Submitted to: Federation of American Societies for Experimental Biology Conference
Publication Type: Abstract Only
Publication Acceptance Date: 11/3/2006
Publication Date: 4/28/2007
Citation: Wu, X., Till, R.S., Badger, T.M., Prior, R.L., Simmen, R.C. 2007. Early effects of blueberry and concord grape intake on rat mammary gland development suggest potential protective mechanisms for mammary tumorigenesis [abstract]. The FASEB Journal. 21(5):A367.
Interpretive Summary: It is becoming increasingly clear that dietary factors other than traditional nutrients can be important in human health. Many phytochemicals found in fruits, vegetables, and grains have been demonstrated to have effects on growth, development, and function of specific organs. We have been especially interested in the potential early effects of such dietary factors in children and how this may affect the normal course of development and health in children and later in life when they mature. This study examined the effects of two fruits commonly consumed by American children: blueberries and concord grapes. We found that young female rats fed diets containing blueberry and concord grape powders have significantly different mammary gland development than rats fed the same diets without these fruits. Importantly, the changes in the development of the mammary gland favor lower mammary tumor risk. These results have potential implications for prevention of breast cancer in women and future studies will extend these findings.
Technical Abstract: Blueberries (BB) and Concord grapes (CG) are rich in anthocyanins and other polyphenols, which may be linked to reduced incidence of chemically induced mammary carcinogenesis in animal models. We evaluated the early effects of dietary exposure to BB and CG on mammary glands of female rat offspring. Dams at gestation day 4 were assigned to AIN-93G (control) or test (AIN-93G + BB or CG freeze-dried powders; 2.5, 5, and 10% w/w) diets. Female pups were sacrificed at postnatal day 21, and their mammary glands isolated and analyzed for morphology and expression of the tumor suppressor PTEN. Carmine-stained whole mounts showed that the mammary 'epithelial trees' of BB and CG rats were more highly branched than those of control rats. The architectural differences between BB or CG and control mammary glands were dose-dependent, with 5% BB and 2.5% CG showing the greatest morphological effects. Immunoreactive PTEN, whose increased expression was previously correlated with mammary tumor protection, was highest in ductal epithelium of 5% BB rats (P<0.026), but did not differ in 2.5% CG rats relative to controls. However, vaginal opening (a measure of sexual maturity) occurred one day earlier in 2.5% CG rats (P<0.04) than in rats of other diet groups. Findings suggest that early exposure to CG and BB may advance mammary gland development to lower mammary tumor risk, albeit through distinct mechanisms.