Restorative Neurology and Neuroscience - Volume 7, issue 2

Authors: Guizar-Sahagun, Gabriel | Grijalva, Israel | Madrazo, Ignacio | Franco-Bourland, Rebecca | Salgado-Ceballos, Hermelinda | Ibarra, Antonio | Larriva-Sahd, Jorge

Article Type: Research Article

Abstract: To evaluate the neuroprotective effect of transplants placed in the lesion zone after a complete spinal cord (SC) laceration, two independent series of experiments were carried out. In the first, allogeneic or xenogeneic fetal SC was transplanted into the gaps of the damaged lower thoracic SC of adult rats. In the transplanted rats the incidence of life-threatening complications was reduced, and the survival rate was increased compared with the control group (lesion, without implant). Histological examination showed less damage to the neighboring SC parenchyma in the transplanted rats. The measurement of this neuroprotective effect was made in a second series …of experiments. Using the same model of SC injury, allogeneic fetal SC, autologous peripheral nerve and/or adipose tissue were implanted. Rats with implants of Gelfoam and damaged rats without implants were the controls. The implanted rats of all groups, including the Gelfoam group, showed a better survival rate than the nonimplanted rats. Significantly less damage to the neighboring SC parenchyma was measured in implanted rats with any of the live tissues tested compared with non-implanted rats, although no significant differences were observed between the Gelfoam group and the nonimplanted rats. Histological evidence of tissue implant survival was observed in all corresponding groups. It is concluded that the transplanted tissues tested here have a neuroprotective effect, possibly by acting as a buffer to neurotoxic substance(s) released by the stumps, and/or by exerting trophic effect(s) on the host. Show more

Keywords: Rat spinal cord injury, Post-traumatic neurodegeneration, Neural transplantation, Neuroprotection, Paraplegia, Life-threatening complications, Autophagia

DOI: 10.3233/RNN-1994-7201

Citation: Restorative Neurology and Neuroscience, vol. 7, no. 2, pp. 61-70, 1994

Authors: Lewin-Kowalik, Joanna | Barski, Jaroslaw-Jerzy | Krause, Mieczyslaw | Górka, Dariusz | Golka, Beata | Larysz-Brysz, Magdalena

Article Type: Research Article

Abstract: Submicrosomal fractions obtained from pre-degenerated distal stumps of sciatic nerves were implanted by means of connective tissue chambers into the injured hippocampus for 8 and 18 weeks. The nerve stumps were allowed to pre-degenerate for 7, 28 and 35 days. The neuronal outgrowth was examined by means of FITC-HRP injected into the chamber. Eight weeks postoperatively the greatest number of traced cells was present in brains treated with the fraction obtained from nerves pre-degenerated for 7 days. Eighteen weeks following implantation the greatest number of FITC-HRP positive cells was found in brains grafted with the fraction from nerves pre-degenerated for …35 days. Show more

Keywords: Peripheral nerve pre-degeneration, Submicrosomal fraction, Neurite outgrowth, Hippocampus, Autologous connective tissue chambers

DOI: 10.3233/RNN-1994-7202

Citation: Restorative Neurology and Neuroscience, vol. 7, no. 2, pp. 71-78, 1994

Authors: Ikeda, Hidetoshi | Asser, Toomas | Yoshimoto, Takashi

Article Type: Research Article

Abstract: The survival, proliferation potential, differentiation, and host tissue reaction of allografts of undifferentiated embryonal diencephalic tissue (E12.5, E17.5) transplanted into or around the third ventricle of adult rats were investigated. Rats harboring grafts were sacrificed at three, six, and nine weeks after transplantation. The proliferative activity of the grafts was assessed by injection of 5′-bromo-2′-deoxyuridine (BrdU) into pregnant rats before the removal of fetuses for transplantation, and staining the grafts using an anti-BrdU antibody. The proliferative activity of the transplanted grafts was evaluated by immunostaining using an anti-proliferating cell nuclear antigen (PCNA) antibody. The differentiation of the grafts into neurons …was estimated by double immunostaining using anti-BrdU and anti-neuron-specific enolase (NSE) antibodies. The survival rate of the grafts was strongly related to the proliferative activity of the graft. Surviving E17.5 grafts contained immunoreactive BrdU cells. E12.5 grafts could survive without immunoreactive BrdU cells. Undifferentiated El2.5 grafts proliferated up to six weeks after transplantation. Thereafter, most graft cells differentiated into mature neurons. E12.5 diencephalic allografts survived well with minimal rejection reactions and resulted in substantial neurite ingrowth into the host brain, while El7.5 allografts caused substantial reactive gliosis and little ingrowth. Show more

Keywords: Transplantation, Bromodeoxyuridine, Proliferating cell nuclear antigen, Diencephalon, Rat, Allograft

DOI: 10.3233/RNN-1994-7203

Citation: Restorative Neurology and Neuroscience, vol. 7, no. 2, pp. 79-87, 1994

Authors: Ribarič, Samo | Cvirn, Pavel | Stefanovska, Aneta

Article Type: Research Article

Abstract: We investigated if continuous 1 µA direct current stimulation of the injured nerve, with the cathode electrode at the distal end of the nerve crush injury (cathode stimulation), accelerated the recovery of choline acetyltransferase (ChAT) and acetylcholinesterase (AChE) activity in transiently denervated extensor digitorum longus (EDL) and soleus (SOL) rat muscles. ChAT is a specific marker of cholinergic nerve terminals and may reflect axon ingrowth, and AChE reflects the re-establishment of neuromuscular junctions and recovery of muscle activity. Compared to sham operated animals, the cathode (CA) stimulated rats had a statistically significant larger ChAT activity in the EDL and SOL …muscles on days 12 and 14 after nerve crush (P < 0.01, n = 6). The difference in ChAT activity between the groups decreased thereafter. Regarding recovery of muscle AChE, CA stimulation of the crushed sciatic nerve did not detectably accelerate the normalization of activity and pattern of AChE molecular forms in the EDL and SOL muscles. This means that the early rise in ChAT muscle activity in CA stimulated rats was not followed by an accelerated normalization of the neuromuscular transmission in the same group. It is more likely that the higher ChAT activity observed after cathode stimulation indicates a higher ChAT content in regenerating motor nerve endings, rather than a greater number of motor axons entering the muscles. It seems possible that cathode stimulation increased ChAT axonal transport, causing the early increase of ChAT content in the nerve endings. This raises the possibility that the axon transport and subsequent secretion of a trophic factor(s) from the nerve to the reinnervated muscle are enhanced as well, thus shortening the overall time of muscle force recovery in the absence of an appreciable acceleration of recovery of the neuromuscular transmission. Show more

Keywords: Acetylcholinesterase, Cathode stimulation, Choline acetyltransferase activity, Implantable stimulator, Nerve crush, Nerve regeneration

DOI: 10.3233/RNN-1994-7204

Citation: Restorative Neurology and Neuroscience, vol. 7, no. 2, pp. 89-94, 1994

Authors: Michele Basso, D. | Murray, Marion | Goldberger, Michael E.

Article Type: Research Article

Abstract: We used behavioral assessment techniques to investigate the recovery of locomotion after spinal cord injury. Complete hemisec-tions were made at T13 and LI in the cat spinal cord. Observational and high-speed kinematic analyses of bipedal treadmill and overground locomotion were made from 1 to 5 weeks postoperatively. Both bipedal and overground locomotion showed partial recovery. The early stage of recovery was characterized by an increased range of joint movement in a proximal to distal progression. During later stages, hindlimb movements became more complex and interjoint coordination markedly improved. Overground locomotion recovered faster and to a greater extent than bipedal locomotion, …as indicated by the time course of recovery, joint angular excursions and intralimb coordination. We propose that the recovery of bipedal locomotion may be more limited by reorganization of segmenta) sensory systems than overground locomotion, perhaps because alternate strategies for overground locomotion are available. Show more

Keywords: Kinematics, Angle-angle diagram, Recovery of function, Paralysis

DOI: 10.3233/RNN-1994-7205

Citation: Restorative Neurology and Neuroscience, vol. 7, no. 2, pp. 95-110, 1994

Authors: Colombo, Jorge A. | Napp, Mónica

Article Type: Research Article

Abstract: Adrenal chromaffin cells from immature or adult rats were grown in one of the following ‘in vitro’ conditions: (1) on coverslips placed on top of confluent, fetal, regional glia cultures; (2) in conditioned media from similar confluent cultures; (3) after direct seeding on top of such confluent cultures. Astroglia was obtained from cerebral cortex, septum, striatum and ventral mesen-cephalon from El6-17 pregnant-dated rats. All regions succesfully generated conditions for the early (less than 24 h) expression of neuritogenesis in about 15% of cells, which was more apparent in immature adrenal cell dissociates than in adult ones. The former grew long …neurites compared with their adult counterparts. In addition to the known effects of glioma conditioned medium and isolated trophic factors described by other authors, it is concluded that adrenal chromaffin cells are responsive to the neuritogenic activity of (central) astroglial diffusible factor(s) in non-supplemented, defined culture media conditioned by astrocytes from various brain regions. Additionally, evidence is offered that adult chromaffin cells show a reduced responsiveness towards such astroglial factor(s). Possible implications for cell trasplantation chimeras are discussed. Show more

Keywords: Trophic factors, Cell processes, Astroglia, Cell phenotype, Development, Cerebral cortex, Corpus striatum, Septum

DOI: 10.3233/RNN-1994-7206

Citation: Restorative Neurology and Neuroscience, vol. 7, no. 2, pp. 111-117, 1994

Authors: Kozlowski, D.A. | Jones, T.A. | Schallert, T.

Article Type: Short Communication

Abstract: Following unilateral injury to the forelimb-representation area of the sensorimotor cortex (FL-SMC) in adult rats, there occurs a biphasic process of overgrowth and partial elimination of neuronal dendrites in layer V pyramidal cells of the homotopic cortex of the opposite hemisphere. These neural events are associated with hyper-reliance on the non-impaired forelimb for postural-supporting and related movements that compensate for impaired function in the other forelimb. The overgrowth appears to be use-dependent because it can be prevented by one-sleeve casts that restrict the range of movements of the unimpaired limb during the period of expected neural growth. In development, “exuberant” …growth of neurons is often followed by pruning, a process that has been associated with activity-dependency and a glutamatergic N-methyl-D-aspartate (NMDA) mechanism. To determine whether a related mechanism might be operating in adult animals recovering from brain damage, MK-801, a non-competitive NMDA receptor antagonist, was administered during the pruning phase in adult rats that had sustained FL-SMC lesions. MK-801 prevented the elimination of dendrites in the FL-SMC rats and had no effect on dendritic arborization in Sham-operated rats. MK-801 reinstated dysfunction in the previously-recovered forelimb in FL-SMC rats, and had no effect in Sham-operated rats. These data are consistent with the possibility that there may be a functionally important pruning mechanism with a glutamatergic component in adults with FL-SMC lesions, just as in the developing brain. Show more

Keywords: Pyramidal neurons, Sensorimotor cortex, Glutamate, NMDA antagonist, Recovery of function, Dendritic pruning

DOI: 10.3233/RNN-1994-7207

Citation: Restorative Neurology and Neuroscience, vol. 7, no. 2, pp. 119-126, 1994