title: Bone regeneration in osteoporotic conditions: healing of subcritical-size calvarial defects in the ovariectomized rat.
abstract: OBJECTIVE
  Osteoporosis is a pathologic condition characterized by low bone mass and changes in the microarchitecture of the bone tissue. Although compromised bone strength and increased susceptibility to fracture have been established, little is known regarding the process of bone regeneration in osteoporotic conditions. Accordingly, this study sought to evaluate the intramembranous bone regeneration process in an ovariectomized rat model following the establishment of calvarial subcritical-size defects (sCSDs).
  
  
  METHODS
  Calvarial sCSDs were established in rats that had been ovariectomized (Ovx) or sham-operated 2 months previously and left to heal, unfilled, for 6 months. Bone regeneration was assessed by radiographic, densitometric, histologic, and histometric analyses.
  
  
  RESULTS
  Radiologic and histologic analyses showed reduced new bone formation in calvarial sCSDs in Ovx animals in comparison to sham animals. Densitometric analysis of radiologic images and histometric analysis showed significant quantitative differences between groups that converged to substantiate reduced bone regeneration in Ovx animals.
  
  
  CONCLUSIONS
  The intramembranous ossification process is impaired in the Ovx rat model. This may suggest an impairment of the bone regeneration process in clinical conditions of postmenopausal osteoporosis and highlight the requirement for selective bone regenerative strategies in affected patients.
authors.affiliation: Faculdade de Medicina Dentária, Universidade do Porto, Porto, Portugal.
authors.forename: Sara F O
authors.initials: SF
authors.lastname: Durão
authors.forename: Pedro S
authors.initials: PS
authors.lastname: Gomes
authors.forename: José M
authors.initials: JM
authors.lastname: Silva-Marques
authors.forename: Hélder R M
authors.initials: HR
authors.lastname: Fonseca
authors.forename: João F C
authors.initials: JF
authors.lastname: Carvalho
authors.forename: José A R
authors.initials: JA
authors.lastname: Duarte
authors.forename: Maria H R
authors.initials: MH
authors.lastname: Fernandes
mesh_terms: D000818:Animals; D015519:Bone Density; D001861:Bone Regeneration / Q000502:physiology*; D003720:Densitometry; D004195:Disease Models, Animal; D005260:Female; D010024:Osteoporosis / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology*; D010052:Ovariectomy; D011859:Radiography; D051381:Rats; D017208:Rats, Wistar; D012886:Skull; D014945:Wound Healing