title: Increased cellular proliferation in rat skeletal muscle and tendon in response to exercise: use of FLT and PET/CT.
abstract: OBJECTIVE
  The purpose of this study is to investigate exercise-induced cellular proliferation in rat skeletal muscle/tendon with the use of 3'-[F-18]fluoro-3'deoxythymidine (FLT) and to quantitatively study concomitant changes in the proliferation-associated factor, Ki67.
  
  
  METHODS
  Wistar rats (n = 13) performed 3 days of treadmill running. Cellular proliferation was investigated 3 days before and 48 h after the running exercise with the use of FLT and positron emission tomography/computed tomography (PET/CT). Results were compared to a sedentary control group (n = 10). Image-derived standardized uptake values were calculated for Achilles tendons and calf muscles and compared to gene expression and immunohistochemical evaluations of Ki67.
  
  
  RESULTS
  Treadmill running induced increased uptake of FLT uptake in calf muscles (30%; p < 0.001) and in Achilles tendon (21%, p < 0.001). The image-derived results were supported by a correlation in calf muscle to Ki67 (protein and mRNA level), while this coherence was not found in tendon.
  
  
  CONCLUSIONS
  FLT-PET seems to be a promising tool for imaging of exercise-induced cellular proliferation in musculo-tendinous tissue.
authors.affiliation: Institute of Sports Medicine Copenhagen, Bispebjerg Hospital and Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark. dskovgaard@dadlnet.dk
authors.forename: Dorthe
authors.initials: D
authors.lastname: Skovgaard
authors.forename: Monika L
authors.initials: ML
authors.lastname: Bayer
authors.forename: Abigail L
authors.initials: AL
authors.lastname: Mackey
authors.forename: Jacob
authors.initials: J
authors.lastname: Madsen
authors.forename: Michael
authors.initials: M
authors.lastname: Kjaer
authors.forename: Andreas
authors.initials: A
authors.lastname: Kjaer
mesh_terms: D000818:Animals; D049109:Cell Proliferation; D015224:Dideoxynucleosides; D005080:Exercise Test; D006965:Hyperplasia / Q000175:diagnosis; D019394:Ki-67 Antigen / Q000235:genetics / Q000378:metabolism; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism / Q000473:pathology / Q000502:physiology*; D010805:Physical Conditioning, Animal / Q000502:physiology*; D049268:Positron-Emission Tomography / Q000379:methods*; D051381:Rats; D017208:Rats, Wistar; D012420:Running / Q000502:physiology; D013710:Tendons / Q000166:cytology / Q000378:metabolism / Q000473:pathology / Q000502:physiology*; D014055:Tomography, Emission-Computed / Q000379:methods; D015854:Up-Regulation
chemical_list: D015224:Dideoxynucleosides; D019394:Ki-67 Antigen; C002854:alovudine