A eletroacupuntura atenua a colite experimental induzida por TNBS via ativação de interleucina 10 e inibição de óxido nítrico sintase induzida

Abstract

The etiology of inflammatory bowel disease (IBD) involves genetic, environmental and immunological factors. There are clinical reports of the use of acupuncture on IBD, however its therapeutic mechanisms are still uncertain. The purpose of this work is to study the anti-inflammatory and analgesic actions of electroacupuncture on a experimental colitis model. Male Swiss rats, divided in six groups (n=6-9), were subjected to induction of colitis by TNBS in 50% ethanol. The controls were saline (SAL) and ethanol (ETNL). The animals with colitis were treated with electroacupuncture (EAC) at the ST-36 acupoint, 100Hz, false electroacupuncture (FEAC), 100Hz, and dexamethasone (DEXA), 1 mg/Kg/day. Visceral hyperalgesia was evaluated by means of the Von Frey test. After three days, a colon segment was obtained for macroscopic and histopathological analysis, quantification of the activity of myeloperoxidase, Immunohistochemistry for iNOS, and quantification of malondialdehyde and cytokines (TNF-α, IL-1β, IL-10). The parametric data were analyzed with ANOVA/Tukey test or test T, and the non-parametric data with Kruskal-Wallis/Dunn test. There was an increase on the wet weight of the colons on group TNBS, and prevention of this event on group EAC. The groups TNBS and EAC showed an increase on neutrophil infiltration, as compared to the other groups. The group TNBS showed increased values for the microscopic scores, as compared to the treated groups. The groups TNBS and EAC showed an increase on the concentration of IL-1β in the colon. The group TNBS showed suppression of the concentration of IL-10 in the colon, prevented by treatment with EAC. The group EAC showed decrease on the concentration of MDA in the colon, as compared to the other groups. The group EAC showed decrease on the expression of iNOS in the connective, as compared to the treated groups. The group TNBS did not show any alterations of hypernociception, as evaluated with Von Frey, at 24 and 72 hours. It can be therefore concluded that electroacupuncture, at the acupoint ST-36, 100Hz, showed anti-inflammatory action on the colitis induced by TNBS in 50% ethanol, by means of increase of IL-10 concentration and decrease on the expression of iNOS.