Functional Recovery in Rats With Chronic Spinal Cord Injuries After Exposure to an Enriched Environment

Abstract

Background/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.Design: 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 ¼ 16) of rats was placed in an enriched environment, whereas the control group (n ¼ 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.Main Outcome Measures: 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. Spinal Cord Med. 2007;30:147-155 J

Traumatic Brain Injury: Current Treatment Strategies and Future Endeavors

“…121 Rats exposed to an EE have shown benefits in both neurobehavior and neuroanatomy. [121][122][123][124][125][126][127][128][129][130][131] Using animal models of TBI, multimodal interventions including exposure to an EE have yielded positive results. 132,133 It has been shown that EE exposure improves spatial memory recovery after cerebral ischemia.…”

“…137 Spinal cord-injured rats also display functional recovery once exposed to an EE. 126 Translating the research on EEs to the clinical arena in humans has significantly positive implications in neurorehabilitation. Individuals sustaining TBIs are known to have a high incidence of depression.…”

Activity-based Therapies in Spinal Cord Injury: Clinical Focus and Empirical Evidence in Three Independent Programs

“…The overall goal is to facilitate neural plasticity using treatment activities based on forced use of involved areas, 4,5 central pattern generation, 6,7 and an enriched environment. 8,9 Duration, session length, and intensity of rehabilitation need to be longer to promote neural plasticity compared to traditional rehabilitation, but effective dosage elements are far from clear. Therefore treatment parameters are based partly on practicality.…”

Chronic Spinal Compression Model in Minipigs: A Systematic Behavioral, Qualitative, and Quantitative Neuropathological Study

“…Using rat models of spinal contusion, weight-drop, or epidural balloon-compressioninduced injury, a correlation between the degree of neurological deficit (as measured by the Basso-Beattie-Bresnahan [BBB] or Combined Behavioral Score [CBS]) and the extent of local tissue degeneration at the injury epicenter has been reported in numerous studies and independently validated in several laboratories (Basso et al, 1996b;Noble and Wrathall, 1989;Vanicky et al, 2001). However, interestingly, even after severe spinal cord injury characterized by 85-95% of axonal loss or overall tissue degeneration, progressive recovery is seen over a 3-to 6-week period after injury, with the average BBB score ranging between 6 and 11 in both T10 contusion and weight-drop models in rats (Basso et al, 1996a;Ek et al, 2010;Fischer and Peduzzi, 2007). The mechanism of this spontaneous recovery is not clear, but progressive remyelination and axonal sprouting from the remaining brainstem-derived descending motor axons below the injury may in part account for this effect (Curtis et al, 1993;SalgadoCeballos et al, 1998).…”