Fetal Spinal Cord Transplants Support Growth of Supraspinal and Segmental Projections after Cervical Spinal Cord Hemisection in the Neonatal Rat
104
Citation
65
Reference
10
Related Paper
Citation Trend
Abstract:
Cervical spinal cord injury at birth permanently disrupts forelimb function in goal-directed reaching. Transplants of fetal spinal cord tissue permit the development of skilled forelimb use and associated postural adjustments (Diener and Bregman, 1998, companion article). The aim of this study was to determine whether transplants of fetal spinal cord tissue support the remodeling of supraspinal and segmental pathways that may underlie recovery of postural reflexes and forelimb movements. Although brainstem-spinal and segmental projections to the cervical spinal cord are present at birth, skilled forelimb reaching has not yet developed. Three-day-old rats received a cervical spinal cord overhemisection with or without transplantation of fetal spinal cord tissue (embryonic day 14); unoperated pups served as normal controls. Neuroanatomical tracing techniques were used to examine the organization of CNS pathways that may influence target-directed reaching. In animals with hemisections only, corticospinal, brainstem-spinal, and dorsal root projections within the spinal cord were decreased in number and extent. In contrast, animals receiving hemisections plus transplants exhibited growth of these projections throughout the transplant and over long distances within the host spinal cord caudal to the transplant. Raphespinal axons were apposed to numerous propriospinal neurons in control and transplant animals; these associations were greatly reduced in the lesion-only animals. These observations suggest that after neonatal cervical spinal cord injury, embryonic transplants support axonal growth of CNS pathways and specifically supraspinal input to propriospinal neurons. We suggest that after neonatal spinal injury in the rat, the transplant-mediated reestablishment of supraspinal input to spinal circuitry is the mechanism underlying the development of target-directed reaching and associated postural adjustments.Keywords:
Forelimb
Primary central nervous system vasculitis (PCNSV) is an uncommon vasculitis restricted to the small- and medium-sized vessels in the brain and spinal cord. Previously, only 9 cases have been reported that initially manifested as an isolated spinal cord lesion with subsequent brain involvement, where the longest interval from the onset to brain involvement was 1 year and 11 months. We herein report the case of an isolated spinal cord lesion with subsequent brain involvement appearing seven years and five months later. This case shows that brain lesions can develop after an extended interval from spinal onset in PCNSV.
Cite
Citations (1)
Dogs were trained for tonic forelimb flexion fixed to a lever in order to hold a cup with meat during eating, when the head was bent down to a foodwell. Before learning, the forelimb flexion is accompanied by the anticipatory lifting of the head bent down to the foodwell; following lowering of the head leads to an extension of the flexed forelimb. Simultaneous holding of the flexed forelimb and lowered head is achieved by learning. During the original learning, the innate head-forelimb coordination was rearranged into the opposite one. After the initial instrumental learning, the "working" forelimb was changed to test whether a transfer of the learned head-forelimb coordination would occur. It was shown that the execution of the instrumental reaction by the untrained forelimb was impossible, because the innate coordination between the head and this forelimb persisted. It could also be rearranged by learning. The involvement of the motor cortex in the unilateral rearrangement of the innate head-forelimb movement coordination is discussed.
Forelimb
Lever
Tonic (physiology)
Cite
Citations (0)
Cite
Citations (17)
These experiments examined motor cortical representation patterns after forelimb postural adjustments in rats. The experiments tested the hypothesis that postural adjustments that stretch muscles that are most strongly activated from the primary motor cortex (MI) enlarge their cortical representation. Intracortical electrical stimulation within MI, forelimb muscle activity and movements, and vibrissa movements were used to evaluate the border between the MI forelimb and vibrissa representations before and after forelimb position changes in anesthetized adults rats. The forelimb was originally maintained in retraction (wrist extension and elbow flexion) and then changed to protraction (wrist flexion and elbow extension). Movements and forelimb EMG evoked by electrical stimulation were evaluated during this period (up to 3 hr) through a set of four electrodes implanted in layer V of MI. Changing the forelimb configuration had both immediate and delayed effects on forelimb muscle activity evoked from MI. At some sites, the magnitude of evoked forelimb muscle activity immediately increased with forelimb protraction. At one-quarter of all sites, forelimb muscle activity was evoked where it was not previously detected following an average delay of 22–31 min after forelimb protraction. This change can be interpreted as an expansion of the forelimb area into the vibrissa representation. These data further support the hypothesis that motor cortical representations are flexible and show that sustained changes in somatic sensory input to MI are sufficient to reorganize MI output.
Forelimb
Representation
Motor area
Cite
Citations (150)
Objective:Investigate the mechanism of blood spinal cord barrier disruption after spinal cord injury.Method:Thirty five male adult Wistar rats(300～350g) were randomly assigned to this study,there were one control group and six spinal cord injury groups(acording to the time of post injury,4h,6h,12h,24h,48h and 72h).Each group contained 5 rats and New York University (NYU) Spinal Cord Injury Model was utilized to create the spinal cord injury.The immunoexpressior changes of immunglobularprotein G(IgG),c fragment of complement3 (C3c) in different time after spinal cord injury were evaluated utilizing immunohistochemistry method.Result:After spinal cord injury, there was a marked chang in the immunoexpressior of IgG and C3c in the impact site, near the impact site and spinal cord microvascular.Conclusion:After spinal cord injury,IgG and C3c may be important factors of barrier disruption and related to neuron secondary injury.
Cite
Citations (0)
Forelimb
Rhizotomy
Cite
Citations (15)
Forelimb skeletal muscle and skin glucose uptake during Escherichia coli endotoxin shock in the dog.
We previously demonstrated an increase in gracilis muscle glucose uptake during endotoxin shock in the dog. The present study was completed to investigate this phenomenon in forelimb skeletal muscle and skin. The isolated forelimb preparation was used. Mongrel dogs were anesthetized with nembutal and heparinized. Shock was induced by i.v. infusion of E. coli endotoxin. When isolated forelimb temperature was maintained at contralateral intact forelimb temperature (which was always the same as core temperature), forelimb skeletal muscle and skin glucose uptake increased by 30 minutes of shock, and remained above control for the 4 hour shock period. Total forelimb blood flow decreased and the limb became severely hypoxic (mean venous PO2 = 24 mmHg). However, when the isolated forelimb temperature was not artificially maintained at contralateral intact forelimb temperature (same as core temperature), the isolated forelimb temperature fell approximately 3 degrees C and the elevation of glucose uptake was not observed. Although forelimb blood flow decreased to the same level as in the temperature controlled group, the forelimbs were only moderately hypoxic. This study emphasizes the important influence of temperature on tissue metabolism and the recognition of its importance in experimental data interpretation, especially when metabolic variables are involved. It also demonstrates that changes in glucose uptake during shock are similar in dog forelimb skeletal muscle, provided that changes in muscle temperature are similar.
Forelimb
Gracilis muscle
Cite
Citations (3)
Unilateral lesions of the sensorimotor cortex (SMC) in adult rats cause major behavioral changes in the ipsilesional, "less-affected" forelimb. An increase in function and reliance on this forelimb can aid compensation for contralesional impairments, but may also promote disuse and reduced functionality of the impaired forelimb. We hypothesized that training focused on the ipsilesional forelimb following a unilateral SMC lesion would reduce the efficacy of later motor rehabilitative training of the impaired forelimb.Rats with ischemic SMC lesions were trained on a skilled reaching task with the ipsilesional forelimb (PriorT) or received control procedures (Cont) for 10 days. Both groups were then trained with the impaired forelimb on the same reaching task for 10 days.In comparison with Cont, PriorT rats had little improvement on the reaching task with the impaired forelimb and had a more enduring disuse of the impaired forelimb for postural support behaviors. Lesion sizes were similar between groups.Behavioral experience with the less-affected forelimb early after unilateral SMC lesions has the potential to increase disuse and dysfunction of the impaired forelimb, consistent with a training-induced exacerbation of learned non-use. These findings are suggestive of competitive processes in experience-dependent neural restructuring after brain damage.
Forelimb
Cite
Citations (83)
Objective To investigate the expression changes of CD44 in spinal cord in 3d,7d and 14d following hemisection of spinal cord injury(hSCI).Furthermore,to explore the relationships of CD44 and spinal cord injury.Besides,to offer the morphological datum for the research concerning the spinal cord repair.Methods 20 adult healthy Sprague-Dawley rats were randomly divided into sham-operated control group and day3,day7,day14 spinal cord injury groups.The spinal cords were hemisected between T9 and T10.The spinal cord of every rat was taken out from the rostral and caudal segments of lesioned areas.Then the tissue blocks were made into 25μm frozen sections and the immunohistochemistry ABC method was performed on these sections.We respectively observe and count the number of CD44 positive cells in spinal cord for all groups,and the average OD(optical density) value of immunoreactant were detected with computer image analysis technique.Results CD44 positive products were mainly distributed in extacellular matrix and neurons and neuroglial cells in spinal cord for the control group.The number of CD44 positive cells and its OD value of rostral or caudal part of injury site for the three spinal cord injury groups were all increased(P0.05).Conclusion The increased-expression CD44 may mutually play inhibitory effect on axon regeneration following SCI.
Cite
Citations (0)