Walking Track Analysis Research Articles

Myricetin promotes peripheral nerve regeneration in rat model of sciatic nerve injury via regulation of BDNFAkt/ GSK-3β/mTOR signalling pathway

Purpose: To investigate the effects of myricetin on peripheral nerve regeneration in sciatic nerve crush injury model.Methods: Separate groups of rats were administered myricetin at 25, 50 or 100 mg/kg body weight/day for 2 weeks. Functional recovery following sciatic nerve injury was assessed by foot position and walking track analyses, measurement of mechanical hyperalgesia, and withdrawal reflex latency (WRL).Results: Myricetin treatment resulted in significantly enhanced recovery of sensorimotor functions as evidenced by increased scores in functional analysis tests. Myricetin treatment remarkably elevated brain derived neurotrophic factor (BDNF) expression, and also enhanced activation of Akt and mTORc1, reflecting up-regulation of PI3K/Akt/mTORC1 signalling involved in nerve regeneration.Conclusion: Myricetin enhances functional recovery and nerve regeneration in rats. These findings suggest that myricetin is a potent neuroprotective agent with potential for the management of peripheral nerve injury.Keywords: Glycogen synthase kinase 3β, Mammalian target of rapamycin (mTOR), Myricetin, Nerve regeneration

Protective distal side-to-side neurorrhaphy in proximal nerve injury\u2014an experimental study with rats

BackgroundSide-to-side neurorrhaphy may protect the denervated end organ and preserve the initial connection with proximal stump. We examined the effect of protective side-to-side anastomosis on nerve and end organ regeneration in proximal nerve injury model.MethodsThe left common peroneal nerve of 24 Sprague Dawley rats was proximally transected. In groups B and C, side-to-side neurorrhaphy was performed distally between the peroneal and tibial nerves without (group B) and with (group C) partial donor nerve axotomy inside the epineural window. Group A served as an unprotected control. After 26 weeks, the proximal transection was repaired with end-to-end neurorrhaphy on all animals. Regeneration was followed during 12 weeks with the walk track analysis. Morphometric studies and wet muscle mass calculations were conducted at the end of the follow-up period.ResultsThe results of the walk track analysis were significantly better in groups B and C compared to group A. Groups B and C showed significantly higher wet mass ratios of the tibialis anterior and extensor digitorum longus muscle compared to group A. Group C showed significantly higher morphometric values compared to group A. Group B reached higher values of the fibre count, fibre density, and percentage of the fibre area compared to group A.ConclusionsProtective distal side-to-side neurorrhaphy reduced muscle atrophy and had an improving effect on the morphometric studies and walk track analysis. Distal side-to-side neurorrhaphy does not prevent the regenerating axons to grow from the proximal stump to achieve distal nerve stump.

Axonotmesis-evoked plantar vasodilatation as a novel assessment of C-fiber afferent function after sciatic nerve injury in rats

Quantitative assessment of the recovery of nerve function, especially sensory and autonomic nerve function, remains a challenge in the field of nerve regeneration research. We previously found that neural control of vasomotor activity could be potentially harnessed to evaluate nerve function. In the present study, five different models of left sciatic nerve injury in rats were established: nerve crush injury, nerve transection/suturing, nerve defect/autografting, nerve defect/conduit repair, and nerve defect/non-regeneration. Laser Doppler perfusion imaging was used to analyze blood perfusion of the hind feet. The toe pinch test and walking track analysis were used to assess sensory and motor functions of the rat hind limb, respectively. Transmission electron microscopy was used to observe the density of unmyelinated axons in the injured sciatic nerve. Our results showed that axonotmesis-evoked vasodilatation in the foot 6 months after nerve injury/repair recovered to normal levels in the nerve crush injury group and partially in the other three repair groups; whereas the nerve defect/non-regeneration group exhibited no recovery in vasodilatation. Furthermore, the recovery index of axonotmesis-evoked vasodilatation was positively correlated with toe pinch reflex scores and the density of unmyelinated nerve fibers in the regenerated nerve. As C-fiber afferents are predominantly responsible for dilatation of the superficial vasculature in the glabrous skin in rats, the present findings indicate that axonotmesis-evoked vasodilatation can be used as a novel way to assess C-afferent function recovery after peripheral nerve injury. This study was approved by the Ethics Committee for Laboratory Animals of Nantong University of China (approval No. 20130410-006) on April 10, 2013.

LONG-TERM FUNCTIONAL AND HISTOLOGICAL OUTCOMES OF RAT’S SCIATIC NERVE RECOVERY AFTER SEVERE INJURY AND EXPERIMENTAL TREATMENT WITH SILICON MICROWIRES

Severe peripheral nerve injuries both with traumatic limb amputations constitute a substantial part in all limb injuries especially during armed conflicts.
 For nerve grafting, nerve fibers alignment and fabrication of mind-controlled prosthetic limbs the concept of regenerative nerve implants with peripheral nerve interfacing was proposed. 
 Silicon showed ideal properties not only for microelictronic devices fabrication but also as a favorable growth medium for neurons in vitro.
 This study aimed at evaluating the impact of silicon wires as a part of nerve conduit on motor and sensory recovery simultaneously with distal nerve stump neurotization using rat sciatic nerve injury model.
 Materials and methods. We performed experiments on 33 male Wistar rats that were divided into the following groups: I – sham-operated, II – those which received right sciatic nerve transection with 10 mm gap formation with autoneurografting, III – with 10 mm nerve gap bridged by allogenic decelullarized aorta with 4% carboxymethylcellulose hydrogel, IV – with 10 mm gap bridged by allogenic decelullarized aorta with 4% carboxymethylcellulose hydrogel and aligned p-type boron-ligated silicon wires.
 12 weeks after operation all rats were examined using von Fray filaments and by Walking track analysis method. For histological analysis right sciatic nerves were harvested. Frozen sections were stained with H&E and nitric silver impregnation was performed. At distal nerve stump nerve fibers density was calculated. The obtained results were compared using nonparametric statistical tests.
 Results. The histological analysis revealed differences in tissue reaction patterns between rats from autoneurografting group and conduit grafting groups.
 Histomorphometric data showed that nerve fibers density in rats from group IV was significantly higher than that in rats from group III (aorta+hydrogel grafting), but remained lower than in group II (autoneurografting).
 Morphometric data were supported by functional tests data: rats from group IV demonstrated higher values of SFI than those in group III and same as those in group II.
 Conclusions. According to histological and functional data we can presume that use of silicon wires as a part of hollow conduit improves results of injured sciatic nerve regeneration.

Tacrolimus- and Nerve Growth Factor-Treated Allografts for Neural Tissue Regeneration.

Treatment of injured peripheral nerves, especially long-distance nerve defects, remains a significant challenge in regenerative medicine due to complex biological conditions and a lack of biomaterials for effective nerve reconstruction. Without proper treatment, nerve injury leads to motor and sensory dysfunction. Here, we have developed an efficacious nerve allograft treated with a dual drug containingacrolimus and nerve growth factor to bridge the nerve gap and achieve rapid neural tissue recovery without immunological rejection. The recovery of the structure, activity, and function of rats treated with the dual drug-treated allograft was investigated by walking track analysis and electrophysiological measurement. The sciatic functional index was measured to be -3.0 after a 12-week treatment. The nerve conduction velocity, peak latency, and peak amplitude of the nerve action potentials demonstrate the functional recovery of the nerve. To study the synergistic effect of the dual drug on the growth of neurites, a neural cell hypoxia model was created. The dual drug exhibited a high efficiency in promoting the growth of nerve cells under the nerve injury-induced hypoxic condition. The dual drug could protect the cells against antioxidative damage from hypoxia by the expression of heat shock protein, hypoxia-inducible factor, β-tubulin, and vimentin.

Effect of Azadirachta indica flower extract on functional recovery of sciatic nerve crush injury in rat models of DM.

Chronic hyperglycemia causes nerves to be more susceptible to compression, which often occurs as a result of hyperglycemia-induced oxidative stress. Oxidative stress impairs nerve function and delays nerve recovery. Azadirachta indica, a herb from Thailand, possesses antioxidant and antidiabetic properties. The aim of the present study was therefore to investigate the effect of A. indica flower extract on the functional recovery of a sciatic nerve crush injury in rat models of diabetes mellitus (DM). Male Wistar rats were randomly assigned into seven groups including the control rats, rats with DM subjected to sham surgery and treated with vehicle, and rats with DM subjected to the crush surgery and treated with vehicle or A. indica flower extract at a dose of 250, 500 or 750 mg/kg animal body weight, or with vitamin C. DM was induced using a single intraperitoneal injection of streptozotocin (55 mg/kg animal body weight). Rats subjected to a sciatic nerve crush injury or sham surgery were orally treated with either vehicle, A. indica flower extract or vitamin C for 21 days. Functional recovery was assessed every 3 days using a walking track analysis, foot withdrawal reflex test and rotarod test. At the end of the study, the rats were sacrificed and their left sciatic nerves were harvested in order to determine malondialdehyde levels, superoxide dismutase activity and axon density. The treatment with A. indica flower extract significantly improved functional recovery, especially motor and sensory functions. The extract significantly decreased malondialdehyde levels, and increased superoxide dismutase activity and axon density. The results of the current study indicate that the mechanism underlying the enhanced functional recovery of the sciatic nerve following treatment with A. indica flower extract may be associated with an antioxidative effect. However, further studies are required to confirm the current results.

Comparison of conduit and autograft efficiency in repairing femoral nerve injury in New Zealand rabbits.

Background: Peripheral nerve injuries may affect all age groups and exert devastating impacts on the professional and personal life of the patients. The investigation of nerve regeneration and use of biomaterials and synthetic materials have resulted in advancements in the treatment of peripheral nerve injuries and lesions. Nerve conduits can be used to adjoin the digital sensory nerve spaces of less than 3 cm, especially when the direct tension-free repair of peripheral nerve lesions is not possible. The present study was conducted to evaluate the use of nerve conduits by functional and nonfunctional parameters (i.e. histological study). Methods: This experimental study was conducted on 30 male rabbits. After cutting or crushing the right femoral nerve of the rabbits, they were divided into 3 groups: group 1, with right femoral nerve cut; group 2, with right femoral nerve crushed; and group 3, with right femoral nerve cut using a conduit. The 3 groups were evaluated after 1, 8, and 16 weeks for functional parameters (i.e. walking track analysis). In addition, they were subjected to nonfunctional examination (i.e. histological study) after 16 weeks, then, the results were compared. Results: The 3 groups showed no statistically significant differences in motor recovery in the eighth and 16th weeks (p>0.05). Based on the histological study, group 3 with an end-to-end nerve cutting using a conduit, showed a significantly higher axon count compared to groups 2 and 3 (p<0.05). Conclusion: End-to-end anastomosis using conduit led to axon growth; moreover, comparable functional recovery was observed with end-to-end neurorrhaphy in a rabbit model. Given that the diameter of the nerves and muscles, which might be neurotized in humans, and is much bigger and not comparable to that of the rabbits, it is highly recommended to conduct studies on animals with the larger size, such as primates, to facilitate the generalization of the results to humans.

Novel spiral structured nerve guidance conduits with multichannels and inner longitudinally aligned nanofibers for peripheral nerve regeneration.

Nerve guidance conduits (NGCs) are artificial substitutes for autografts, which serve as the gold standard in treating peripheral nerve injury. A recurring challenge in tissue engineered NGCs is optimizing the cross-sectional surface area to achieve a balance between allowing nerve infiltration while supporting maximum axonal extension from the proximal to distal stump. In this study, we address this issue by investigating the efficacy of an NGC with a higher cross-sectional surface composed of spiral structures and multi-channels, coupled with inner longitudinally aligned nanofibers and protein on aiding nerve repair in critical sized nerve defect. The NGCs were implanted into 15-mm-long rat sciatic nerve injury gaps for 4 weeks. Nerve regeneration was assessed using an established set of assays, including the walking track analysis, electrophysiological testing, pinch reflex assessment, gastrocnemius muscle measurement, and histological assessment. The results indicated that the novel NGC design yielded promising data in encouraging nerve regeneration within a relatively short recovery time. The performance of the novel NGC for nerve regeneration was superior to that of the control nerve conduits with tubular structures. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1410-1419, 2019.

Polypyrrole-coated poly(l-lactic acid-co-ε-caprolactone)/silk fibroin nanofibrous nerve guidance conduit induced nerve regeneration in rat

According to our previous study, polypyrrole (Ppy) possessed good conductivity and non-cytotoxicity. In this study, the surface of electrospun poly(l-lactic acid-co-ε-caprolactone)/silk fibroin (PLCL/SF) was coated with Ppy to fabricate Ppy-coated nerve guidance conduit (NGC). Firstly, the presence of Ppy on the prepared NGC was characterized and confirmed by scanning electron microscopy (SEM), X-ray photoelectron spectroscopic spectra (XPS) and Fourier transforms infrared spectroscopy (FTIR). Subsequently, Ppy-coated NGC was used to repair a 10 mm sciatic nerve gap in vivo. 4 and 12 weeks after implantation, the regenerated nerve tissues on defect sites were removed and sectioned for further evaluation. Histological analysis with hematoxylin-eosin (HE), toluidine blue (TB), and luxol fast blue (LFB) staining indicated that the coated Ppy could promote SCs proliferation in early post-surgery, and enhance myelin formation in later post-surgery. In consideration of immunofluorescence and morphology observation with SEM and TEM, it showed that the nerve regeneration of Ppy-coated NGC group was close to autograft group, which was better than PLCL/SF NGC. In addition, walking track analysis indicated that Ppy-coated NGC group showed a similar performance compared with the autograft group, and significantly better than PLCL/SF NGC group. These promising results showed the potential of Ppy-coated NGC in peripheral nerve regeneration.

Diosgenin improves functional recovery from sciatic crushed nerve injury in rats.

Peripheral nerve injuries are commonly encountered clinical problem and often result in chronic pain and severe functional deficit. Diosgenin is a plant steroidal saponin and has anti-inflammatory and anticancer effects. In the present study, we investigated the effect of diosgenin on functional recovery following sciatic crushed nerve injury in rats. Walking track analysis for the functional recovery which can be quantified with the sciatic function index (SFI) was conducted. Immunohistochemistry for c-Fos in the ventrolateral periaqueductal gray (vlPAG) and paraventricular nucleus (PVN) and western blot for brain-derived neurotrophic factor (BDNF), tyrosine kinase B (TrkB), cyclooxygenase-2 (COX-2), and inducible nitric oxide synthesis (iNOS) in the sciatic nerve were performed. The right sciatic nerve was crushed for 30 sec using a surgical clip. The animals in the diosgenin-treated groups received orally once a day at the respective doses for 7 consecutive days, starting one day after surgery. Sciatic crushed nerve injury showed characteristic gait changes showing decrease of SFI value. Diosgenin treatment increased the SFI value and suppressed nerve injury-induced c-Fos expression in the vlPAG and PVN. Diosgenin treatment inhibited nerve injury-induced increase of BDNF, TrkB, COX-2, and iNOS expressions. It is possible that diosgenin can be used as the new therapeutic agent for pain control and functional recovery following peripheral nerve injury.

Abstract 8.25 HOLEY SILK FIBROIN NERVE CONDUITS IMPROVE VASCULARIZATION OF THE REGENERATING RAT SCIATIC NERVE

INTRODUCTION: The pro-regenerative potential of nerve conduits for bridging large defects in peripheral nerves is inferior to the gold standard, the autologous transplant. This might be due to diminished vascularization and therefore nutrition of the nerve. Conduits with holes could improve vessel ingrowth, yet they might have a negative impact due to fibrotic infiltration and loss of growth factors. We aimed to compare the effects of silk fibroin conduits with or without pores on vascularization of the regenerating nerve. MATERIALS AND METHODS: In 36 male rats the sciatic nerve was transsected creating a gap of 8mm. Defects were bridged with conduits fabricated from silk fibroin, either pored with 50µm holes by laser in a distance of 2 mm (P) or without pores (NP). Nerve regeneration was evaluated by walking track analysis and 7 weeks post surgery by µCT, histology and assessment of wet muscle mass. RESULTS: Ingrowth of vessels was increased in P group compared to NP based on CT-scan (p<0.05). Yet, overall nerve density, assessed by 3 dimensional reconstructions of tubes and nerves showed higher density in NP compared to P (n.s.). Similarly, average weight of M.tibialis anterior was significantly higher in NP compared to P (p<0.05). Analysis of gait revealed comparable results. CONCLUSION: For the first time this study shows that holey silk tubes are able to improve vascularization of the regenerating nerve without causing negative effects on the functional outcome when compared to tubes without pores. 3D CT-scans proved to be a valuable tool for visualization of peripheral nerves and their vascularization. Future preclinical studies are needed to verify the potential of holey conduits to support nerve regeneration in critical size defects.

Tissue-engineered spiral nerve guidance conduit for peripheral nerve regeneration

Recently in peripheral nerve regeneration, preclinical studies have shown that the use of nerve guidance conduits (NGCs) with multiple longitudinally channels and intra-luminal topography enhance the functional outcomes when bridging a nerve gap caused by traumatic injury. These features not only provide guidance cues for regenerating nerve, but also become the essential approaches for developing a novel NGC. In this study, a novel spiral NGC with aligned nanofibers and wrapped with an outer nanofibrous tube was first developed and investigated. Using the common rat sciatic 10-mm nerve defect model, the in vivo study showed that a novel spiral NGC (with and without inner nanofibers) increased the successful rate of nerve regeneration after 6 weeks recovery. Substantial improvements in nerve regeneration were achieved by combining the spiral NGC with inner nanofibers and outer nanofibrous tube, based on the results of walking track analysis, electrophysiology, nerve histological assessment, and gastrocnemius muscle measurement. This demonstrated that the novel spiral NGC with inner aligned nanofibers and wrapped with an outer nanofibrous tube provided a better environment for peripheral nerve regeneration than standard tubular NGCs. Results from this study will benefit for future NGC design to optimize tissue-engineering strategies for peripheral nerve regeneration. Statement of SignificanceWe developed a novel spiral nerve guidance conduit (NGC) with coated aligned nanofibers. The spiral structure increases surface area by 4.5 fold relative to a tubular NGC. Furthermore, the aligned nanofibers was coated on the spiral walls, providing cues for guiding neurite extension. Finally, the outside of spiral NGC was wrapped with randomly nanofibers to enhance mechanical strength that can stabilize the spiral NGC. Our nerve histological data have shown that the spiral NGC had 50% more myelinated axons than a tubular structure for nerve regeneration across a 10 mm gap in a rat sciatic nerve. Results from this study can help further optimize tissue engineering strategies for peripheral nerve repair.

In vivo anti-arthritic and anti-nociceptive effects of ethanol extract of Moringa oleifera leaves on complete Freund's adjuvant (CFA)-induced arthritis in rats

BackgroundThe medicinal uses of plants are in many cases based exclusively on traditional knowledge without enough scientific evidences. Different parts of Moringa oleifera were traditionally used for the treatment of wide variety of ailments including arthritis and joints pain. The present study had been designed to evaluate the anti-arthritic and anti-nociceptive activities of ethanol extract of Moringa leaves, this being the most abundant plant part suitable for commercial mass production of botanical medicinal products. MethodsComplete Freund's adjuvant (CFA)-induced arthritis in rats was used as disease model. CFA-induced inflammatory paw edema, body weight, arthritic index, X-ray radiography, hematological parameters, and walk track and locomotion analysis were all evaluated for the assessment of disease progression. In addition to that, anti-nociceptive activity was examined at different dose levels in both normal and arthritic-induced rats using Eddy's hot plate and tail flick thermal analgesia. ResultsThe analysis of various arthritic assessment parameters used in this study revealed that Moringa extract has a considerable effect in preventing development or ameliorate arthritis disease severity. Moreover, the ethanol extract of Moringa leaves revealed significant anti-nociceptive activity at in both normal and CFA-induced arthritis rats in a dose-dependent manner. ConclusionEthanol extract of Moringa leaves appears to be a really promising as analgesic and arthritis medication, but a larger and more detailed preclinical and clinical studies especially in human is highly recommended.

Split-sciatic nerve surgery: A new microsurgical model in experimental nerve repair

Sciatic experimental surgery in rat often leads to hindlimb autophagy, with considerable ethical and research issues. In this work, the distal part of the sciatic nerve was split following the natural bifurcation between tibial and peroneal branches, before applying regenerative stem cells in a fibrin conduit on the peroneal segment. The new microsurgical model was tested in terms of animal morbidity and consistency of research outcomes, particularly comparing to the standard total sciatic axotomy procedure. After dissection of sciatic the nerve, the tibial and peroneal fibres were split upwards and a total axotomy was performed in the peroneal side. The 1 cm nerve gap between the proximal sciatic nerve and peroneal nerve was crossed using fibrin conduits. The tibial nerve was not included. Experimental groups involved either empty or fibrin conduit seeded with Schwann cell-like differentiated adipose derived stem cells (dASC) (Fib + dASC). Autografts and sham rats were used as controls (total n = 20). At 12 weeks post-implantation, an extensive histomorphometric analysis was performed. Functional aspects of regeneration were analysed by walking track analysis. No major autophagy occurred using the split-sciatic technique. A detailed histomorphometric analysis showed consistent results with previous literature using fibrin conduits in a full sciatic axotomy experimental setting. Walking track analysis reflected the histological regeneration pattern, displaying superior regeneration in both autograft and dASC groups. Split-Sciatic nerve surgery reduced animal morbidity, while being representative of the whole nerve as regeneration outcomes were consistent with previous data obtained on the whole sciatic nerve. The decreased autophagy rate allowed for a more efficient functional evaluation.

End-to-side versus end-to-end neurorrhaphy at the peroneal nerve in rats

To evaluate three different kinds of neurorrhaphy of the peroneal nerve. Eigthy rats were divided into 5 groups. Control: nerve had no intervention. End-to-end (EE): nerve was cut and elongated with a nerve graft with two end-to-end neurorrhaphies. End-to-side (ES): nerve was cut and sutured to the graft with at the lateral side of the nerve. Side-to-end (SE): the nerve was cut and sutured to the graft with end-to-end neurorrhaphy. Denervated: nerve was cut and both endings were buried into the muscle. The evaluation was done by walking track analysis, electrophysiology, body mass, cranial tibial muscle mass, nerve and muscle fibers morphometry. The EE, ES and SE have the same potential of reinnervation. There is no functional or histological difference between these different types of neurorrhaphy.

Knockout of toll-like receptor impairs nerve regeneration after a crush injury

BackgroundToll-like receptors (TLRs) are involved in the initiation of Schwann cell activation and subsequent recruitment of macrophages for clearance of degenerated myelin and neuronal debris after nerve injury. The present study was designed to investigate the regenerative outcome and expression of myelination-related factors in Tlr-knockout mice following a sciatic nerve crush injury.Materials and methodsA standard sciatic nerve crush injury, induced by applying constant pressure to the nerve with a No. 5 jeweler's forceps for 30 s, was performed in C57BL/6, Tlr2−/−, Tlr3−/−, Tlr4−/−, Tlr5−/−, and Tlr7−/− mice. Quantitative histomorphometric analysis of toluidine blue-stained nerve specimens and walking track analysis were performed to evaluate nerve regeneration outcomes. PCR Arrays were used to detect the expression of neurogenesis-related genes of dorsal root ganglia as well as of myelination-related genes of the distal nerve segments.ResultsWorse nerve regeneration after nerve crush injury was found in all Tlr-knockout mice than in C57BL/6 mice. Delayed expression of myelin genes and a different expression pattern of myelination-related neurotrophin genes and transcription factors were found in Tlr-knockout mice in comparison to C57BL/6 mice. In these TLR-mediated pathways, insulin-like growth factor 2 and brain-derived neurotrophic factor, as well as early growth response 2 and N-myc downstream-regulated gene 1, were significantly decreased in the early and late stages, respectively, of nerve regeneration after a crush injury.ConclusionsKnockout of Tlr genes decreases the expression of myelination-related factors and impairs nerve regeneration after a sciatic nerve crush injury.

Development of Nanofiber Sponges-Containing Nerve Guidance Conduit for Peripheral Nerve Regeneration in Vivo.

In the study of hollow nerve guidance conduit (NGC), the dispersion of regenerated axons always confused researchers. To address this problem, filler-containing NGC was prepared, which showed better effect in the application of nerve tissue engineering. In this study, nanofiber sponges with abundant macropores, high porosity, and superior compressive strength were fabricated by electrospinning and freeze-drying. Poly(l-lactic acid-co-ε-caprolactone)/silk fibroin (PLCL/SF) nanofiber sponges were used as filler to prepare three-dimensional nanofiber sponges-containing (NS-containing) NGC. In order to study the effect of fillers for nerve regeneration, hollow NGC was set as control. In vitro cell viability studies indicated that the NS-containing NGC could enhance the proliferation of Schwann cells (SCs) due to the macroporous structure. The results of hematoxylin-eosin (HE) and immunofluorescence staining confirmed that SCs infiltrated into the nanofiber sponges. Subsequently, the NS-containing NGC was implanted in a rat sciatic nerve defect model to evaluate the effect in vivo. NS-containing NGC group performed better in nerve function recovery than hollow NGC group. In consideration of the walking track and triceps weight analysis, NS-containing NGC was close to the autograft group. In addition, histological and morphological analyses with HE and toluidine blue (TB) staining, and transmission electron microscope (TEM) were conducted. Better nerve regeneration was observed on NS-containing NGC group both quantitatively and qualitatively. Furthermore, the results of three indexes' immuno-histochemistry and two indexes' immunofluorescence all indicated good nerve regeneration of NS-containing NGC as well, compared with hollow NGC. The results demonstrated NS-containing NGC had great potential in the application of peripheral nerve repair.

Seeding nerve sutures with minced nerve-graft (MINE-G): a simple method to improve nerve regeneration in rats

Background: The aim of this study was to assess the effect of seeding the distal nerve suture with nerve fragments in rats.Methods: On 20 rats, a 15 mm sciatic nerve defect was reconstructed with a nerve autograft. In the Study Group (10 rats), a minced 1 mm nerve segment was seeded around the nerve suture. In the Control Group (10 rats), a nerve graft alone was used. At 4 and 12 weeks, a walking track analysis with open field test (WTA), hystomorphometry (number of myelinated fibers (n), fiber density (FD) and fiber area (FA) and soleus and gastrocnemius muscle weight ratios (MWR) were evaluated. The Student t-test was used for statistical analysis.Results: At 4 and 12 weeks the Study Group had a significantly higher n and FD (p = .043 and .033). The SMWR was significantly higher in the Study Group at 12 weeks (p = .0207).Conclusions: Seeding the distal nerve suture with nerve fragments increases the number of myelinated fibers, the FD and the SMWR. The technique seems promising and deserves further investigation to clarify the mechanisms involved and its functional effects.

Therapeutic role of Schwann cells and resveratrol or melatonin combination in peripheral nerve injured rat models

Peripheral nerve injuries (PNI) are a frequent and disabling condition which affects 13 to 23 per 100,000 persons each; it remains a major cause of morbidity and social disruption. The aim of this study is to evaluate the possible therapeutic potency of melatonin (100 mg/kg) or resveratrol (100 mg/kg) in enhancing the recovery after Schwann cells transplantation in injured sciatic nerves of albino rats in an attempt to overcome multiple factors that limit axons growth after injury. Recovery of function was analyzed by biochemical quantification of malondialdehyde (MDA) and total antioxidant capacity levels, assessment of the sciatic function index (SFI) based on walk track analysis, measurement of brain derived neurotrophic factor (BDNF) mRNA levels as a relative ratio to glyceraldehyde-3-phosphate dehydrogenase (GAPDH) by using real time polymerase chain reaction (RT-PCR), electrophysiological assessment and histopathological evaluation. The results showed that there were significant improvements in serum MDA and serum total antioxidant capacity levels, the relative expression of BDNF mRNA by RT-PCR, the SFI values, the electrophysiological evaluations and the histopathological examinations after intralesional injection of SCs and its combination with melatonin or resveratrol when compared with the sciatic nerve injured untreated group, but the combined groups (SCS and melatonin and SCs and resveratrol treated groups) were significantly superior to the SCs cells only treated group in most of the assessments. We proved the presence of the transplanted cells in the injured tissue by the immunohistochemistry.

Sciatic nerve regeneration by transplantation of in vitro differentiated nucleus pulposus progenitor cells.

To assess the applicability of mouse intervertebral disc-derived nucleus pulposus (NP) progenitor cells as a cell source for sciatic nerve regeneration. P0-Cre/Floxed-EGFP-transgenic mouse-derived NP progenitor cells were differentiated to Schwann-like cells in conventional induction medium. Schwann-like cells were subsequently transplanted into a mouse model of sciatic nerve transection, and nerve regeneration assessed by immunohistochemistry, electron microscopy and functional walking track analysis and heat stimulus reflex. NP progenitor cells differentiated into Schwann-like cells. Transplantation of these cells promoted myelinated axon formation, morphology restoration and nerve function improvement. NP progenitor cells have the capacity to differentiate into neuronal cells and are candidates for peripheral nerve regeneration therapy.