Spinal Cord Transection (spinal + cord_transection)

Distribution by Scientific Domains


Selected Abstracts


Changes in contractile properties of motor units of the rat medial gastrocnemius muscle after spinal cord transection

EXPERIMENTAL PHYSIOLOGY, Issue 5 2006
Jan Celichowski
The effects of complete transection of the spinal cord at the level of Th9/10 on contractile properties of the motor units (MUs) in the rat medial gastrocnemius (MG) muscle were investigated. Our results indicate that 1 month after injury the contraction time (time-to-peak) and half-relaxation time were prolonged and the maximal tetanic force in most of the MUs in the MG muscle of spinal rats was reduced. The resistance to fatigue also decreased in most of the MUs in the MG of spinal animals. Moreover, the post-tetanic potentiation of twitches in MUs diminished after spinal cord transection. Criteria for the division of MUs into three types, namely slow (S), fast fatigue resistant (FR) and fast fatigable (FF), applied in intact animals, could not be directly used in spinal animals owing to changes in contractile properties of MUs. The ,sag' phenomenon observed in unfused tetani of fast units in intact animals essentially disappeared in spinal rats and it was only detected in few units, at low frequencies of stimulation only. Therefore, the MUs in spinal rats were classified as fast or slow on the basis of an adjusted borderline of 20 ms, instead of 18 ms as in intact animals, owing to a slightly longer contraction time of those fast motor units with the ,sag'. We conclude that all basic contractile properties of rat motor units in the medial gastrocnemius muscle are significantly changed 1 month after complete spinal cord transection, with the majority of motor units being more fatigable and slower than those of intact rats. [source]


Protection of corticospinal tract neurons after dorsal spinal cord transection and engraftment of olfactory ensheathing cells

GLIA, Issue 4 2006
Masanori Sasaki
Abstract Transplantation of olfactory ensheathing cells (OECs) into the damaged rat spinal cord leads to directed elongative axonal regeneration and improved functional outcome. OECs are known to produce a number of neurotrophic molecules. To explore the possibility that OECs are neuroprotective for injured corticospinal tract (CST) neurons, we transplanted OECs into the dorsal transected spinal cord (T9) and examined primary motor cortex (M1) to assess apoptosis and neuronal loss at 1 and 4 weeks post-transplantation. The number of apoptotic cortical neurons was reduced at 1 week, and the extent of neuronal loss was reduced at 4 weeks. Biochemical analysis indicated an increase in BDNF levels in the spinal cord injury zone after OEC transplantation at 1 week. The transplanted OECs associated longitudinally with axons at 4 weeks. Thus, OEC transplantation into the injured spinal cord has distant neuroprotective effects on descending cortical projection neurons. © 2005 Wiley-Liss, Inc. [source]


Fibroblast growth factor-2 mRNA expression in the brainstem and spinal cord of normal and chronic spinally transected urodeles

JOURNAL OF NEUROSCIENCE RESEARCH, Issue 15 2008
Marie Moftah
Abstract Descending pathways in the spinal cord of adult urodele amphibians show a high regenerative ability after body spinal cord transection; regenerated axons regrow into the transected spinal cord, and hindlimb locomotor recovery occurs spontaneously. Little is currently known about the molecular basis of spinal cord regeneration in urodeles, but it is believed that fibroblast growth factor-2 (FGF2) may play an important role by inducing proliferation of neural progenitor cells. The aim of our study, using in situ hybridization in adult Pleurodeles waltlii, was twofold: 1) to document FGF2 mRNA expression pattern along the brainstem-spinal cord of intact salamanders and 2) to investigate the changes in this pattern in animals unable to display hindlimb locomotor movements and in animals having fully recovered hindlimb locomotor activity after body spinal cord transection. This design establishes a firm basis for further studies on the role of FGF2 in functional recovery of hindlimb locomotion. Our results revealed a decreasing rostrocaudal gradient in FGF2 mRNA expression along the brainstem-spinal cord in intact animals. They further demonstrated a long-lasting up-regulation of FGF2 mRNA expression in response to spinal transection at the midtrunk level, both in brainstem and in the spinal cord below the injury. Finally, double immunolabeling showed that FGF2 was up-regulated in neuroglial, presumably undifferentiated, cells. Therefore, we propose that FGF2 may be involved in cell proliferation and/or neuronal differentiation after body spinal cord transection in salamander and could thus play an important role in functional recovery of locomotion after spinal lesion. © 2008 Wiley-Liss, Inc. [source]


Gene and protein expression associated with protein synthesis and breakdown in paraplegic skeletal muscle

MUSCLE AND NERVE, Issue 4 2008
Micah J. Drummond PhD
Abstract Spinal cord injury reduces the rate of skeletal muscle protein synthesis and increases protein breakdown, resulting in rapid muscle loss. The purpose of this study was to determine whether long-term paraplegia would eventually result in a downregulation of muscle mRNA and protein expression associated with both protein synthesis and breakdown. After 10 weeks of spinal cord transection, soleus muscle from 12 rats (6 sham-control, 6 paraplegic) was studied for mRNAs and proteins associated with protein synthesis and breakdown using real-time polymerase chain reaction and immunoblotting techniques. Protein kinase B (PKB/Akt), ribosomal S6 kinase 1 (S6K1), and myogenin mRNA were downregulated, whereas muscle ring finger 1 (MuRF1) and phospho-forkhead transcription factor 4 (FoxO4) protein were increased in paraplegic rats. We conclude that gene and protein expression of pathways associated with protein synthesis are reduced, whereas some markers of protein breakdown remain elevated following chronic paraplegia. Clinical interventions designed to increase muscle protein synthesis may be helpful in preventing excessive muscle loss during long-term paraplegia. Muscle Nerve, 2008 [source]


Urinary bladder hyperreflexia: A rat animal model

NEUROUROLOGY AND URODYNAMICS, Issue 7 2003
Hassan Shaker
Abstract In this work, we are presenting a rat animal model for bladder hyperreflexia after suprasacral spinal cord transection. Our aim was to standardize an animal model that can be useful in studying this condition. After standardizing the animal model in a pilot study, 26 female Sprague,Dawley rats were subjected to spinal cord transection at the level of T10 vertebra. Four animals were subjected to cystometrogram (CMG) 24 hr after spinalization and six rats 3 weeks post-spinalization. These CMGs were compared to that of six normal controls. The detailed description of the model presented in this manuscript, is the final result after several modifications. All the animals consistently developed hyperreflexia after an initial period of spinal shock phase. Expressed volume of urine continued to decrease until it reached a plateau after peaking at 1-week post-spinalization. The attrition rate reached 27.3% after several improvements in the animal model and was mostly from self-inflicted injuries. Post-operative complications included hypothermia, decubitus ulcers, hematuria, urinary tract infection in addition to the unexplained death of two animals. In conclusion, we believe that this animal model closely resembles the clinical condition of hyperreflexia and follows similar course. The relative low cost of this animal model and the easy maintenance makes it a valuable tool to study such a condition. Neurourol. Urodynam. 22:693,698, 2003. © 2003 Wiley-Liss, Inc. [source]


Histomorphometric and Densitometric Changes in the Femora of Spinal Cord Transected Mice

THE ANATOMICAL RECORD : ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY, Issue 3 2008
Sylvain Picard
Abstract Spinal cord injury (SCI) leads generally to significant bone tissue loss within a few months to a few years post,trauma. Although, increasing data from rat models are available to study the underlying mechanisms of SCI-associated bone loss, little is known about the extent and rapidity of bone tissue changes in mouse models of SCI. The objectives are to characterize and describe quantitatively femoral bone tissue changes during 1 month in adult paraplegic mice. Histomorphometric and densitometric measurements were performed in 3- to 4-month-old CD1 mice spinal cord transected at the low-thoracic level (Th9/10). We found a general decrease in bone volume (,22%), trabecular thickness (,10%), and trabecular number (,14%) within 30 days post-transection. Dual-energy X-ray absorptiometric measurements revealed no change in bone mineral density but a significant reduction (,14%) in bone mineral content. These results show large structural changes occurring within only a few weeks post,spinal cord transection in the femora of adult mice. Given the increasing availability of genetic and molecular research tools for research in mice, this murine model may be useful to study further the cellular and molecular mechanisms of demineralization associated with SCI. Anat Rec, 291:303,307, 2008. © 2008 Wiley-Liss, Inc. [source]


ORIGINAL RESEARCH,BASIC SCIENCE: Effect of the Destruction of Cells Containing the Serotonin Reuptake Transporter on Urethrogenital Reflexes

THE JOURNAL OF SEXUAL MEDICINE, Issue 2 2007
Karla Gravitt BSc
ABSTRACT Introduction., The urethrogenital (UG) reflex is an autonomic and somatic response that mimics some of the physiological changes seen during ejaculation. The UG reflex is tonically inhibited by neurons in the ventral medulla, an area containing serotonin neurons. Aim., To examine the effect of lesions of brain neurons containing the serotonin reuptake transporter (SERT) on ejaculatory-like reflexes. Methods., Anti-SERT saporin (80 nL, 1 mM) or saline was injected bilaterally into the ventrolateral medulla of male Sprague,Dawley rats. Ten to 18 days later, animals were deeply anesthetized and the presence of the UG reflex was examined before and after acute spinal cord transection (T9,10). Following the experiment the presence and number of serotonin and norepinephrine containing neurons (using tryptophan hydroxylase and dopamine beta-hydroxylase, respectively) was performed. Main Outcome Measures., The UG reflex and cell counts. Results., In saline-injected controls the UG reflex was not evoked in the anesthetized, intact preparation, indicating the presence of the supraspinal inhibition, as previously reported. Injection of anti-SERT saporin into the ventrolateral medulla allowed the UG reflex to be activated in the intact preparation, thus removed the inhibition. This was associated with a decrease in the number of serotonin neurons in the ventrolateral medulla and raphe. No change in the number of noradrenergic neurons was observed. Conclusion., These studies suggest that ventral medullary neurons containing SERT are involved in the tonic inhibition of the UG reflex. Gravitt K, and Marson L. Effect of the destruction of cells containing the serotonin reuptake transporter on urethrogenital Reflexes. J Sex Med 2007;4:322,331. [source]


Haemodynamic changes after spinal cord transection are anaesthetic agent dependent

AUTONOMIC & AUTACOID PHARMACOLOGY, Issue 4 2007
P. R. Leal
Summary 1 To evaluate the effect of high spinal cord transection (SCT), between T4 and T5, on the mean arterial pressure (MAP) and heart rate in animals anaesthetized with different anaesthetic agents: ether (n = 12), 20% urethane, 1.2 g kg,1 (n = 12), 2% tri-bromide-ethanol, 200 mg kg,1 (n = 12); chloral hydrate and urethane, 75 and 525 mg kg,1 respectively (n = 12). 2 In the animals anaesthetized with ether or urethane, SCT caused an immediate major drop in MAP, with hypotension and bradycardia throughout the next 10 min. In the animals anaesthetized with urethane + chloralose or tri-bromide-ethanol, SCT transiently increased MAP with subsequent hypotension and bradycardia. 3 In summary, the haemodynamic changes after complete, high SCT are anaesthetic agent dependent. Further research about the exact mechanisms responsible for these diverse autonomic changes is warranted. [source]