title: Lack of efficacy of blueberry in nutritional prevention of azoxymethane-initiated cancers of rat small intestine and colon.
abstract: BACKGROUND
  Blueberries may lower relative risk for cancers of the gastrointestinal tract. Previous work indicated an inhibitory effect of consumed blueberry (BB) on formation of aberrant crypt foci (ACF) in colons of male Fisher F344 rats (inbred strain). However, effects of BB on colon tumors and in both genders are unknown.
  
  
  METHODS
  We examined efficacy of BB in inhibition of azoxymethane (AOM)-induced colon ACF and intestine tumors in male and female Sprague-Dawley rats (outbred strain). Pregnant rats were fed a diet with or without 10% BB powder; progeny were weaned to the same diet as their dam and received AOM as young adults.
  
  
  RESULTS
  Male and female rats on control diet had similar numbers of ACF at 6 weeks after AOM administration. BB increased (P < 0.05) ACF numbers within the distal colon of female but not male rats. There was a significant (P < 0.05) diet by gender interaction with respect to total colon ACF number. Colon and duodenum tumor incidences were less in females than males at 17 weeks after AOM. BB tended (0.1 > P > 0.05) to reduce overall gastrointestinal tract tumor incidence in males, however, tumor incidence in females was unaffected (P > 0.1) by BB. There was a tendency (0.1 > P > 0.05) for fewer adenocarcinomas (relative to total of adenomatous polyps plus adenocarcinomas) in colons of female than male tumor-bearing rats; in small intestine, this gender difference was significant (P < 0.05). BB favored (P < 0.05) fewer adenocarcinomas and more adenomatous polyps (as a proportion of total tumor number) in female rat small intestine.
  
  
  CONCLUSIONS
  Results did not indicate robust cancer-preventive effects of BB. Blueberry influenced ACF occurrence in distal colon and tumor progression in duodenum, in gender-specific fashion. Data indicate the potential for slowing tumor progression (adenomatous polyp to adenocarcinoma) by BB.
authors.affiliation: Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, 4301 W. Markham Street, Little Rock, AR 72205, USA. simmenfranka@uams.edu
authors.forename: Frank A
authors.initials: FA
authors.lastname: Simmen
authors.forename: Julie A
authors.initials: JA
authors.lastname: Frank
authors.forename: Xianli
authors.initials: X
authors.lastname: Wu
authors.forename: Rijin
authors.initials: R
authors.lastname: Xiao
authors.forename: Leah J
authors.initials: LJ
authors.lastname: Hennings
authors.forename: Ronald L
authors.initials: RL
authors.lastname: Prior
mesh_terms: D000230:Adenocarcinoma / Q000139:chemically induced / Q000453:epidemiology / Q000517:prevention & control*; D018256:Adenomatous Polyps / Q000139:chemically induced / Q000453:epidemiology / Q000517:prevention & control; D000818:Animals; D001397:Azoxymethane / Q000009:adverse effects; D029798:Blueberry Plants; D002096:C-Peptide / Q000097:blood; D003110:Colonic Neoplasms / Q000139:chemically induced / Q000453:epidemiology / Q000517:prevention & control*; D004195:Disease Models, Animal; D018450:Disease Progression; D004379:Duodenal Neoplasms / Q000139:chemically induced / Q000453:epidemiology / Q000517:prevention & control*; D005260:Female; D015994:Incidence; D008297:Male; D044623:Nutrition Therapy; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D002096:C-Peptide; D001397:Azoxymethane