Lifelong exposure to dietary fish oil alters macrophage responses in Walker 256 tumor-bearing rats.
Supplementation of the diet with fish oil (FO) decreases growth of the Walker 256 tumor and decreases the cachexia associated with tumor-bearing. The mechanisms by which FO inhibits tumor growth and cachexia are unknown. Macrophages are very important in host defence against tumors since they produce several anti-tumor agents which in turn have been shown to be modified by dietary FO, but rarely in the setting of tumor bearing and never in relation to lifelong exposure. In this study, we compared the effects of supplementation of the diet of pregnant and lactating rats and subsequent supplementation of the offspring with coconut fat or FO on macrophage activities involved in anti-tumor defence. FO supplementation was able to induce an increase in phagocytosis, in O2-, H2O2, nitric oxide, and TNF-alpha production by macrophages and in lysosomal volume in non-tumor-bearing rats. However, phagocytosis, production of O2- and H2O2 and lysosomal volume were not affected by the FO diet when rats were bearing tumors, although nitric oxide production was higher in these animals. It appears that tumor bearing activates the innate immune system and that dietary FO has little effect on innate immunity in the presence of Walker 256 tumors. Thus, it is still unclear how FO decreases the growth of Walker 256 tumors and the associated cachexia.
Bonatto
Sandro J R
SJ
Department of Physiology, Biological Sciences Building, Federal University of Paraná, 81540-990 Curitiba-PR, Brazil.
Folador
Alessandra
A
Aikawa
Júlia
J
Yamazaki
Ricardo K
RK
Pizatto
Nathalia
N
Oliveira
Heloisa H P
HH
Vecchi
Rodrigo
R
Curi
Rui
R
Calder
Philip C
PC
Fernandes
Luiz C
LC
D000375:Aging / Q000502:physiology; D000818:Animals; D002279:Carcinoma 256, Walker / Q000276:immunology*; D002478:Cells, Cultured; D004042:Dietary Fats, Unsaturated / Q000008:administration & dosage* / Q000494:pharmacology*; D005260:Female; D005395:Fish Oils / Q000008:administration & dosage* / Q000494:pharmacology*; D006861:Hydrogen Peroxide / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology; D008247:Lysosomes / Q000187:drug effects / Q000378:metabolism; D008264:Macrophages / Q000166:cytology / Q000187:drug effects* / Q000276:immunology* / Q000378:metabolism; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism; D010587:Phagocytosis / Q000187:drug effects; D011247:Pregnancy; D051381:Rats; D017208:Rats, Wistar; D013481:Superoxides / Q000378:metabolism; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis / Q000378:metabolism; D023041:Xenograft Model Antitumor Assays
D004042:Dietary Fats, Unsaturated; D005395:Fish Oils; D008070:Lipopolysaccharides; D014409:Tumor Necrosis Factor-alpha; D013481:Superoxides; D009569:Nitric Oxide; D006861:Hydrogen Peroxide