Neural cell transplantation effects on sciatic nerve regeneration after a standardized crush injury in the rat
ABSTRACT The goal of the present study was to assess whether in vitro-differentiated N1E-115 cells supported by a collagen membrane would enhance rat sciatic nerve regeneration after a crush injury. To set up an appropriate experimental model for investigating the effects of neural cell transplantation, we have recently described the sequence of functional and morphologic changes occurring after a standardized sciatic nerve crush injury with a nonserrated clamp. Functional recovery was evaluated using the sciatic functional index, the static sciatic index, the extensor postural thrust, the withdrawal reflex latency, and ankle kinematics. In addition, histomorphometric analysis was carried out on regenerated nerve fibers by means of the 2D-disector method. Based on the results of the EPT and of some of the ankle locomotor kinematic parameters analyzed, the hypothesis that N1E-115 cells may enhance nerve regeneration is partially supported although histomorphometry disclosed no significant difference in nerve fiber regeneration between the different experimental groups. Therefore, results suggest that enrichment of equine type III collagen membrane with the N1E-115 cellular system in the rat sciatic nerve crush model may support recovery, at least in terms of motor function. The discrepancy between functional and morphological results also suggests that the combined use of functional and morphological analysis should be recommended for an overall assessment of recovery in nerve regeneration studies.
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ABSTRACT: Many studies have been dedicated to the development of scaffolds for improving post-traumatic nerve regeneration. The goal of this study was to develop and test hybrid chitosan membranes to use in peripheral nerve reconstruction, either alone or enriched with N1E-115 neural cells. Hybrid chitosan membranes were tested in vitro, to assess their ability in supporting N1E-115 cell survival and differentiation, and in vivo to assess biocompatibility as well as to evaluate their effects on nerve fiber regeneration and functional recovery after a standardized rat sciatic nerve crush injury. Functional recovery was evaluated using the sciatic functional index (SFI), the static sciatic index (SSI), the extensor postural thrust (EPT), the withdrawal reflex latency (WRL) and ankle kinematics. Nerve fiber regeneration was assessed by quantitative stereological analysis and electron microscopy. All chitosan membranes showed good biocompatibility and proved to be a suitable substrate for plating the N1E-115 cellular system. By contrast, in vivo nerve regeneration assessment after crush injury showed that the freeze-dried chitosan type III, without N1E-115 cell addition, was the only type of membrane that significantly improved posttraumatic axonal regrowth and functional recovery. It can be thus suggested that local enwrapping with this type of chitosan membrane may represent an effective approach for the improvement of the clinical outcome in patients receiving peripheral nerve surgery.Biomaterials 12/2008; 29(33):4409-19. DOI:10.1016/j.biomaterials.2008.07.043 · 8.31 Impact Factor
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ABSTRACT: This paper addresses several basic issues that are important for the experimental model design to investigate peripheral nerve regeneration. First, the importance of carrying out adequate preliminary in vitro investigation is emphasized in light of the ethical issues and with particular emphasis on the concept of the Three Rs (Replacement, Reduction, and Refinement) for limiting in vivo animal studies. Second, the various options for the selection of the animal species for nerve regeneration research are reviewed. Third, the two main experimental paradigms of nerve lesion (axonotmesis vs. neurotmesis followed by microsurgical reconstruction) are critically outlined and compared. Fourth, the various nerve models that have most commonly been employed are overviewed focusing in particular on forearm mixed nerves and on behavioural tests for assessing their function: the ulnar test and the grasping test which is useful for assessing both median and radial nerves in the rat. Finally, the importance of considering the influence of various factors and diseases which could interfere with the nerve regeneration process is emphasized in the perspective of a wider adoption of experimental models which more closely mimic the environmental and clinical conditions found in patients.International Review of Neurobiology 02/2009; 87:47-79. DOI:10.1016/S0074-7742(09)87004-9 · 2.46 Impact Factor