Dietary effects of conjugated docosahexaenoic acid on N-methyl-N-nitrosourea-induced mammary carcinogenesis in female Sprague-Dawley rats.
The dietary effects of conjugated docosahexaenoic acid (CDHA) were examined in an N-methyl-N-nitrosourea (MNU)-induced rat mammary carcinogenesis model. Female Sprague-Dawley rats were administered 50 mg/kg MNU intraperitoneally at 49 days of age. A powdered AIN-76A diet containing 0, 0.2 or 1.0% CDHA was fed to the rats from 21 to 49 days of age (before MNU; pre-initiation phase) or from 49 days to 40 weeks of age (after MNU; post-initiation phase). Rats were sacrificed when their largest mammary tumor was > or =1 cm in size or when they reached 40 weeks of age. All histologically detected mammary carcinomas were evaluated. In rats that received CDHA after MNU, development of mammary carcinoma > or =1 cm was inhibited, and there was a significant decrease in the final mammary cancer incidence and multiplicity, compared with rats that did not receive CDHA. Consumption of the 0.2% CDHA diet after MNU significantly prolonged latency. Suppression of mammary cancer yield by consumption of a CDHA diet after MNU administration was not dose-dependent. In rats that received CDHA before MNU, suppression of mammary cancer was not observed. These results indicate that CDHA administration in the post-initiation period suppressed mammary carcinogenesis, whereas CDHA administration in the pre-initiation period was ineffective.
Danbara
Naoyuki
N
Department of Pathology II, Kansai Medical University, Moriguchi, Osaka 570-8506, Japan.
Uehara
Norihisa
N
Shikata
Nobuaki
N
Takada
Hideho
H
Hada
Takahiko
T
Tsubura
Airo
A
D000477:Alkylating Agents / Q000633:toxicity*; D000818:Animals; D016588:Anticarcinogenic Agents / Q000008:administration & dosage*; D004032:Diet; D004281:Docosahexaenoic Acids / Q000008:administration & dosage*; D005260:Female; D008325:Mammary Neoplasms, Experimental / Q000473:pathology / Q000517:prevention & control*; D008770:Methylnitrosourea / Q000633:toxicity*; D051381:Rats; D017207:Rats, Sprague-Dawley
D000477:Alkylating Agents; D016588:Anticarcinogenic Agents; D004281:Docosahexaenoic Acids; D008770:Methylnitrosourea