Adaptations in the Walking Pattern of Spinal Cord Injured Rats

Abstract

Walking ability is a measure of recovery used in many studies that test experimental strategies to treat injuries or diseases of the central nervous system (CNS) in animal models. A common measure in the rat animal model of thoracic spinal cord injury (SCI) is visual inspection and scoring of hind limb activity, which allows the documentation of movements associated with the recovery of locomotor function. In this study, we expand on previously documented visible changes in the locomotor pattern following SCI. The spontaneous recovery of locomotion in rats with thoracic SCIs of variable extent was evaluated using electromyographic (EMG) and kinematic analysis while rats walked on an elevated runway. Comparisons with pre-lesion walking sequences revealed changes in the kinematics and in the muscle activation pattern of various muscles, including enhanced fore limb extensor activity, possibly reflecting an increased contribution to propulsion, altered recruitment of back muscles inserting into the hip (possibly to support stepping movements), and elevated posture during stance, which may compensate for deficits in weight support. These changes were noted in spinal cord injured rats with varying degrees of impairment, including animals with no visually detectable deficit in open-field walking. In summary, the presented results demonstrate that spinal cord injured rats develop alternative locomotor patterns following SCI that cannot be discriminated by the use of qualitative visually based analysis, thus urging the use of quantitative outcome measures in assessing motor function after SCI.

Exacerbated mechanical allodynia in rats with depression-like behavior

“…Open field test was used to examine exploratory and locomotor activities (Wesierska et al, 2006;Pertsov, 2006;Bellermann et al, 2006;Dias et al, 2006). This test was performed under room lights in an open box (57 × 57 cm with a 43 cm tall wall) marked with peripheral and internal squares (Bellermann et al, 2006;Dias et al, 2006;Pertsov, 2006).…”

“…This test was performed under room lights in an open box (57 × 57 cm with a 43 cm tall wall) marked with peripheral and internal squares (Bellermann et al, 2006;Dias et al, 2006;Pertsov, 2006). During a 5-min session, the rat's locomotor activity was recorded as the number of crossings into peripheral and internal squares, whereas exploratory activities were assessed as the episodes of rearing against the field wall.…”

Comparison of two methods for quantitative assessment of unrestrained locomotion in the rat

“…: +48 225892230; fax: +48 228225342. E-mail address: h.majczynski@nencki.gov.pl (H. Majczyński). changes in locomotion which cannot be evaluated using the BBB scale (Ballerman et al, 2006). Thus, it would be more expedient to use methods which permit analysis of various indices of locomotion such as velocity, swing phase, stance phase and step cycle duration, and interlimb coordination.…”

“…Despite extensive use of the rat as an experimental model for studying the recovery of locomotor functions, there are few studies that have used quantitative methods for analyzing gait deficits in this rodent (Ribotta et al, 2000;Sławińska et al, 2000;Majczyński et al, 2005;Ballerman et al, 2006).…”

Assessment of in vivo spinal cord conduction velocity in rats in an experimental model of ischemic spinal cord injury

“…7 Electromyographic activity obtained from flexor and extensor muscles on walking has been used for quantitative determination of locomotor recovery after SCI in rats. 8,9 Epidural electrical stimulation has been performed in rat models of SCI to facilitate posture and locomotion, 10,11 to measure spinal cord-evoked potentials 12 and to alleviate certain forms of neuropathic pain. 13 Magnuson et al 14 used transcranial magnetic stimulation to generate motor-evoked potentials, recorded EMG responses by inserting subdermal needle electrodes into the gastrocnemius muscle, and observed prolonged latency in a contusion model of SCI.…”