The photobiomodulation (658, 830 and 904nm) on wound healing in histomorphometric analysis

The wound healing effects of linearly polarized irradiation in photobiomodulation

We report the fabrication of a polarization-based photobiomodulation (PBM) system and its performance on wound healing effects. The light source for PBM was a 625 nm LED and two different linear polarizations (P-wave and S-wave) were generated using the wire grid linear polarizers. To confirm the effect of PBM on polarization, wounds were created on hairless mice, and the healing process was compared. The light source conditions for comparison were control, two linearly polarized light, and unpolarized light. The light irradiation conditions for each group were based on the energy settings (energy 18 J/cm2, power density 30 mW/cm2, exposure time 600 sec) commonly used in LED masks. After creating the wound, the light was irradiated only once. To confirm the wound healing effect over time, it was evaluated through wound surface area measurements, self-made optical coherence tomography images, and histological images. In the group irradiated with S-wave polarized light, the percentage from the initial wound size was reduced to 70.73%, and the epithelial tongue ratio reached 58.36% on day 7 after PBM, indicating the fastest recovery. In this way, the potential of a new product that can increase the effect of wound healing or skin regeneration by adjusting the polarization state without irradiating high energy was confirmed.

Evaluation of Totarol for Promoting Open Wound Healing in Dogs

This study investigates the susceptibility of common pathogens to totarol and assesses its clinical effectiveness in promoting wound healing in client-owned dogs with open wounds. Twenty-three client-owned dogs with open wounds were divided into two groups: (1) the treatment group (T-group) and (2) the control group (C-group). Clinical samples were collected from the wounds for the bacterial identification and determination of the minimum inhibitory concentrations (MICs) of totarol. In the T-group, wounds were treated with standard wound care together with the application at a dosage of 0.3 mL (two sprays) of commercial totarol product per 25 cm2 of the wound area. The C-group received only standard wound care. This in vitro study found that totarol exhibited antimicrobial activity against both standard pathogens and clinical wound pathogens. The MIC values of totarol dissolved in absolute ethyl alcohol were 4 µg/mL for Gram-positive pathogens and ranged from 256 to 512 µg/mL for Gram-negative pathogens. However, the MIC values of the commercial totarol product ranged from 512 to 1024 for both Gram-positive and Gram-negative pathogens. Clinically, the use of a commercial totarol product as an adjunctive therapy significantly improved wound healing, as indicated by a greater percentage of wound area reduction (p < 0.05). From day 2 to day 7 of the treatment, the percentage of wound area reduction differed significantly between the T-group and the C-group. At the end of the study, the average percentage of wound area reduction was 69.18% ± 18.12 and 41.50% ± 20.23 in the T-group and C-group, respectively. The finding of this study illustrates the antimicrobial properties of totarol and its product against prevalent wound pathogens. These results suggest the potential of totarol as an adjunctive option for canine wound care.

Effects of Photobiomodulation Associated with Platelet-Rich Plasma in Acute Rheumatoid Arthritis Induced in Female Wistar Rats' Knee

Objective: Rheumatoid arthritis causes inflammation, pain, and joint degradation, necessitating treatment with anti-inflammatory drugs and corticosteroids, posing various challenges. We aimed to evaluate the effects of photobiomodulation (PBM) at two different doses associated to platelet-rich plasma (PRP) in an in vivo model of induced acute arthritis in Wistar rats' knee. Methods: Eighty-four Wistar rats were assigned into seven groups, including animals treated with PBM and/or PRP. On day 0, arthritis was induced in sham and treated groups through the intra-articular injection of zymosan (200 μg). Twenty-four hours after induction, the PBM groups were treated with an AsGaAl laser, whereas the PRP-treated groups received intra-articular injections with a concentration of 8 × 105 platelets obtained from another four animals. After 3 days, the animals were euthanized, and the interleukin (IL)-6 and complement C3 gene and protein expression levels were analyzed. Statistical analysis was performed using the mean ± SD with analysis of variance and Tukey's posttest, with a significance level set at 5% (p < 0.05). Results: Synovial inflammation decreased in PBM-treated groups; however, PRP alone showed no significant difference. Gene expression analysis revealed a significant difference in IL-6 and C3 levels in the PBM and PBM+PRP-treated groups. Meanwhile, the PRP alone group exhibited significance for IL-6. Moreover, the PBM and PBM+PRP-treated groups showed a significant difference in C3 protein expression levels, whereas the PRP alone group showed no difference. Conclusion: The increase in cellular activity in the synovial membrane and the decrease protein expression levels are owing to the reduction in proinflammatory mediators following PBM therapy.

LED phototherapy in tissue repair of chronic wounds in people with diabetes: a systematic review

OBJECTIVE

To identify scientific evidence of LED photobiomodulation in the treatment and tissue repair of chronic wounds in people with Diabetes Mellitus, types I and II.

METHOD

Systematic review conducted from September/2021 to April/2022 in PubMed, LILACS, SCIELO, COHRANE, EMBASE and Web of Science. Randomized and observational clinical trials using LED in wound healing in diabetics, published between 2015 and 2022 were included. Data were descriptively analyzed with title/abstract screening, full text articles reading and definitive selection after meeting the predefined inclusion and exclusion criteria.

RESULTS

Fromthe total of 840 references, eight articles were selected, that evaluated the effectiveness of LED phototherapy in wounds of diabetic patients.

CONCLUSION

LED light proved to be beneficial in tissue repair, with increased production in collagen and fibroblasts, angiogenesis, reduction of inflammation and, consequently, a decrease in lesion size.

Features of cellular and molecular mechanisms of re-gulation of reparative processes in chronic wounds using photobiomodulation therapy

Introduction: Treatment of chronic wounds is an urgent worldwide problem for medicine. Among the many efforts in wound healing techniques, photobiomodulation therapy has shown promising results.

Aim: To study the effect of photobiomodulation therapy on optimisation of the regulation of reparative processes in chronic wounds by cytokines (through the example of interleukin-1β, tumour necrosis factor-alpha, interleukin-6, interleukin-4, interleukin-10, and granulocyte macrophage colony stimulating factor).

Materials and methods: The study involved 12 Wistar rats. A trophic wound was modelled in the animals. After the operation, the animals were divided into two groups of 6 animals each. The wound defects of animals in the experimental group were exposed to low-intensity laser radiation. Photobiomodulation therapy was applied once a day for 5 days, starting the day after wound modelling. The device Lika-therapist M (Ukraine) was used in a continuous mode at a wavelength of 660 nm, an output power of 50 mW, and an energy density of 1 J/cm², and 60 s exposure time.

Results: The study showed the following changes in the expression of intercellular mediators in the blood serum of animals with chronic wounds when using photobiomodulation therapy: a decrease in the levels of interleukin-1β (p&gt;0.05) and tumour necrosis factor-alpha (p&lt;0.05); increased concentrations of interleukin-4 (p&lt;0.05); the concentrations of interleukin-6, granulocyte macrophage colony stimulating factor, and interleukin-10 were not significantly changed. The histological study showed better organization of collagen fibers in the experimental group.

Conclusions: Photobiomodulation therapy can be an instrument for optimizing the reparative process by correcting the regulation by intercellular mediators.

Effects of photobiomodulation on wound contraction in rats undergoing doxorubicin extravasation: a histomorphometric analysis

OBJECTIVE

To analyze wound contraction and histomorphometric pattern of lesions in Wistar rats undergoing doxorubicin extravasation.

METHOD

Sixty adult female rats were used, divided into four groups of fifteen animals: Group 1 (Control, without antidote); Group 2 (Hyaluronidase); Group 3 (Photobiomodulation), and Group 4 (Hyaluronidase + Photobiomodulation). Doxorubicin 1mg (0.5 ml) was applied subcutaneously on the animals' back, inducing the wound. Macroscopic and morphometric evaluation of the lesions was performed every two days for 28 days. On the 30th day, euthanasia was performed and the material was collected for histological evaluation.

RESULTS

The animals in the photobiomodulation and photobiomodulation + Hyaluronidase groups presented regeneration tissue with neovascularization and acute inflammation, with improvement in wound healing, which did not occur in the other groups. The contraction rates were better in those treated with photobiomodulation and photobiomodulation + Hyaluronidase, with healing percentages of 76.6% and 72.1%, respectively.

CONCLUSION

The combination of photobiomodulation (660 nm-1 J) with topical hyaluronidase (65 UTR) proved to be effective in the process of wound healing due to extravasation of doxorubicin, and can be incorporated into the practice of clinical oncology.

Assessment of wound area reduction on chronic wounds in dogs with photobiomodulation therapy: A randomized controlled clinical trial

Background and Aim

Chronic wounds are a clinical problem and require intensive standard wound care. However, this is sometimes insufficient to promote healing. Photobiomodulation therapy (PBMT) can be used as an adjunctive therapy to improve wound healing. Various PBMT devices with different properties and parameter settings as well as different animal species can influence a variety of clinical outcomes. This study aims to assess the use of 830 nm PBMT or simultaneous superpulsed and multiple wavelengths (SPMW; 660, 875, and 905 nm) PBMT on chronic wounds in client-owned dogs.

Materials and Methods

This study included 21 client-owned dogs with chronic wounds allocated into three groups: (1) Control group (C) treated with irrigated saline and without PBMT (n=7); (2) L1 group treated with irrigated saline together with the radiation of 830 nm PBMT (n=7); and (3) L2 group treated with irrigated saline together with the radiation of simultaneous SPMW-PBMT (n=7). Wound healing was assessed on the basis of wound size reduction as a percentage of wound area every 2^nd day for 15 days using image analysis software (ImageJ software^®, National Institutes of Health, Rockville, Maryland, USA).

Results

A significant difference in the percentage of wound area reduction was noted between the C and PBMT groups (L1 and L2; p<0.05). The average percentages of wound area reduction at the end of the study (15 days) were 42.39±20.58, 56.98±24.82, and 61.81±27.18 in the C, L1, and L2 groups, respectively. A steady decrease in wound size was noted in both PBMT and non-PBMT groups, and coefficients were 7.77, 8.95, and 10.01 in the C, L1, and L2 groups, respectively. The percentage of wound area reduction was found to be significantly different between the PBMT and non-BPMT groups on day 7 (p<0.05).

Conclusion

Based on the results of the current study, using either 830 nm PBMT or simultaneous SPMW-PBMT can accelerate the chronic wound healing process in dogs with a significant reduction in wound area. Therefore, it can be used as an adjunctive therapy to improve wound healing in dogs with reduced treatment duration.