Effects of amber LED on inflammatory and regulatory monocytes and lymphocytes.

The primary objective of the present study was to assess the impact of amber LED photobiomodulation (PBM) on human monocytes and lymphocytes that were polarized into proinflammatory and regulatory/reparative phenotypes. Human leukocytes were polarized with LPS or LPS + IL-4 for 2 h and irradiated after 2 and 6 h with amber LED (590 nm). Cell absorbance spectrum and gene and protein expression of IL-1ß, IL-6, IL-10, IL-17, TNF-α and IFNγ determined after 24 h. The results showed that irradiation did not significantly alter absorbance of non-polarized monocytes, whereas irradiated polarized monocytes presented reduction in absorbance in 625-850 nm region. Irradiated monocytes polarized with LPS + IL-4 presented reduction in absorbance in 600-725 nm region compared to non-irradiated group. Irradiated non-polarized lymphocytes presented absorbance peaks between 650 and 820 nm not seen in non-irradiated group. No difference was found in absorbance pattern of polarized lymphocytes after irradiation. Irradiation led to reduction in protein synthesis of IL-6 and TNFα in monocytes polarized to proinflammatory phenotype and increase in production of IL-17 in lymphocytes. Irradiation reduced production of IL-10 in monocytes and lymphocytes polarized to immunoregulatory phenotype. In conclusion, amber LED modulates light absorbance and expression of important cytokines in inflammatory/repair processes in monocytes and lymphocytes.

Effects of the invasive and non-invasive systemic photobiomodulation using low-level laser in experimental models: A systematic review.

Systemic photobiomodulation (PBM) of the blood or over blood vessels has been associated with bio-stimulating, vasodilating, and anti-inflammatory properties. This treatment modality has been used for modulating inflammatory processes, tissue repair, atherosclerosis, and systemic arterial hypertension, and is described more often in clinical studies than experimental models. Therefore, the aim of the present study was to conduct a literature review regarding the effect of systemic PBM involving the intravascular laser irradiation of blood (ILIB) or non-invasive vascular photobiomodulation (VPBM) using low-level laser (LLL) in experimental (animal) models. The PubMed/MEDLINE®, Scopus, SPIE Digital Library, and Web of Science databases were searched for articles on the use of VPBM with LLL in animal models. Nine original articles met the inclusion criteria and were critically evaluated. The variables of interest were the dosimetric laser parameters, different methods for delivering energy, and the main results. The use laser in the red spectrum was more prevalent and VPBM (non-invasive) predominated over ILIB (invasive). No standardization was found in the dosimetric parameters. However, the studies showed the positive effects of VPBM on arterial pressure and blood circulation, the positive effects of ILIB on blood composition and hematological markers, as well as positive effects of both forms of systemic PBM (ILIB and VPBM) on the tissue repair process. In conclusion, the studies evaluated in the present review showed that the use of systemic PBM with ILIB or non-invasive VPBM induced positive effects, modulating metabolic conditions and tissue repair. However, there is a need for standardization in the dosimetric parameters for the different conditions and processes evaluated using experimental models.

Vascular photobiomodulation increases muscle fiber diameter and improves the gait during compensatory hypertrophy of plantar muscle in rats.

The local photobiomodulation (LPBM) has demonstrated positive effects during compensatory hypertrophy (CH) in skeletal muscle as a response to an overload. The aim was to compare the effects of the transcutaneous vascular photobiomodulation (VPBM) and the LPBM on muscle fiber size, gait functionality, and on mechanical sensitivity during the CH model in rats. VPBM was administered over the rat's main tail vein and LPBM was applied over the plantar muscle region. VPBM induced an increase in muscle fiber diameter and cross-sectional area (CSA) after 7 days. At 14 days, an increase in the fiber diameter was found in both irradiated groups. The VPBM and LPBM promoted the reestablishment of normal gait evaluated by the sciatic functional index after 14 days. No changes were found in the mechanical (nociceptive) sensitivity in VPBM and LPBM groups in comparison to the CH group but there was an increase in the nociceptive sensitivity in the CH groups in comparison to the control after 7 and 14 days. In conclusion, both PBM, vascular and local, were able to improve the muscle size and gait during the CH process with more pronounced effects when irradiation was performed systemically (VPBM).