Comparison of Mechanical Allodynia and Recovery of Locomotion and Bladder Function by Different Parameters of Low Thoracic Spinal Contusion Injury in Rats.
BACKGROUND
The present study was designed to examine the functional recovery following spinal cord injury (SCI) by adjusting the parameters of impact force and dwell-time using the Infinite Horizon (IH) impactor device.


METHODS
Sprague-Dawley rats (225-240 g) were divided into eight injury groups based on force of injury (Kdyn) and dwell time (seconds), indicated as Force-Dwell time: 150-4, 150-3, 150-2, 150-1, 150-0, 200-0, 90-2 and sham controls, respectively.


RESULTS
After T10 SCI, higher injury force produced greater spinal cord displacement (P < 0.05) and showed a significant correlation (r = 0.813) between the displacement and the force (P < 0.05). In neuropathic pain-like behavior, the percent of paw withdrawals scores in the hindpaw for the 150-4, 150-3, 150-2, 150-1 and the 200-0 injury groups were significantly lowered compared with sham controls (P < 0.05). The recovery of locomotion had a significant within-subjects effect of time (P < 0.05) and the 150-0 group had increased recovery compared to other groups (P < 0.05). In addition, the 200-0 and the 90-2 recovered significantly better than all the 150 kdyn impact groups that included a dwell-time (P < 0.05). In recovery of spontaneous bladder function, the 150-4 injury group took significantly longer recovery time whereas the 150-0 and the 90-2 groups had the shortest recovery times.


CONCLUSIONS
The present study demonstrates SCI parameters optimize development of mechanical allodynia and other pathological outcomes.
Department of Neuroscience and Cell Biology, University of Texas Medical Branch at Galveston, TX, USA.
Michael W
MW
Carter
Department of Neuroscience and Cell Biology, University of Texas Medical Branch at Galveston, TX, USA.
Kathia M
KM
Johnson
Department of Physiology, Daegu Haany University, Daegu, Korea.
Jun Yeon
JY
Lee
Department of Neuroscience and Cell Biology, University of Texas Medical Branch at Galveston, TX, USA.
Claire E
CE
Hulsebosch
Department of Physiology, Daegu Haany University, Daegu, Korea.
Young Seob
YS
Gwak
Bladder function; Blood brain barrier; Locomotion; Neuropathic pain; Parameters; Rats; Spinal cord injury