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Proceedings Paper

Low-level light therapy for Zymosan induced arthritis in rats
Author(s): Ana P. Castano; Tianhong Dai; Tatiana N. Demidova-Rice; Elena V. Salomatina; Anna N. Yaroslavsky; Ilya Yaroslavsky; Richard Cohen; William A Apruzzese; Michael H. Smotrich; Michael R. Hamblin
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Paper Abstract

It has been known for many years that low level laser (or light) therapy (LLLT) can ameliorate the pain, swelling and inflammation associated with various forms of arthritis. Light is absorbed by mitochondrial chromophores leading to an increase in ATP, reactive oxygen species and/or cyclic AMP production and consequent gene transcription via activation of transcription factors. However, despite many reports about the positive effects of LLLT in medicine, its use remains controversial. Our laboratory has developed animal models designed to objectively quantify response to LLLT and compare different light delivery regimens. In the arthritis model we inject zymosan into rat knee joints to induce inflammatory arthritis. We have compared illumination regimens consisting of a high and low fluence (3 J/cm2 and 30 J/cm2), delivered at a high and low irradiance (5 mW/cm2 and 50 mW/cm2) using 810-nm laser light daily for 5 days, with the effect of conventional corticosteroid (dexamethasone) therapy. Results indicated that illumination with 810-nm laser is highly effective (almost as good as dexamethasone) at reducing swelling and that longer illumination time was more important in determining effectiveness than either total fluence delivered or irradiance. Experiments carried out using 810-nm LLLT on excisional wound healing in mice also confirmed the importance of longer illumination times. These data will be of value in designing clinical trials of LLLT.

Paper Details

Date Published: 21 February 2007
PDF: 10 pages
Proc. SPIE 6428, Mechanisms for Low-Light Therapy II, 64280F (21 February 2007); doi: 10.1117/12.698193
Show Author Affiliations
Ana P. Castano, Wellman Ctr. for Photomedicine, Massachusetts General Hospital (United States)
Harvard Medical School (United States)
Tianhong Dai, Wellman Ctr. for Photomedicine, Massachusetts General Hospital (United States)
Harvard Medical School (United States)
Tatiana N. Demidova-Rice, Wellman Ctr. for Photomedicine, Massachusetts General Hospital (United States)
Tufts Univ. School of Medicine (United States)
Elena V. Salomatina, Wellman Ctr. for Photomedicine, Massachusetts General Hospital (United States)
Anna N. Yaroslavsky, Wellman Ctr. for Photomedicine, Massachusetts General Hospital (United States)
Harvard Medical School (United States)
Ilya Yaroslavsky, Palomar Medical Technologies, Inc. (United States)
Richard Cohen, Palomar Medical Technologies, Inc. (United States)
William A Apruzzese, Palomar Medical Technologies, Inc. (United States)
Michael H. Smotrich, Palomar Medical Technologies, Inc. (United States)
Michael R. Hamblin, Wellman Ctr. for Photomedicine, Massachusetts General Hospital (United States)
Harvard Medical School (United States)
Harvard-MIT Division of Health Sciences and Technology (United States)


Published in SPIE Proceedings Vol. 6428:
Mechanisms for Low-Light Therapy II
Michael R. Hamblin; Ronald W. Waynant; Juanita Anders, Editor(s)

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