laser in inflammation

Publications

Matías Mantineo, João P. Pinheiro, and António M. Morgado; Low-level laser therapy on skeletal muscle inflammation: evaluation of irradiation parameters, J. Biomed. Opt., 19(9), 098002 (2014). doi:10.1117/1.JBO.19.9.098002.
Matias Mantineo, João P. Pinheiro, António M. Morgado, Evaluation of low level laser therapy irradiation parameters on rat muscle inflammation through systemic blood cytokines. Proc. SPIE 8932, Mechanisms for Low-Light Therapy IX, 89320M (February 18, 2014); doi:10.1117/12.2039342.
M. Mantineo, J. P. Pinheiro and A. M. Morgado. Low level laser therapy on injured rat muscle: assessment of irradiation parameters, Proceedings of SPIE 8785, 8th Iberoamerican Optics Meeting and 11th Latin American Meeting on Optics, Lasers, and Applications, 8785DU (November 18, 2013); doi:10.1117/12.2021689
M. Mantineo, J. P. Pinheiro and A. M. Morgado. Methodology for assessment of low level laser therapy (LLLT) irradiation parameters in muscle inflammation treatment, Proceedings of SPIE 9032, Biophotonics—Riga 2013, 90320P. doi:10.1117/12.2044689
M. Mantineo ; J. P. Pinheiro and A. M. Morgado, Low level laser therapy on injured rat muscle, Proc. SPIE 8803, Medical Laser Applications and Laser-Tissue Interactions VI, 88030E (June 24, 2013); doi:10.1117/12.2032496
Mantineo, M.; Morgado, A.M.; Pinheiro, J.P., Low level laser therapy on injured rat muscle, Proceedings of 2013 IEEE 3rd Portuguese Meeting in Bioengineering (ENBENG), 20-23 Feb. 2013, doi: 10.1109/ENBENG.2013.6518401
M Mantíneo, A. M. Morgado, J. P. Pinheiro. Effects of Low Level Laser Therapy (LLLT) on Injured Muscle: A pilot study, Proceedings of CASEIB2012 - XXX Congreso Anual de la Sociedad Española de Ingeniería Biomédica.
PhD Thesis: M.E.A. Mantineo, Laser Therapy in inflammation: mechanisms, techniques and instrumentation, PhD Thesis in Biomedical Engineering, University of Coimbra, 2014

To evaluate the influence of irradiation parameters on Low Level Laser Therapy (LLLT) treatment of the acute phase of skeletal muscle inflammation, through the measurement of cytokines expression in systemic serum and analysis of muscle tissue.

know more about Low Level Laser Therapy or Photobiomodulation

Images from gastrocnemius muscle cuts. Control rat: (a) 20X; (b) 40X; rat from 40-mW group:(c) 20X; (d) 40X. In the control rat without treatment, it is possible to observe an infiltration of inflammatory cells. The treated rat shows an improved condition, although still presents inflammatory cells.

Background

There are several studies that show the effectiveness of low power laser radiation in reducing some types of pain, treating inflammation and wound healing. However, more evidence is required to prove the effectiveness of low power laser therapy (LLLT - now called Photobiomodulation) and many aspects of the cellular and molecular mechanisms, triggered by irradiation of tissue with laser, remain unknown.

Considering these facts, we intended to determine the influence of laser irradiation parameters, including wavelength, dose, power and time of interaction on the expression of anti-inflammatory cytokines (IL-2, IL-6) and pro-inflammatory cytokines (IL-1b, TNF-a) in the injured region and assess the clinical consequences of this cellular level effect.

We began by evaluating the effect of wavelength and dose delivered under conditions of continuous illumination in the treatment of inflammation induced in the gastrocnemius muscle of Wistar rats, by quantification of cytokines and histological and immunohistochemical analysis of muscle tissue. In a second phase, we evaluated the more adequate radiant power for inflammation treatment. The work ended with a comparative assessment of continuous and pulsed laser irradiation and between coherent and non-coherent irradiation.

This project was concluded in 2014.

Team

Matías Mantineo receiving the Best Paper award from SPIE President Toyohiko Yatagai. RIAO/OPTILAS 2013 - VIII Iberoamerican Conference on Optics/ XI Latin-American meeting on Optics, Lasers and Applications, 2013

Comparison between laser irradiation at 830 nm, at 980 nm and LED irradiation at 850 nm. Constant power: 50 mW; Time: 3 minutes; Spot size: 8 mm (diameter)

Wistar rat TNF-a and IL-1b concentrations at day 6 after muscle inflammation and treatment with 830 nm laser: Groups: 10 mW, 20 mW, 30 mW, 40 mW, 50 mW and Control (without treatment). Time: 3 minutes. Spot size: 8 mm (diameter).

Results

We were able to quantify the effect of LLLT on the treatment of inflammation induced in the gastrocnemius muscle of Wistar rats by measuring the concentration of pro-inflammatory cytokines in the systemic blood, a method that allows following the treatment effect without sacrificing animals.

The results showed that continuous wave (CW) irradiation at 830nm produced the largest treatment effects, a result in accordance with the action spectrum of cytochrome c oxidase (CCO). Best results were obtained with an irradiation power of 40 mW, with the data suggesting a biphasic dose response. This suggestion requires further confirmation through experiments using higher radiant powers.

Pulsed wave (PW) irradiation at 830 nm and 40 mW average power was only effective for the tested frequencies equal to or higher than 50Hz. This result might be related to the rate constants of the CCO internal electron transfer stage between cytochrome a and cytochrome a3.

We found a large difference in treatment effect between coherent and non-coherent sources providing equal doses of radiation with similar wavelength. While the 830 nm laser source produced a treatment effect, measured by the statistically significant reduction of pro-inflammatory cytokynes, the non-coherent 850 nm LED source failed to produce any significant cytokine concentration decrease when compared with the non-treated control group.

The mechanism responsible for the additional therapeutic effect of the laser field inside the irradiated tissue it is not known and needs to be elucidated.

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