Dietary nucleosides and nucleotides do not affect tumor incidence but reduce amyloidosis incidence in B6C3F1 mice irradiated with californium-252.
OBJECTIVE
We investigated the effects of a dietary mixture of nucleosides and nucleotides (NS) on the systemic incidence rates of postirradiation carcinogenesis and non-neoplastic lesions in mice.


METHODS
Five-week-old male B6C3F1 mice were fed AIN-76B Purified Diet supplemented with NS for 1 wk and 13 mo before and after irradiation of neutron with californium-252 ((252)Cf); specifically NS was added to the AIN-76B Purified Diet (without nucleotide) to obtain a final concentration of 0%, 0.5%, or 2.5% NS. A commercial stock diet was also given to mice, and half of the mice were irradiated. Both irradiated and non-irradiated mice were used for reference controls.


RESULTS
The incidence of liver tumors in each NS group was lower than that in the reference control group (P < 0.01), but there were no differences between the 0%, 0.5%, and 2.5% NS groups. In contrast, the incidence rate of mice with non-neoplastic lesions in the 0% NS group was significantly higher than the reference control group (P < 0.05). This higher incidence of mice with non-neoplastic lesions was significantly decreased upon supplementation of the nucleotide-free diet with 0.5% or 2.5% NS (P < 0.01 and P < 0.05, respectively). Of the non-neoplastic lesions observed, the incidence of amyloidosis was decreased significantly upon supplementation of the nucleotide-free diet with 0.5% NS (P < 0.05).


CONCLUSIONS
Supplementation of a nucleotide-free diet with NS inhibits the development of non-neoplastic lesions, such as those associated with amyloidosis, without promoting the carcinogenesis induced by (252)Cf irradiation.
Yokoyama
Hiroomi
H
Department of Cellular Biology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima, Japan. yokoyahr@otsukakj.co.jp
Fujiwara
Hiroshi
H
Watanabe
Hiromitsu
H
D000686:Amyloidosis / Q000209:etiology / Q000473:pathology / Q000517:prevention & control*; D000818:Animals; D001835:Body Weight; D002142:Californium; D004032:Diet; D004435:Eating; D007674:Kidney Diseases / Q000473:pathology / Q000517:prevention & control; D008107:Liver Diseases / Q000473:pathology / Q000517:prevention & control; D008297:Male; D051379:Mice; D009381:Neoplasms, Radiation-Induced / Q000453:epidemiology*; D009705:Nucleosides / Q000008:administration & dosage*; D009711:Nucleotides / Q000008:administration & dosage*; D009929:Organ Size; D013158:Splenic Diseases / Q000473:pathology / Q000517:prevention & control
D009705:Nucleosides; D009711:Nucleotides; D002142:Californium