title: Histologic, morphometric, and densitometric study of peri-implant bone in rabbits with local administration of growth hormone.
abstract: OBJECTIVE
  The objective of this study was to evaluate whether the local administration of growth hormone (GH) would influence the formation of peri-implant bone around titanium sheets placed in the tibiae of young rabbits.
  
  
  METHODS
  Thirty-two New Zealand rabbits were randomly placed in 1 of 2 groups: the experimental group, in which 4 IU (1.2 mg) of lyophilized powder (GH) was added to a surgically created defect at implant placement, or the control group, in which an implant sheet was placed without hormonal treatment. Animals were sacrificed at 1, 2, 3, and 6 weeks after surgery, and histologic sections were stained with Masson, Alcian blue, picrosirius, and hematoxylin-eosin and observed under light microscopy. The sections were analyzed morphometrically and densitometrically to calculate the amount of newly formed bone.
  
  
  RESULTS
  At week 2, GH-group sections showed enhanced growth of the trabeculae from the periosteal tissue, with thicker and more irregular trabeculae than those observed in control group specimens. A tendency toward greater bone area and lesser density was observed in the GH group, although the groups did not differ significantly. Nevertheless, bone-to-implant contact in weeks 2 and 6 was significantly greater in the GH group (P < .05).
  
  
  CONCLUSIONS
  An increase in the cortical response from periosteal and endosteal reactions was observed with the high local administration of GH, in disagreement with most authors. In the first phases of bone repair, the osteons were more disorganized; they were more organized by the sixth week.
  
  
  CONCLUSIONS
  Local administration of GH could stimulate the first phases of the bone remodeling process in this experimental model.
authors.affiliation: Department of Health Sciences III, Faculty of Health Sciences, Rey Juan Carlos University, Alcorcón, Madrid, Spain. isatresguerres@yahoo.es
authors.forename: Isabel F
authors.initials: IF
authors.lastname: Tresguerres
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Alobera
authors.forename: Rafael
authors.initials: R
authors.lastname: Baca
authors.forename: Jesús A F
authors.initials: JA
authors.lastname: Tresguerres
mesh_terms: D000287:Administration, Topical; D000818:Animals; D015519:Bone Density / Q000187:drug effects*; D016723:Bone Remodeling / Q000187:drug effects; D004396:Coloring Agents; D005260:Female; D005456:Fluorescent Dyes; D019382:Human Growth Hormone / Q000008:administration & dosage / Q000627:therapeutic use*; D016348:Osseointegration / Q000187:drug effects; D010012:Osteogenesis / Q000187:drug effects; D010027:Osteotomy; D019736:Prostheses and Implants; D011817:Rabbits; D011897:Random Allocation; D011994:Recombinant Proteins; D013977:Tibia / Q000187:drug effects* / Q000473:pathology / Q000601:surgery; D014025:Titanium
chemical_list: D004396:Coloring Agents; D005456:Fluorescent Dyes; D011994:Recombinant Proteins; D019382:Human Growth Hormone; D014025:Titanium