[Animal model of grading skeletal muscle contusion due to blunt impact in rats].
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.
Yu
Tian-Shui
TS
Department of Forensic Pathology, School of Forensic Medicine, China Medical University, Shenyang 110001, China. yutianshui-2000@sohu.com
Guan
Da-Wei
DW
Cheng
Zi-Hui
ZH
Zhao
Rui
R
Hu
Geng-Yi
GY
Zhu
Rui-Xia
RX
Wang
Ling
L
Guo
Xiao-Chong
XC
Wang
Chang-Liang
CL
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