Dietary lignin, and insoluble fiber, enhance uterine cancer but did not influence mammary cancer induced by N-methyl-N-nitrosourea in rats.
Previous investigations suggested potential breast cancer-preventive properties of dietary fiber from cabbage. The purpose of the present investigation was to determine whether lignin, a component of cabbage fiber, would protect against mammary carcinogenesis by N-methyl-N-nitrosourea (MNU) in Sprague-Dawley rats. A six-week study was conducted using diets containing 0.5-5% dietary wood lignin (a readily available, purified source). These diets were well tolerated by the rats, and a carcinogenesis study using 5 mg MNU/100 g body wt i.v. at 50 days of age was conducted, with the 2.5% lignin diet fed from 6 through 8 weeks of age followed by 5% lignin diet until 20 weeks after MNU. Dietary lignin and MNU treatment increased food consumption (p < 0.05), and body weight was slightly reduced at 10 and 20 weeks after MNU in the MNU-5% lignin diet group (p < 0.05). Serum estradiol was not altered by dietary lignin or MNU treatment, but uterine weights were highest in the MNU-control diet group 4 and 12 weeks after MNU. Expression of creatine kinase B, and estrogen-responsive gene, was lower in eh uteri of the MNU-lignin diet group than in other groups at 20 weeks. Mammary carcinogenesis was not altered by dietary lignin. However, uterine endometrial adenocarcinoma was observed only in the MNU-lignin diet group (4 carcinomas/40 effective rats) (p < 0.05).
Birt
D F
DF
Eppley Institute for Research in Cancer and Allied Disease, University of Nebraska Medical Center, Omaha 69198, USA.
Markin
R S
RS
Blackwood
D
D
Harvell
D M
DM
Shull
J D
JD
Pennington
K L
KL
D000230:Adenocarcinoma / Q000209:etiology*; D000818:Animals; D001835:Body Weight; D001937:Brassica; D002294:Carcinoma, Squamous Cell / Q000209:etiology; D004043:Dietary Fiber / Q000494:pharmacology*; D004435:Eating; D016889:Endometrial Neoplasms / Q000209:etiology*; D005260:Female; D008031:Lignin / Q000494:pharmacology*; D008325:Mammary Neoplasms, Experimental / Q000139:chemically induced / Q000517:prevention & control*; D008770:Methylnitrosourea; D051381:Rats; D017207:Rats, Sprague-Dawley; D002583:Uterine Cervical Neoplasms / Q000209:etiology
D004043:Dietary Fiber; D008770:Methylnitrosourea; D008031:Lignin