Document Detail


Functional recovery and regeneration of descending tracts in rats after spinal cord transection in infancy.
MedLine Citation:
PMID:  11389386     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
STUDY DESIGN: The functional recovery of rats that underwent spinal cord transection in infancy was evaluated by multimodal examination (functional tests, electrophysiologic evaluation, tract-tracing) to determine the basis for the recovery. OBJECTIVES: To determine whether the hind limb function in rats that underwent spinal cord transection in infancy is regained completely, which descending tracts regenerate after the transection, and whether the functional recovery is correlated with axonal reconnection. SUMMARY OF BACKGROUND DATA: It is widely accepted that a newborn rat recovers its hind limb function after spinal cord transection even without any specific treatments. This functional recovery might be attributed to possible regeneration of some descending pathways, although there is a counterargument that well-trained spinal cord reflexes may bring about functional compensation. METHODS: The thoracic spinal cord of infant rats was completely transected at Th10 when they were 2 weeks of age. Multimodal functional tests and electrophysiologic studies were performed 5 weeks later. Some recovered rats (i.e., those able to walk after the transection) underwent spinal cord retransection, with subsequent reevaluation of locomotion and muscle-evoked potentials. At 6 weeks after the initial transection, tract-tracing studies were performed in some animals. RESULTS: A motor performance score detected the functional differences between the control and the recovered rats. Muscle-evoked potentials of hind limbs after electrical stimulation to the brain were recorded in some of the recovered rats, but never in the unrecovered rats. Moreover, the muscle-evoked potentials of the recovered rats disappeared after spinal cord retransection that resulted in loss of voluntary movement. Morphologic studies in two rats provided evidence that reconnection of rubrospinal, vestibulospinal, and reticulospinal tracts had occurred, whereas corticospinal regeneration was not detected. CONCLUSIONS: It can be concluded that the hind limb function of rats that underwent spinal cord transection in infancy was partially regained; that axonal regeneration of the rubrospinal, vestibulospinal, or reticulospinal tracts was demonstrated, whereas the reconnection of the corticospinal tract was not observed; and that the axonal regeneration of these tracts is involved in the functional recovery.
Authors:
Y Wakabayashi; H Komori; T Kawa-Uchi; K Mochida; M Takahashi; M Qi; K Otake; K Shinomiya
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Spine     Volume:  26     ISSN:  0362-2436     ISO Abbreviation:  Spine     Publication Date:  2001 Jun 
Date Detail:
Created Date:  2001-06-04     Completed Date:  2001-07-26     Revised Date:  2009-07-09    
Medline Journal Info:
Nlm Unique ID:  7610646     Medline TA:  Spine (Phila Pa 1976)     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1215-22     Citation Subset:  IM    
Affiliation:
Department of Frontier Surgical Therapeutics, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan.
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MeSH Terms
Descriptor/Qualifier:
Animals
Animals, Newborn / growth & development,  physiology*
Efferent Pathways / physiopathology
Electrophysiology
Evoked Potentials, Motor
Hindlimb / physiopathology
Motor Activity / physiology
Nerve Regeneration*
Pyramidal Tracts / physiopathology
Rats
Rats, Wistar
Recovery of Function
Red Nucleus / physiopathology
Spinal Cord / physiopathology*
Spinal Cord Injuries / physiopathology*
Survival Analysis
Synaptic Transmission

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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