Lack of enhancing effects of degraded λ-carrageenan on the development of β-catenin-accumulated crypts in male DBA/2J mice initiated with azoxymethane

Effect of degraded λ-carrageenan, which induces colitis in rodents, on the development of β-catenin-accumulated crypts (BCAC) being putative precancer lesions of colon cancer was investigated in male DBA/2J mice initiated with azoxymethane (AOM). In a preliminary experiment, male DBA/2J mice among seven different strains (A/J, BALB/c, C3H/HeN, C57BL/6J, CBA/N, DBA/1J, and DBA/2J) of male mice were most sensitive to degraded λ-carrageenan. Therefore, male DBA/2J mice were intraperitonially injected AOM (10 mg/kg body weight), and then 2% degraded λ-carrageenan in drinking water for one or two weeks, starting one week after dosing of AOM. Thereafter animals were no further treated up to week 26. At week 26, the frequency of BCAC in the colonic mucosa was 12.50±2.46 in the AOM alone group, 11.30±3.50 in the AOM/degraded λ-carrageenan (for one week) group, and 11.60±2.27 in the AOM/degraded λ-carrageenan (for two weeks) group. The findings suggest that degraded λ-carrageenan treatment for one or two weeks did not affect the occurrence of BCAC. Our results may indicate no enhancing or promoting effects of degraded λ-carrageenan on colon carcinogenesis in mice initiated with AOM.