Histologic and Functional Outcomes of Conduit Wrapping for Peripheral Nerve Repair: Early Results in a Rat Model

Abstract Background The concept of utilizing a nerve conduit for augmentation of a primary nerve repair has been advocated as a method to prevent neural scarring and decrease adhesions. Despite clinical use, little is known about the effects of a nerve conduit wrapped around a primary repair. To better understand this, we investigated the histologic and functional effects of use of a nerve conduit wrapped around a rat sciatic nerve repair without tension. Methods Twenty Lewis' rats were divided into two groups of 10 rats each. In each group, unilateral sciatic nerve transection and repair were performed, with the opposite limb utilized as a matched control. In the first group, direct repair alone was performed; in the second group, this repair was augmented with a porcine submucosa conduit wrapped around the repair site. Sciatic functional index (SFI) was measured at 6 weeks with walking track analysis in both groups. Nonsurvival surgeries were then performed in all animals to harvest both the experimental and control nerves to measure histomorphometric parameters of recovery. Histomorphometric parameters assessed included total number of neurons, nerve fiber density, nerve fiber width, G-ratio, and percentage of debris. Unpaired t-test was used to compare outcomes between the two groups. Results All nerves healed uneventfully but compared with direct repair; conduit usage was associated with greater histologic debris, decreased axonal density, worse G-ratio, and worse SFI. No significant differences were found in total axon count or gastrocnemius weight. Conclusion In the absence of segmental defects, conduit wrapping primary nerve repairs seem to be associated with worse functional and mixed histologic outcomes at 6 weeks, possibly due to debris from conduit resorption. While clinical implications are unclear, more basic science and clinical studies should be performed prior to widespread adoption of this practice.

Download Full-text

LONG-TERM OUTCOMES OF RAT SCIATIC NERVE INJURY AND ITS GRAFTING WITH SILICON WIRES-BASED CONDUIT: DISTAL NERVE STUMP HISTOLOGY AND ELECTROMYOGRAPHY RESULTS

Medical Science of Ukraine (MSU) ◽

10.32345/2664-4738.3-4.2019.01 ◽

2019 ◽

Vol 15 (3-4) ◽

pp. 3-9

Author(s):

V. Likhodiievskyi ◽

A. Korsak ◽

D. Skopets ◽

S. Olefir ◽

S. Chukhrai ◽

...

Keyword(s):

Sciatic Nerve ◽

Nerve Fiber ◽

Fiber Diameter ◽

Negative Impact ◽

Nerve Fibers ◽

Nerve Injuries ◽

Nerve Stump ◽

Distal Nerve ◽

G Ratio

Relevance. The investigations on trauma epidemiology have shown that both combat- and noncombat-related extremity injuries are often accompanied by nerve injuries. These injuries disproportionately affect young healthy civilians and military officers and has a devastating impact on a patients’ quality of life. Severe nerve injuries, such as nerve trunk injury in continuity (Sunderland 5), that cannot be treated by neurorraphy without tension, require use of nerve gap bridging strategies with different materials and techniques. Objective. This study was aimed to evaluate any positive or negative impact of implanted silicon wires on the quality of nerve fibers at distal nerve stump. Materials and Methods. An experiment was performed on 40 male Whistar rats 2-4 month that were divided to the next groups: I, (n=10) sham-operated, only surgical access to sciatic nerve was performed. II (n=10) with 10 mm sciatic nerve gap that was bridged with autoneurografting. III (n=10) with 10 mm nerve gap that was bridged with allogenic decell aorta filled with 4% carboxymethylcellulose hydrogel. IV (n=10) with 10 mm nerve gap that was bridged with allogenic decell aorta filled with 4% carboxymethylcellulose hydrogel and aligned p-type silicon microvires. Decellularization of allogenic aortas was performed by freeze-thaw cycles. Silicon whiskers were fabricated by Vapor-Liquid-Solid (VLS) method in a cold wall Catalytic Chemical Vapor Deposition (Cat-CVD) chamber, pre-cleaned with hydrofluoric acid and sterilized via 180*C dry heat. 12 weeks after surgery under general anesthesia all rats underwent invasive needle electroneurpmyography with proximal nerve stump stimulation and registration from gastrocnemius muscle. Myograms were recorded and compared by the shape of M-reflex and its amplitude. After myography rats were euthanized under thiopentone overdosage and distal stumps of injured sciatic nerves were harvested for light microscopy. Sciatic nerve transverse slices were stained with nitric silver by modified Bielschowsky method Nerve fiber diameter, axon diameter, myelin sheath thickness and axon-to-nerve fiber diameter ratio (g-ratio) were measured. Results. Performed analysis showed that rats from ІІ and IV groups demonstrated the best quality of nerve fibers in distal nerve stump. That was evidenced by bigger nerve fibers diameter in rats from autologous nerve grafting group and aorta with gel and wires grafting group in comparison with aorta with gel grafting group. Rats from IV demonstrated higher voltage and lower latency of M-reflexes during electromyography. Conclusions. It can be concluded about the possible pro-regenerative impact of implanted silicon wires that was evidenced by better nerve fibers quality at distal nerve stump.

Download Full-text

Evaluation of artificial nerve conduit and autografts in peripheral nerve repair in the rat model of sciatic nerve injury

Neurological Research ◽

10.1080/01616412.2016.1181346 ◽

2016 ◽

Vol 38 (5) ◽

pp. 461-466 ◽

Cited By ~ 10

Author(s):

Rongbo Wu ◽

Li Wang ◽

Fangyi Chen ◽

Yongmei Huang ◽

Jimin Shi ◽

...

Keyword(s):

Sciatic Nerve ◽

Peripheral Nerve ◽

Nerve Injury ◽

Rat Model ◽

Nerve Repair ◽

Sciatic Nerve Injury ◽

Nerve Conduit ◽

Peripheral Nerve Repair

Download Full-text

Changes in nerve fiber numbers distal to a nerve repair in the rat sciatic nerve model

Muscle & Nerve ◽

10.1002/mus.880141113 ◽

1991 ◽

Vol 14 (11) ◽

pp. 1116-1122 ◽

Cited By ~ 188

Author(s):

Susan E. MacKinnon ◽

A. L. Dellon ◽

J. P. O'Brien

Keyword(s):

Sciatic Nerve ◽

Nerve Fiber ◽

Nerve Repair ◽

Rat Sciatic Nerve ◽

Nerve Model

Download Full-text

Faculty Opinions recommendation of Intraepidermal nerve fiber density and its application in sarcoidosis.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1165688.628719 ◽

2009 ◽

Author(s):

Richard A Lewis

Keyword(s):

Nerve Fiber ◽

Fiber Density ◽

Intraepidermal Nerve Fiber Density ◽

Nerve Fiber Density ◽

Intraepidermal Nerve Fiber

Download Full-text

Schwann cell plasticity regulates neuroblastic tumor cell differentiation via epidermal growth factor-like protein 8

Nature Communications ◽

10.1038/s41467-021-21859-0 ◽

2021 ◽

Vol 12 (1) ◽

Cited By ~ 3

Author(s):

Tamara Weiss ◽

Sabine Taschner-Mandl ◽

Lukas Janker ◽

Andrea Bileck ◽

Fikret Rifatbegovic ◽

...

Keyword(s):

Peripheral Nerve ◽

Primary Repair ◽

Nerve Repair ◽

Peripheral Nerve Regeneration ◽

Neuroblastoma Cells ◽

Tumor Development ◽

Matricellular Protein ◽

Neuroblastic Tumor ◽

Plastic Potential ◽

Neuroblastic Tumors

AbstractAdult Schwann cells (SCs) possess an inherent plastic potential. This plasticity allows SCs to acquire repair-specific functions essential for peripheral nerve regeneration. Here, we investigate whether stromal SCs in benign-behaving peripheral neuroblastic tumors adopt a similar cellular state. We profile ganglioneuromas and neuroblastomas, rich and poor in SC stroma, respectively, and peripheral nerves after injury, rich in repair SCs. Indeed, stromal SCs in ganglioneuromas and repair SCs share the expression of nerve repair-associated genes. Neuroblastoma cells, derived from aggressive tumors, respond to primary repair-related SCs and their secretome with increased neuronal differentiation and reduced proliferation. Within the pool of secreted stromal and repair SC factors, we identify EGFL8, a matricellular protein with so far undescribed function, to act as neuritogen and to rewire cellular signaling by activating kinases involved in neurogenesis. In summary, we report that human SCs undergo a similar adaptive response in two patho-physiologically distinct situations, peripheral nerve injury and tumor development.

Download Full-text

IL-17F depletion accelerates chitosan conduit guided peripheral nerve regeneration

Acta Neuropathologica Communications ◽

10.1186/s40478-021-01227-1 ◽

2021 ◽

Vol 9 (1) ◽

Author(s):

Feixiang Chen ◽

Weihuang Liu ◽

Qiang Zhang ◽

Ping Wu ◽

Ao Xiao ◽

...

Keyword(s):

Bone Marrow ◽

Sciatic Nerve ◽

Peripheral Nerve ◽

Nerve Regeneration ◽

Knockout Mice ◽

Inflammatory Markers ◽

Nerve Repair ◽

Peripheral Nerve Regeneration ◽

Wild Type ◽

Anti Inflammatory

AbstractPeripheral nerve injury is a serious health problem and repairing long nerve deficits remains a clinical challenge nowadays. Nerve guidance conduit (NGC) serves as the most promising alternative therapy strategy to autografts but its repairing efficiency needs improvement. In this study, we investigated whether modulating the immune microenvironment by Interleukin-17F (IL-17F) could promote NGC mediated peripheral nerve repair. Chitosan conduits were used to bridge sciatic nerve defect in IL-17F knockout mice and wild-type mice with autografts as controls. Our data revealed that IL-17F knockout mice had improved functional recovery and axonal regeneration of sciatic nerve bridged by chitosan conduits comparing to the wild-type mice. Notably, IL-17F knockout mice had enhanced anti-inflammatory macrophages in the NGC repairing microenvironment. In vitro data revealed that IL-17F knockout peritoneal and bone marrow derived macrophages had increased anti-inflammatory markers after treatment with the extracts from chitosan conduits, while higher pro-inflammatory markers were detected in the Raw264.7 macrophage cell line, wild-type peritoneal and bone marrow derived macrophages after the same treatment. The biased anti-inflammatory phenotype of macrophages by IL-17F knockout probably contributed to the improved chitosan conduit guided sciatic nerve regeneration. Additionally, IL-17F could enhance pro-inflammatory factors production in Raw264.7 cells and wild-type peritoneal macrophages. Altogether, IL-17F may partially mediate chitosan conduit induced pro-inflammatory polarization of macrophages during nerve repair. These results not only revealed a role of IL-17F in macrophage function, but also provided a unique and promising target, IL-17F, to modulate the microenvironment and enhance the peripheral nerve regeneration.

Download Full-text

The Use of Fiber-Reinforced Scaffolds Cocultured with Schwann Cells and Vascular Endothelial Cells to Repair Rabbit Sciatic Nerve Defect with Vascularization

BioMed Research International ◽

10.1155/2013/362918 ◽

2013 ◽

Vol 2013 ◽

pp. 1-7 ◽

Cited By ~ 4

Author(s):

Hongyang Gao ◽

Yang You ◽

Guoping Zhang ◽

Feng Zhao ◽

Ziyi Sha ◽

...

Keyword(s):

Endothelial Cells ◽

Sciatic Nerve ◽

Nerve Fiber ◽

Schwann Cells ◽

Vascular Endothelial Cells ◽

Neurological Function ◽

Control Group ◽

Vascular Endothelial ◽

Fiber Reinforced ◽

3D Scaffolds

To explore the feasibility of biodegradable fiber-reinforced 3D scaffolds with satisfactory mechanical properties for the repair of long-distance sciatic nerve defect in rabbits and effects of vascularized graft in early stage on the recovery of neurological function, Schwann cells and vascular endothelial cells were cocultured in the fiber-reinforced 3D scaffolds. Experiment group which used prevascularized nerve complex for the repair of sciatic nerve defect and control group which only cultured with Schwann cells were set. The animals in both groups underwent electromyography to show the status of the neurological function recovery at 4, 8, and 16 weeks after the surgery. Sciatic nerve regeneration and myelination were observed under the light microscope and electron microscope. Myelin sheath thickness, axonal diameter, and number of myelinated nerve fiber were quantitatively analyzed using image analysis system. The recovery of foot ulcer, the velocity of nerve conduction, the number of regenerating nerve fiber, and the recovery of ultrastructure were increased in the experimental group than those in the control group. Prevascularized tissue engineered fiber-reinforced 3D scaffolds for the repair of sciatic nerve defects in rabbits can effectively promote the recovery of neurological function.

Download Full-text