Study of superoxide dismutase's expression in the colon produced by azoxymethane and inositol hexaphosfate's paper, in mice<A NAME="volta1"></A>

Abstract

Study of superoxide dismutase's expression in the colon produced by azoxymethane and inositol hexaphosfate's paper, in mice RESUMOObjetivo: Investigar a expressão de superóxido dismutase, com uso de antioxidante inositol hexafosfato, na presença do carcinógeno azoximetano em FCA de cólon de ratos. Métodos: Quarenta e oito ratos Wistar, distribuídos em 4 grupos, divididos em controle (n=12); com administração de azoximetano AOM (n=12); administração de IP6 (n=12) e com administração de IP6/AOM (n=12). A administração subcutânea de azoximetano aconteceu na semana 3 e 4 do experimento, em dose 20mg/Kg, semanal; e administração de IP6 a 1% em água de beber durante 6 semanas no grupo 3 e 4. A identificação da expressão SOD1 foi realizada através da quantificação imunohistoquimíca pelo processamento de imagem assistida por computador em criptas e focos de cripta aberrante em cólon direito. -ORIGINAL ARTICLE

The role of Fas ligand protein in the oxidative stress induced by azoxymethane on crypt colon of rats

“…FasL expression by normal colonic epithelium and hyperplastic polyps was restricted to the luminal surface, where expression coincides with epithelial apoptosis 15 .…”

“…In previous reports we demonstrated the association of AOM and the occurrence of ACF in a rat model. In this research we used the similar model to induce the oxidative stress [13][14][15] .…”

“…A functional apoptotic pathway appears to be essential to maintain low numbers of mutated cells. Cells that have acquired resistances to apoptosis either before or as a result of mutational changes fail to be eliminated by apoptosis, and are in this way able to continue the progression towards a neoplastic phenotype [15][16][17][18][19][20][21] . Failure of apoptosis may be of particular importance in the development of colorectal cancer 15,[22][23][24] .…”

“…The Fas is widely expressed in most cell types, including epithelial cells, and Fas mediated apoptosis may be involved in cell turnover in many tissues. The FasL also contributes to immune privilege in certain tissues where it is expressed, by triggering the apoptosis of infiltrating inflammatory cells 15,[25][26][27] .…”

“…However, in the tumorigenesis dysplastic cells are located at the apex of the crypts and luminal surface, a situation that generates controversy. We proposed to study the apoptosis in the base and apex of the crypt of colon with the biomarker-Fas ligand participating in an early stage and prior to the morphologic cellular changes, thus allowing to identify the activation of apoptosis in apex-base of the crypt and thus quantify the stimulation induces apoptosis in the crypt 15,29 .…”