Effect of Locomotor Training in Completely Spinalized Cats Previously Submitted to a Spinal Hemisection

Abstract

After a spinal hemisection in cats, locomotor plasticity occurring at the spinal level can be revealed by performing, several weeks later, a complete spinalization below the first hemisection. Using this paradigm, we recently demonstrated that the hemisection induces durable changes in the symmetry of locomotor kinematics that persist after spinalization. Can this asymmetry be changed again in the spinal state by interventions such as treadmill locomotor training started within a few days after the spinalization? We performed, in 9 adult cats, a spinal hemisection at thoracic level 10 and then a complete spinalization at T13, 3 weeks later. Cats were not treadmill trained during the hemispinal period. After spinalization, 5 of 9 cats were not trained and served as control while 4 of 9 cats were trained on the treadmill for 20 min, 5 d a week for 3 weeks. Using detailed kinematic analyses, we showed that, without training, the asymmetrical state of locomotion induced by the hemisection was retained durably after the subsequent spinalization. By contrast, training cats after spinalization induced a reversal of the left/right asymmetries, suggesting that new plastic changes occurred within the spinal cord through locomotor training. Moreover, training was shown to improve the kinematic parameters and the performance of the hindlimb on the previously hemisected side. These results indicate that spinal locomotor circuits, previously modified by past experience such as required for adaptation to the hemisection, can remarkably respond to subsequent locomotor training and improve bilateral locomotor kinematics, clearly showing the benefits of locomotor training in the spinal state.

Emergence of Deletions during Treadmill Locomotion as a Function of Supraspinal and Sensory Inputs

“…In all cats, the hemisection was confined to the left side and always involved a significant portion of the left hemicord while sparing the most medial part of the left ventral funiculus, as described previously (Martinez et al, 2011;Martinez et al, 2012a). The second spinal lesion was complete in all cats.…”

“…Adult female (n ϭ 7) and male (n ϭ 3) cats weighing from 2.5 to 4.8 kg were engaged in a dual spinal lesion paradigm. The procedures for EMG implantation, spinal lesions, EMG and kinematic recordings, and histology were similar to those described previously (Martinez et al, 2011(Martinez et al, , 2012a. All cats were chronically implanted with intramuscular electrodes to record EMG activity from the sartorius anterior (Srt), semitendinosus (St), vastus lateralis (VL), gastrocnemius lateralis (GL), gastrocnemius medialis (GM), and tibialis anterior (TA).…”

“…We first counted and characterized the deletions of electromyographic (EMG) activity of several hindlimb muscles during treadmill walking and evaluated their impact on the other muscles activity and on the locomotor pattern. Second, we evaluated the role of supraspinal inputs on the occurrence of deletions by performing sequentially a unilateral hemisection on the left side and then a complete SCI in the same animals to respectively isolate partially and then totally the CPG from the brain (Martinez et al, 2011(Martinez et al, , 2012b. Because cats previously submitted to a spinal hemisection are able to walk early after the complete SCI (Martinez et al, 2011(Martinez et al, , 2012a, we were able to investigate, in the same animal, whether decreasing and then abolishing supraspinal inputs could affect the number of deletions obtained in each hindlimb.…”

Desenvolvimento de caminhar espinal em cães paraplégicos com fraturas e luxações vertebrais toracolombares

“…O protocolo fisioterapêutico desempenhou um papel importante no desenvolvimento do caminhar espinal nestes cães, corroborando com De Leon (1998), Pearson (2001, Dietz (2001), Behrman et al (2006), Martinez et al 2012, Gallucci et al (2015 e Melo (2015), quando mencionam que o fortalecimento do tônus muscular e o condicionamento dos membros pélvicos por meio de movimentos passivos e repetitivos podem contribuir para a padronização da atividade motora e na formação e estimulação do caminhar espinal. Esses dados confirmam os relatos de Shurrager & Dykman (1951) A taxa total de eutanásia no presente estudo foi de 13,5% (5 animais), resultado inferior aos de outros autores descritos na literatura (Turner 1987, McKee 1990, Selcer et al 1991, Olby et al 2003, Bruce et al 2008, Mendes & Arias 2012, permitindo com que a maioria dos animais sem nocicepção que não recuperaram a deambulação voluntária permanecessem vivos e tivessem continuidade do seu tratamento de reabilitação.…”

Effect of Progressive Locomotor Treadmill Compared to Conventional Training on Bone Mineral Density and Bone Remodeling in Paraplegia

“…For more than a decade it was illustrated that LT in animals can increase locomotor function following spinal cord transaction (7). LT is a safe therapy (8) for treatment of neuromuscular disorders (9).…”