Restorative Neurology and Neuroscience - Volume 20, issue 5

Authors: Verdú, Enrique | Labrador, Rafael O. | Rodríguez, Francisco J. | Ceballos, Dolores | Forés, Joaquim | Navarro, Xavier

Article Type: Research Article

Abstract: Purpose: Placement of extracellular matrix components has been used as a mean to enhance axonal growth across nerve long gaps repaired by tubulization. However, such matrices may impede axonal regeneration depending on its density and microgeometry. Methods: Silicone tubes were prefilled with collagen or laminin-containing gels and implanted into a 6 mm gap, a length considered limiting for regeneration, in the mouse sciatic nerve. Gels were polymerized prior to implantation either in horizontal position or …subjected to gravitational (in vertical position) or to magnetic forces to induce longitudinal alignment of the fibrils. Recovery of motor, sensory and sudomotor functions in the hindpaw was evaluated during 4 months postoperation. Results: Reinnervation started earlier and achieved slightly higher levels with aligned collagen gels than with the horizontal gel. For the three groups repaired with tubes with Matrigel, there was a gradation of the functional results, reinnervation started earlier and reached higher values in matrix with magnetically-induced, longitudinal orientation than with the horizontal gel, whereas gravitational alignment followed an intermediate evolution. Final morphological evaluation showed more dense residual mass of collagen than of Matrigel at the center of the regenerate nerves. The number of myelinated fibers was increased in tubes with alignment compared to horizontal gels. Conclusions: Alignment of collagen and laminin gels within a silicone tube increases the success and the quality of regeneration in long nerve gaps. The laminin gel performed better than the collagen gel under each condition tested. The combination of an aligned matrix with embedded Schwann cells should be considered in further steps for the development of an artificial nerve graft for clinical application. Show more

Keywords: nerve regeneration, tube repair, alignment, collagen, laminin, mouse, sciatic nerve

Citation: Restorative Neurology and Neuroscience, vol. 20, no. 5, pp. 169-180, 2002

Authors: Lewin-Kowalik, Joanna | Gołka, Beata | Larysz-Brysz, Magdalena | Świech-Sabuda, Ewa | Granek, Arkadiusz

Article Type: Research Article

Abstract: Purpose: The aim of the study was to ascertain whether experimental hyperthyroidism changes the neurotrophic activity of 14- and 21-day-predegenerated peripheral nerve grafts towards CNS neurites. Methods: Hyperthyroidism was induced by subcutaneous injections of T_4 . Autologous peripheral nerve grafts were implanted into the hippocampus of both euthyrotic and hyperthyrotic animals 14 or 21 days after sciatic nerve transection (groups ET14, Et21, Ht14 and Ht21, respectively). Non-predegenerated grafts were used …as a control group (groups EtN adn HtN). Cells extending their neurites into the grafts were traced with FITC-HRP. Results: The number of traced cells in individual groups was as follows: EtN -- 39.4 ± 9.46, Et14 -- 1 ± 0.94, Et21 - 0.6 ± 0.69; HtN -- 95 ± 19.46; Ht14 -- 95.94 ± 16.3, Ht21 -- 99.94 ± 7.26. Conclusions: We found that experimentally induced hyperthyroidism strongly enhanced the regeneration of injured hippocampal neurites after implantation of peripheral nerve grafts that were practically inactive in euthyrotic animals. Show more

Citation: Restorative Neurology and Neuroscience, vol. 20, no. 5, pp. 181-187, 2002

Authors: Michele Basso, D. | Beattie, Michael S. | Bresnahan, Jacqueline C.

Article Type: Research Article

Abstract: Purpose: Locomotor recovery after spinal cord contusion injury (SCI) may be mediated by descending axons spared at the lesion epicenter. Greater axonal sparing is associated with more extensive recovery. Therefore, we identified the source and relative proportion of spared axons associated with extensive or limited locomotor recovery after SCI. Methods: Female Sprague Dawley rats underwent mild or moderate SCI using the OSU device. Results: Locomotor recovery was greater for the mild than moderate group with …the primary differences being restitution of limb coordination, very little toe dragging and minor paw rotation. Conclusions: The following brain nuclei with substantial neuronal labeling after mild but not moderate SCI may play an important role in locomotor recovery: raphe pallidus and magnus, ventral medullary and pontine reticular formation, lateral vestibular nucleus, red nucleus and locus coeruleus. We review the normal anatomical distribution of descending systems to the lumbar cord in rat and the role they play in motor control. Show more

Citation: Restorative Neurology and Neuroscience, vol. 20, no. 5, pp. 189-218, 2002