SUPPRESSION OF AZOXYMETHANE-INDUCED COLONIC ABERRANT CRYPT FOCI BY DIETARY EXPOSURE TO A NOVEL SYNTHESIZED RETINOIDAL BUTENOLIDE, 5-HYDROXY-4-(2-PHENYL-(E)ETHENYL)-2(5H)-FURANONE, IN RATS

The modifying effect of dietary exposure to a novel synthesized retinoidal butenolide, 5-hydroxy-4-(2-phenyl(E)ethenyl)-2(5H)-furanone (KYN-5) on the development of azoxymethane (AOM)-induced colonic aberrant crypt foci (ACF) was investigated in male F344 rats. Animals were given weekly s.c. injections of AOM (15 mg/kg body wt.) for 3 weeks to induce ACF. These rats were fed diet containing 100 or 200 ppm KYN-54 for 5 weeks, starting 1 week before the first dosing of AOM. All rats were killed 2 weeks after the last AOM injection, to measure the number of ACF, ornithine decarboxylase (ODC) activity, mucosal polyamine level, and silver-stained nucleolar organizer regions protein (AgNORs) count per nucleus in the colon. In rats given AOM and KYN-54, the frequency of ACF/colon was significantly decreased compared with that in rats given AOM alone, ODC activity and polyamine levels, and the mean AgNORs number in the colon of rats given AOM and KYN-54 at both doses were also significantly lower than that of rats treated with AOM alone. These results provide further evidence that KYN-54 could be a chemopreventive agent against rat colon carcinogenesis.