Effect of diets with different protein levels on the growth of walker 256 carcinosarcoma in rats

RESUMO

1. The effect of different nutritional situations on the growth of experimental Walker 256 carcinosarcoma was investigated in rats. Fifty adult male Wistar rats were randomly assigned to three groups: group NN received standard chow throughout the experiment; group DD initiaslly received an isocaloric protein-free diet, and some of the animals in this group (DN) were fed normal chow from the 34 th to The 53 rd day of the study. 2. On the 42 and day of the experimentas all animals were incolulated subcutaneously in the flank with 2.5 to 3.0 x 10*5 viable Walker 256 carcinosarcoma dells and tumor growth and rat body weight were monitored daily thereafter. 3. Significantly greater tumor growth was detected in well-nourished (group NNT) as compared with malnourished animals (group DDT), but not protein-depleted-refed (group NNT) as compared with malnourished animals (group DDT), but not in protein-depleted-refed (group DNT) animals, whose tumor growth was not significantly different from that of constantly malnourished (group DDT) rats. 4. Comparasion of tumor weight and of the tumor weight/carcass weight (TW/CW) ratio showed no significant difference between malnourished and malnourished/ refed animals, whereas well-nourishedd animals showed higher tumor weight and TW/CW ratios. 5. TW/CW curves for malnourished rats were parallel to those for malnourished/refed rats. TW/CW curves for constantly malnourished rats differed from those for well-nourished rats during the first observation period but ther was no difference during the second week of tumor growth. 6. although the protein-free diet inhibited tumor growth and refeeding enhanced it, carcass weight increased at the same rate, and therefore no change was observed in the TW/CW ratio. We conclude that nutritional rehabilitation should be considered for tumor-bearing hosts because the advantage in body weight for the host outweighs that for the tumor