Inhibition of chemically induced mammary and non-mammary carcinogenesis by astaxanthin in Wistar rats

Abstract

Astaxanthin is a fat-soluble, oxygenated pigment called a xanthophyll and a member of the carotenoid family. It has a unique molecular structure that gives it powerful antioxidant function. Astaxanthin is extracted from microalgae, salmon and Pfaffia (a yeast) (1, 2). The aim of the study is to follow up the effect of astaxanthin (ASTA) in chemoprevention of the chemically induced mammary carcinogenesis in immature Wistar female rats. There were established five groups of 37 days old Wistar rats: group I inoculated with the carcinogen MNU (N-methyl-N-nitroso-urea) (n=9), group II with MNU and ASTA in diet (n=8), group III which received oil in diet (oil was used as solvent for ASTA) (n=4), and group IV with ASTA in diet (n=4). The ASTA was administered orally in a dose of 50µg astaxanthin/rat/day, during 7 months. The experiment was finished at 14 months from MNU intake. Mammary tumor induction determined by MNU was reduced, representing 33,3% respectively 37,5% from all cases in groups I and II. There were diagnosed several other tumor types in several organs (nephroblastoma, liposarcoma, hemangiosarcoma, squamous carcinoma, pulmonary carcinoma, cholangiocarcinoma). Involvement of oxidative stress in (mammary and non-mammary) carcinogenesis was revealed by partial protection conferred by astaxanthin in cancer chemoprevention. Present study is one of the few long term experiments (420 days) that resemble the effect of astaxanthin in chemically induced carcinogenesis in rats. Concluding, a diet enriched in astaxanthin yield beneficial effects in cancer chemoprevention, minimizing the bad effects of oxidative stress induced by MNU.