Original Article

Korean J Pain 2016; 29(2): 86-95

Published online May 1, 2016 https://doi.org/10.3344/kjp.2016.29.2.86

Copyright © The Korean Pain Society.

Comparison of Mechanical Allodynia and Recovery of Locomotion and Bladder Function by Different Parameters of Low Thoracic Spinal Contusion Injury in Rats

Michael W. Carter, Kathia M. Johnson, Jun Yeon Lee*, Claire E. Hulsebosch, and Young Seob Gwak**

Department of Neuroscience and Cell Biology, University of Texas Medical Branch at Galveston, TX, USA.

*Department of Physiology, Daegu Haany University, Daegu, Korea.

Correspondence to: Young Seob Gwak. Department of Physiology, Daegu Haany University, 136 Shincheondong-ro, Suseong-gu, Daegu 42158, Korea. Tel: +82-53-770-2288, Fax: +82-53-770-2254, ysgwak@dhu.ac.kr

Received: January 6, 2016; Revised: February 12, 2016; Accepted: March 5, 2016

This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/), which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.



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.


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.


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.


The present study demonstrates SCI parameters optimize development of mechanical allodynia and other pathological outcomes.

Keywords: Blood brain barrier, Bladder function, Locomotion, Neuropathic pain, Spinal cord injury, Parameters, Rats