title: Tibolone inhibits aortic atherosclerotic lesionformation in oophorectomized cholesterol-fed rabbits.
abstract: BACKGROUND
  Tibolone is a synthetic steroid effective for the treatment of climacteric symptoms and osteoporosis. Long term treatment with tibolone is associated with a significant decrease in cholesterol levels due to a parallel decrease in high-density lipoprotein. However, the effect of these changes on atherogenesis is not known.
  
  
  OBJECTIVE
  To investigate the effect of tibolone therapy on aorta atherogenesis.
  
  
  METHODS
  Thirty-two New Zealand white rabbits were fed cholesterol-rich feed and studied for four months. The rabbits underwent laparotomy and were randomly assigned to four groups. Twenty-four rabbits underwent bilateral ovariectomy; of these, eight received tibolone (group T), eight received estradiol valerate (group E), eight received placebo after sterilization (group C), and eight were sham operated (group S).
  
  
  RESULTS
  After receiving the cholesterol-rich diet, total levels of cholesterol increased in group C from 3.17+/-0.72 mmol/L to 35.36+/-9.01 mmol/L, in group S from 2.88+/-0.9 mmol/L to 28.76+/-9.442 mmol/L, in group E from 1.69+/-0.44 mmol/L to 1.69+/-0.44 mmol/L and in group T from 2.03+/-0.22 mmol/L to 26.33+/-13.45 mmol/L (no significant differences were observed among the groups at the end of the study). At four months, the cholesterol- rich diet caused atherosclerotic lesions in both treated and untreated rabbits, affecting 30.47+/-12.2%, 24.51+/-16.1%, 17.91+/-10.19% and 10.21+/-6.8% of the aortic surface for groups C, S, E and T, respectively (P<0.01 for treated groups).
  
  
  CONCLUSIONS
  The principal result from this study was that treatment with tibolone in cholesterol-fed ovariectomized rabbits reduces aortic atherosclerotic lesion formation and that this reduction is not related to plasma lipid levels.
authors: Menopause Clinic, Department of Gynecology and Obstetrics, Hospital Clínic Provincial, University of Barcelona, Barcelona, Spain;
authors: Camil
authors: C
authors: Castelo-Branco
authors: Alex
authors: A
authors: Sanjuán
authors: Carles
authors: C
authors: Ascaso
authors: Marta
authors: M
authors: Colodrón
authors: Juan Enrique
authors: JE
authors: Blümel
authors: Elena
authors: E
authors: Casals
authors: Jaume
authors: J
authors: Ordi
authors: Juan Antonio
authors: JA
authors: Vanrell