title: Effects of calcitonin on the biomechanics, histopathology, and radiography of callus formation in rats.
abstract: BACKGROUND
  This study was designed to examine the effect of salmon calcitonin on fracture repair.
  
  
  METHODS
  A transverse middiaphyseal fracture of the right tibia was surgically induced, and stabilized by an intramedullary Kirschner wire. Eighty male Wistar rats were arbitrarily assigned to four groups of 20 animals each. Groups I and II were the controls and did not receive any medication but did receive placebo injections. The other two groups received 5 IU/kg/day salmon calcitonin intramuscularly for 6 weeks (Group III) or for 10 weeks (Group IV) postoperatively. The formation and healing of the bones were determined by radiographic and histopathological analyses and by biomechanical tests.
  
  
  RESULTS
  In radiographic examinations, there were no statistically significant differences between groups I and III at week 6 or between groups II and IV at week 10. However, the histopathological evaluation scores were higher in the calcitonin group at the early stage (6 weeks) of fracture healing, which indicates a more mature callus formation (P < 0.05). The values for maximum torsional moment during fracture were higher in the calcitonin group in both stages of fracture healing (P < 0.01).
  
  
  CONCLUSIONS
  This study could have two important clinical implications. (1) Higher scores for the histopathological evaluation and a greater resistance to moment force applied at an early stage (week 6) of fracture healing imply that calcitonin intake might enable us to allow earlier mobilization and weight-bearing in clinical cases with rigid fixation. (2) At a late stage of fracture healing (week 10), the significantly better (P < 0.0001) results obtained in the biomechanical parameters used might imply that calcitonin intake could enable us to perform early implant removal, and strongly suggest that the strength and quality of the callus formation could be improved by administering calcitonin following a fracture.
authors.affiliation: Vakif Gureba Training and Research Hospital, Department of Orthopaedic Surgery, Adnan Menderes Bulvari, Fatih, Vakif Gureba Training and Research Hospital, Istanbul, 34296, Turkey.
authors.forename: Murat
authors.initials: M
authors.lastname: Bulbul
authors.forename: Cem Zeki
authors.initials: CZ
authors.lastname: Esenyel
authors.forename: Meltem
authors.initials: M
authors.lastname: Esenyel
authors.forename: Semih
authors.initials: S
authors.lastname: Ayanoglu
authors.forename: Bilge
authors.initials: B
authors.lastname: Bilgic
authors.forename: Turgut
authors.initials: T
authors.lastname: Gulmez
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D050071:Bone Density Conservation Agents / Q000008:administration & dosage*; D002146:Bony Callus / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology; D002116:Calcitonin / Q000008:administration & dosage*; D005593:Fracture Fixation, Internal; D017102:Fracture Healing / Q000187:drug effects*; D007273:Injections, Intramuscular; D008297:Male; D011859:Radiography; D051381:Rats; D017208:Rats, Wistar
chemical_list: D050071:Bone Density Conservation Agents; D002116:Calcitonin