Antioxidative and antiproliferative effects of astaxanthin during the initiation stages of 1,2-dimethyl hydrazine-induced experimental colon carcinogenesis.

Colon cancer is one of the major causes of cancer mortality worldwide. Several carotenoids with antioxidant properties are reported for their chemopreventive nature. In this study, we have evaluated the chemopreventive efficacy of astaxanthin on lipid peroxidation, antioxidant status, total number of aberrant crypt foci (ACF), and cell proliferation in 1,2 dimethylhydrazine (DMH)-induced colon carcinogenesis using a rat model. DMH was induced subcutaneously at a dosage of 40 mg/kg body weight, twice a week for 2 weeks. Astaxanthin was administered before and after the DMH induction, orally at a concentration of 15 mg/kg body weight throughout the experimental period. At the end of 16 weeks, pre-treatment with astaxanthin markedly reduced the degree of histological lesions, ACF development and also lowered the number of argyrophilic nucleolar organizer regions. Our results also showed the decreased levels of colon enzymic and non-enzymic antioxidants and increased levels of lipid peroxidation marker levels in DMH-induced rats, which were significantly reversed on astaxanthin administration. In conclusion, the results of this study suggest that astaxanthin has an affirmative and beneficial effect against chemically induced colonic pre-neoplastic progression in rats induced by DMH.