Ações antioxidante e antigenotóxica da goma arábica na mucosa intestinal, fígado, medula óssea e sangue de camundongos swiss submetidos à carcinogênese colorretal pelo azoximetano

Abstract

Colorectal carcinoma is one of the most frequent neoplasms characterized by the formation in its early stages of aberrant crypts. Gum arabic (GA) is a natural product with antioxidant and anti-inflammatory properties. The objective of this study was to evaluate the effects of GA on the formation of aberrant crypts, on the genotoxicity and local and systemic oxidative stress of Swiss mice submitted to colorectal carcinogenesis by azoxymethane (AOM). The study included 3 control groups (I-III) and 3 experimental groups (IV-VI): GI-water, GII-GA 2.5%, GIII-GA 5%, GIV- AOM + water, GV- AOM + GA 2.5%, GVI-AOM + GA 5%. Once a week, for 2 weeks, the animals in the control groups received saline (ip) and those in the experimental groups received AOM (ip). Over the next 12 weeks, the mice received water, GA 2.5% or GA 5% via gavage. At the end, the colon was evaluated by stereoscopic microscopy to determine the number of aberrant crypts, aberrant crypt foci (FCA) and crypts by focus (multiplicity) by colon segment, in addition to the collection of material for the study of genotoxicity and stress oxidative (proximal and distal colon, liver, blood and bone marrow). The number of crypts observed in the GIV group (12.67 ± 7.05) was significantly higher than in the GV (5.00 ± 4.58; p = 0.03) and GVI (5.39 ± 8.75; p = 0.04). The number of FCA in the GIV group (8.75 ± 3.55) was also higher than in the GV groups (3.18 ± 2.99; p = 0.0004) and GVI (2.46 ± 2.79; p <0.0001), as well as the number of FCA with less than 5 crypts per focus in the GIV group (8.42 ± 3.45) compared to the GV groups (3.18 ± 2.99; p = 0.0006) and GVI (2.31 ± 2.53; p <0.0001). There was a decrease in genotoxicity and reactive oxygen species (EROS) in the proximal colon, distal colon and liver with both GA doses (p <0.01). In the bone marrow, there was a reduction in genotoxicity with GA 2.5% (p <0.001) and 5% (p <0.01) and a reduction in the formation of EROS in the blood with GA 5% (p <0.001). GA exerted an inhibitory action on colorectal carcinogenesis by reducing the formation of aberrant crypts, genotoxicity and local and systemic oxidative stress.