Functional recovery in rats with chronic spinal cord injuries after exposure to an enriched environment.
OBJECTIVE
The objective of this study was to determine the effect of environmental enrichment on the sensorimotor function of rats with chronic spinal cord injuries.


METHODS
Adult Sprague-Dawley rats received a contusive injury of moderate severity at vertebral level T8 using a weight-drop device. Three months after injury, 1 randomized group (n = 16) of rats was placed in an enriched environment, whereas the control group (n = 16) remained housed in standard laboratory cages (2/cage).


METHODS
Animals were placed in an enriched environment for 4 weeks beginning at 3 months after injury. The enriched environment consisted of a large cage (5-6 rats/cage) with access to items such as tubes, ramps, and running wheel, with items changed daily.


METHODS
Functional evaluation consisted of the open field Basso, Beattie and Bresnahan (BBB) locomotor test and the tests that form the combined behavioral score (CBS). The CBS includes motor score, toe spread, placing, withdrawal, righting, inclined plane, hot plate, and swim tests. Behavioral testing was repeated 7 times before and after the period of intervention.


RESULTS
The group placed in the enriched environment scored significantly better on the BBB (ANOVA repeated-measures, P < 0.01) test and CBS (ANOVA repeated-measures, P < 0.01).


CONCLUSIONS
Environmental enrichment results in significant functional improvement in animals with spinal cord injury even with a substantial delay in initiating treatment after injury. The features of an enriched environment that may be responsible for the improvement include social interactions, exercise, and novel items in an interesting environment. These findings suggest a continued plasticity of the chronically injured rat spinal cord and a possible therapeutic intervention for people with spinal cord injury.
Fischer
Florence R
FR
Wayne State University School of Medicine, 8137 Scott Hall, 540 E. Canfield Avenue, Detroit, MI 48201, USA.
Peduzzi
Jean D
JD
D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D002908:Chronic Disease; D004185:Disability Evaluation; D004195:Disease Models, Animal; D004777:Environment; D005081:Exercise Therapy / Q000379:methods*; D005106:Exploratory Behavior / Q000502:physiology; D005260:Female; D009043:Motor Activity / Q000502:physiology; D009416:Nerve Regeneration / Q000502:physiology; D009434:Neural Pathways / Q000503:physiopathology; D009473:Neuronal Plasticity / Q000502:physiology; D010805:Physical Conditioning, Animal / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D020127:Recovery of Function / Q000502:physiology*; D012683:Sensory Deprivation / Q000502:physiology; D012919:Social Behavior; D013116:Spinal Cord / Q000503:physiopathology; D013119:Spinal Cord Injuries / Q000503:physiopathology* / Q000534:rehabilitation*; D016896:Treatment Outcome