 0.324J/cm²); iii) metformin; and iv) laser+metformin. Rats received daily intraperitoneal injections of metformin (50mg/kg). On days 7and 15 we inspected the microbial flora of each wound. On day 15 we obtained a standard sample from each healing wound for biomechanical analyses. PBM significantly decreased colony-forming units (CFUs) 7days after wound infliction compared to the placebo group (LSD test, p=0.012). Metformin significantly enhanced the biomechanical property (stress high load) of the wounds compared to the placebo group (LSD test, p=0.028). We observed the same significant result for PBM compared to the placebo group (LSD test, p=0.047). PBM significantly accelerated the wound healing process and significantly reduced CFUs of bacteria in a non-genetic rat model of TII DM.

Curcumol Promotes Vascular Endothelial Growth Factor (VEGF)-Mediated Diabetic Wound Healing in Streptozotocin-Induced Hyperglycemic Rats

BACKGROUND Wound healing in chronic diabetic mellitus is mainly associated with the management of angiogenesis. The angiogenic mechanism of vascular endothelial growth factor (VEGF) has been widely studied in the context of diabetic ulcers. The aim of this study was to investigate the wound-healing potential of curcumol in streptozotocin-induced diabetic rats. MATERIAL AND METHODS Sixty male SD (Sprague Dawley) rats were purchased and randomly assigned into four groups: a control group and a model group treated with blank ointment, a high-dose curcumol group, and a low-dose curcumol group. The number of animals in each group was 15. Diabetes was induced by an intraperitoneal injection of streptozotocin. Two cutaneous wounds were incised at the dorsal region of all the experimental animals. Wound healing was assessed for all animal groups by observing the rate of wound closure. The expression of VEGF at the wound sites was studied by immunohistochemical staining to evaluate the vascular endothelial cell reaction. VEGF protein and related mRNA levels were analyzed by Western blotting and RT-PCR (reverse transcription-polymerase chain reaction). RESULTS Curcumol treatment significantly increased the rates of wound closure in treated animals, and hence wound healing was drastically enhanced for treatment groups compared to control groups. Histological observations and related mRNA and protein levels showed a higher VEGF expression in the treatment groups. CONCLUSIONS Our analyses clearly suggested that the observed enhancement in wound healing as a result of curcumol administration was attributable to VEGF-mediated angiogenesis.

Wound-Healing potential of Sebastiania hispida (Mart.) Pax (Euphorbiaceae) ointment compared to low power laser in rats

Abstract Impaired wound healing represents a serious complication in some pathologies and the use of plant extracts has proved to improve tissue repair. The objectives of this study were to evaluate the healing potential of the ointment of Sebastiana hispida compared with Aluminum-Gallium Indium-Phosphide Laser (InGaAlP) in surgically induced wounds in rats and to perform the phytochemical analysis. The phytochemical analysis was performed in the classic way and also by HPLC. A controlled study was developed with 80 rats (200-250 g) in which a linear excision was performed in the dorsal region after shaving, measuring 2 cm × 1 cm (epidermis and dermis) exposing the muscle fascia. The rats were randomly divided into four groups of twenty animals each. The experimental groups (n = 5) were G1 (Saline); G2 (crude methanol plant extract 2% + Carbopol Gel 98%); G3 (crude methanol plant extract 2% + lanolin/vaseline) and G4 (laser). The incision healing processes were monitored during 3, 7, 14 and until 21 days after excision. The histologic parameters evaluated were Collagen fiber types, microscopic examination and neovascularization. There was a significant increase in the deposition of collagen fibers, as evidenced by a better organized epithelial tissue, keratinized and showing greater proliferation of new blood vessels in the inflammatory phase in the group treated with both the extract and laser. The results were correlated to the phenolic derivatives found after qualitative and quantitative analysis. These compounds were considered responsible for the healing process. The topical treatment with S. hispida leaves, in the two different formulations, was more effective than the application of the laser (Ingan ALP) 660 nm in the model used.

Organic light emitting diode improves diabetic cutaneous wound healing in rats

A major complication for diabetic patients is chronic wounds due to impaired wound healing. It is well documented that visible red wavelengths can accelerate wound healing in diabetic animal models and patients. In vitro and in vivo diabetic models were used to investigate the effects of organic light emitting diode (OLED) irradiation on cellular function and cutaneous wound healing. Human dermal fibroblasts were cultured in hyperglycemic medium (glucose concentration 180 mM) and irradiated with an OLED (623 nm wavelength peak, range from 560 to 770 nm, power density 7 or 10 mW/cm2 at 0.2, 1, or 5 J/cm2). The OLED significantly increased total adenosine triphosphate concentration, metabolic activity, and cell proliferation compared with untreated controls in most parameters tested. For the in vivo experiment, OLED and laser (635 ± 5 nm wavelength) treatments (10 mW/cm2 , 5 J/cm2 daily for a total of seven consecutive days) for cutaneous wound healing were compared using a genetic, diabetic rat model. Both treatments had significantly higher percentage of wound closure on day 6 postinjury and higher total histological scores on day 13 postinjury compared with control. No statistical difference was found between the two treatments. OLED irradiation significantly increased fibroblast growth factor-2 expression at 36-hour postinjury and enhanced macrophage activation during initial stages of wound healing. In conclusion, the OLED and laser had comparative effects on enhancing diabetic wound healing.

Photoactivation of Dok1/ERK/PPARγ signaling axis inhibits excessive lipolysis in insulin-resistant adipocytes

Insulin resistance is a hallmark of the metabolic syndrome and type 2 diabetes. Increased plasma FFA level is an important cause of obesity-associated insulin resistance. Over-activated ERK is closely related with FFA release from adipose tissues in patients with type 2 diabetes. Nevertheless, there are no effective strategies to lower plasma FFA level. Low-power laser irradiation (LPLI) has been reported to regulate multiple biological processes. However, whether LPLI could ameliorate metabolic disorders and the molecular mechanisms involved remain unknown. In this study, we first demonstrated that LPLI suppresses excessive lipolysis of insulin-resistant adipocytes by activating tyrosine kinases-1(Dok1)/ERK/PPARγ pathway. Our data showed that LPLI inhibits ERK phosphorylation through the activation of Dok1, resulting in decreased phospho-PPARγ level. Non-phosphorylated PPARγ maintains in nucleus to promote the expression of adipogenic genes, reversing excessive lipolysis in insulin-resistant adipocytes. In summary, the present research highlights the important roles of Dok1/ERK/PPARγ pathway in lowering FFA release from adipocytes, and our research extends the knowledge of the biological effects induced by LPLI.

Effects of low-power light therapy on wound healing: LASER x LED

Several studies demonstrate the benefits of low-power light therapy on wound healing. However, the use of LED as a therapeutic resource remains controversial. There are questions regarding the equality or not of biological effects promoted by LED and LASER. One objective of this review was to determine the biological effects that support the use of LED on wound healing. Another objective was to identify LED´s parameters for the treatment of wounds. The biological effects and parameters of LED will be compared to those of LASER. Literature was obtained from online databases such as Medline, PubMed, Science Direct and Scielo. The search was restricted to studies published in English and Portuguese from 1992 to 2012. Sixty-eight studies in vitro and in animals were analyzed. LED and LASER promote similar biological effects, such as decrease of inflammatory cells, increased fibroblast proliferation, stimulation of angiogenesis, granulation tissue formation and increased synthesis of collagen. The irradiation parameters are also similar between LED and LASER. The biological effects are dependent on irradiation parameters, mainly wavelength and dose. This review elucidates the importance of defining parameters for the use of light devices.

Are the mitochondrial respiratory complexes blocked by NO the targets for the laser and LED therapy?

Effects of laser (442 and 532 nm) and light-emitting diode (LED) (650 nm) radiation on mitochondrial respiration and mitochondrial electron transport rate (complexes II-III and IV) in the presence of nitric oxide (NO) were investigated. It was found that nitric oxide (300 nM-10 μM) suppresses mitochondrial respiration. Laser irradiation of mitochondria (442 nm, 3 J cm(-2)) partly restored mitochondrial respiration (approximately by 70 %). Irradiation with green laser (532 nm) or red LED (650 nm) in the same dose had no reliable effect. Evaluation of mitochondrial electron transport rate in complexes II-III and IV and effects of nitric oxide demonstrated almost similar sensitivity of complex II-III and IV to NO, with approximately 50 % inhibition at NO concentration of 3 μM. Subsequent laser or LED irradiation (3 J cm(-2)) showed partial recovery of electron transport only in complex IV and only under irradiation with blue light (442 nm). Our results support the hypothesis of the crucial role of cytochrome c oxidase (complex IV) in photoreactivation of mitochondrial respiration suppressed by NO.

Evaluating the effect of low-level laser therapy on healing of tentomized Achilles tendon in streptozotocin-induced diabetic rats by light microscopical and gene expression examinations

Tendon healing is impaired in individuals diagnosed with diabetes mellitus (DM). According to research, there is considerable improvement in the healing of surgically tenotomized Achilles tendons following low-level laser therapy (LLLT) in non-diabetic, healthy animals. This study uses light microscopic (LM) and semi-quantitative reverse transcription PCR (RT-PCR) analyses to evaluate the ability of LLLT in healing Achilles tendons from streptozotocin-induced diabetic (STZ-D) rats. A total of 88 rats were randomly divided into two groups, non-diabetic and diabetic. DM was induced in the rats by injections of STZ. The right Achilles tendons of all rats were tenotomized 1 month after administration of STZ. Laser-treated rats were treated with a helium-neon (He-Ne) laser that had a 632.8-nm wavelength and 7.2-mW average power. Experimental group rats received a daily dose of 0.014 J (energy density, 2.9 J/cm(2)). Control rats did not receive LLLT. Animals were sacrificed on days 5, 10, and 15 post-operatively for semi-quantitative LM and semi-quantitative RT-PCR examinations of transforming growth factor-beta1 (TGF-β1) gene expression. The chi-square test showed that LLLT significantly reduced inflammation in non-diabetic rats compared with their non-diabetic controls (p = 0.02). LLLT significantly decreased inflammation in diabetic rats on days 5 (p = 0.03) and 10 (p = 0.02) compared to the corresponding control diabetic rats. According to the student's t test, LLLT significantly increased TGF-β1 gene expression in healthy (p = 0.000) and diabetic (p = 0.000) rats compared to their relevant controls. The He-Ne laser was effective in altering the inflammatory reaction and increasing TGF-β1 gene production.

Effects of low intensity laser irradiation during healing of infected skin wounds in the rat

BACKGROUND AND OBJECTIVE

Low intensity laser irradiation remains a controversial treatment for non-healing wounds. This study examines the effect of low intensity light on healing of infected skin wounds in the rat.

MATERIALS AND METHODS

Wounds on the rat dorsum were inoculated with Pseudomonas aeruginosa. Wounds were irradiated or sham-irradiated three times weekly from day 1 to 19 using 635-nm or 808-nm diode lasers delivering continuous wave (CW) or intensity modulated (3800 Hz) laser radiation, all at radiant exposures of 1 and 20 J/cm². Wound area and bacterial growth on the wound surface were evaluated three times a week. Histological and immunohistochemical analyses were performed at day 8 and 19.

RESULTS

Wounds that were irradiated using a wavelength of 635 nm (1 and 20 J/cm²) or intensity modulated 808-nm laser light at 20 J/cm² were smaller in area at day 19 than the sham-irradiated controls (achieved significance level=0.0105-0.0208) and were similar to controls in respect of bacterial growth. The remaining light protocols had no effect on wound area at day 19 although they increased Staphylococcus aureus growth across the time line compared with controls (p<0.0001 to p<0.004). CW 808-nm light at 20 J/cm² significantly delayed half-heal time. Histological and immunohistochemical analyses supported wound closure findings: improved healing was associated with faster resolution of inflammation during the acute phase and increased signs of late repair at day 19. Significant inflammation was seen at day 19 in all irradiated groups regardless of radiant exposure, except when using 635 nm at 1 J/cm².

CONCLUSIONS

Red light improved healing of wounds. Only one 808-nm light protocol enhanced healing; lack of benefit using the remaining 808-nm light protocols may have been due to stimulatory effects of the light on S. aureus growth.

Histological and gene expression analysis of the effects of pulsed low-level laser therapy on wound healing of streptozotocin-induced diabetic rats

Diabetes mellitus (DM) is associated with poor wound healing. Studies have shown accelerated wound healing following pulsed low-level laser therapy (LLLT) in non-diabetic animals. The present study aims to evaluate the effect of pulsed LLLT on wound healing in streptozotocin-induced diabetic (STZ-D) rats. We divided 48 rats into two groups of non-diabetic and diabetic. Type 1 DM was induced in the diabetic rat group by injections of STZ. Two, full-thickness skin incisions were made on the dorsal region of each rat. One month after the STZ injection, wounds of the non-diabetic and diabetic rats were submitted to a pulsed, infrared 890-nm laser with an 80-Hz frequency and 0.2 J/cm(2) for each wound point. Control wounds did not receive LLLT. Animals were sacrificed on days 4, 7, and 15 post-injury for histomorphometry and reverse transcription polymerase chain reaction (RT-PCR) analyses of basic fibroblast growth factor (bFGF) gene expression. Pulsed LLLT significantly increased the numbers of macrophages, fibroblasts, and blood vessel sections compared to the corresponding control groups. Semi-quantitative analysis of bFGF gene expression at 48 h post-injury revealed a significant increase in gene expression in both non-diabetic and diabetic rats following LLLT (the ANOVA test). Pulsed LLLT at 0.2 J/cm(2) accelerated the wound healing process in both non-diabetic and diabetic rats as measured by histological characteristics and semi-quantitative bFGF gene expression.

808 nm wavelength light induces a dose-dependent alteration in microglial polarization and resultant microglial induced neurite growth

BACKGROUND AND OBJECTIVE

Despite the success of using photobiomodulation (PBM), also known as low level light therapy, in promoting recovery after central nervous system (CNS) injury, the effect of PBM on microglia, the primary mediators of immune and inflammatory response in the CNS, remains unclear. Microglia exhibit a spectrum of responses to injury, with partial or full polarization into pro- and anti-inflammatory phenotypes. Pro-inflammatory (M1 or classically activated) microglia contribute to chronic inflammation and neuronal toxicity, while anti-inflammatory (M2 or alternatively activated) microglia play a role in wound healing and tissue repair; microglia can fall anywhere along this spectrum in response to stimulation.

MATERIALS AND METHODS

The effect of PBM on microglial polarization therefore was investigated using colorimetric assays, immunocytochemistry, proteomic profiling and RT-PCR in vitro after exposure of primary microglia or BV2 microglial cell line to PBM of differing energy densities (0.2, 4, 10, and 30 J/cm(2) , 808 nm wavelength, 50 mW output power).

RESULTS

PBM has a dose-dependent effect on the spectrum of microglial M1 and M2 polarization. Specifically, PBM with energy densities between 4 and 30 J/cm(2) induced expression of M1 markers in microglia. Markers of the M2 phenotype, including CD206 and TIMP1, were observed at lower energy densities of 0.2-10 J/cm(2) . In addition, co-culture of PBM or control-treated microglia with primary neuronal cultures demonstrated a dose-dependent effect of PBM on microglial-induced neuronal growth and neurite extension.

CONCLUSION

These data suggest that the Arndt-Schulz law as applied to PBM for a specific bioassay does not hold true in cells with a spectrum of responses, and that PBM can alter microglial phenotype across this spectrum in a dose-dependent manner. These data are therefore of important relevance to not only therapies in the CNS but also to understanding of PBM effects and mechanisms.

Effect of low-level laser therapy on the release of interleukin-6 and basic fibroblast growth factor from cultured human skin fibroblasts in normal and high glucose mediums

INTRODUCTION

This study evaluated the effects of low-level laser therapy (LLLT) on human skin fibroblasts (HSFs) that have been cultured in high glucose concentration media.

MATERIALS AND METHODS

HSFs were cultured under physiological glucose condition medium, and then cultured in high glucose concentration medium (15 mM/L) for 1 or 2 weeks prior to LLLT. Experimental HSFs were irradiated with three energy densities (0.5, 1, and 2 J/cm(2)) once daily for three consecutive days. Release of interleukin-6 (IL-6) and basic fibroblast growth factor (bFGF) was evaluated using the enzyme-linked immunosorbent assay (ELISA) method.

RESULTS

Statistical analysis showed three doses of 0.5 (p = 0.049), 1 (p = 0.027), and 2 J/cm(2) (p = 0.004) stimulated the release of IL-6 in HSFs cultured in high glucose concentration medium compared with that of non-irradiated HSFs that were cultured in the same medium. LLLT with 2 J/cm(2) induced the release of bFGF from HSFs cultured in high glucose concentration medium for 1 or 2 weeks (both p = 0.04).

CONCLUSION

Our study showed that LLLT stimulated the release of IL-6 and bFGF from HSFs cultured in high glucose concentration medium. LLLT was more effective in releasing IL-6 and bFGF while HSFs which were cultured in physiologic glucose concentration medium during laser irradiation.

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

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.

Inibição da expressão de ciclooxigenase 2 em feridas cutâneas de camundongos NOD submetidos à terapia a laser de baixa intensidade

CONTEXTO: A terapia a laser de baixa intensidade (LLLT) tem sido relatada como importante moduladora da cicatrização de feridas cutâneas aumentando a proliferação fibroblástica associada ao aumento da expressão da citocina fator transformador de crescimento- β2 (TGF-βB2). OBJETIVO: No presente estudo foram avaliados os efeitos da LLLT sobre a expressão da enzima ciclooxigenase 2 (COX2) no sítio do reparo tecidual utilizando o modelo experimental com camundongos diabéticos não obesos (NOD) para estudar a cicatrização de feridas cutâneas. MÉTODOS: Foram utilizados 30 camundongos NOD, destes 14 ficaram diabéticos e foram divididos em dois grupos: o grupo I (n=7) foi submetido a um procedimento cirúrgico de feridas cutâneas e o grupo II (n=7) foi submetido a um procedimento cirúrgico de feridas cutâneas e tratados com LLLT. O grupo II foi submetido à LLLT nos seguintes parâmetros: 15 mW de potência, dose de 3,8 J/cm² e tempo de aplicação de 20 segundos. Após sete dias do ato cirúrgico e após aplicação do laser, os animais foram eutanasiados com sobredose de anestesia e amostras das feridas foram colhidas para posterior análise histopatológica, histomorfométrica e imuno-histoquímica. RESULTADOS: A LLLT promoveu a inibição da expressão da COX2 em feridas cutâneas de camundongos diabéticos. CONCLUSÃO: Em conjunto, os resultados sugeriram que a LLLT é capaz de modular negativamente a expressão da enzima COX2 contribuindo para o controle da resposta inflamatória em feridas cutâneas de camundongos NOD.

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

Introduction:

Light-emitting diode (LED) therapy uses different wavelengths of light and has been reported to accelerate cutaneous wound healing. Carnosic acid is an antioxidant that is also thought to be photoprotective. We designed an in vitro study to examine the effects of LED and carnosic acid on the proliferation and migration of human keratinocytes.

Materials and Methods:

Clinically normal human keratinocytes were cultured and exposed to two wavelengths: 620 nm and 660 nm LED at different fluences. In the second part of this study, a different batch of human keratinocytes was grown in culture, and different concentrations of carnosic acid were added.

Results:

At the two wavelengths that were used, LED did not appear to have any therapeutic effect and was not effective in stimulating keratinocyte proliferation. Exposure to greater energy levels (increased fluence) produced increased cell damage that was directly proportional to the increase in energy. On the other hand, treatment of the cell cultures with the antioxidant carnosic acid resulted in an increase of keratinocyte cell proliferation, and this increase was also proportional to the concentration of carnosic acid.

Conclusions:

This study did not support the hypothesis that LED treatment results in keratinocyte proliferation; however, carnosic acid, a potent antioxidant, stimulated keratinocyte production and could be implicated in wound healing and rejuvenation.

Spectroscopic and histological evaluation of wound healing progression following Low Level Laser Therapy (LLLT)

The present study focuses on the evaluation of the effect of He-Ne laser on tissue regeneration by monitoring collagen synthesis in wound granulation tissues in Swiss albino mice using analysis of laser induced fluorescence (LIF) and light microscopy techniques. The spectral analyses of the wound granulation tissues have indicated a dose dependent increase in collagen levels during the post-wounding days. The histological examinations on the other hand have also shown a significant increase in collagen deposition along with the reduced edema, leukocytes, increased granulation tissue, and fibroblast number in the optimal laser dose treated group compared to the non-illuminated controls.

Healing activity of laser InGaAlP (660nm) in rats

PURPOSE: To evaluate the effect the healing activity of diode laser Indium Gallium Aluminum Phosphorus (InGaAlP) ë660nm on healing of surgical wounds in rats. METHODS: Fifty-four female Wistar rats were used, divided into three groups (n=18) and subdivided into three subgroups (n=6) to be studied in 5, 10 and 15th days after surgical procedures. The wound was induced in the dorsal-cervical using punch. The lesions were irradiated on alternate days with InGaAlP laser, the energy densities of 3J/cm² (L3) or 6J/cm² (L6). The control group received no irradiation. At 5, 10 and 15th days after surgery the animals were euthanized and the repair area was removed and histological sections were stained with hematoxylin-eosin and picrossírius. We evaluated macroscopic and histological lesions in the times cited, as well as morphometric analysis of angiogenesis and collagen content. RESULTS: The wound healing activity InGaAlP laser was evidenced by increased angiogenesis group L3 and L6 in relation to control group (CG) at the 5th day (p=0.0001) and decreased polymorphonuclear infiltrate and hemorrhage (p=0.045 and p=0.07 respectively) in the groups L3 and L6 in relation to control group (GC). On the 10 and 15th days was also observed in groups treated with laser L3 and L6 stimulation was pronounced fibroplasia (p=0.0003 and p=0.034 respectively) when compared with the control group (CG). CONCLUSION: The InGaAlP laser acted positively on the healing of skin wounds in rats.