Selectivity in the Reinnervation of the Lateral Gastrocnemius Muscle after Nerve Repair with Ethyl Cyanoacrylate in the Rat

Abstract

There is a need for complementary surgical techniques that enable rapid and reliable primary repair of transected nerves. Previous studies after peripheral nerve transection and repair with synthetic adhesives have demonstrated regeneration to an extent comparable to that of conventional techniques. The aim of this study was to compare two different repair techniques on the selectivity of muscle reinnervation after repair and completed regeneration. We used the cholera toxin B technique of retrograde axonal tracing to evaluate the morphology, the number, and the three-dimensional location of α-motoneurons innervating the lateral gastrocnemius muscle and compared the results after repair with either ethyl cyanoacrylate (ECA) or epineural sutures of the transected parent sciatic nerve. In addition, we recorded the wet weight of the muscle. Six months after transection and repair of the sciatic nerve, the redistribution of the motoneuron pool was markedly disorganized, the motoneurons had apparently increased in number, and they were scattered throughout a larger volume of the spinal cord gray matter with a decrease in the synaptic coverage compared to controls. A reduction in muscle weight was observed as well. No difference in morphometric variables or muscle weight between the two repair methods could be detected. We conclude that the selectivity of motor reinnervation following sciatic nerve transection and subsequent repair with ECA is comparable to that following conventional micro suturing.

Somatotopic Changes in the Nucleus Ambiguus After Section and Regeneration of the Recurrent Laryngeal Nerve of the Rat

“…Disorganization of the topography following a peripheral nerve injury have been described not only in the Amb but also in other cranial nuclei including; the facial nucleus (Thomander, ; Aldskogius and Thomander, ; Nakao et al, ; Angelov and Neiss, ; Angelov et al, ; Streppel et al, ; Choi and Raisman, ; Guntinas‐Lichius et al, ; Franchi et al, ; Grosheva et al ), extraocular nuclei (Fernández et al, ; Scherer, ; Sibony et al, ), hypoglossal nucleus (Mizuno et al, ), and in the spinal cord after a lesion in the sciatic nerve (Aldskogius et al, ; Wasserschaff, ; Fernández et al, ; Katada et al, ; de Ruiter et al, ; Landegren et al, ). These reports indicate that following a transection and repair of any peripheral nerve in the adult, the reinnervation of the denervated structures is not as selective as that occurring during development and the resulting disorganization of the somatotopic distribution of the denervated motoneurons persists.…”

In Vivo Peripheral Nerve Repair Using Tendon-Derived Nerve Guidance Conduits

“…This difference may be a result of nerve degeneration and subsequent random reinnervation, resulting in aberrant motor neuron projections in the muscle that were later remodeled and “pruned” over time in the conduit treated animals . Temporary innervation by nerves at the incorrect target muscle, followed by removal, and reinnervation by the appropriate nerve may have allowed functional restoration, but did not result in muscle growth. , Such biased regeneration may be a result of different trophic cues that could be selectively influenced by the presence of the conduit, either chemical cues or an effect of the nanotopography.…”

“…43 Temporary innervation by nerves at the incorrect target muscle, followed by removal, and reinnervation by the appropriate nerve may have allowed functional restoration, but did not result in muscle growth. 44,45 Such biased regeneration may be a result of different trophic cues that could be selectively influenced by the presence of the conduit, either chemical cues or an effect of the nanotopography.…”