Research reportSciatic nerve regeneration in mice and rats: recovery of sensory innervation is followed by a slowly retreating neuropathic pain-like syndrome
Introduction
The sciatic nerve crush model is a well-characterized model for peripheral nerve regeneration. After a crush lesion, nerve fibers in the distal stump degenerate. Myelin and axon debris are removed by the process of Wallerian degeneration. The endoneurial tubes remain intact, enabling fast and qualitatively good anatomical and functional recovery [2], [7], [10], [23]. Fibers in the proximal nerve stump start to sprout and new axons extend through the distal endoneurial tube to reinnervate their target organs. During this process of axonal regeneration, numerous changes in morphology (chromatolysis) and gene expression occur in the neuronal cell bodies [1], [10], [11], [14].
Recently, a new method for gait analysis was described by one of us, the CatWalk [13]. This technique gives more detailed information on how the animal uses its paw during locomotion than the conventional techniques, e.g., the De Medinacelli method, which essentially measures the ability to use the muscles in the lower paw and foot [9]. The CatWalk has, for example, been successful in showing that animals suffering from neuropathic pain do not support weight upon their paw, although they do place it [26]. Neuropathic pain is a well-known phenomenon in nerve injury models with impaired regeneration, e.g., sciatic nerve transection, in models of neural inflammation, and in models with chronic nerve damage, e.g., chronic constriction injury (CCI) [5], [15], [22], [30].
We performed the sciatic nerve crush in mice and rats, and measured functional recovery of sensory and motor functions using the foot reflex withdrawal test and the De Medinacelli method. The CatWalk paradigm was used to investigate walking performance in more detail. In rats, tactile allodynia was also scored using von Frey filament testing. We demonstrate that, although full functional recovery of sensory and motor function occurred in both species, the animals developed a state of neuropathic pain which only became apparent after full sensory recovery as measured with the foot reflex withdrawal test was present. As such, recovery as assessed by the De Medinacelli method or the foot reflex withdrawal test indicates successful regeneration of damaged axons to their previous target area, but does not indicate renormalization of function.
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Animals and surgery
All procedures in this study were performed in accordance with the Ethical Guidelines of the International Association for the Study of Pain [31] and were approved by the Ethical Committee on Animal Experiments of the University of Utrecht. A crush lesion was placed in both rats and mice in the sciatic nerve of the right paw, at mid-thigh level, as described by de Koning et al. [8]. In short, Wistar rats (Charles River) were anesthetized with Hypnorm® (Janssen Pharmaceutics, Tilburg, the
Results
We investigated recovery of sensory and motor functions in C57BL/6J mice and Wistar rats. Recovery of sensory function was assessed using the foot reflex withdrawal test. At 18 dpo, 5 of the 6 mice (86%) and at 20 dpo, 6/6 mice reacted to the 0.1 mA electric current, indicating recovery of sensory function (Fig. 1). At 20 dpo, 7 of the 10 rats, and at 21 dpo, 10/10 rats reacted to the 0.1 mA electric current. These observations indicate that the time course of sensory recovery was roughly
Discussion
These data indicate that although sensory and motor innervation of the paw were fully recovered at 24 dpo, the animals did not yet support their weight on the lesioned paw. The print area, although recovered on the photographic films (De Medinacelli method), where one does not need much pressure to get a print, did not return to normal in either rats or mice during the follow-up period when visualized with the CatWalk system. This reduction in pressure applied during stance was also shown by
References (31)
- et al.
Behavioural pain-related disorders and contribution of the saphenous nerve in crush and chronic constriction injury of the rat sciatic nerve
Pain
(1994) - et al.
Quantitative assessment of tactile allodynia in the rat paw
J. Neurosci. Methods
(1994) - et al.
Org.2766 improves functional and electrophysiological aspects of regenerating sciatic nerve in the rat
Peptides
(1987) - et al.
Methods for producing a reproducible crush in the sciatic and tibial nerve of the rat and rapid and precise testing of return of sensory function. Beneficial effects of melanocortins
J. Neurol. Sci.
(1986) - et al.
On the neurotrophic action of melanocortins
Prog. Brain Res.
(1987) - et al.
Messenger plasticity in primary sensory neurons following axotomy and its functional implications
Trends Neurosci.
(1994) - et al.
Long-term changes in the distribution of galanin in dorsal root ganglia after sciatic or spinal nerve transection in rats
Neuroscience
(2001) - et al.
A role for nerve growth factor in sympathetic sprouting in rat dorsal root ganglia
Pain
(1999) - et al.
The resolution of neuropathic hyperalgesia following motor and sensory functional recovery in sciatic axonotmetic mononeuropathies
Pain
(1994) - et al.
Recovery of function after sciatic nerve crush lesion in rats selected for diverging locomotor activity in the open field
Neurosci. Lett.
(1997)
Comparison of immunohistochemical and functional re-innervation of skin and muscle after peripheral nerve injury
Exp. Neurol.
‘CatWalk’ automated quantitative gait analysis as a novel method to assess mechanical allodynia in the rat; a comparison with von Frey testing
Pain
Axotomy-induced changes in primary sensory neurons
Pathology of the peripheral nerve
A device for measuring plantar pressures under the sole of the foot
Eng. Med.
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Currently working at MRC Cambridge University Centre for Brain Repair, Robinson Way, Cambridge, CB2 2PY, United Kingdom.