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

Adipose stromal vascular fraction: a promising treatment for severe burn injury

Thermal skin burn injury affects both adults and children globally. Severe burn injury affects a patient's life psychologically, cosmetically, and socially. The pathophysiology of burn injury is well known. Due to the complexity of burn pathophysiology, the development of specific treatment aiding in tissue regeneration is required. Treatment of burn injury depends on burn severity, size of the burn and availability of donor site. Burn healing requires biochemical and cellular events to ensure better cell response to biochemical signals of the healing process. This led to the consideration of using cell therapy for severe burn injury. Adult mesenchymal stem cells have become a therapeutic option because of their ability for self-renewal and differentiation. Adipose stromal vascular fraction (SVF), isolated from adipose tissues, is a heterogeneous cell population that contains adipose-derived stromal/stem cells (ADSC), stromal, endothelial, hematopoietic and pericytic lineages. SVF isolation has advantages over other types of cells; such as heterogeneity of cells, lower invasive extraction procedure, high yield of cells, and fast and easy isolation. Therefore, SVF has many characteristics that enable them to be a therapeutic option for burn treatment. Studies have been conducted mostly in animal models to investigate their therapeutic potential for burn injury. They can be used alone or in combination with other treatment options. Treatment with both ADSCs and/or SVF enhances burn healing through increasing re-epithelization, angiogenesis and decreasing inflammation and scar formation. Research needs to be conducted for a better understanding of the SVF mechanism in burn healing and to optimize current techniques for enhanced treatment outcomes.

Effects of photobiomodulation therapy with red LED on inflammatory cells during the healing of skin burns

The aim of this study was to evaluate the effects of red light emitting diode (LED) photobiomodulation therapy protocol on inflammatory cells during the healing of third-degree skin burns. Fifty Wistar rats were randomly divided into control group (CTRL) (n = 25) and red group (RED) (n = 25), with subgroups (n = 5) for each time of euthanasia (7, 14, 21, 28, and 32 days). Treatment animals were daily irradiated (630 nm ± 10 nm, 300 mW, 9 J/cm² per point, 30 s, continuous emission mode) at the 4 angles of the wound (total: 36 J/cm²). After specimen removal, histological sections were stained with hematoxylin and eosin for quantitative analysis of the inflammatory infiltrate (neutrophils and lymphocytes) under light microscopy. Greater number of inflammatory cells was observed in irradiated groups when compared to CTRL at 7, 14, 21, and 28 days, but with statistically significant difference only at 14 days (p = 0.02). At 32 days, higher inflammatory cell value was observed in CTRL when compared to RED, but with no statistically significant difference (p = 0.91). The results suggest that red LED, according to the protocol used, modulates the number of inflammatory cells in the early stages of the healing of third-degree skin burns. Nevertheless, this low-intensity light therapy may not, be efficient in reducing the number of neutrophils and lymphocytes in advanced stages of the repair process of skin burns. Further studies with other therapy protocols are needed to assess the effects of this type of light on the inflammatory response of skin burns.

Photobiomodulation therapy upregulates the growth kinetics and multilineage differentiation potential of human dental pulp stem cells-an in vitro Study

This study aims to evaluate the impact of red LED irradiation on the viability, proliferation, colonogenic potential, markers expression along with osteogenic and chondrogenic differentiation of dental pulp stem cells. DPSCs were isolated from sound human permanent teeth using enzymatic digestion method and seeded with regular culture media. Cells at P4 were irradiated using red LED Light (627 nm, 2 J/cm²) and examined for growth kinetics, and multilineage differentiation using the appropriate differentiation media. The irradiated groups showed an increase in cellular growth rates, cell viability, clonogenic potential, and decrease in population doubling time compared to the control group. Cells of the irradiated groups showed enhanced differentiation towards osteogenic and chondrogenic lineages as revealed by histochemical staining using alizarin red and alcian blue stains. Photobiomodulation is an emerging promising element of tissue engineering triad besides stem cells, scaffolds, and growth factors.

Electromedical devices in wound healing management: a narrative review

Wound healing is the sum of physiological sequential steps, leading to skin restoration. However, in some conditions, such as diabetes, pressure ulcers (PU) and venous legs ulcers (VLU), healing is a major challenge and requires multiple strategies. In this context, some electromedical devices may accelerate and/or support wound healing, modulating the inflammatory, proliferation (granulation) and tissue-remodelling phases. This review describes some helpful electromedical devices including: ultrasonic-assisted wound debridement; electrotherapy; combined ultrasound and electric field stimulation; low-frequency pulsed electromagnetic fields; phototherapy (for example, laser therapy and light-emitting diode (LED) therapy); biophotonic therapies, and pressure therapies (for example, negative pressure wound therapy, and high pressure and intermittent pneumatic compression) The review focuses on the evidence-based medicine and adequate clinical trial design in relation to these devices.

Effects of photobiomodulation therapy in the integration of skin graft in rats

Skin graft is one of the most common techniques used in plastic surgery and repair. However, there are some complications that can lead to loss of the skin graft. Thus, several features have been studied with the aim of promoting the integration of skin grafts. Among these resources, the use of laser photobiomodulation (laser PBM) has been highlighted. The present study aimed to investigate the effects of laser PBM on the viability and integration of skin grafts in rats. Twenty male Wistar rats (± 250 g) were randomly assigned into two experimental groups with 10 animals each: control group, animals submitted to skin graft and simulation of laser PBM; laser PBM group, submitted to the skin graft and submitted to laser PBM at 660 nm, 40 mW, 60 s, 2.4 J. The animals were submitted to laser photobiomodulation immediately after the surgical procedure and each 24 h. Animal euthanasia occurred on the 7th day after surgery, 24 h after the last treatment session. The histopathological analysis revealed that the laser PBM showed better adhesion of the graft when compared to the control group. Likewise, the morphometric analysis of mast cells, blood vessels, and collagen showed a statistically significant increase in the animals irradiated with the laser PBM when compared to the control group. In addition, immunohistochemical analysis demonstrated that the laser PBM showed statistically higher immunoexpression of FGF when compared to the CG. However, IL-4 immunoexpression did not show statistical difference between the experimental groups. From the results obtained in the present study, it can be suggested that laser photobiomodulation was effective in promoting the integration and viability of total skin grafts in rats.

Applications of photobiomodulation in hearing research: from bench to clinic

Hearing loss is very common and economically burdensome. No accepted therapeutic modality for sensorineural hearing loss is yet available; most clinicians emphasize rehabilitation, placing hearing aids and cochlear implants. Photobiomodulation (PBM) employs light energy to enhance or modulate the activities of specific organs, and is a popular non-invasive therapy used to treat skin lesions and neurodegenerative disorders. Efforts to use PBM to improve hearing have been ongoing for several decades. Initial in vitro studies using cell lines and ex vivo culture techniques have now been supplanted by in vivo studies in animals; PBM protects the sensory epithelium and triggers neural regeneration. Many reports have used PBM to treat tinnitus. In this brief review, we introduce PBM applications in hearing research, helpful protocols, and relevant background literature.

Laser and LED phototherapy on midpalatal suture after rapid maxilla expansion: Raman and histological analysis

The aim of this study was to analyze the effect of laser or LED phototherapy on the acceleration of bone formation at the midpalatal suture after rapid maxilla expansion. Forty-five rats were divided into groups at 7 days (control, expansion, expansion and laser irradiation, and expansion and LED irradiation) and into 14 days (expansion, expansion and laser in the 1st week, expansion and LED in the 1st week, expansion and laser in the 1st and 2nd weeks, expansion and LED in the 1st and 2nd weeks). Laser/LED irradiation occurred every 48 h. Expansion was accomplished with a spatula and maintained with a triple helicoid of 0.020-in stainless steel orthodontic wire. A diode laser (λ780 nm, 70 mW, spot of 0.04 cm², t = 257 s, SAEF of 18 J/cm²) or a LED (λ850 ± 10 nm, 150 ± 10 mW, spot of 0.5 cm², t = 120 s, SAEF of 18 J/cm²) was applied in one point in the midpalatal suture immediately behind the upper incisors. Raman spectroscopy and histological analyses of the suture region were carried and data was submitted to statistical analyses (p ≤ 0.05). Raman spectrum analysis demonstrated that irradiation increases hydroxyapatite in the midpalatal suture after expansion. In the histological analysis of various inflammation, there was a higher production of collagen and osteoblastic activity and less osteoclastic activity. The results showed that LED irradiation associated to rapid maxillary expansion improves bone repair and could be an alternative to the use of laser in accelerating bone formation in the midpalatal suture.

Photobiomodulation with low-level diode laser promotes osteoblast migration in an in vitro micro wound model

Laser photobiomodulation can improve bone healing, but well-defined treatment parameters are lacking. Saos-2 human osteoblast-like cells were subjected to an in vitro scratch-wound healing assay and irradiated by a 915-nm gallium-aluminum-arsenide diode laser for 0, 48, 96, and 144 s using doses of, respectively, 0, 5, 10, and 15 J/cm(2) . Wound area was measured after 4, 24, 48, and 72 h. Cell viability, DNA content, gene expression, and release of bone-related proteins were evaluated after 24, 48, and 72 h. Laser significantly improved wound healing compared with nonirradiated controls. Cells treated with laser doses of 5 and 10 J/cm(2) reached wound closure after 72 h, followed by 15 J/cm(2) after 96 h. With the cell proliferation inhibitor Mitomycin C, the doses of 10 and 15 J/cm(2) maintained an improved wound healing compared with controls. Laser increased collagen type 1 gene expression with higher doses inducing a longer-lasting effect, whereas transforming growth factor-beta 1 showed comparable or decreased levels in irradiated versus nonirradiated groups, with no effect on protein release. This study demonstrated that laser photobiomodulation at 915 nm promoted wound healing mainly through stimulation of cell migration and collagen deposition by osteoblasts.

Phototherapy promotes healing of cutaneous wounds in undernourished rats

BACKGROUND

Various studies have shown that phototherapy promotes the healing of cutaneous wounds.

OBJECTIVE

To investigate the effect of phototherapy on healing of cutaneous wounds in nourished and undernourished rats.

METHODS

Forty rats, 20 nourished plus 20 others rendered marasmus with undernourishment, were assigned to four equal groups: nourished sham, nourished Light Emitting Diode treated, undernourished sham and undernourished Light Emitting Diode treated. In the two treated groups, two 8-mm punch wounds made on the dorsum of each rat were irradiated three times per week with 3 J/cm2 sq cm of combined 660 and 890 nm light; wounds in the other groups were not irradiated. Wounds were evaluated with digital photography and image analysis, either on day 7 or day 14, with biopsies obtained on day 14 for histological studies.

RESULTS

Undernourishment retarded the mean healing rate of the undernourished sham wounds (p < 0.01), but not the undernourished Light emission diode treated wounds, which healed significantly faster (p < 0.001) and as fast as the two nourished groups. Histological analysis showed a smaller percentage of collagen in the undernourished sham group compared with the three other groups, thus confirming our photographic image analysis data.

CONCLUSION

Phototherapy reverses the adverse healing effects of undernourishment. Similar beneficial effects may be achieved in patients with poor nutritional status.

Effect of laser (λ 660 nm) and LED (λ 630 nm) photobiomodulation on formocresol-induced oral ulcers: a clinical and histological study on rodents

The aim of this study was to evaluate, clinically and histologically, the influence of laser and LED photobiomodulation in the healing of formocresol-induced oral mucosa ulcers of rats. We used 60 Wistar rats in which oral ulcers were induced on the gingiva of the lower incisors. Forty-eight hours after inducing the ulcers, the animals were divided into three groups: laser, LED, and untreated. Animals from the laser group received irradiation with GaAlAs, 660 nm, CW, 40 mW, φ 4 mm(2), 4.8 J/cm(2). Animals from the LED group received irradiation with InGaAIP, 630 nm, 150 mW, 4.8 J/cm(2), 0.8 cm spot. Forty-eight hours after oral ulcer induction, both irradiations were applied in a punctuate manner in the center of the ulcer at 48-h interval until the end of the experimental period. The animals were killed at 3, 5, 7, and 11 days after day 0. The results of the clinical evaluation showed that the laser and LED phototherapies were able to accelerate the healing of formocresol-induced oral ulcers, which occurred first in the laser group (ANOVA, p < 0.05). Histologically, there was a slight variation between LED and laser therapy; therefore, the laser group proved to be effective in accelerating wound healing, especially at 5 days, whereas the LED group was more effective at the end of the experimental period. It was concluded that laser and LED photobiomodulation were effective in accelerating the healing of formocresol-induced oral ulcers in both clinical and histological aspects.