Effects of exercise and fetal spinal cord implants on the H-reflex in chronically spinalized adult rats

doi:10.1016/0006-8993(96)00556-2

Brain Research

Volume 729, Issue 1, 5 August 1996, Pages 127-131

https://doi.org/10.1016/0006-8993(96)00556-2 Get rights and content

Abstract

This study investigated the modulation of hindlimb reflex excitability after transection of the spinal cord in adult rats. After transection, the H-reflex exhibited decreased depression at high stimulation frequencies compared to intact animals. Groups of animals which received a spinal cord transection followed by either an exercise regimen for the hindlimbs or a fetal spinal cord implant, showed high stimulation frequency depression similar to controls. This suggests that each of these palliative strategies helped to ‘normalize’ the excitability of specific spinal reflexes.

Reference (23)

BurkeD.
Spasticity as an adaptation to spinal cord injury
Adv. Neurol.
(1988)
BurkeD. et al.
Monosynaptic and oligosynaptic contributions to human ankle jerk and H-reflex
J. Neurophysiol.
(1984)
CopeT.C. et al.
Acute effects of spinal transection on EPSPs produced by single homonymous la fibers in soleus alpha-motoneurons
J. Neurophysiol.
(1988)
CurtisD.R. et al.
Synaptic action during and after repetitive stimulation
J. Physiol.
(1960)
DelwaideP.J.
Human monosynaptic reflexes and presynaptic inhibition: an interpretation of spastic hyperreflexia
EcclesJ.C. et al.
The mode of operation of the synaptic mechanism producing presynaptic inhibition
J. Neurophysiol.
(1963)
GuttmanL.
Spinal Cord Injuries. Comprehensive Management and Research
HouleJ.D.
The structural integrity of glial scar tissue associated with a chronic spinal cord lesion can be altered by transplanted fetal spinal cord tissue
J. Neurosci. Res.
(1992)
HouleJ.D. et al.
Bridging a complete transection lesion of adult rat spinal cord with growth factor-treated nitrocellulose implants
J. Neural Transpl. Plast.
(1994)
HultbornH. et al.
Changes in segmental reflexes following chronic spinal hemisection in the cat. I. Increased monosynaptic and polysynaptic ventral root discharges
Acta Phys-iol. Scand.
(1983)

LloydD.P.C. et al.

Reflex depression in rhythmically active monosynaptic reflex pathways

J. Gen. Physiol.

(1957)

Cited by (119)

Multi-session transcutaneous spinal cord stimulation prevents chloride homeostasis imbalance and the development of hyperreflexia after spinal cord injury in rat
2024, Experimental Neurology
Spasticity is a complex and multidimensional disorder that impacts nearly 75% of individuals with spinal cord injury (SCI) and currently lacks adequate treatment options. This sensorimotor condition is burdensome as hyperexcitability of reflex pathways result in exacerbated reflex responses, co-contractions of antagonistic muscles, and involuntary movements. Transcutaneous spinal cord stimulation (tSCS) has become a popular tool in the human SCI research field. The likeliness for this intervention to be successful as a noninvasive anti-spastic therapy after SCI is suggested by a mild and transitory improvement in spastic symptoms following a single stimulation session, but it remains to be determined if repeated tSCS over the course of weeks can produce more profound effects. Despite its popularity, the neuroplasticity induced by tSCS also remains widely unexplored, particularly due to the lack of suitable animal models to investigate this intervention. Thus, the basis of this work was to use tSCS over multiple sessions (multi-session tSCS) in a rat model to target spasticity after SCI and identify the long-term physiological improvements and anatomical neuroplasticity occurring in the spinal cord. Here, we show that multi-session tSCS in rats with an incomplete (severe T9 contusion) SCI (1) decreases hyperreflexia, (2) increases the low frequency-dependent modulation of the H-reflex, (3) prevents potassium-chloride cotransporter isoform 2 (KCC2) membrane downregulation in lumbar motoneurons, and (4) generally augments motor output, i.e., EMG amplitude in response to single pulses of tSCS, particularly in extensor muscles. Together, this work displays that multi-session tSCS can target and diminish spasticity after SCI as an alternative to pharmacological interventions and begins to highlight the underlying neuroplasticity contributing to its success in improving functional recovery.
Combined effect of trifluoperazine and sodium cromoglycate on reducing acute edema and limiting lasting functional impairments after spinal cord injury in rats
2024, Experimental Neurology
Edema formation is one of the very first events to occur after spinal cord injury (SCI) leading to an increase of the intrathecal pressure and consequently to serious spinal tissue and functional impairments. Current edema treatments are still symptomatic and/or non-specific. Since edema formation mechanisms are mainly described as vasogenic and cytotoxic, it becomes crucial to understand the interplay between these two subtypes. Acting on key targets to inhibit edema formation may reduce secondary damage and related functional impairments. In this study, we characterize the edema kinetic after T9–10 spinal contusion. We use trifluoperazine (TFP) to block the expression and the functional subcellular localization of aquaporin-4 supposed to be implicated in the cytotoxic edema formation. We also use sodium cromoglycate (SCG) to deactivate mast cell degranulation known to be implicated in the vasogenic edema formation. Our results show a significant reduction of edema after TFP treatment and after TFP-SCG combined treatment compared to control. This reduction is correlated with limited onset of initial sensorimotor impairments particularly after combined treatment. Our results highlight the importance of potential synergetic targets in early edema therapy after SCI as part of tissue sparing strategies.
Effects of ankle continuous passive motion on soleus hypertonia in individuals with cerebral palsy: A case series
2022, Biomedical Journal
Citation Excerpt :
A previous study showed that ankle CPM training restored the PAD in individuals with complete spinal cord injury, suggesting that the mechanism by which ankle CPM restored PAD was primarily through the plasticity of segmental spinal circuitry function rather than suprasegmental functions [9]. The possible mechanisms include alterations in presynaptic inhibition and interneuron activity as a result of passive training [31,38,39]. It has been suggested that exercise training was sufficient to cause plasticity in the spinal cord [39].
Continuous passive motion device (CPM) provides repetitive movement over extended periods of time for those who have low functional ability. The purpose of this research was to evaluate the effects of a four-week program of continuous passive motion of the ankle joint on the changes in soleus hypertonia in individuals with cerebral palsy who suffered from life-long hypertonia.
A single group, repeated-measures study was conducted. Eight individuals (7 males and 1 female with a mean age of 21.8 ± 8.5 years) with spastic cerebral palsy underwent bilateral ankle CPM for 1 h a day, 5 days a week, for 4 weeks. The outcome measures included the Modified Ashworth Scale (MAS) score, passive range of motion (PROM) of the ankle, the ratio of maximum H reflex to maximum soleus M-response (H/M ratio), and post-activation depression (PAD). All outcomes were measured before and after the intervention. A paired t-test was used to examine treatment effects pre-versus post-intervention.
Paired t-tests showed that the CPM program significantly decreased the MAS score (p = 0.006), decreased the maximum H/M ratio (p=0.001), improved PAD (p = 0.003, p = 0.040, and p = 0.032 at 0.2 Hz, 1 Hz, and 2 Hz, respectively), and increased the passive ankle range of motion (p = 0.049).
Ankle CPM not only reduced soleus hypertonia but also improved the PROM in individuals with cerebral palsy. The results of this study show ankle CPM to be an effective intervention for individuals with cerebral palsy.
Exercise as a therapeutic intervention for neuropathic pain after spinal cord injury
2022, Spinal Cord Injury Pain
After spinal cord injury (SCI) there is a progressive cascade of events that greatly effects the health and well-being of the injured subject, beyond the devastating loss of intentional movement. Exercise or physical training has a demonstrated role in the relearning of motor tasks and there is gathering evidence that some secondary consequences of SCI, such as autonomic dysreflexia, muscle spasticity, and chronic inflammation, respond to exercise as a treatment strategy. We have extended these findings by examining the effects of exercise on molecular and cellular components of the injured spinal cord and dorsal root ganglia to begin to understand how exercise might be useful in preventing and/or alleviating the devastating neuropathic pain that develops in the majority of SCI individuals. We briefly discuss ways in which exercise can bring about neuroprotection, neuroplasticity, and axon regeneration that we feel provide clues about why different forms of exercise are proving to be effective in modulating pain in acute and chronic injury models.
Practical Application of Recent Advances in Diagnostic, Prognostic, and Therapeutic Modalities for Spinal Cord Injury
2020, World Neurosurgery
Spinal cord injury remains a highly morbid entity, with limited treatment modalities in both acute and chronic settings. Clinical research efforts to improve therapeutic guidelines are confounded by initial evaluation inaccuracies, as presentations are frequently complicated by trauma and objective diagnostic and prognostic methods are poorly defined. The purpose of our study was to review recent practical advances for further delineation of these injuries and how such classification may benefit the development of novel treatments.
A review was carried out of recent studies reported within the last 5 years for prognostic and diagnostic modalities of acute spinal cord injury.
Substantial efforts have been made to improve the timeliness and accuracy of the initial assessment, not only for the purpose of enhancing prognostication but also in determining the efficacy of new treatments. Whether it be applying traumatic brain injury principles to limit injury extent, external stimulators used for chronic pain conditions to enhance the effects of physical therapy, or creative algorithms incorporating various nerve or muscle transfer techniques, innovative and practical solutions continue to be developed in lieu of definitive treatment. Further development will benefit from enhanced stratification of injury from accurate and practical assessment modalities.
Recent advances in accurate, timely, and practical classification methods of acute spinal cord injury will assist in the development of novel treatment approaches for both acute and chronic injury alike.
Motor and sensitive recovery after injection of a physically cross-linked PNIPAAm-g-PEG hydrogel in rat hemisectioned spinal cord
2020, Materials Science and Engineering C
In line with experiments showing that implanted hydrogels are promising tools, we designed and injected, after a C2 spinal cord hemisection, a thermoresponsive and thermoreversible physically cross-linked poly(N-isopropylacrylamide)-poly(ethylene glycol) copolymer in order to reduce functional deficits and provide a favorable environment to axotomized axons.
Nasal olfactory ecto-mesenchymal stem cells were cultured on the hydrogel in order to verify its biocompatibility. Then, inflammatory reaction (Interleukin-1β and 6, Tumor Necrosis Factor-α) was examined 15 days post-hydrogel injection. Functional recovery (postural and locomotor activities, muscle strength and tactile sensitivity) was assessed once a week, during 12 weeks. Finally, at 12 weeks post-injection, spinal reflexivity and ventilatory adjustments were measured, and the presence of glial cells and regenerated axons were determined in the injured area.
Our results indicate that cells survived and proliferated on the hydrogel which, itself, did not induce an enhanced inflammation. Furthermore, we observed significant motor and sensitive improvements in hydrogel-injected animals. Hydrogel also induced H-reflex recovery close to control animals but no improved ventilatory adjustment to electrically-evoked isometric contractions. Finally, regrowing axons were visualized within the hydrogel with no glial cells colonization.
Our results emphasize the effectiveness of our copolymer and its high therapeutic potential to repair the spinal cord after injury.

View all citing articles on Scopus

View full text

Effects of exercise and fetal spinal cord implants on the H-reflex in chronically spinalized adult rats

Abstract

Spasticity as an adaptation to spinal cord injury

Adv. Neurol.

Monosynaptic and oligosynaptic contributions to human ankle jerk and H-reflex

J. Neurophysiol.

Acute effects of spinal transection on EPSPs produced by single homonymous la fibers in soleus alpha-motoneurons

J. Neurophysiol.

Synaptic action during and after repetitive stimulation

J. Physiol.

Human monosynaptic reflexes and presynaptic inhibition: an interpretation of spastic hyperreflexia

The mode of operation of the synaptic mechanism producing presynaptic inhibition

J. Neurophysiol.

Spinal Cord Injuries. Comprehensive Management and Research

The structural integrity of glial scar tissue associated with a chronic spinal cord lesion can be altered by transplanted fetal spinal cord tissue

J. Neurosci. Res.

Bridging a complete transection lesion of adult rat spinal cord with growth factor-treated nitrocellulose implants

J. Neural Transpl. Plast.

Changes in segmental reflexes following chronic spinal hemisection in the cat. I. Increased monosynaptic and polysynaptic ventral root discharges

Acta Phys-iol. Scand.

Reflex depression in rhythmically active monosynaptic reflex pathways

J. Gen. Physiol.