title: Comparison between phytoestrogens and estradiol in the prevention of atheroma in ovariectomized cholesterol-fed rabbits.
abstract: OBJECTIVE
  There is increasing interest in the role of complementary and alternative medicines for the treatment of menopause-related problems. This study compared the preventive effect on atheroma formation of a commercially available mixed phytoestrogen concentrate with that of estradiol.
  
  
  METHODS
  An ovariectomized cholesterol-fed rabbit model of atheroma formation was used. Rabbits were ovariectomized before the commencement of the 12-week treatment period. There were two control groups. Control Group 1 received isoflavone-free rabbit chow whilst Control Group 2 received 1% cholesterol-enriched isoflavone-free rabbit chow. Rabbits in Group 3 received 1% cholesterol-enriched isoflavone-free rabbit chow plus a 500 mg tablet containing a concentrated extract of Trifolium pretense (red clover). Rabbits in Group 4 received 1% cholesterol-enriched isoflavone-free rabbit chow plus a 0.5 mg tablet of oral estradiol. Atheroma formation was measured by, first, calculation of the area of atheroma on the intimal surface, and, second, measuring the cholesterol content in the aorta.
  
  
  RESULTS
  There were no significant differences in serum cholesterol between the cholesterol-fed control Group 2 and the treatment Groups 3 and 4. However, there was significantly less staining for atheroma and significantly less cholesterol accumulation in the aorta in Group 4 (estradiol-treated) rabbits compared with either control Group 2 or Group 3 (phytoestrogen-treated) rabbits.
  
  
  CONCLUSIONS
  In this study, only estradiol was shown to have a significant protective effect against atheroma formation.
authors.affiliation: Departments of Obstetrics and Gynaecology, The Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, NT, Hong Kong.
authors.forename: C
authors.initials: C
authors.lastname: Haines
authors.forename: A
authors.initials: A
authors.lastname: James
authors.forename: D
authors.initials: D
authors.lastname: Sahota
authors.forename: Z Y
authors.initials: ZY
authors.lastname: Chen
authors.forename: N
authors.initials: N
authors.lastname: Panesar
authors.forename: B
authors.initials: B
authors.lastname: Tomlinson
authors.forename: L
authors.initials: L
authors.lastname: Chow
authors.forename: I
authors.initials: I
authors.lastname: Benzie
authors.forename: A
authors.initials: A
authors.lastname: Husband
mesh_terms: D000284:Administration, Oral; D000818:Animals; D001011:Aorta / Q000473:pathology; D050197:Atherosclerosis / Q000097:blood / Q000473:pathology / Q000517:prevention & control*; D002784:Cholesterol / Q000097:blood / Q000378:metabolism*; D002791:Cholesterol, Dietary / Q000008:administration & dosage; D004195:Disease Models, Animal; D004958:Estradiol / Q000627:therapeutic use*; D005260:Female; D010052:Ovariectomy; D048789:Phytoestrogens / Q000627:therapeutic use*; D011817:Rabbits; D011897:Random Allocation
chemical_list: D002791:Cholesterol, Dietary; D048789:Phytoestrogens; D004958:Estradiol; D002784:Cholesterol