Temporal progression and extent of the return of sensation in the foot provided by the saphenous nerve after sciatic nerve transection and repair in the rat - Implications for nociceptive assessments
ABSTRACT Sensory testing, by providing stimuli for nociceptors of the foot, is a popular method of evaluating sensory regeneration after damage to the sciatic nerve in the rat. In the following study, 20 rats were submitted to double transection of the sciatic nerve. The subsequent 14 mm gap was repaired through guidance interponation. In order to evaluate nerve regeneration, sensory testing was performed additionally to other methods, which included motor testing, morphometry, and electron microscopic assessments of nerves. Somatosensory testing revealed that all animals exhibited next to the same amount of sensory reinnervation on their foot regardless of their experimental group. In motor tests, however, two out of the three experimental groups did not improve at all. These groups also failed to show neural regrowth in morphometric and electron microscopic assessments of the associated nerve. Retrograde tracing was able to prove the saphenous nerve as an alternative source of sensory reinnervation in animals with failed sciatic regeneration. This means that results of sensory testing in the rat should be treated with caution, taking into account the areas tested and the likelihood that in these areas saphenous sprouting could have taken place. Furthermore, it is strongly advised that somatosensory testing should be conducted only on toe 5.
- SourceAvailable from: Nikolaos A Papadopulos
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- "The surgical approach for exposing the sciatic nerve, the length and location of the segment excised from the sciatic nerve, the type and location of closing-up sutures, anaesthesia and perioperative management were identical to those applied in the previous study (Rupp et al., 2007b). "
ABSTRACT: Striking inconsistencies between the results of morphometric and electrophysiologic examinations of the regenerating nerve were observed in a previous study featuring the bridging of a 14 mm gap in the rat sciatic nerve. To shed light on this dichotomy, seven further rats were subjected to permanent sciatic nerve transection and assessed electrophysiologically, histologically and by retrograde axonal tracing at various postoperative intervals (1 h to 8 weeks). The results of the histological examinations and retrograde tracing revealed that in spite of the fact that compound muscle action potentials could be recorded in the gastrocnemius muscle, no reinnervation of the gastrocnemius muscle, either physiological or aberrant, had actually taken place. Furthermore, it was established that the electrical activity recorded in the gastrocnemius muscle after stimulation of the proximal or distal stump is generated by surrounding hind limb muscles unaffected by denervation. These are stimulated either directly, or indirectly due to spreading of the impulse. It is therefore strongly recommended that caution should be exercised when interpreting recordings from the gastrocnemius muscle after stimulation of a regenerating sciatic nerve in laboratory rodents.Journal of Neuroscience Methods 12/2007; 166(2):266-77. DOI:10.1016/j.jneumeth.2007.07.015 · 2.05 Impact Factor
Article: Soerensen, A.B.*, Lund, A.H.*, Kunder, S., Quintanilla-Martinez, L., Schmidt, J., Wang, B.*, Wabl, M.*, Pedersen, F.S.*: Impairment of alternative splice sites defining a novel gammaretroviral exon within gag modifies the oncogenic properties of Akv murine leukemia virus. Retrovirology 4:46, 1-19 (2007)
Conference Paper: Dynamic simulation of a four-legged gait[Show abstract] [Hide abstract]
ABSTRACT: The authors deal with the behavior of a walking machine when the dynamic effects are considered. For this study a dynamic model of the RIMHO walking robot is used. The RIMHO is a four-legged robot developed for acquiring knowledge in walking machines. This model is derived considering the Lagrange-Euler approach. The main assumption is that the machine has massless legs, although some contribution of the legs to the body inertia is considered. Using this dynamic model the dynamic behavior of a wave-crab gait has been determinedSystems, Man and Cybernetics, 1992., IEEE International Conference on; 11/1992