Aged rats lose vasoprotective and anti-inflammatory actions of estrogen in injured arteries

Academic Article


  • OBJECTIVE: 17β-Estradiol (E2) negatively modulates neointima formation, leukocyte infiltration, and proinflammatory mediator expression after vascular injury in young (10-wk-old) ovariectomized (OVX) rats. Trials of E2 in elderly postmenopausal women have not confirmed a vasoprotective effect. This study tested the hypothesis that responsiveness to E2 is lost in injured arteries of aged (12-mo-old) OVX rats. DESIGN: E2- or vehicle-treated OVX rats underwent balloon injury of the carotid artery and were killed after 2 weeks for morphometric examination of arteries, after 24 hours for assessment of leukocyte infiltration, and after 2 hours for quantification of proinflammatory mediator mRNA expression. RESULTS: Neointima formation was significantly reduced in aged compared with young vehicle-treated rats. E2 treatment had directionally opposite effects on intima/media ratios in aged (+75%) and young (-40%) rats. Injury induced increases in infiltrating total leukocytes, neutrophils, monocytes/macrophages, and expression of proinflammatory mediators in arteries of aged rats; E2 had no effect on these inflammatory responses to injury. Estrogen receptor α and β protein expression were similar in carotid arteries of young and aged rats on immunofluorescence testing. CONCLUSIONS: Aged OVX rats lose the vasoprotective and anti-inflammatory responses to exogenous E2 seen in younger animals. These results may be relevant to the lack of vasoprotection observed in outcome trials of estrogen therapy in postmenopausal women. © 2007 by The North American Menopause Society.
  • Digital Object Identifier (doi)

    Author List

  • Miller AP; Xing D; Feng W; Fintel M; Chen YF; Oparil S
  • Start Page

  • 251
  • End Page

  • 260
  • Volume

  • 14
  • Issue

  • 2