Effects of motor and sensory nerve transplants on amount and specificity of sciatic nerve regeneration

Abstract

Nerve regeneration after complete transection does not allow for adequate functional recovery mainly because of lack of selectivity of target reinnervation. We assessed if transplanting a nerve segment from either motor or sensory origin may improve specifically the accuracy of sensory and motor reinnervation. For this purpose, the rat sciatic nerve was transected and repaired with a silicone guide containing a predegenerated segment of ventral root (VR) or dorsal root (DR), compared to a silicone guide filled with saline. Nerve regeneration and reinnervation was assessed during 3 months by electrophysiologic and functional tests, and by nerve morphology and immunohistochemistry against choline acetyltransferase (ChAT) for labeling motor axons. Functional tests showed that reinnervation was successful in all the rats. However, the two groups with a root allotransplant reached higher degrees of reinnervation in comparison with the control group. Group VR showed the highest reinnervation of muscle targets, whereas Group DR had higher levels of sensory reinnervation than VR and saline groups. The total number of regenerated myelinated fibers was similar in the three groups, but the number of ChAT+ fibers was slightly lower in the VR group in comparison with DR and saline groups. These results indicate that a predegenerated root nerve allotransplant enhances axonal regeneration, leading to faster and higher levels of functional recovery. Although there is not clear preferential reinnervation, regeneration of motor axons is promoted at early times by a motor graft, whereas reinnervation of sensory pathways is increased by a sensory graft.

Effects of Chitosan-Zinc Oxide Nanocomposite Conduit on Transected Sciatic Nerve: An Animal Model Study

“…V arious materials and techniques have been used to enhance nerve regeneration [1,2]. Biodegradable nerve guides as a temporary scaffold are better than non-degradable biomaterials because the latter remain in place as a foreign body and ultimately result in limiting recovery of nerve function [3].…”

Polyethylene Glycol Rapidly Restores Axonal Integrity and Improves the Rate of Motor Behavior Recovery After Sciatic Nerve Crush Injury

“…For example, nerve grafts (Jeng and Coggeshall 1986;Lago et al 2007), connective tissue matrices (Bozkurt et al 2007;Herbert et al 1996;Lore et al 1999), and nerve growth guides (Aebischer et al 1990;Kalbermatten et al 2009) have all been reported to improve the extent of regeneration by severed PNS axons, but not the rate or time at which PNS axons reestablish their connections.…”

Evaluation of periodic electrodiagnostic measurements to monitor motor recovery after different peripheral nerve lesions in the rat

“…11,[18][19][20][21] There have been only a few studies describing repeated electrodiagnostic measurements during long-term investigations of peripheral nerve regeneration. [22][23][24] The advantage of minimally invasive electrodiagnostic methods that allow periodic evaluation of reinnervation at predefined time intervals without euthanizing the animals or interfering with the progress of regeneration 16 seems not to be widely recognized or routinely used to assess the progress of peripheral nerve regeneration. 17 The development of tissue-engineered nerve grafts is an emerging field, [25][26][27][28] and evaluation protocols that allow objective assessment of different regeneration parameters are of high importance.…”