title: Protective effects of insulin-like growth factor-I on the decrease in myogenic differentiation by ionizing radiation.
abstract: OBJECTIVE
  The aim of the work is to evaluate the effects of insulin-like growth factor-1 (IGF-1) on the decrease in myotube formation induced by ionizing radiation.
  
  
  METHODS
  We induced C2C12 cells to a myogenic linage following X-ray irradiation at 2 and 4 Gy. Myogenic differentiation was estimated using immnocytochemical staining with anti-myosin antibody, and the anti-myosin antibody positive areas, the total number of nuclei, the number of nuclei included in multinucleated myotubes per field, and the myotube formation ratio were analyzed.
  
  
  RESULTS
  In the myogenic differentiation in the presence of IGF-1, the decrease in anti-myosin antibody positive areas, the nuclei included in myotubes, and the myotube formation ratio induced by X-ray irradiation at 2 Gy was restored to control levels.
  
  
  CONCLUSIONS
  The addition of IGF-1 protected against the decrease myotube formation induced by X-ray irradiation at 2 Gy. Since X-ray irradiation at 2 Gy is usually used for multi-fractionated irradiation in radiotherapy, our findings suggest that IGF-1 could be useful to protect against impairment of muscle repair induced by therapeutic dose radiation.
authors.affiliation: Department of Radiological Life Sciences, Division of Medical Life Sciences, Hirosaki University, 66-1 Hon-cho, Japan.
authors.forename: Tomonori
authors.initials: T
authors.lastname: Sakurai
authors.forename: Takanori
authors.initials: T
authors.lastname: Ueda
authors.forename: Miyuki
authors.initials: M
authors.lastname: Kawai
authors.forename: Hideki
authors.initials: H
authors.lastname: Tobita
authors.forename: Junji
authors.initials: J
authors.lastname: Miyakoshi
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects / Q000528:radiation effects*; D002460:Cell Line; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D051379:Mice; D018485:Muscle Fibers, Skeletal / Q000166:cytology / Q000187:drug effects / Q000528:radiation effects*; D017570:MyoD Protein / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis; D011837:Radiation-Protective Agents / Q000494:pharmacology*; D014965:X-Rays
chemical_list: D017570:MyoD Protein; C057363:MyoD1 myogenic differentiation protein; D012333:RNA, Messenger; D011837:Radiation-Protective Agents; D007334:Insulin-Like Growth Factor I