Failure of dietary lyophilized strawberries to inhibit 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone-and benzo[a]pyrene-induced lung tumorigenesis in strain A/J mice

In the present study, we examined the ability of lyophilized strawberries in the diet to inhibit 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)- and benzo[a]pyrene (B[a]P)-induced lung tumorigenesis in the A/J mouse. Groups of 20 mice were administered purified AIN-76A diet containing 10% lyophilized strawberries 1 week before carcinogen dosing, and for the duration of the study. NNK was administered by i.p. injection in five. 0.414 mg doses. B[a]P was administered by gavage in five, 0.2 mg doses. At 20 weeks, there were no significant differences in tumor incidence or tumor multiplicity between the NNK + 10% lyophilized strawberry group and the NNK control group. Similarly, at 13 weeks, there were no differences in tumorigenesis between the B[a]P + 10% lyophilized strawberry group and the B[a]P control group. Therefore, lyophilized strawberries at 10% in the diet failed to inhibit NNK- and B[a]P-induced mouse lung tumorigenesis. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.