title: Effect of sexual steroids on the calcium content of aortic atherosclerotic plaque of oophorectomized rabbits.
abstract: We determined the effect of conjugated equine estrogen plus medroxyprogesterone acetate on calcium content of aortic atherosclerotic lesions in oophorectomized adult New Zealand rabbits submitted to a cholesterol rich diet. Five groups of 10 animals each were studied: G1 = control, G2 = cholesterol diet only, G3 = diet plus conjugated equine estrogen (0.625 mg/day); G4 and G5 = diet, conjugated equine estrogen (0.625 mg/day) plus medroxyprogesterone acetate (5 and 10 mg/day, respectively). Mean weight varied from 2.7 +/- 0.27 to 3.1 +/- 0.20 kg (P = 0.38) between groups at the beginning and 3.1 +/- 0.27 to 3.5 +/- 0.20 kg (P = 0.35) at the end of the experiment. Cholesterol and triglyceride levels were determined at the time of oophorectomy, 21 days after surgery (time 0), and at the end of follow-up of 90 days. The planimetric method was used to measure plaque and caryometric method for histopathologic examination of the aorta. Calcium content was determined by the method of von Kossa. A similar increase in cholesterol occurred in all treated groups without differences between them at the end of the study. Groups G4 and G5 had smaller areas of atherosclerotic lesions (2.33 +/- 2.8 and 2.45 +/- 2.1 cm(2), respectively) than the groups receiving no progestogens (G2: 5.6 +/- 4 and G3: 4.6 +/- 2.8 cm(2); P = 0.02). The relation between lesion area and total aorta area was smaller in groups treated with combined drugs compared to the groups receiving no progesterone (G4: 14.9 +/- 13 and G5: 14.2 +/- 13.4 vs G2: 35.8 +/- 26 and G3: 25 +/- 8 cm(2), respectively; P = 0.017). Oral conjugated equine estrogen (0.625 mg/day) plus medroxyprogesterone acetate (5 or 10 mg/day) provoked a greater reduction in atherosclerotic plaque area and calcium content in treated groups, suggesting a dose-dependent effect.
authors.affiliation: Faculdade de Saúde Pública, Faculdade de Medicina, Universidade de São PauloSão Paulo, SP, Brasil. jmaldri@usp.br
authors.forename: J M
authors.initials: JM
authors.lastname: Aldrighi
authors.forename: J R
authors.initials: JR
authors.lastname: Lanz
authors.forename: A P
authors.initials: AP
authors.lastname: Mansur
authors.forename: T L R
authors.initials: TL
authors.lastname: Martinez
authors.forename: J A F
authors.initials: JA
authors.lastname: Ramires
mesh_terms: D000818:Animals; D001011:Aorta / Q000737:chemistry* / Q000187:drug effects; D050197:Atherosclerosis / Q000209:etiology / Q000378:metabolism*; D002118:Calcium / Q000032:analysis* / Q000378:metabolism; D002784:Cholesterol / Q000032:analysis; D004036:Diet, Atherogenic; D004305:Dose-Response Relationship, Drug; D004966:Estrogens, Conjugated (USP) / Q000494:pharmacology*; D005260:Female; D017258:Medroxyprogesterone Acetate / Q000494:pharmacology*; D010052:Ovariectomy; D011817:Rabbits; D011897:Random Allocation; D013997:Time Factors; D014280:Triglycerides / Q000032:analysis
chemical_list: D004966:Estrogens, Conjugated (USP); D014280:Triglycerides; D002784:Cholesterol; D017258:Medroxyprogesterone Acetate; D002118:Calcium