Light-emitting diodes at 940nm attenuate colitis-induced inflammatory process in mice

Inflammatory bowel disease (IBD) presents intense inflammatory infiltrate, crypt abscesses, ulceration and even loss of function. Despite the clinical relevance of IBD, its current therapy remains poorly effective. Infrared wavelength phototherapy shows therapeutic potential on inflammation. Our goal was to evaluate whether light-emitting diodes (LED) at 940nm are capable of mitigating the colitis-induced inflammatory process in mice. Forty male Swiss mice were assigned into five groups: control; control treated with LED therapy; colitis without treatment; colitis treated with LED therapy; colitis treated with Prednisolone. Experimental colitis was induced by acetic acid 7.5% (pH2.5) rectal administration. LED therapy was performed with light characterized by wavelength of 940nm, 45nm bandwidth, intensity of 4.05J/cm(2), total power of 270mW and total dose of 64.8J for 4min in a single application. Colitis-induced intestinal transit delay was inhibited by LED therapy. Colitis caused an increase of colon dimensions (length, diameter, total area) and colon weight (edema), which were inhibited by LED therapy. LED therapy also decreased colitis-induced tissue gross lesion, myeloperoxidase activity, microscopic tissue damage score and the presence of inflammatory infiltrate in all intestinal layers. Furthermore, LED therapy inhibited colitis-induced IL-1β, TNF-α, and IL-6 production. We conclude LED therapy at 940nm inhibited experimental colitis-induced colon inflammation in mice, therefore, rendering it a promising therapeutic approach that deserves further investigation.