Combined effects of metformin and photobiomodulation improve the proliferation phase of wound healing in type 2 diabetic rats.

We determined the impact of Photobiomodulation (PBM) and metformin administration alone and combined on the inflammation and proliferation steps of wound healing of incisions in type two diabetes mellitus (T2DM) rats. 40 rats were divided into 4 groups (n = 10 each group). A non-genetic model of T2DM was induced in all rats, and an incision was made on each rat. There were 4 groups as follows: Group 1 was control group. Group 2 received PBM alone (890 nm, 80 Hz, 0.324 J/cm2, daily). Group 3 received metformin alone (50 mg/kg, i.p., daily) and the fourth group received combination of PBM + metformin. At inflammation (day 4) and proliferation (day 7) steps, tensiometerical, stereological, and immunohistochemical examinations were performed. PBM and PBM + metformin treatments significantly increased wound strength at inflammation and proliferation steps of wound healing respectively. PBM, metformin, and PBM + metformin groups significantly decreased inflammatory cells at inflammation and proliferation steps of wound healing. PBM, metformin, and PBM + metformin groups significantly improved granulation tissue formation by increasing fibroblasts, and new blood vessel formation at inflammation and proliferation steps of wound healing. Metformin significantly increased M2 macrophages than other treatment groups at inflammation and proliferation steps of wound healing. Simultaneously, PBM significantly decreased M2 macrophages than control group. We concluded PBM and PBM + metformin treatments significantly hastened repair at the inflammation and proliferation steps of repairing skin injury in a non-genetic model of T2 DM. PBM + metformin showed a synergistic impact. There were not a positive relation between M2 macrophage number and wound strength in the studied groups. The details of the molecular mechanisms of PBM, and PBM + metformin treatments of repairing wounds in animals, and treatment of DFUs of patients with T2 DM should be elucidated by further research.

Effect of blue LED on the healing process of third-degree skin burns: clinical and histological evaluation.

The aim of this study was to evaluate the effects of blue light-emitting diode (LED) on the healing process of third-degree skin burns in rats through clinical and histological parameters. Forty male Wistar rats were divided into two groups: control (CTR) (n = 20) and blue LED (BLUE) (n = 20), with subgroups (n = 5) for each time of euthanasia (7, 14, 21, and 28 days). LED (470 nm, 1 W, 12.5 J/cm2 per point, 28 s) was applied at four points of the wound (total, 50 J/cm2). Feed intake was measured every other day. It was observed that there were no statistically significant differences in the Wound Retention Index (WRI) of the BLUE group in relation to CTR group (p > 0.05) at the evaluation times. After 14, 21, and 28 days, it was observed that the animals in the BLUE group consumed more feed than animals in the CTR group (p < 0.05). At 7 days, there was a statistically significant increase in the angiogenic index (AI) in BLUE (median: 6.2) when compared to CTR (median: 2.4) (p = 0.01) and all animals in BLUE had already started re-epithelialization. This study suggests that blue LED, at the dosimetry used, positively contributed in important and initial stages of the healing process of third-degree skin burns.

Effects of neodymium-yttrium-aluminum garnet (Nd:YAG) pulsed high-intensity laser therapy on full thickness wound healing in an experimental animal model.

OBJECTIVE: Wound healing can be aided by the use of low- and medium-intensity lasers. The use of pulsed neodymium-doped yttrium aluminum garnet (Nd:YAG) high-intensity laser therapy (HILT) with a 1064-nm wavelength laser provides deeper and more efficient penetration into tissue as it is being less absorbed by chromophores in tissue, e.g., hemoglobin, melanin, and water, thereby enhancing the wound-healing process. In this study, we examined the effect of HILT on wound healing with a Q-switched pulsed Nd:YAG laser in an animal model. DESIGN: Sixty SKH1 hairless male mice (seven weeks old) were randomly divided into four groups according to the amount of laser fluence: control, group 1 (0.8 J/cm2), group 2 (1.6 J/cm2), and group 3 (2.0 J/cm2). Laser treatment was provided to groups 1, 2, and 3 with a 1064-nm Q-switched Nd:YAG laser. Histological analysis was performed with hematoxylin and eosin staining, Masson's Trichrome staining, and Ki-67 staining. RESULTS: Statistically significant increases in the accumulation of collagen fibers, thickness of granulation tissue, and numbers of fibroblasts were observed in group 2 (treated with 1.6 J/cm2) as compared with the control (no laser treatment), group 1 (treated with 0.8 J/cm2), and group 3 (treated with 2.0 J/cm2). CONCLUSION: Nd:YAG HILT stimulated fibroblast proliferation and increased extracellular matrix production. We expect that this therapy could accelerate the wound-healing process.

Effect of Low-Power Laser (LPL) and Light-Emitting Diode (LED) on Inflammatory Response in Burn Wound Healing.

The aim of the study was to investigate the biochemical and molecular changes in the process of epidermal healing of burn injuries after therapeutic treatment with low-power laser (LPL) and light-emitting diode (LED). Rats were divided into six groups: skin without injury (Sham), burn wounds (BWs), BW + 660-nm LPL, BW + 904-nm LPL, BW + 632-nm LED, and BW + 850-nm LED. The burn wound model was performed using a 100 °C copper plate, with 10 s of contact in the skin. The irradiations started 24 h after the lesion and were performed daily for 7 days. The burn wound groups showed an increase in the superoxide production, dichlorofluorescein, nitrites, and high protein oxidative damage. The activities of glutathione peroxidase and catalase were also increased, and a significant reduction in glutathione levels was observed compared to the control group. However, treatments with 660-nm LPL and 850-nm LED promoted protection against to oxidative stress, and similar results were also observed in the IL-6 and pERK1/2 expression. Taken together, these results suggest that LPL 660 nm and LED 850 nm appear reduced in the inflammatory response and oxidative stress parameters, thus decreasing dermal necrosis and increasing granulation tissue formation, in fact accelerating the repair of burn wounds.

Low-level red laser improves healing of second-degree burn when applied during proliferative phase.

The aim of this study was to investigate the effects of low-level red laser on tissue repair in rats submitted to second-degree burn, evaluating if the timing of laser treatment influences the healing process. The animals had their backs shaved and divided as follows: control group (n = 12)-rats burned and not irradiated, early laser group (n = 12)-rats burned and irradiated from day 1 after injury for five consecutive days, and late laser group (n = 14)-rats burned and irradiated from day 4 after injury for five consecutive days. Laser irradiation was according to a clinical protocol (20 J/cm(2), 100 mW, continuous wave emission mode, 660 nm) as recommended by the laser device manufacturer. Half of the animals were sacrificed 10 days after burn, and the other animals were sacrificed 21 days after burn. The late laser group accelerated wound contraction 10 and 21 days after burn. The late laser group accelerated reepithelialization 18 days after burn. The late laser group increases the granulation tissue 10 and 21 days after burn. Both irradiated groups increased type III collagen expression and TGF-ß 21 days after burn. Both irradiated groups increased macrophage and myofibroblast numbers 10 days after burn and decreased 21 days after. Low-level red laser exposure contributes to the process of tissue repair of second-degree burns, but the intervention during proliferative phase is crucial in the final outcome of the repair process.

Low-level laser therapy (LLLT) at 830 nm positively modulates healing of tracheal incisions in rats: a preliminary histological investigation.

OBJECTIVE: The aim of the present study was to evaluate whether LLLT at 830 nm is able to positively modulate trachea incisional wound healing in Sprague-Dawley rats. BACKGROUND DATA: Tracheotomy may be associated with numerous complications. Development of excess granulation tissue represents a late complication that may lead to airway occlusion. Low-level laser therapy (LLLT) has been shown to have stimulatory effects on wound healing of different tissues. Therefore, it may be suggested that LLLT could be able to positively modulate trachea wound healing as well. MATERIALS AND METHODS: Using general anesthesia, a median incision was performed from the second to the fifth tracheal cartilage ring in 24 rats. Animals were then randomly divided into sham-irradiated control and laser-treated groups. LLLT (power density: 450 mW/cm(2); total daily dose: 60 J/cm(2); irradiated area ∼1 cm(2)) treatment was performed daily during the first week after surgery. Samples for histological evaluation were removed 7 and 28 days after surgical procedure. Histological sections were stained with hematoxylin-eosin and van Gieson. RESULTS: Results from our investigation showed that LLLT was able to reduce granulation tissue formation and simultaneously increase new cartilage development at both evaluated time intervals. CONCLUSIONS: From this point of view, LLLT at 830 nm may be a valuable tool in trachea wound healing modulation. Nevertheless, further detailed research is needed to find optimal therapeutic parameters and to test these findings on other animal models.

Effect of low-level treatment with an 80-Hz pulsed infrared diode laser on mast-cell numbers and degranulation in a rat model of third-degree burn.

BACKGROUND DATA: Low-level laser therapy (LLLT) has been reported to be capable of changing mast cell numbers and degranulation in experimental burns in rats. OBJECTIVE: We conducted a study of the influence of LLLT on mast cells in a rat model of third-degree burn. METHODS: In this study we divided 48 rats equally into two groups of 24 rats each. Third-degree burns were inflicted at three different locations on each rat in each group. The first burn site on rats in group I was treated with 890-nm pulsed laser, 75W peak, 80 Hz, 180 ns, average power 1mW, illuminated area 1 cm(2), 1 mW/cm(2), 856 sec, 0.924 J/cm(2). The second burn site on both groups of rats was treated with 0.2% nitrofurazone cream. Mast cell numbers and degranulation at each burn site on each group of rats were then assessed at 4, 8, 13, and 20 days after the infliction of burns. RESULTS: Analysis of variance on day 4 showed that the total numbers of mast cells were significantly lower at the laser-treated burn sites than at other burn sites on both groups of rats. On day 8 the total numbers of mast cells were again significantly lower at the laser-treated burn sites than at other burn sites, and on day 13, the numbers of both types 1 and 2 mast cells were significantly lower at the laser-treated burn sites than at other burn sites. CONCLUSIONS: We conclude that LLLT can significantly decrease total numbers of mast cells during the proliferation and remodeling phases of healing in a rat model of third-degree burn.

Laser photobiostimulation of wound healing: defining a dose response for splinted wounds in diabetic mice.

BACKGROUND AND OBJECTIVES: We have used a 660 nm, 80 mW 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). The purpose of our study was to examine the effects of irradiating the wounds for different time intervals in order to determine a dose response relationship. MATERIALS AND METHODS: A circular excisional wound was made on the left flank of diabetic mice using a 5-mm skin punch, and covered with a Tegaderm HP dressing. Mice were allocated to four groups in which wounds were irradiated 660 nm, 80 mW for 0, 10, 20, or 40 seconds each day for 7 days. In total, 51 mice were used. Wounds were harvested on day 14 and the healing assessed from hematoxylin-eosin stained sections examined by light microscopy. RESULTS: The wounds were splinted in 40 of the mice, and splinting caused a retardation of healing. The findings for the four treatments showed that irradiation for 20 second/day for 7 days brought about the greatest extent of healing. The wounds healed mainly by re-epithelization and granulation tissue formation. This duration of irradiation represents an energy dose of 1.6 J per irradiation and, for an estimated area of irradiation of 32-43 mm², corresponds to an energy density of 3.7-5.0 J/cm². CONCLUSION: Irradiation with 660 nm, 80 mW at an energy density of 3.7-5.0 J/cm² each day for 7 days caused the maximal stimulation of healing in splinted wounds of diabetic mice.

Phototherapy promotes healing of chronic diabetic leg ulcers that failed to respond to other therapies.

OBJECTIVE: We tested the hypothesis that combined 660 and 890 nm LED phototherapy will promote healing of diabetic ulcers that failed to respond to other forms of treatment. RESEARCH DESIGN AND METHODS: A double-blind randomized placebo controlled design was used to study 23 diabetic leg ulcers in two groups of 14 patients. Group one ulcers were cleaned, dressed with 1% silver sulfadiazine cream and treated with "placebo" phototherapy (<1.0 J cm(-2)) twice per week, using a Dynatron Solaris 705(R) device. Group two ulcers were treated similarly but received 3 J cm(-2) dose. RESULTS: At each of 15, 30, 45, 60, 75, and 90 days of healing, mean ulcer granulation and healing rates were significantly higher for group two than the "placebo" group (P < 0.02). While "placebo" treated ulcers worsened during the initial 30 days, group two ulcers healed rapidly; achieving 56% more granulation and 79.2% faster healing by day 30, and maintaining similarly higher rates of granulation and healing over the "placebo" group all through. By day 90, 58.3% of group two ulcers had healed fully and 75% had achieved 90-100% healing. In contrast, only one "placebo" treated ulcer healed fully by day 90; no other ulcer attained > or =90% healing. CONCLUSION: Combined 660 and 890 nm light promotes rapid granulation and healing of diabetic ulcers that failed to respond to other forms of treatment.

[Plasma technologies in treatment of purulent wounds].

The article is devoted to using plasma flow for treatment of purulent wounds. The authors have shown an anti-inflammatory, antibacterial, stimulating effect of plasma radiation on the basis of clinical methods of control of the wound process in 143 patients (hypothermia, pain syndrome in rest, the presence of purulent discharge, edema, granulation tissue).

Macroscopic and microscopic effects of GaAIAs diode laser and dexamethasone therapies on oral mucositis induced by fluorouracil in rats.

PURPOSE: To present an animal model for mucositis induced by fluorouracil in rats, and test two therapeutic options, the GaAIAs laser and topical dexamethasone, analysing them with regard to the quality and quantity of tissue alterations and comparing them with the phases of mucositis. MATERIALS AND METHODS: Forty-five Wistar rats (250 g) were treated with fluorouracil (60 mg/kg) and, in order to mimic the clinical effect of chronic irritation, the palatal mucosa was irritated by superficial scratching with an 18-gauge needle. When all of the rats presented oral ulcers of mucositis, they were randomly allocated to one of three groups: group I was treated with laser (GaAIAs), group II was treated with topical dexamethasone, and group III was not treated. Excisional biopsies of the palatal mucosa were then performed, and the rats were killed. Tissue sections were stained with haematoxylin and eosin for morphological analyses, and with toluidine blue for mast-cell counts. RESULTS: Group I specimens showed higher prevalence of ulcers, bacterial biofilm, necrosis and vascularisation, while group II specimens showed higher prevalance of granulation tissue formation. There were no significant statistical differences in the numbers of mast cells and epithelial thickness between groups. CONCLUSION: For the present model of mucositis, rats with palatal mucositis treated with laser (GaAIAs) showed characteristics compatible with the ulcerative phase of oral mucositis, and rats treated with topical dexamethasone showed characteristics compatible with the healing phase of mucositis. Topical dexamethasone was more efficient in the treatment of rats' oral mucositis than the laser.

Effect of low intensity helium-neon (He-Ne) laser irradiation on diabetic wound healing dynamics.

OBJECTIVE: 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. BACKGROUND DATA: 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. MATERIALS AND METHODS: 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. RESULTS: 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. CONCLUSION: Laser photostimulation promotes the tissue repair process of diabetic wounds.

Improvement of colonic healing by preoperative rectal irrigation with short-chain fatty acids in rats given radiotherapy.

BACKGROUND: We investigated the effect of preoperative rectal irrigation with short-chain fatty acids on irradiated colonic anastomosis in rats. METHODS: Sixty male Wistar rats were divided into four groups. Group I (control group, n = 15) underwent left colon resection and primary anastomosis. Group II (Short-chain fatty acids pretreatment group, n = 15) had short-chain fatty acids rectal irrigation for five days preoperatively. Group III (preoperative radiotherapy group, n = 15) underwent irradiation to the whole pelvis eight and four days before the operation, for a total dose of 20 Gy. Group IV (preoperative radiotherapy group + short-chain fatty acids pretreatment group, n = 15) had rectal irrigation with short-chain fatty acids for five days after the second irradiation. Within each group, animals were anesthetized to assess the clinical, mechanical, histologic, and biochemical parameters of anastomotic healing on either the third or seventh postoperative days. RESULTS: The mean bursting pressure was significantly low in Group III on Day 3 and was significantly high in Group IV on Day 7 (P = 0.001, P = 0.021). The burst occurred at the anastomoses in all animals tested on the third postoperative day, and outside of the anastomoses in all animals tested on the seventh postoperative day. The histologic parameters of anastomotic healing, such as epithelial regeneration and formation of granulation tissue, were significantly improved by use of preoperative rectal irrigation with short-chain fatty acids on Day 7. The amount of total and salt-soluble collagen concentrations significantly increased in Group IV compared with the control group on Day 3 (P = 0.008, P = 0.004). CONCLUSION: Some mechanical and histologic aspects of colonic anastomotic healing can be adversely affected by preoperative radiotherapy, but rectal irrigation with short-chain fatty acids may improve anastomotic healing.

Does low output laser stimulation enhance the healing of crural ulceration? Some critical remarks.

The objective of the experiment was to evaluate the impact of laser stimulation on crural ulceration healing. Three groups were established at random from patients with crural ulceration: A, B and C. Group A included 21 patients, group B included 22 patients and group C, 22 patients. Patients in all groups were treated with pharmaceuticals and with compressive therapy. The ulcers in group A were additionally irradiated with laser light of wavelength 810 nm, so that a dose of 4 J/cm2 was applied in each procedure. Patients in group B were additionally subjected to a blind test (with placebo in the form of quasi-laser therapy). At the end of the treatment a statistically significant reduction of the area and volume of the ulcers was found in all groups. No statistically significant difference was found between the groups in terms of average rate of change per week of the relative area of ulceration and average rate of change per week of the relative volume of ulceration. Reduction of infected area was observed in all groups, but a significant change was only observed in group C. No significant impact of laser light (lambda=810 nm, P=65 mW, p=4 J/cm2) on any of the stages of ulceration healing was observed.

Efeitos de baixas doses de radiaçäo sobre a gênese e a evoluçäo do tecido de granulaçäo / Effects of low doses of radiation on the genesis and evolution of granulation tissue

O presente trabalho teve por finalidade pesquisar a gênese e a evoluçäo do tecido de granulaçäo induzido experimentalmente em ratos, sob a açäo local de baixas doses de radiaçäo X, comparando-se os possíveis efeitos produzidos quando da aplicaçäo em dose única e em dose dividida com o tecido de granulaçäo normal. O tecido de granulaçäo foi estudado aos 2, 4, 7, 11, 14, 21 e 28 dias de evoluçäo. Os estudos realizados foram: técnica histofotométrica, com coloraçäo pelo azul de toluidina pH=4, para se verificar a síntese dos mucopolissacarídeos ácidos, e técnica de impregnaçäo pela prata, para se verificar o dicroísmo entre as fibras colágenas e a conseqüente organizaçäo macromolecular do tecido neoformado. Os animais foram divididos em 3 (três) grupos experimentais, sendo eles: controle, dose única (7,0 R) e dose dividida (7,0 R, divididos igualmente em três fraçöes). Os resultados encontrados mostraram näo haver efeitos qualitativos da radiaçäo X sobre a gênese e a evoluçäo do tecido de granulaçäo nestas condiçöes experimentais, pois näo observamos alteraçöes na organizaçäo do tecido de reparo