title: Muscle regeneration is undisturbed by repeated polytraumatic injury.
abstract: BACKGROUND
  Clinical observations suggest that repeated injury within a week after a traumatic event impairs the regeneration of tissues. Our aim was to investigate the effect of repeated trauma on the proliferation of satellite cells in skeletal muscle tissue.
  
  
  METHODS
  Cold lesion injury was performed in the soleus muscle and in the motor cortex of anesthetized male Wistar rats 0, 1, or 2 times with 7 day intervals between the interventions. Following the last operation, 5-bromo-2'-deoxyuridine was injected i.p. for 6 or 12 days to label dividing cells. Gut epithelium was used as positive control. Immunohistochemistry was performed 1 and 5 weeks after the last injury and the sections were analyzed with confocal microscopy.
  
  
  RESULTS
  In the case of repeated trauma, the percentage of proliferating cells remained the same compared to single hit animals after 1 week (28.0 ± 2.5% and 29.6 ± 3.0%) as well as after 5 weeks (13.9 ± 1.8% and 14.5 ± 2.2%).
  
  
  CONCLUSIONS
  The second hit phenomenon is probably due to systemic factors rather than to a diminished regenerating potential of injured soft tissues.
authors.forename: D B
authors.initials: DB
authors.lastname: Horváthy
authors.forename: P P
authors.initials: PP
authors.lastname: Nardai
authors.forename: T
authors.initials: T
authors.lastname: Major
authors.forename: K
authors.initials: K
authors.lastname: Schandl
authors.forename: A
authors.initials: A
authors.lastname: Cselenyák
authors.forename: G
authors.initials: G
authors.lastname: Vácz
authors.forename: L
authors.initials: L
authors.lastname: Kiss
authors.forename: M
authors.initials: M
authors.lastname: Szendrői
authors.forename: Z
authors.initials: Z
authors.lastname: Lacza