Acellular Nerve Scaffold Research Articles

Effect of acellular nerve scaffold containing human umbilical cord-derived mesenchymal stem cells on nerve repair and regeneration in rats with sciatic nerve defect.

BackgroundThe aim of the present study was to investigate the effect of acellular nerve scaffold (ANS) containing human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) on nerve repair and regeneration in rats with sciatic nerve defect.MethodsSciatic nerve trunks were removed from 6 female Sprague-Dawley (SD) rats, and ANS was prepared by lyophilization + enzymatic method and divided into A, B, C, D and E groups according to different treatment times. hUC-MSCs were isolated from the collected umbilical cords and cultured, and then ANS-hUC-MSCs complexes were made. The other 24 adult female SD rats were randomly divided into the control, autograft, ANS, and ANS-hUC-MSCs groups, and a rat model of sciatic nerve defect was established. Hematoxylin-eosin (HE) staining, Luxol fast blue (LFB) staining, Masson staining, and scanning electron microscopy were used to observe the morphology and tissue structure of ANS. The performance of ANS was evaluated by mechanical detection, and hydroxyproline (HYP) content was evaluated using a biochemical kit. Flow cytometry was adopted to detect the levels of hUC-MSCs surface antigens CD29, CD44, and CD34, as well as electrophysiological detection and muscle wet weight recovery rate for measuring rat muscle performance.ResultsANS was prepared according to group A method and had good mechanical properties, with less residues of cells and myelin, and higher HYP content, indicating that this scaffold had the best performance. ANS-hUC-MSCs significantly reduced myelin injury in the sciatic nerve, and increased axonal regeneration, effectively improving sciatic nerve injury in rats. In addition, ANS-hUC-MSCs significantly increased compound muscle action potential (CMAP), nerve conduction velocity (NCV), and muscle wet weight, and reduced muscle atrophy.ConclusionsANS containing hUC-MSCs can promote nerve repair and regeneration in rats with sciatic nerve defects.

A comparison of the use of adipose-derived and bone marrow-derived stem cells for peripheral nerve regeneration in vitro and in vivo

BackgroundTo date, it has repeatedly been demonstrated that infusing bone marrow-derived stem cells (BMSCs) into acellular nerve scaffolds can promote and support axon regeneration through a peripheral nerve defect. However, harvesting BMSCs is an invasive and painful process fraught with a low cellular yield.MethodsIn pursuit of alternative stem cell sources, we isolated stem cells from the inguinal subcutaneous adipose tissue of adult Sprague–Dawley rats (adipose-derived stem cells, ADSCs). We used a co-culture system that allows isolated adult mesenchymal stem cells (MSCs) and Schwann cells (SCs) to grow in the same culture medium but without direct cellular contact. We verified SC phenotype in vitro by cell marker analysis and used red fluorescent protein-tagged ADSCs to detect their fate after being injected into a chemically extracted acellular nerve allograft (CEANA). To compare the regenerative effects of CEANA containing either BMSCs or ADSCs with an autograft and CEANA only on the sciatic nerve defect in vivo, we performed histological and functional assessments up to 16 weeks after grafting.ResultsIn vitro, we observed reciprocal beneficial effects of ADSCs and SCs in the ADSC–SC co-culture system. Moreover, ADSCs were able to survive in CEANA for 5 days after in vitro implantation. Sixteen weeks after grafting, all results consistently showed that CEANA infused with BMSCs or ADSCs enhanced injured sciatic nerve repair compared to the acellular CEANA-only treatment. Furthermore, their beneficial effects on sciatic injury regeneration were comparable as histological and functional parameters evaluated showed no statistically significant differences. However, the autograft group was roundly superior to both the BMSC- or ADSC-loaded CEANA groups.ConclusionThe results of the present study show that ADSCs are a viable alternative stem cell source for treating sciatic nerve injury in lieu of BMSCs.

Comparison of SB‐SDS and other decellularization methods for the acellular nerve graft: Biological evaluation and nerve repair in vitro and in vivo

We aimed to compare the performance of acellular nerves prepared by different decellularization methods, screening out the optimal decellularization protocol, repairing the sciatic nerve defects in rats by the allogeneic transplantation, and evaluating the effect of regenerative nerve on the function reconstruction. The Sondell, SB-SDS, TnBP, and the high/low permeation methods were used to decellularize donor nerves. Nerves without any treatment were as the control group. The histological results were evaluated by HE staining and toluidine blue (TB) staining. The proliferation activity of L929 cells was detected by CCK-8 assay. The adhesion of Schwann cells was observed and quantified by SEM. Balb/c mice were used to evaluate the cellular and humoral immunogenicity of the nerve scaffolds. The rat sciatic nerve defect model was applied to observe the repair effect of acellular nerve scaffold in vivo. To SB-SDS group, it remained the original state of the nerves, with no observed nucleus and axons, the neurotoxicity grade detected by CCK-8 being almost 0, and it kept the largest number of Schwann cells adhered to the acellular nerve and the better morphology. Further, it showed that the selected SB-SDS rats acellular nerve scaffold could promote the nerve repair of the rats by HE staining and TB staining. We could conclude that the acellular nerve matrix prepared by the SB-SDS method effectively removes the cellular components in the nerve tissue and retains the main components of the extracellular matrix of the nerve tissue, whose rats decellularized nerve scaffold could promote the sciatic nerve repair better.

Modulation of angiogenic potential of tissue-engineered peripheral nerve by covalent incorporation of heparin and loading with vascular endothelial growth factor

One of prominent shortcomings of nerve tissue engineering for repairing large segmental peripheral nerve defects is the poor ability to support angiogenesis. We report here an experiment to enhance angiogenic properties of tissue-engineered peripheral nerves. Our aim is to achieve this goal by covalently incorporating heparin into acellular nerve scaffolds and by physically immobilizing VEGF to heparin. We evaluated the growth of prevascularized tissue-engineered peripheral nerve in vitro and in vivo in dorsal subcutaneous pockets of nude mice. On histology, the structure of prepared acellular nerve scaffold was maintained, and the scaffolds were void of cellular components. Cellular viability assay revealed no cytotoxic effects. There was no significant difference in mechanical properties between scaffolds and fresh nerves (P > 0.05). Based on these scaffolds, tissue-engineered peripheral nerve with angiogenic potential had been prepared. In conclusion, this vascularized tissue-engineered peripheral nerve can be used as a new kind of material for repairing large segmental nerve defects.

Effects of Dexamethasone on Regeneration Process after Sciatic Nerve Transect and Acellular Scaffold Graft in a Rat Animal Model

Introduction: Peripheral nervous system has an innate regenerative ability, and in severe injuries leading to nerve destruction, repair does not occur spontaneously and medical intervention is required. In this regard, dexamethasone is one of useful drugs prescribed for neurological recovery after spinal cord injury. The objective of the present study was to assess the effect of dexamethasone on functional recovery and histological changes following sciatic nerve transect and regeneration with the acellular scaffolds in male Wistar rats. Materials & Methods: Fifty male Wistar rats were randomly divided into five groups of 10. The groups included: negative control group(left sciatic nerve was transecte), sham-operated group) surgical procedure without the nerve transect ), and experimental groups 1 and 2 (sciatic nerve was transected and regenerated with acellular nerve scaffold) treated with 1 and 2 mg/kg of dexamethasone, respectively. Experimental group 3 (sciatic nerve was transected and regenerated with acellular nerve scaffold) was injected with vehicle. Then, 1 cm of left sciatic nerve was exposed and replaced with a piece of scaffold. Behavioral, electrophysiological, and morphological alterations were evaluated during the experiment. Findings: with dexamethasone in comparison with the control group (P less-than 0.05). Analysis of gastrocnemius muscle mass in groups treated with dexamethasone in comparison with negative control group showed that muscle atrophy was reduced; also the dexamethasone-treated group presented significantly greater nerve fiber, axon diameter, and myelin sheath thickness (P less-than 0.05). Discussion & Conclusions: The results showed that the administration of dexamethasone after sciatic nerve transects and grafting the acellular scaffold increased motor function in a rat animal model.

Xenogeneic acellular nerve scaffolds supplemented with autologous bone marrow-derived stem cells promote axonal outgrowth and remyelination but not nerve function.

Autologous nerves, artificial scaffolds or acellular nerve scaffolds are commonly used in bridging treatment for peripheral nerve defects. Xenogeneic acellular nerve scaffolds and allogeneic cellular nerve scaffolds have the same structural characteristics. Due to the wider source of raw materials, these latter scaffolds have high-potential value for applications. However, whether their heterogeneity will affect nerve regeneration is unknown. The current study evaluated the efficiency of xenogeneic acellular nerve scaffolds (XANs) combined with 5-ethynyl-2'-deoxyuridine (EdU)-labeling of autologous bone marrow-derived stem cells (BMSCs) for repair of a 1.5 cm gap in rat sciatic nerves. XANs from rabbit tibial nerves were prepared, the structure and components of the scaffolds were evaluated after completely removing the cellular components. Animals were divided into four groups based on graft: the simple XAN group, the XAN + BMSC group, the XAN + Media (from BMSC culture) group, and the autograft group. Serological immune tests showed that XANs induce an immune response in the first 2 weeks after transplantation. Moreover, cell tracking revealed that the proportion of EdU+ cells decreased over time, as shown by the measures at 2 days (70%), 4 days (20%), and 8 days (even <3%) postoperatively. Nerve functional analyses revealed that in contrast to the autograft group results, the XAN-BMSC, XAN + Media, and XAN groups did not exhibit good restoration of the sciatic functional index (SFI) or electrophysiological results (the peak action potential amplitudes) 12 weeks, postoperatively. However, the XAN-BMSC and autograft groups demonstrated greater remyelination and increased axon numbers and myelin thickness than the XAN + Media and XAN groups 12 weeks, postoperatively (p < .05). In conclusion, in the early stage of transplantation, XANs induce a certain degree of inflammation. Although the combination of XANs with autologous BMSCs enhanced the number of regenerated axons and the remyelination, the combination did not effectively improve the recovery of nervous motor function. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 3065-3078, 2018.

Development of an apoptosis-assisted decellularization method for maximal preservation of nerve tissue structure

Preservation of tissue structure is often a primary goal when optimizing tissue and organ decellularization methods. Many current protocols nonetheless rely on detergents that aid extraction of cellular components but also damage tissue architecture. It may be more beneficial to leverage an innate cellular process such as apoptosis and promote cell removal without the use of damaging reagents. During apoptosis, a cell detaches from the extracellular matrix, degrades its internal components, and fragments its contents for easier clearance. We have developed a method that leverages this process to achieve tissue decellularization using only mild wash buffers. We have demonstrated that treating peripheral nerve tissue with camptothecin induced both an early marker of apoptosis, cleaved caspase-3 expression, as well as a late stage marker, TUNEL+ DNA fragmentation. Clearance of the cellular components was then achieved in an apoptosis-dependent manner using a gentle wash in hypertonic phosphate buffered saline followed by DNase treatment. This wash paradigm did not significantly affect collagen or glycosaminoglycan content, but it was sufficient to remove any trace of the cytotoxic compound based on conditioned media experiments. The resulting acellular tissue graft was immunogenically tolerated in vivo and exhibited an intact basal lamina microarchitecture mimicking that of native, unprocessed nerve. Hence, ex vivo induction of apoptosis is a promising method to decellularize tissue without the use of harsh reagents while better preserving the benefits of native tissue such as tissue-specific composition and microarchitecture. Statement of SignificanceTissue decellularization has expanded the ability to generate non-immunogenic organ replacements for a broad range of health applications. Current technologies typically rely on the use of harsh agents for clearing cellular debris, altering the tissue structure and potentially diminishing the pro-regenerative effects. We have developed a method for effectively, yet gently, removing cellular components from peripheral nerve tissue while preserving the native tissue architecture. The novelty of this process is in the induction of programmed cell death – or apoptosis – via a general cytotoxin, thereby enabling antigen clearance using only hypertonic wash buffers. The resulting acellular nerve scaffolds are nearly identical to unprocessed tissue on a microscopic level and elicit low immune responses comparable to an isograft negative control in a model of subcutaneous implantation.

Comparison of the Effects of BMSC-derived Schwann Cells and Autologous Schwann Cells on Remyelination Using a Rat Sciatic Nerve Defect Model.

Schwann cells (SCs) are primarily responsible for the formation of myelin sheaths, yet bone marrow mesenchymal stem cell (BMSC)-derived SCs are often used to replace autologous SCs and assist with the repair of peripheral nerve myelin sheaths. In this study, the effects of the two cell types on remyelination were compared during the repair of peripheral nerves. Methods: An acellular nerve scaffold was prepared using the extraction technique. Rat BMSCs and autologous SCs were extracted. BMSCs were induced to differentiate into BMSC-derived SCs (B-dSCs) in vitro. Seed cells (BMSCs, B-dSCs, and autologous SCs) were cocultured with nerve scaffolds (Sca) in vitro. Rats with severed sciatic nerves were used as the animal model. A composite scaffold was used to bridge the broken ends. After surgery, electrophysiology, cell tracking analyses (EdU labeling), immunofluorescence staining (myelin basic protein (MBP)), toluidine blue staining, and transmission electron microscopy were conducted to compare remyelination between the various groups and to evaluate the effects of the seed cells on myelination. One week after transplantation, only a small number of B-dSCs expressed MBP, which was far less than the proportion of MBP-expressing autologous SCs (P<0.01) but was higher than the proportion of BMSCs expressing MBP (P<0.05). Four weeks after surgery, the electrophysiology results (latency time, conductive velocity and amplitude) and various quantitative indicators of remyelination (thickness, distribution, and the number of myelinated fibers) showed that the Sca+B-dSC group was inferior to the Sca+autologous SC group (P<0.05) but was superior to the Sca+BMSC group (P<0.05). Conclusions: Within 4 weeks after surgery, the use of an acellular nerve scaffold combined with B-dSCs promotes remyelination to a certain extent, but the effect is significantly less than that of the scaffold combined with autologous SCs.

Role of Demyelination Efficiency within Acellular Nerve Scaffolds during Nerve Regeneration across Peripheral Defects.

Hudson's optimized chemical processing method is the most commonly used chemical method to prepare acellular nerve scaffolds for the reconstruction of large peripheral nerve defects. However, residual myelin attached to the basal laminar tube has been observed in acellular nerve scaffolds prepared using Hudson's method. Here, we describe a novel method of producing acellular nerve scaffolds that eliminates residual myelin more effectively than Hudson's method through the use of various detergent combinations of sulfobetaine-10, sulfobetaine-16, Triton X-200, sodium deoxycholate, and peracetic acid. In addition, the efficacy of this new scaffold in repairing a 1.5 cm defect in the sciatic nerve of rats was examined. The modified method produced a higher degree of demyelination than Hudson's method, resulting in a minor host immune response in vivo and providing an improved environment for nerve regeneration and, consequently, better functional recovery. A morphological study showed that the number of regenerated axons in the modified group and Hudson group did not differ. However, the autograft and modified groups were more similar in myelin sheath regeneration than the autograft and Hudson groups. These results suggest that the modified method for producing a demyelinated acellular scaffold may aid functional recovery in general after nerve defects.

Decellularized nerve xenograft combined with lycium barbarum polysaccharide for repair of sciatic nerve defect in rats

Objective To explore the effect of lycium barbarum polysaccharide (LBP) and decellularized nerve xenograft combination on nerve regeneration and recovery in repairing rat sciatic nerve defects. Methods Xenogeneic acellular nerve scaffolds were prepared by chemical extraction of tibial nerves from rabbits. A 10 mm left sciatic nerve defect model was created in 90 healthy adult Sprague-Dawley rats who were randomly divided into 5 groups: blank group (n=18), model group (n=18), LBP group (n=18), scaffold group (n=18), LBP and scaffold combination group (n=18). Two weeks after model creation. The sciatic nerve defect in LBP, scaffold and combination groups was repaired either by LBP, by scaffold, or by the LBP xenograft combination. After the second surgery, the rats survived for 4, 8 and 12 weeks, respectively. Gross observation of the scaffold, nerve conduction study to measure sciatic nerve motor nerve conduction velocity (MNCV), and neuromorphometry analysis of the graft were carried out at these three time points. Results Neuroma formation at the proximal nerve end was observed in the model group and LBP group. Adhesion of nerve ends to the surrounding tissue was more severe in the model group than in the LBP group. The sizes of the nerve grafts in the scaffold group and combination group were comparable. Proficient vascularization on the surface of these grafts was seen. There was only slight adhesion to the surrounding tissue. The regenerated nerve fibers in the combination group were denser and better oriented. Motor nerve conduction velocity recovery and the number of myelinated nerve fibers in the grafts were measured at 12 weeks postoperatively for blank, model, LBP, scaffold and combination groups, respectively. The differences among the groups were significant (P<0.05). Conclusion The combination of LBP and xenogeneic acellular nerve scaffold enhances peripheral nerve regeneration and recovery when used to repair nerve defects. Key words: Sciatic nerve; Nerve regeneration; Xenogeneic acellular nerve scaffold; Lycium barbarum polysaccharide

Co-Graft of Bone Marrow Stromal Cells and Schwann Cells Into Acellular Nerve Scaffold for Sciatic Nerve Regeneration in Rats

The conventional strategy for bridging large nerve defects, namely nerve autograft transplantation, results in donor-site morbidity. This detrimental consequence currently drives the search for alternatives. The authors used an acellular nerve scaffold filled with bone marrow stromal cells (BMSCs) and Schwann cells (SCs) to enhance regeneration. In 60 adult rats, a 10-mm sciatic nerve defect was bridged with a nerve autograft (positive control), an acellular nerve scaffold (negative control), an acellular nerve scaffold with BMSCs (group I), an acellular nerve scaffold with SCs (group II), or an acellular nerve scaffold with BMSCs plus SCs (group III). After regenerating for 4 and 16 weeks after surgery, nerve regeneration was functionally assessed by a walking track analysis. The compound muscle action potential (CMAP), nerve conduction velocity (NCV) along regenerated sciatic nerves, and gastrocnemius muscle index (GMI) were recorded to assess the conduction properties and extent of denervation atrophy. The number of retrograde-labeled lumbar motor neurons identified by fluorescent dyes in the ipsilateral ventral horn and spinal ganglia were counted to assess the regeneration of axons. After 4 and 16 weeks, improvement of the sciatic function index of the sciatic nerve in group III was statistically greater than that of the negative control group, group I, and group II. At 16 weeks after grafting, obvious differences in the GMI were found among groups. Group III had a statistical increase in GMI compared with the negative control group, group I, and group II. The CMAP and NCV measurements showed comparable results at 16 weeks after reconstruction: group III had statistically better results compared with the negative control group, group I, and group II. Fluorescent dye analysis of the retrograde-labeled lumbar motoneurons in the ipsilateral ventral horn and spinal ganglia showed that more motor neurons in the ipsilateral ventral horns and spinal ganglia were labeled in group III than in the negative control group, group I, and group II at 16 weeks after the operation. All results consistently showed that when BMSCs and SCs were loaded together in an acellular nerve scaffold, functional recovery of the sciatic nerve was enhanced to the greatest degree among the 3 cell-treated groups; furthermore, its beneficial effect on sciatic injury regeneration was similar to the autograft group, although it never exceeded it. This study is a step forward in the search for an alternative to the nerve autograft because it showed that co-grafting of BMSCs and SCs into an acellular nerve scaffold enhanced sciatic nerve functional recovery in rats. Its beneficial effect on sciatic injury regeneration was similar to the autograft group, although it did not exceed it.

An acellular nerve scaffold fabricated by hypotonic buffer combined with freeze-drying

Objective To explore the feasibility of fabricating an acellular nerve scaffold by the technique of hypotonic buffer combined with freeze-drying.Methods Fresh rabbit sciatic nerves deprived of surrounding connective tissue were prepared and divided into 3 groups:non-treatment group where the fresh nerve received no treatment,conventional group where the acellularization process was completed by Hudsom method,and modified group where the acellularization process was completed by the technique of hypotonic buffer combined with freeze-drying.After the acellularization process,the scaffolds were investigated by histological staining,SEM observation,interval porosity and void diameter measurement,biomechanical test,and biocompatibility analysis.MTT assay was done to access the cytotoxicity of scaffold leaching liquor.Rabbit adipose-derived stem cells (ADSCs) were isolated and seeded into the modified scaffold.Cell viability was analyzed using HE staining and dead/live assay.Results Compared with the non-treatment and conventional groups,in the modified group the blue-stained nucleoli disappeared and only the basement membrane was observed of Schwann cells which were loosely disposed in waves.Laminin immunofluorescence was positive in all groups.Compared with the non-treatment group,in the acellular nerve scaffolds in the conventional and modified groups,the myelin sheaths,axons and cells all disappeared and the vessels of basilar membrane paralleled in longitudinal sections,but the structure of the modified scaffold was looser.The interval porosity (49.34％ ± 9.76％) and void diameter (17.61 μm ± 3.69 μm) of the modified scaffold were significantly larger than those (34.50％ ± 7.26％ and 11.96 μm ± 3.10 μm) of the conventional scaffold (P ＜ 0.05).The differences regarding biomechanical properties were not statistically significant between the 3 groups (P ＞ 0.05).MTT showed no significant differences in the effects of leaching liquor and control culture medium of different concentrations on the cellular proliferation (P ＞ 0.05).HE staining and dead/live assay showed fine cellular viability in the modified scaffold.Conclusion The improved acellular nerve scaffold fabricated by the technique of hypotonic buffer combined with freeze-drying may be a proper cell-carrier candidate for nerve tissue engineering,because it is characterized by good pore diameter and porosity,appropriate biomechanical character,non-toxicity and good biocompatibility. Key words: Tissue engineering; Tissue scaffolds; Biomechanics; Freeze-drying; Hypotonic buffer

Comparison of morphology and biocompatibility of acellular nerve scaffolds processed by different chemical methods

To investigate the morphological differences among acellular rat nerve scaffolds processed by different chemical methods and compare the biocompatibility between rat nerve grafts processed by different chemical methods and rat adipose-derived stem cells in vitro. Acellular rat sciatic nerve scaffolds processed by two different chemical methods (the Sondell method and the optimized method) and normal rat sciatic nerves were used as control. The structure and components of nerve scaffold were observed under microscopy, the degrees of decellularization and demyelination of nerve scaffold and integrity of nerve fiber tubes were assessed. The rat adipose-derived stem cells growth and adherence on scaffold were studied by scanning electron microscopy, the activity and adhesive ratio of rat adipose-derived stem cells in the nerve scaffold were compared. The basal lamina tubes and the extracellular matrix in the epineurium and perineurium in the nerve graft of optimized method were better preserved than the nerve graft of the Sondell method. After co-cultured with scaffolds, the difference of cell activity between three groups (two cell-scaffold combinations and control group) at the same observation time were not statistically significant (P > 0.05),the adhesive ratio of rat adipose-derived stem cells in the scaffold of the optimized method was better than that of the Sondell method. The scaffold of the optimized method is more effective than the scaffold of the Sondell method for peripheral nerve tissue engineering.

Combination of acellular nerve graft and schwann cells-like cells for rat sciatic nerve regeneration.

Objective. To investigate the effect of tissue engineering nerve on repair of rat sciatic nerve defect. Methods. Forty-five rats with defective sciatic nerve were randomly divided into three groups. Rats in group A were repaired by acellular nerve grafts only. Rats in group B were repaired by tissue engineering nerve. In group C, rats were repaired by autogenous nerve grafts. After six and twelve weeks, sciatic nerve functional index (SFI), neural electrophysiology (NEP), histological and transmission electron microscope observation, recovery ratio of wet weight of gastrocnemius muscle, regenerated myelinated nerve fibers number, nerve fiber diameter, and thickness of the myelin sheath were measured to assess the effect. Results. After six and twelve weeks, the recovery ratio of SFI and wet weight of gastrocnemius muscle, NEP, and the result of regenerated myelinated nerve fibers in groups B and C were superior to that of group A (P < 0.05), and the difference between groups B and C was not statistically significant (P > 0.05). Conclusion. The tissue engineering nerve composed of acellular allogenic nerve scaffold and Schwann cells-like cells can effectively repair the nerve defect in rats and its effect was similar to that of the autogenous nerve grafts.

Improved preparation of acellular nerve scaffold and application of PKH26 fluorescent labeling combined with in vivo fluorescent imaging system in nerve tissue engineering

Acellular nerve scaffold has been widely used for peripheral nerve defect treatment. However, the structure of traditional acellular nerve scaffold is dense; the interval porosity and void diameter are too small to meet the requirement of cell seeding, which limits the application. This study was designed to prepare a novel acellular nerve scaffold by the technique of hypotonic buffer combined with freeze-drying, and use PKH26 fluorescent labeling combined with in vivo fluorescent imaging system to evaluate the biological behavior of tissue-engineered nerve in vitro and in vivo. According to light and electron microscopy, the scaffold, which microarchitecture was similar to the fibrous framework of rabbit sciatic nerves, was cell-free and rich in laminin, collagen I and collagen III. In vitro experiment showed that the novel acellular nerve scaffold could provide a 3-D environment to support the attachment, proliferation and migration of adipose-derived stem cells (ADSCs). ADSCs labeled with fluorescent dye PKH26 were then seeded on scaffolds and implanted subcutaneously into nude mice. After 4 weeks, nerve-like tissue rounded by vessels formed. Cells in the tissue seemed to confirm that they originated from the labeled ADSCs, as confirmed by in vivo fluorescent imaging. In conclusion, the prepared novel acellular nerve scaffold can be used as a new kind of nerve scaffold material, which is more conducible for seeding cells; And PKH26 fluorescent labeling and in vivo fluorescent imaging can be useful for cell tracking and analyzing cell-scaffold constructs in vivo.

Component analysis of a natural acellular sciatic nerve scaffold

Component analysis of a natural acellular sciatic nerve scaffold

Research on nerve regeneration and recovery in xenogeneic acellular nerve scaffold graft through co-application of NGF and GM1

Research on nerve regeneration and recovery in xenogeneic acellular nerve scaffold graft through co-application of NGF and GM₁

Study on repair of sciatic nerve lesions using acellular nerves implanted with adipose tissue-derived stromal cells

Objective To evaluate the effectiveness of using adipose-derived stromal cells (ADSCs)into a tissue-engineered peripheral nerve on bridging sciatic nerve gaps.Methods Forty-eight F344 female rats weighing 200 - 220 g were randomly divided into 6 groups of nerve grafting to repair 15 mm long asiatic nerve lesions,with 8 mrs in each group.Group A:ADSCs-laden acellular nerves;group B:differentiated ADSCs-laden acellular nerves;group C:Schwann cells-laden acellular nerves;group D:acellular nerves without cells;group E:autografts;group F:nonimplanted grafts.The effects were evaluated in terms of electrophysiulogy,Fluorogold retrograde tracing,histology and tracking studies.Results At 12 weeks after surgery,there was no graft bridging nerve gap in nonimplanted grafts.All the examinations of group A and B were better than group D,respectively (P＜0.05 or P＜0.01).But there were no statistically significant differences among group A,B,C,and D (P＞0.05).Conclusion ADSCs and differentiated ADSCs could promote nerve regeneration when used as seed cells to build tissue-engineered peripheral nerves with acellular nerve scaffolds. Key words: Adipose derived stromal cells; Schwann cells; Tissue engineering; Nerve graft; Microsurgery

Cavernous nerve regeneration using acellular nerve grafts

The restoration of erectile function following complete transection of nerve tissue during surgery remains challenging. Recently, graft procedures using sural nerve grafts during radical prostatectomy have had favorable outcomes, and this has rekindled interest in the applications of neural repair in a urologic setting. Although nerve repair using autologous donor graft is the gold standard of treatment currently, donor nerve availability and the associated donor site morbidity remain a problem. In this study, we investigated whether an "off-the-shelf" acellular nerve graft would serve as a viable substitute. We examined the capacity of acellular nerve scaffolds to facilitate the regeneration of cavernous nerve in a rodent model. Acellular nerve matrices, processed from donor rat corporal nerves, were interposed across nerve gaps. A total of 80 adult male Sprague-Dawley rats were divided into four groups. A 0.5-cm segment of cavernosal nerve was excised bilaterally in three of the four groups. In the first group, acellular nerve segments were inserted bilaterally at the defect site. The second group underwent autologous genitofemoral nerve grafts at the same site, and the third group had no repair. The fourth group underwent a sham procedure. Serial cavernosal nerve function assessment was performed using electromyography (EMG) at 1 and 3 months following initial surgery. Histological and immunocytochemical analyses were performed to identify the extent of nerve regeneration. Animals implanted with acellular nerve grafts demonstrated a significant recovery in erectile function when compared with the group that received no repair, both at 1 and 3 months. EMG of the acellular nerve grafts demonstrated adequate intracavernosal pressures by 3 months (87.6% of the normal non-injured nerves). Histologically, the retrieved regenerated nerve grafts demonstrated the presence of host cell infiltration within the nerve sheaths. Immunohistochemically, antibodies specific to axons and Schwann cells demonstrated an increase in nerve regeneration across the grafts over time. No organized nerve regeneration was observed when the cavernous nerve was not repaired. These findings show that the use of nerve guidance channel systems allow for accelerated and precise cavernosal nerve regeneration. Acellular nerve grafts represent a viable alternative to fresh autologous grafts in a rodent model of erectile dysfunction.