J Korean Acad Rehabil Med.  2005 Aug;29(4):392-397.

The Development of Abnormal Spontaneous Activities in the Experimental Radiculopathy in the Rat

• Han TR
• Lee SJ
• Kwon BS
• Hyun JK
• Park WB

Abstract

OBJECTIVE
Through a animal study using rats, we investigated whether abnormal spontaneous activities (ASAs) could be observed in the radiculopathies of biochemical and mechanical model. METHOD: A total of 30 Sprague-Dawley male rats were randomly assigned into sham, nucleus pulposus (NP) and ligation groups. In the sham group, the right L4 and L5 nerve roots were exposed by laminectomies. In the NP group, nucleus pulposus was transplanted onto nerve roots from tail. In the ligation group, exposed nerve roots were ligated by silk ligatures. All rats were evaluated by mechanical allodynia, motor paresis, and the needle electromyography (EMG) examination.
RESULTS
Mechanical allodynia was observed on the 4th and 7th postoperative days in NP and ligation groups. Motor paresis was observed only in the ligation group. The needle EMG showed ASAs on the 4th postoperative day, but decreased in incidence and amount on the 7th postoperative day in the NP and ligation groups.
CONCLUSION
The ASAs can be observed by the biochemical action of nucleus pulposus as well as the mechanical compression. The results of this study may help explain the discrepancy between radiologic and electrodiagnostic findings.

Keyword

Radiculopathy; Nucleus pulposus; Compression; Electromyography; Abnormal spontaneous activity

MeSH Terms

Animals
Electromyography
Humans
Hyperalgesia
Incidence
Laminectomy
Ligation
Male
Needles
Paresis
Radiculopathy*
Rats*
Rats, Sprague-Dawley
Silk
Tail
Silk