title: [Animal model of grading skeletal muscle contusion due to blunt impact in rats].
abstract: OBJECTIVE
  To establish a new animal model of grading skeletal muscle contusions that could be controllable and repetitive.
  
  
  METHODS
  The rats' gastrocnemius was injured by a new weight-dropping device designed. The force acting on gastrocnemius with a comparatively constant duration and inducing elastic deformation of the gastrocnemius was expressed with velocity (v) and deformation (DF). Instant velocity was changed to create gastrocnemius contusions. Pathological changes of gastrocnemius were graded by the gross and histological examinations of 39 rats.
  
  
  RESULTS
  At low level of impact (v: 2 m/s, DF: 5.5 mm), mild injuries were detected in epimysium and superficial layer of gastrocnemius. At moderate level of impact (v: 2.5 m/s, DF: 6.5 mm), the injuries were observed in epimysium and whole gastrocnemius. At high level of impact (v: 3 m/s, DF: 7.5 mm), severe injuries were seen deeper to soleus with more extensive skeletal muscle damage.
  
  
  CONCLUSIONS
  Grading of skeletal muscle blunt force contusion is created by parameter of velocity and muscle deformation. The model could be used for further research on skeletal muscle contusions.
authors: Department of Forensic Pathology, School of Forensic Medicine, China Medical University, Shenyang 110001, China. yutianshui-2000@sohu.com
authors: Tian-Shui
authors: TS
authors: Yu
authors: Da-Wei
authors: DW
authors: Guan
authors: Zi-Hui
authors: ZH
authors: Cheng
authors: Rui
authors: R
authors: Zhao
authors: Geng-Yi
authors: GY
authors: Hu
authors: Rui-Xia
authors: RX
authors: Zhu
authors: Ling
authors: L
authors: Wang
authors: Xiao-Chong
authors: XC
authors: Guo
authors: Chang-Liang
authors: CL
authors: Wang
mesh_terms: D000818:Animals; D003288:Contusions / Q000145:classification*; D004195:Disease Models, Animal; D049429:Forensic Pathology; D008297:Male; D018482:Muscle, Skeletal / Q000293:injuries*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014949:Wounds, Nonpenetrating