Estudo da ação imunobiológica do laser de baixa intensidade sobre modelo de hipersensibilidade tardia à ovalbumina.

Abstract

The aim of this study was to evaluate the effect of Low Level Laser Therapy (LLLT) in an experimental model of delayed hypersensitivity reaction (DTH). LLLT has been studied for some time and its clinical effects have been used to treat numerous diseases. LLLT has been tested in different experimental models and some of its effects have yet to be explained. We tried to assess the effects of LLLT on the DTH reaction to ovalbumin (OVA), a protein that has been used as an antigen to sensitize lab animals. This is a broadly used experimental model to assess the effects of substances that have the potential to modulate the immune system and inflammatory reactions. Balb/C mice were randomly divided into four groups, (I) immunized, untreated and challenged (n=6), (II) not immunized, untreated and challenged (n=6); (III) immunized, treated with Azathioprine (AZA) and challenged (n=6); and group (IV) immunized, treated with LLLT and challenged (n=6). Forty-eight hours after the challenge, the animals were submitted to a paw edema check and were euthanized for histopathology analysis of their plantar pads. Proliferations tests were made (spontaneous, in the presence of concanavalin A and Ovalbumin) to determine the production in cell cultures of TNF- , INF- and IL-10. Immunohistochemical analyzes for expression of COX-2 were also performed. In the group of animals irradiated with lasers and those treated with AZA, footpad thickness measurements were significantly reduced in comparison to the control group. This was accompanied by a very significant drop in the density of the inflammatory infiltration as well as by a significant reduction in the levels of concentration of TNF- , INF- and IL-10 and in the expression of COX-2. Our results suggest that treatment with LLLT has immunomodulatory effect and may have important contribution to the immunotherapeutic of kidney transplants.