The effect of dietary lycopene on bioavailability, tissue distribution, in vivo antioxidant properties and colonic preneoplasia in rats

摘要

Lycopene in the form of 6% oleoresin was incorporated into an antioxidant stripped AIN93M diet at a concentration of 10 ppm lycopene. Male Fischer 344 rats were divided into 2 groups and fed AIN93M diet or AIN93M diet + lycopene for 100 days. Coloncancer was induced by a single azoxymethane (AOM) injection (15 mg/kg body mass). Serum and tissue lycopene concentrations were measured as estimates of lycopene uptake and tissue distribution. Serum TBARS and thiols were measured as indicators of lipidand protein oxidation. Incidence and size of aberrant crypt foci (ACF) were measured as preneoplastic markers. Dietary lycopene was absorbed and distributed to various tissues. An increase in serum thiols and a decrease in serum TBARS was observed in rats fed the lycopene diet. Incidence of ACF in lycopene fed rats showed a trend towards reduced numbers and size. Effects were more pronounced when lycopene was fed during the promotion stage than during the initiation stage. Based on these results it is concluded that dietary lycopene is absorbed by rats and distributed to various tissues. It acts as an antioxidant in reducing oxidation and thereby may protect against AOM induced ACF incidence. Dietary lycopene may play an important role in protecting against oxidative stress and colon carcinogenesis.