title: Evaluating glucocorticoid administration on biomechanical properties of rats' tibial diaphysis.
abstract: BACKGROUND
  Osteoporosis is a disease, which causes bone loss and fractures. Although glucocorticoids effectively suppress inflammation, their chronic use is accompanied by bone loss with a tendency toward secondary osteoporosis.
  
  
  OBJECTIVE
  This study took into consideration the importance of cortical bone in the entire bone's mechanical competence. Hence, the aim of this study was to assess the effects of different protocols of glucocorticoid administration on the biomechanical properties of tibial bone diaphysis in rats compared to control and low-level laser-treated rats.
  
  
  METHODS
  This experimental study was conducted at Shahid Beheshti University of Medical Sciences, Tehran, Iran. We used systematic random sampling to divide 40 adult male rats into 8 groups with 5 rats in each group. Groups were as follows: 1) control, 2) dexamethasone (7 mg/week), 3) dexamethasone (0.7 mg/week), 4) methylprednisolone (7 mg/kg/week), 5) methylprednisolone (5 mg/kg twice weekly), 6) dexamethasone (7 mg/kg three times per week), 7) dexamethasone (0.7 mg/kg thrice per week), and 8) low-level laser-treated rats. The study periods were 4-7 weeks. At the end of the treatment periods, we examined the mechanical properties of tibial bone diaphysis. Data were analyzed by statistical analyses.
  
  
  RESULTS
  Glucocorticoid-treated rats showed weight loss and considerable mortality (21%). The biomechanical properties (maximum force) of glucocorticoid-treated rats in groups 4 (62 ± 2.9), 6 (63 ± 5.1), and 7 (60 ± 5.3) were comparable with the control (46 ± 1.5) and low-level laser-treated (57 ± 3.2) rats.
  
  
  CONCLUSIONS
  In contrast to the findings in humans and certain other species, glucocorticoid administration caused anabolic effect on the cortical bone of tibia diaphysis bone in rats.
authors.affiliation: Department of Biology and Anatomical Sciences, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, IR Iran.
authors.forename: Mohammadjavad
authors.initials: M
authors.lastname: Freidouni
authors.affiliation: Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, IR Iran.
authors.forename: Hossein
authors.initials: H
authors.lastname: Nejati
authors.affiliation: Department of Biology and Anatomical Sciences, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, IR Iran.
authors.forename: Maryam
authors.initials: M
authors.lastname: Salimi
authors.affiliation: Department of Biology and Anatomical Sciences, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, IR Iran.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Bayat
authors.affiliation: Department of Biology and Anatomical Sciences, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, IR Iran.
authors.forename: Abdollah
authors.initials: A
authors.lastname: Amini
authors.affiliation: Department of Biology and Anatomical Sciences, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, IR Iran.
authors.forename: Mohsen
authors.initials: M
authors.lastname: Noruzian
authors.affiliation: Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, IR Iran.
authors.forename: Mohammad Ali
authors.initials: MA
authors.lastname: Asgharie
authors.affiliation: Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, IR Iran.
authors.forename: Milad
authors.initials: M
authors.lastname: Rezaian
keywords: Biomechanical Phenomena; Glucocorticoids; Rats; Tibia