title: Characterization of bone defect repair in young and aged rat femur induced by xenogenic demineralized bone matrix.
abstract: BACKGROUND
  The osteoinductive effect of some biomaterials could be affected by those systemic conditions typical of old age. The aim of the present paper was to assess the effects of age on the healing of bone defects treated with demineralized bone matrix (DBM).
  
  
  METHODS
  The study was conducted in young (3 month old) and aged (18 month old) rats to assess the efficacy of DBM in the treatment of osseous defects in bone with limited repair capacities. A standard bone defect was created in the distal femoral condyles of male Wistar rats: the left condyle was filled with rabbit DBM granules, while the right condyle was left empty (control). Histological and microhardness analyses were performed at 30 and 45 days after implant surgery.
  
  
  RESULTS
  After implantation of xenogenic DBM, bone healing areas of the aged and young groups showed a significant increase in the formation of newly mineralized bone relative to controls. Measurements of trabecular thickness on day 45 revealed no differences between newly formed and preexisting bone in the young group, while control values were lower. Microhardness measurements demonstrated that newly mineralized bone, either induced by DBM or not, and preexisting bone were comparable in terms of trabecular hardness after 45 days.
  
  
  CONCLUSIONS
  In conclusion, xenogenic DBM seems to be effective in bone defect healing, since it increases mineralized tissue volume. In both DBM-filled and empty sites, age seems to have a detrimental effect on the volume of new bone formation but no influence on bone maturation.
authors.affiliation: Experimental Surgery Department, Research Institute Codivilla-Putti, Bologna, Italy. paola.torricelli@ior.it
authors.forename: Paola
authors.initials: P
authors.lastname: Torricelli
authors.forename: Milena
authors.initials: M
authors.lastname: Fini
authors.forename: Gianluca
authors.initials: G
authors.lastname: Giavaresi
authors.forename: Lia
authors.initials: L
authors.lastname: Rimondini
authors.forename: Roberto
authors.initials: R
authors.lastname: Giardino
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D018775:Bone Demineralization Technique; D015519:Bone Density; D001857:Bone Matrix / Q000637:transplantation*; D001861:Bone Regeneration / Q000502:physiology*; D016025:Bone Transplantation / Q000379:methods*; D002113:Calcification, Physiologic / Q000502:physiology; D005270:Femur Head; D006244:Hardness; D008297:Male; D011817:Rabbits; D051381:Rats; D017208:Rats, Wistar; D018709:Statistics, Nonparametric; D014184:Transplantation, Homologous