title: Growth hormone can decrease muscle damage complication in tibia lengthening by external fixation.
abstract: OBJECTIVE
  The purpose of this study was to investigate the effects of growth hormone (GH) on muscles during limb lengthening.
  
  
  METHODS
  Sixty rats underwent tibial lengthening of approximately 30% after a latency period of 4 days, a distraction period of 30 days with a rate of 0.25 mm twice per day, and a consolidation period of 27 days. Recombinant GH was administered to 30 rats (100 g/kg/d) and the same dose of normal saline to the remaining 30 rats, between operation and sacrifice. Histopathologic, immunohistochemical, and electrophysiological studies were performed on the tibialis anterior to compare the muscle responses of GH-treated lengthened limbs, GH-treated nonlengthened limbs, saline-treated lengthened limbs, and saline-treated nonlengthened limbs at postoperative days 34 and 61.
  
  
  RESULTS
  Histologic injury scores were worst in the saline-treated lengthened limbs, where vimentin expression was also highest. Cell proliferation, determined by proliferating cell nuclear antigen staining, was highest in the GH-treated lengthened limbs, where desmin expression was also highest. Electrophysiological methods that showed better muscle function was retained in the GH-treated lengthened limbs than in the saline-treated lengthened limbs.
  
  
  CONCLUSIONS
  Our results suggest that GH can reduce muscle damage during limb lengthening by enhancing myogenesis and decreasing fibrogenesis.
authors.affiliation: Department of Orthopaedic Surgery, Dongguk University International Hospital, Ilsan, Korea. pse0518@duih.org
authors.forename: Sang Eun
authors.initials: SE
authors.lastname: Park
authors.forename: Pan Kun
authors.initials: PK
authors.lastname: Park
mesh_terms: D000818:Animals; D001852:Bone Lengthening / Q000009:adverse effects / Q000379:methods*; D049109:Cell Proliferation / Q000187:drug effects; D003893:Desmin / Q000378:metabolism; D055724:Electrophysiological Phenomena; D013006:Growth Hormone / Q000494:pharmacology*; D008297:Male; D024510:Muscle Development / Q000187:drug effects; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000473:pathology; D011183:Postoperative Complications / Q000517:prevention & control; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013194:Staining and Labeling; D013977:Tibia / Q000601:surgery*
chemical_list: D003893:Desmin; D018809:Proliferating Cell Nuclear Antigen; D013006:Growth Hormone