title: Flaxseed does not enhance the estrogenic effect of low-dose estrogen therapy on markers of uterine health in ovariectomized rats.
abstract: Flaxseed (FS) is an oilseed rich in phytoestrogens and n-3 polyunsaturated fatty acids, compounds that may attenuate bone loss during aging. We previously demonstrated using the ovariectomized (OVX) rat model of postmenopausal osteoporosis that 10% dietary FS combined with low-dose estrogen therapy (LD) preserves vertebral bone mass and strength more so than either treatment alone. However, it was prudent to also consider the effect of this intervention on uterine tissue as LD, and possibly FS, may have estrogenic, and thus negative, effects on uterine tissue. The present study investigated if FS enhances the estrogenic effect of LD on markers of uterine health in OVX rats. Three-month-old rats were randomized to groups: (1) SHAM, (2) OVX, (3) OVX+FS, (4) OVX+LD, or (5) OVX+FS+LD. Ground FS was added to the AIN-93M diet (100 g/kg of diet), and LD was delivered by subcutaneous implant (0.42 μg of 17β-estradiol/kg of body weight/day) to mimic LD in postmenopausal women. After 12 weeks, histological analyses of uterine tissue demonstrated flattened or cuboidal luminal epithelia organized in a single layer in the OVX group, while FS, LD, and FS+LD induced a single layer of elongated luminal epithelia, columnar in shape. The SHAM group had the greatest epithelial mass. Cell proliferation was similar among all OVX groups. Therefore FS and FS+LD similarly induce estrogen-like effects on the morphology of luminal epithelia that are weaker than in the SHAM group without inducing cell proliferation in OVX rats. Thus, FS does not enhance the estrogenic effect of LD on markers of uterine health in OVX rats.
authors.affiliation: Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Sandra M
authors.initials: SM
authors.lastname: Sacco
authors.forename: Jessica M Y
authors.initials: JM
authors.lastname: Jiang
authors.forename: Lilian U
authors.initials: LU
authors.lastname: Thompson
authors.forename: Wendy E
authors.initials: WE
authors.lastname: Ward
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D049109:Cell Proliferation / Q000187:drug effects; D048430:Cell Shape / Q000187:drug effects; D019587:Dietary Supplements / Q000009:adverse effects; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D015914:Estrogen Replacement Therapy / Q000379:methods*; D005260:Female; D019597:Flax / Q000009:adverse effects / Q000737:chemistry*; D018565:Food-Drug Interactions; D006965:Hyperplasia; D008593:Menopause / Q000378:metabolism; D010052:Ovariectomy / Q000009:adverse effects; D048789:Phytoestrogens / Q000009:adverse effects / Q000627:therapeutic use*; D011208:Powders; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D012639:Seeds / Q000009:adverse effects / Q000737:chemistry*; D014599:Uterus / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology
chemical_list: D015415:Biomarkers; D048789:Phytoestrogens; D011208:Powders; D018809:Proliferating Cell Nuclear Antigen