Background: Studies have shown fibers to be effective in reducing the appearance of aberrant crypt foci (ACF) in rodents. Objective: The goal of this study was to investigate the preventive effects of fructooligosaccharide (FOS) and inulin prebiotics on the appearance of ACF in mice. Materials and Methods: The techniques used were: RT-PCR to evaluate the gene expression of p16, p21, p54, cyclin D1 and cyclin E in the distal colon; the quantification of Number of aberrant crypt foci (ACF) and measurement of catalase activity in the liver and distal colon. The animals were divided into five treatments (n=8); C-: AIN93M diet without fibers + DMH (1,2-dimethylhydrazine); INL: AIN93M diet with inulin; INLCA: AIN93M diet with inulin + DMH; FOS: AIN93M diet with FOS; FOSCA: AIN93M diet with FOS + DMH, during 15 weeks. Results: Inulin prevented the appearance of ACF in the proximal, middle and distal colon, compared to the control without fibers. In the middle and distal colon, FOS was also effective in preventing the incidence of ACF. This effectiveness may be attributed to the increased gene expression of p16 following FOS treatment. Both prebiotics also decreased catalase activity in the distal colon, thus suggesting an antioxidant effect. Conclusion: These results suggesting an antioxidant effect prebiotics that may be attributed to the increased gene expression of p16.

Introducción: Existen estudios que demuestran la eficacia de fibras para reducir la aparición de focos de cripta aberrantes (FCA) en roedores. Objetivo: El objetivo de este estudio consistió en investigar los efectos preventivos de los fructooligosacáridos (FOS) y el prebiótico inulina sobre la aparición de FCA en ratones. Materiales y métodos: Las técnicas empleadas fueron: RT-PCR para evaluar la expresión gènica de p16, p21, p54, ciclina D1 y ciclina E en el colon distal; la cuantificación del Número de FCA y la medición de la actividad de la catalasa en el hígado y el colon distal. Los animales fueron divididos en cinco tratamientos (n=8); C-: dieta AIN93M sin fibra + DMH (1.2-dimetilhidrazina); INL: dieta AIN93M con inulina; INLCA: dieta AIN93M con inulina + DMH; FOS: dieta ANIN93M con FOS; FOSCA: dieta AIN93M con FOS + DMH, durante 15 semanas. Resultados: La inulina previno la aparición de FCA en el colon proximal, medio y distal, comparado con el control sin fibras. En el colon medio y distal, FOS también fue efectiva para prevenir la incidencia de FCA. Esta efectividad podría ser atribuida al aumento de la expresión génica de p16 tras el tratamiento con FOS. Ambos prebióticos también disminuyeron la actividad de la catalasa en el colon distal, lo que sugiere un efecto antioxidante. Conclusión: Estos resultados sugieren un efecto antioxidante de los prebióticos que podría atribuirse a un aumento de la expresión génica de p16.

PURPOSE: To investigate the hemopreventive effect of defatted flaxseed meal in C57BL/6 mice after induction of precancerous colon lesions with 1.2-dimethylhydrazine (DMH). METHODS: Thirty-six 12-week-old C57BL/6 mice were divided into three treatment groups(n=12 in each group): (1) diet with 10% defatted flaxseed meal; (2) diet with defatted flaxseed meal and precancerous colon lesions induced by DMH; and (3) precancerous colon lesions induced by DMH, without defatted flaxseed meal. The incidence of aberrant crypt foci (ACF), oxidative processes, expression of tumor suppressor proteins and cyclins, as well as the profile of short-chain fatty acids (SCFA) in animal feces were investigated in the presence and absence of DMH. RESULTS: The rats consuming defatted flaxseed meals showed lesions with lower multiplicity and a reduced incidence of lesions. No changes in the expression of tumor suppressor proteins and those involved in cell cycle control were detected. CONCLUSION: Defatted flaxseed meal protected the distal colon of mice from precancerous lesions.