Participation of the Immune System and Hedgehog Signaling in Neoangiogenesis Under Laser Photobiomodulation

Photobiomodulation Recovers the Submandibular Gland in Vismodegib-Treated Rats

Objective: The submandibular gland (SMG) produces the most saliva, and factors such as aging and chemotherapy can affect its structure and function. However, there are only temporary treatments available for salivary hypofunction. This study aimed to evaluate the effects of photobiomodulation (PBM) on the function of SMG by using a rat animal model and vismodegib, an antagonist of the sonic hedgehog (SHH) pathway. Methods: Vismodegib (10 mg/kg) drug was gavaged orally for 14 days in rats to significantly decrease the SHH signaling proteins [SHH, protein patched homolog 1 (PTCH1), smoothened protein (SMO), glioma-associated oncogene homolog 1 (GLI1)], induce damage in SMG tissue, and affect salivary functional markers AQP5 and Keratin5. After that, in conjunction with vismodegib administration, PBM was performed using an 850 nm high-power light-emitting diode (LED) device treated daily for 6 days at varying total energy densities of 60, 120, and 180 J/cm2 in at least 3 rats per group. The test results were confirmed by Western blot, immunofluorescence staining, and hematoxylin and eosin staining, and the statistics were t-test or one-way analysis of variance (ANOVA) with Tukey's multiple comparisons tests. Results: Significant decreases in the expression of SHH-related proteins (PTCH1, SMO, GLI1, p < 0.05) with damage of SMG ductal cells were observed with vismodegib administration. However, a significant increase in the expression levels of SHH-related proteins (SHH, SMO, GLI1, p < 0.05) and recovery of SMG ductal cells damaged after vismodegib administration were observed for PBM-treated groups. Salivary functional marker AQP5 also showed the same increase or decrease. Conclusions: This study found that vismodegib damages SMG ductal cells and decreases SHH-related proteins and associated salivary functional markers. Also, 850 nm high-power LED recovered the damaged structure of SMG and increased SHH-related proteins and salivary functional markers. The study results suggest that PBM can restore SMG structure and function through SHH signaling.

Mitochondria and light: An overview of the pathways triggered in skin and retina with incident infrared radiation

Slightly more than half of the solar radiation that passes through the atmosphere and reaches the Earth's surface is infrared. Over the past few years, many papers have been published on the possible positive effects of receiving this part of the electromagnetic spectrum. In this article we analyse the role of mitochondria in the supposed effects of infrared light based on the published literature. It is claimed that ATP synthesis is stimulated, which has a positive effect on the skin by increasing fibroblast proliferation, anchorage and production of collagen fibres, procollagen, and various cytokines responsible for the wound healing process, such as keratinocyte growth factor. Currently there are infrared light emitting equipment whose manufacturers and the centres where this service or treatment is offered claim that they are used for skin rejuvenation among other positive effects. Based on the literature review, it is necessary to deepen the scientific study of the mechanism of absorption of infrared radiation through the skin to better understand its possible positive effects, the risks of overexposure and to improve consumer health protection.

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.

Experimental and Clinical Applications of Red and Near-Infrared Photobiomodulation on Endothelial Dysfunction: A Review

BACKGROUND

Under physiological conditions, endothelial cells are the main regulator of arterial tone homeostasis and vascular growth, sensing and transducing signals between tissue and blood. Disease risk factors can lead to their unbalanced homeostasis, known as endothelial dysfunction. Red and near-infrared light can interact with animal cells and modulate their metabolism upon interaction with mitochondria's cytochromes, which leads to increased oxygen consumption, ATP production and ROS, as well as to regulate NO release and intracellular Ca²⁺ concentration. This medical subject is known as photobiomodulation (PBM). We present a review of the literature on the in vitro and in vivo effects of PBM on endothelial dysfunction.

METHODS

A search strategy was developed consistent with the PRISMA statement. The PubMed, Scopus, Cochrane, and Scholar electronic databases were consulted to search for in vitro and in vivo studies.

RESULTS

Fifty out of >12,000 articles were selected.

CONCLUSIONS

The PBM can modulate endothelial dysfunction, improving inflammation, angiogenesis, and vasodilatation. Among the studies, 808 nm and 18 J (0.2 W, 2.05 cm²) intracoronary irradiation can prevent restenosis as well as 645 nm and 20 J (0.25 W, 2 cm²) can stimulate angiogenesis. PBM can also support hypertension cure. However, more extensive randomised controlled trials are necessary.