Clinical Features of Central Neuropathic Pain after Contusive Spinal Cord Injury in Rats

ABSTRACT

OBJECTIVE: To investigate the characteristics of the central neuropathic pain (CNP) after contusive spinal cord injury in rats. METHOD: Twenty Sprague-Dawley rats (300+/-50 g, male) undergone the free-drop contusion injury from the drop-height of 2.5 cm at T10 cord (n=20) and ten rats undergone sham operation (n=10) were subjected to the neurobehavioral analyses by the Basso Beattie Bresnahan (BBB) locomotor rating scales, Touch test(TM) sensory evaluator (TTSE, North Coast Medical Inc., Canada) and Plantar test(R)(Ugo Basile, Italy) after contusion at the 1(st), 3(rd), 5(th), 7(th), 14(th), 21(st) and 28(th) day. RESULTS: The scores of BBB scales were the lowest at the 1st day and then slowly increased to spontaneous recovery state, but they were significantly lower than those of control group (p<0.05). The thresholds of mechanical allodynia were significantly increased just after cord contusion, but progressed to decline, and significantly decreased after the 21(st) day (p<0.05). The latencies of thermal hyperalgesia were delayed just after cord contusion, but significantly shorter than those of the control group after the 7(th) day (p<0.05). CONCLUSION: These results would be helpful for the study of the CNP after contusive spinal cord injury in rats.