Aspects of the Macro and Microscopic Anatomy of the Sciatic Nerve in Wistar Rats

Suaid, Carla Adelino; Santos, Ana Paula; Yamane, Fernanda de Oliveira; Fazan, Valéria Paula Sassoli; Barreira, Amilton Antunes

doi:10.4067/s0717-95022016000300010

Cited by 15 publications

(11 citation statements)

References 20 publications

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“…12). Of note, axonal diameters for NF-200 positive neurons reported here do not include myelin and are in good agreement with previous literature (Suaid et al, 2016). Peripherin labelled neurons displayed much shorter stems, as compared to NF-200 positive neurons (60.7±4.2 m vs. 232.5±22.9 m, p<0.001; Fig.…”

Section: Does the Soma Have More Influence Over The T-junction In C-t...supporting

confidence: 92%

Dorsal root ganglia control nociceptive input to the central nervous system

Han

Ramli

Wang

et al. 2021

Preprint

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Accumulating observations suggest that peripheral somatosensory ganglia may regulate pain transmission, yet direct evidence is sparse. Here we show that the peripheral afferent nociceptive information undergoes dynamic filtering within dorsal root ganglia (DRG) and suggest that this filtering occurs at the axonal bifurcations (t-junctions). Using simultaneous in vivo electrophysiological recordings from the peripheral (spinal nerve) and central (dorsal root) aspects of rodent spinal nerves, ganglionic transplantation of GABAergic progenitor cells, and optogenetics we demonstrate tonic and dynamic filtering of action potentials traveling through the DRG. Filtering induced by focal application of GABA or optogenetic GABA release from the DRG-transplanted GABAergic progenitor cells was specific to nociceptive fibers. Light-sheet imaging and computer modeling demonstrated that, compared to other somatosensory fiber types, nociceptors have shorter stem axons, making somatic control over t-junctional filtering more efficient. Optogenetically-induced GABA release within DRG enhanced filtering and reduced both acute and chronic inflammatory and neuropathic pain in vivo. These findings support the potential gating of pain information within the somatosensory system, and suggests new therapeutic approaches for pain relief.

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Section: Does the Soma Have More Influence Over The T-junction In C-t...supporting

confidence: 92%

Dorsal root ganglia control nociceptive input to the central nervous system

Han

Ramli

Wang

et al. 2021

Preprint

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“…The rat sciatic nerve exhibits a similar organization of specific axon populations. For instance, Suaid et al, 2016 ; Ravagli et al, 2020 both demonstrated that the axons contributing to the main branches of the sciatic (peroneal, tibial, and sural) stay discretely organized and do not intermingle for a significant distance proximal to the trifurcation. The same organization was found in the tibial branch of the sciatic nerve after retrogradely labeling individual distal branches contributing to small populations of muscles and tissue in the rat hindlimb ( Badia et al, 2010 ).…”

Section: Discussionmentioning

confidence: 99%

“…It has been previously reported in a variety of species that axons which serve specific distal branches of peripheral nerves travel in organized bundles along the course of the nerve ( Sunderland, 1978 ; Brushart, 1991 ; Hallin et al, 1991 ). The sciatic nerve of rats has been shown to exhibit a similar organization of its major branches ( Suaid et al, 2016 ; Ravagli et al, 2020 ) as well as its more distal branches ( Badia et al, 2010 ). We investigated the topographic organization of axons within the rat sciatic nerve at the level of an individual muscle (TA), and looked for consistencies in this topography bilaterally within animals as well as across animals and sexes.…”

Section: Introductionmentioning

confidence: 99%

Intraneural Topography of Rat Sciatic Axons: Implications for Polyethylene Glycol Fusion Peripheral Nerve Repair

Hibbard

Sengelaub²

2022

Front. Cell. Neurosci.

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Peripheral nerve injuries are the most common type of nerve trauma. We have been working with a novel repair technique using a plasmalemmal fusogen, polyethylene glycol (PEG), to re-fuse the membranes of severed axons. PEG-fusion repair allows for immediate re-innervation of distal targets, prevents axonal degeneration, and improves behavioral recovery. PEG-fusion of severed axons is non-specific, and we have previously reported that following injury and PEG-fusion misconnections between spinal motoneurons and their distal targets were present. Surprisingly, appropriately paired proximal and distal motor axons were observed in all PEG-fused animals. We hypothesized that a topographic organization of axons contributing to the sciatic nerve could explain the incidence of appropriate connections. We traced the course of specific axon populations contributing to the sciatic nerve in young adult male and female rats. Following intraneural injection of Fast Blue into the tibial branch, labeled axons were confined to a discrete location throughout the course of the nerve. Following intramuscular injection of cholera toxin-conjugated horseradish peroxidase into the anterior tibialis, labeled axons were confined to a smaller but still discrete location throughout the nerve. In both cases, the relative locations of labeled axons were consistent bilaterally within animals, as well as across animals and sexes. Thus, the relatively consistent location of specific axon populations could allow for realignment of appropriate populations of axons, and enhanced behavioral recovery seen in PEG-fused animals. Knowing the organization of axons within the sciatic nerve promotes accurate territory realignment during repair, therefore aiding in recovery outcomes.

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“…In order to test the safety and efficacy of epineural injections, 3 experimental steps were designed using the rat sciatic nerve as a model because its diameter (1-1.5 mm) is similar to that of the human digital nerves [22].…”

Section: Experimental Designmentioning

confidence: 99%

“…The aim of this study is to identify a simple nerve staining technique which could aid intraoperative location of the digital nerve by improving its visibility and facilitating separation of the nerve from the Dupuytren's tissue. The rat sciatic nerve was used as a model in this study as its diameter is comparable to human digital nerves [22].…”

Section: Introductionmentioning

confidence: 99%

Epineural Methylene Blue Injection May Aid Localization of Digital Nerves in Dupuytren’s Surgery

et al. 2021

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Background: In Dupuytren’s surgery, limited fasciectomy is still the gold-standard treatment. A relatively high risk of iatrogenic nerve injury has been observed especially when the spiral cords of the Dupuytren’s tissue pull digital nerves away from their normal anatomical location. Intraoperative neural marking could facilitate locating the potentially displaced nerves. Hence, surgery could be undertaken more quickly with a lower risk of iatrogenic nerve injury. Objectives: We hypothesize that digital nerves may be stained with methylene blue (MB) in vivo providing a visual aid to distinguish them from Dupuytren’s tissue. We aim to (a) test an in vivo nerve staining technique using MB in a rat sciatic nerve model and to (b) assess the safety of epineural MB injection. Methods: Three experiments were performed: first, the effects of (a) sham surgery, (b) epineural needle insertion, and (c) 40 μL epineural saline injection were tested in the rat sciatic nerve. Second, we determined the (a) histoanatomical localization of the epineurally injected 40 µL 1 m/m% MB stock solution and (b) we tested which saline dilution (i.e., 1:40, 1:80, and 1:160) of the stock solution does provide optimal blue color upon 40 µL epineural injection. Third, the functional and morphological effect of 40 µL 1:80 diluted MB injection was compared with that of saline, injected into the contralateral sciatic nerve. The functional effects were tested by assessing the pain threshold by using a dynamic plantar esthesiometer (DPA) and by examination of the animal’s gate and paw posture. Sciatic nerves were subjected to histological examination and morphometry to test structural damage. Results: Neither epineural needle insertion nor saline injection caused any functional or morphological changes. Histological examination revealed that the MB stained the epineural compartment. Epineural injection of 40 μL 1:80 diluted MB into the sciatic nerve stained an 18.18-mm segment of the nerve distal to the puncture point. DPA revealed unchanged pain threshold values on the plantar surface of the limbs. Normal gait and foot posture suggested normal motor functions in all groups. No histological changes were seen in the stained nerves, and the nerve fiber density remained unchanged. Conclusion: We demonstrated that in vivo nerve staining with MB is a suitable method to mark nerves without causing detectable negative effect to the stained nerve. Human trials are required to prove the efficacy of the technique in Dupuytren’s disease.

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Aspects of the Macro and Microscopic Anatomy of the Sciatic Nerve in Wistar Rats

Cited by 15 publications

References 20 publications

Dorsal root ganglia control nociceptive input to the central nervous system

Dorsal root ganglia control nociceptive input to the central nervous system

Intraneural Topography of Rat Sciatic Axons: Implications for Polyethylene Glycol Fusion Peripheral Nerve Repair

Epineural Methylene Blue Injection May Aid Localization of Digital Nerves in Dupuytren’s Surgery

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