Regeneration Of Nerve Fibers Research Articles

Polylactic-co-glycolic acid microspheres containing three neurotrophic factors promote sciatic nerve repair after injury.

A variety of neurotrophic factors have been shown to repair the damaged peripheral nerve. However, in clinical practice, nerve growth factor, neurotrophin-3 and brain-derived neurotrophic factor are all peptides or proteins that may be rapidly deactivated at the focal injury site; their local effective concentration time following a single medication cannot meet the required time for spinal axons to regenerate and cross the glial scar. In this study, we produced polymer sustained-release microspheres based on the polylactic-co-glycolic acid copolymer; the microspheres at 300-μm diameter contained nerve growth factor, neurotrophin-3 and brain-derived neurotrophic factor. Six microspheres were longitudinally implanted into the sciatic nerve at the anastomosis site, serving as the experimental group; while the sciatic nerve in the control group was subjected to the end-to-end anastomosis using 10/0 suture thread. At 6 weeks after implantation, the lower limb activity, weight of triceps surae muscle, sciatic nerve conduction velocity and the maximum amplitude were obviously better in the experimental group than in the control group. Compared with the control group, more regenerating nerve fibers were observed and distributed in a dense and ordered manner with thicker myelin sheaths in the experimental group. More angiogenesis was also visible. Experimental findings indicate that polylactic-co-glycolic acid composite microspheres containing nerve growth factor, neurotrophin-3 and brain-derived neurotrophic factor can promote the restoration of sciatic nerve in rats after injury.

Biological conduit small gap sleeve bridging method for peripheral nerve injury: regeneration law of nerve fibers in the conduit.

The clinical effects of 2-mm small gap sleeve bridging of the biological conduit to repair peripheral nerve injury are better than in the traditional epineurium suture, so it is possible to replace the epineurium suture in the treatment of peripheral nerve injury. This study sought to identify the regeneration law of nerve fibers in the biological conduit. A nerve regeneration chamber was constructed in models of sciatic nerve injury using 2-mm small gap sleeve bridging of a biodegradable biological conduit. The results showed that the biological conduit had good histocompatibility. Tissue and cell apoptosis in the conduit apparently lessened, and regenerating nerve fibers were common. The degeneration regeneration law of Schwann cells and axons in the conduit was quite different from that in traditional epineurium suture. During the prime period for nerve fiber regeneration (2–8 weeks), the number of Schwann cells and nerve fibers was higher in both proximal and distal ends, and the effects of the small gap sleeve bridging method were better than those of the traditional epineurium suture. The above results provide an objective and reliable theoretical basis for the clinical application of the biological conduit small gap sleeve bridging method to repair peripheral nerve injury.

Evaluation of biodegradable electric conductive tube-guides and mesenchymal stem cells.

To study the therapeutic effect of three tube-guides with electrical conductivity associated to mesenchymal stem cells (MSCs) on neuro-muscular regeneration after neurotmesis. Rats with 10-mm gap nerve injury were tested using polyvinyl alcohol (PVA), PVA-carbon nanotubes (CNTs) and MSCs, and PVA-polypyrrole (PPy). The regenerated nerves and tibialis anterior muscles were processed for stereological studies after 20 wk. The functional recovery was assessed serially for gait biomechanical analysis, by extensor postural thrust, sciatic functional index and static sciatic functional index (SSI), and by withdrawal reflex latency (WRL). In vitro studies included cytocompatibility, flow cytometry, reverse transcriptase polymerase chain reaction and karyotype analysis of the MSCs. Histopathology of lung, liver, kidneys, and regional lymph nodes ensured the biomaterials biocompatibility. SSI remained negative throughout and independently from treatment. Differences between treted groups in the severity of changes in WRL existed, showing a faster regeneration for PVA-CNTs-MSCs (P < 0.05). At toe-off, less acute ankle joint angles were seen for PVA-CNTs-MSCs group (P = 0.051) suggesting improved ankle muscles function during the push off phase of the gait cycle. In PVA-PPy and PVA-CNTs groups, there was a 25% and 42% increase of average fiber area and a 13% and 21% increase of the "minimal Feret's diameter" respectively. Stereological analysis disclosed a significantly (P < 0.05) increased myelin thickness (M), ratio myelin thickness/axon diameter (M/d) and ratio axon diameter/fiber diameter (d/D; g-ratio) in PVA-CNT-MSCs group (P < 0.05). Results revealed that treatment with MSCs and PVA-CNTs tube-guides induced better nerve fiber regeneration. Functional and kinematics analysis revealed positive synergistic effects brought by MSCs and PVA-CNTs. The PVA-CNTs and PVA-PPy are promising scaffolds with electric conductive properties, bio- and cytocompatible that might prevent the secondary neurogenic muscular atrophy by improving the reestablishment of the neuro-muscular junction.

Combination of edaravone and neural stem cell transplantation repairs injured spinal cord in rats.

This study sought to observe the effect of the combination of edaravone and neural stem cell (NSC) transplantation on the repair of complete spinal cord transection in rats. Eighty adult female Sprague-Dawley (SD) rats were used to establish the injury model of complete spinal cord transection at T9. Animals were divided randomly into four groups (N = 20 each): control, edaravone, transplantation, and edaravone + transplantation. The recovery of spinal function was evaluated with the Basso, Beattie, Bresnahan (BBB) rating scale on days 1, 3, and 7 each week after the surgery. After 8 weeks, the BBB scores of the control, edaravone, transplantation, and combination groups were 4.21 ± 0.11, 8.46 ± 0.1, 8.54 ± 0.13, and 11.21 ± 0.14, respectively. At 8 weeks after surgery, the spinal cord was collected; the survival and transportation of transplanted cells were observed with PKH-26 labeling, and the regeneration and distribution of spinal nerve fibers with fluorescent-gold (FG) retrograde tracing. Five rats died due to the injury. PKH-26-labeled NSCs had migrated into the spinal cord. A few intact nerve fibers and pyramidal neurons passed the injured area in the transplantation and combination groups. The numbers of PKH-26-labeled cells and FG-labeled nerve fibers were in the order: combination group > edaravone group and transplantation group > control group (P < 0.05 for each). Thus, edaravone can enhance the survival and differentiation of NSCs in injured areas; edaravone with NSC transplantation can improve the effectiveness of spinal cord injury repair in rats.

Pulsed electrical stimulation protects neurons in the dorsal root and anterior horn of the spinal cord after peripheral nerve injury.

Most studies on peripheral nerve injury have focused on repair at the site of injury, but very few have examined the effects of repair strategies on the more proximal neuronal cell bodies. In this study, an approximately 10-mm-long nerve segment from the ischial tuberosity in the rat was transected and its proximal and distal ends were inverted and sutured. The spinal cord was subjected to pulsed electrical stimulation at T10 and L3, at a current of 6.5 mA and a stimulation frequency of 15 Hz, 15 minutes per session, twice a day for 56 days. After pulsed electrical stimulation, the number of neurons in the dorsal root ganglion and anterior horn was increased in rats with sciatic nerve injury. The number of myelinated nerve fibers was increased in the sciatic nerve. The ultrastructure of neurons in the dorsal root ganglion and spinal cord was noticeably improved. Conduction velocity of the sciatic nerve was also increased. These results show that pulsed electrical stimulation protects sensory neurons in the dorsal root ganglia as well as motor neurons in the anterior horn of the spinal cord after peripheral nerve injury, and that it promotes the regeneration of peripheral nerve fibers.

Edaravone combined with Schwann cell transplantation may repair spinal cord injury in rats.

Edaravone has been shown to delay neuronal apoptosis, thereby improving nerve function and the microenvironment after spinal cord injury. Edaravone can provide a favorable environment for the treatment of spinal cord injury using Schwann cell transplantation. This study used rat models of complete spinal cord transection at T9. Six hours later, Schwann cells were transplanted in the head and tail ends of the injury site. Simultaneously, edaravone was injected through the caudal vein. Eight weeks later, the PKH-26-labeled Schwann cells had survived and migrated to the center of the spinal cord injury region in rats after combined treatment with edaravone and Schwann cells. Moreover, the number of PKH-26-labeled Schwann cells in the rat spinal cord was more than that in rats undergoing Schwann cell transplantation alone or rats without any treatment. Horseradish peroxidase retrograde tracing revealed that the number of horseradish peroxidase-positive nerve fibers was greater in rats treated with edaravone combined withSchwann cells than in rats with Schwann cell transplantation alone. The results demonstrated that lower extremity motor function and neurophysiological function were better in rats treated with edaravone and Schwann cells than in rats with Schwann cell transplantation only. These data confirmed that Schwann cell transplantation combined with edaravone injection promoted the regeneration of nerve fibers of rats with spinal cord injury and improved neurological function.

Effect of neural stem cell transplantation combined with erythropoietin injection on axon regeneration in adult rats with transected spinal cord injury.

We investigated the effect of neural stem cells (NSC) and erythropoietin (EPO) on axon regeneration in adult rats with transected spinal cord injury, and provided an experimental basis for clinical treatment. Forty Wistar rats with T10-transected spinal cord injury were randomly divided into four groups of ten rats: a control group (group A), an NSC-transplant group (group B), an NSC-transplant and EPO group (group C), and an EPO group (group D). Biotinylated dextran amines (BDA) anterograde corticospinal cord neuronal tracing and Fluoro-Gold (FG) retrograde tracing were carried out at the 8th week after operation to observe the regeneration of nerve fibers. The Basso, Beattie, and Bresnahan (BBB) locomotor score was used to evaluate restoration. 1) BDA and FG immunofluorescence staining: in group C, a large number of regenerated axons were observed and some penetrated the injured area. In group B, only a small number of regenerated axons were observed and none penetrated the injured area. In group D, only sporadic regenerated nerve fibers were observed occasionally, while in group A, no axonal regeneration was observed. In group C, a small number of cones and axons emitted yellow fluorescence, and no FG-labeled cells were observed in the other groups. 2) The BBB scores for group C were higher than those for the other groups, and the differences were statistically significance (P < 0.05). NSC transplantation combined with EPO intraperitoneal injection may benefit axon regeneration in rats with transected spinal cord injury, and accelerate the functional recovery of the hindlimb locomotor.

Ultrastructural evaluation of recovery of injured sciatic nerve at autografting of it’s large defects in rats: Experimental study

Introduction . The purpose of the experimental study was ultrastructural and morphometric evaluation of reconstruction efficacy at nerve’s large defects, comparison of efficacy of combined autografting and stimulation for sciatic nerve recovery. Materials and methods . For sciatic nerve’s recovery evaluation we studied it’s distal segment using electron microscopy. Results . Autografting allows to reconstruct large defects of sciatic nerve but it is characterized by low regeneration efficacy and glial and connective scars forming in areas of neurorrhaphy. After 30 days only 47% nerve fibers regenerated. Platelet rich plasma (PRP), NGF and thyroxine stimulate nerve fibers regeneration in distal segment of the nerve. Efficacy of regeneration at PRP using was 85%, thyroxine — 66%, NGF — 65%. Conclusions . Autografting is the «gold standard» for reconstruction of old and large defects of peripheral nerve’s. NGF, thyroxine and PRP stimulate recovery processes after reconstruction: NGF activates myelin fibers regeneration, thyroxine — stimulates myelination, PRP — activates regeneration of unmyelinated nerve fibers and axon – glial interaction.

Morphological Proof of nerve regeneration after long-term defects of rat sciatic nerves

Unsatisfactory efficacy of clinical cure for long-term delayed injuries and other disadvantages such as the low regeneration rate and speed of axotomized neurons and the questionable reinnervation ability of atrophic target organ lead to inaction to the long-term delayed injuries. Here we attempted to use autologous nerve to bridge a long-term delayed 10-mm defect in SD rats based on some previous positive messages of basic and clinical research. In this study, for experimental groups, the rat sciatic nerve had been transected leaving a 10-mm defect, which was maintained for 3 or 6 months before implantation with the autologous graft. The non-grafted animals served as negative control. Measuring with electrophysiological and histological techniques, we find: (1) A number of long-term axotomized neurons survived and sustained certain degree of axonal regenerative capacity; (2) A few denervated Schwann cells survived and retained their ability to provide trophic support and myelinate axons in at least 6 months; (3) the chronically denervated muscle can partially be reinnervated by regenerated axons. But the quantity and the quality of the regenerated nerve fibers and the reinnervated muscle fibers were all poor. Thus these observations provide new positive morphological proof of nerve regeneration after long-term defects and further studies will be needed to increase the survival rate and the regenerative speed of long-term chronic axotomized neurons, enhance the support provided by denervated distal stumps and protect the target muscle.

Desmoplakin is involved in organization of an adhesion complex in peripheral nerve regeneration after injury

Peripheral nerves have the unique capability to regenerate after injury. Insights into regeneration of peripheral nerves after injury may have implications for neurodegenerative diseases of the nervous system. In this study, we analyzed the expression and function of desmoplakin in peripheral nerve regeneration. Desmoplakin was upregulated in spinal cord motoneurons after sciatic nerve injury. Conditional ablation of desmoplakin in motoneurons demonstrated that desmoplakin is necessary for normal motor regeneration. SiRNA and desmoplakin deletion-constructs revealed a role of desmoplakin in neurite extension in vitro. A complex of N-cadherin, plakoglobin, desmoplakin and vimentin was shown in motoneuronal cell cultures and peripheral nerves after injury in vivo. Motor nerve fiber regeneration and localization of N-cadherin and vimentin to axonal growth fronts were reduced in conditionally desmoplakin-ablated mice.These data indicate a function of desmoplakin in motor nerve regeneration by linking N-cadherin to intermediate filaments in regenerating motor axons.

Improved peripheral nerve regeneration using acellular nerve allografts loaded with platelet-rich plasma.

Acellular nerve allografts (ANAs) behave in a similar manner to autografts in supporting axonal regeneration in the repair of short peripheral nerve defects but fail in larger defects. The objective of this article is to evaluate the effect of ANA supplemented with platelet-rich plasma (PRP) to improve nerve regeneration after surgical repair and to discuss the mechanisms that underlie this approach. Autologous PRP was obtained from rats by double-step centrifugation and was characterized by determining platelet numbers and the release of growth factors. Forty-eight Sprague-Dawley rats were randomly divided into 4 groups (12/group), identified as autograft, ANA, ANA loaded with PRP (ANA+PRP), and ANA loaded with platelet-poor plasma (PPP, ANA+PPP). All grafts were implanted to bridge long-gap (15 mm) sciatic nerve defects. We found that PRP with a high platelet concentration exhibited a sustained release of growth factors. Twelve weeks after surgery, the autograft group displayed the highest level of reinnervation, followed by the ANA+PRP group. The ANA+PRP group showed a better electrophysiology response for amplitude and conduction velocity than the ANA and ANA+PPP groups. Based on histological evaluation, the ANA+PRP and autograft groups had higher numbers of regenerating nerve fibers. Quantitative real-time polymerase chain reaction (qRT-PCR) demonstrated that PRP boosted expression of neurotrophins in the regenerated nerves. Moreover, the ANA+PRP and autograft groups showed excellent physiological outcomes in terms of the prevention of muscle atrophy. In conclusion, ANAs loaded with PRP as tissue-engineered scaffolds can enhance nerve regeneration and functional recovery after the repair of large nerve gaps nearly as well as autografts.

Effect of allotransplants containing dissociated cells of rat embryonic spinal cord on nerve fiber regeneration in a recipient.

Regeneration of nerve fibers in rat sciatic nerve was quantitatively assessed after injury (ligation) and injection of dissociated cells derived from embryonic spinal cord. A suspension of dissociated spinal cord cells from rat embryos was transplanted under the perineurium of a nerve trunk. After transplantation, bromodeoxyuridine-labeled precursor cells survived and retained the label for more than 2 months; some of these cells differentiated into NeuNpositive neurons. Analysis of semithin sections of the distal nerve segment from the recipient taken at a distance of 0.5 cm from the site of injury showed that transplantation of dissociated cells of embryonic spinal cord led to an increase in the number of myelinated nerve fibers in the recipient nerve.

Study of effect of embryonic anlage allografts of the rat spinal cord on growth of regenerating fibers of the recipient nerve

A comparative study of the effect of tissue and suspension allografts of an embryonic spinal cord on regeneration of nerve fibers of impaired (by application of a ligature) sciatic nerve in rats was conducted. It was demonstrated that unlike tissue grafts that reach a large volume 21 and 60 days after transplantation, suspension grafts do not inhibit the growth of axons of the recipient to the periphery. It was established that introduction of a suspension of dissociated cells of the spinal cord embryonic anlages (but not fragments of these anlages) into the impaired sciatic nerve in rats results in an increase in the amount of myelinated regenerating nerve fibers of the recipient 60 days after the operation.

Are we sure to count myelinated fibers entirely? Calibration of a stereological study

Peripheral nerves are subject to many different types of injuries frequently and these injuries may result in partial or total loss of motor and sensory functions. In contrast to the central nervous system, peripheral nervous system are able to undergo spontaneous regeneration. But clinical and experimental studies show that this regeneration is mostly not satisfactory. One of the most important neuropathological indicators of nerve regeneration is quantitative estimation of myelinated axons. Quantitative estimation of the total number of myelinated fibers can be obtained both by light microscopy (LM) and electron microscopy (EM) and depends on using appropriate sampling strategy. In this study, we made a direct comparison between LM and EM estimation of myelinated nerve fibers. Ten female Wistar albino rats were divided into two experimental groups; control group (n=5) and gap group (n=5). In the gap group, 5 mm right sciatic nerve segment of rats were resected to form a gap. Proximal and distal nerve stumps were surrounded by collagen membrane following resection. In the control group, rats received neither any operation nor any treatment. Rats were sacrificed at 12 week after surgery. Nerve samples were embedded in resin. Semi and ultra thin sections (of 1 μm and 100 nm thickness, respectively) were cut and stained with 1% toluidine blue (for LM) and uranyl acetate-lead citrate (for EM). Histological assessment of myelinated fibers was performed with both LM and EM using unbiased stereological counting techniques. There was a significant difference in the total number of myelinated nerve fibers between LM and EM examinations in terms of the both pure and regenerating axons. This difference is probably related to different magnification capacities in LM and EM. LM causes to underestimates as a result of possessing very small myelinated fibers, which are only detectable with EM. According to our results it may be concluded that the combination of both light and electron microscopical results is essential especially in revealing regenerating nerve fibers since very small myelinated fibers can not be distinguishable with LM.

Pure sensory Guillain-Barré syndrome: A case report and review of the literature.

Sensory Guillain-Barré syndrome (GBS) is an acute demyelinating neuropathy that presents clinically with involvement of the sensory peripheral nerve only. To date, <10 cases of pure sensory GBS have been reported; thus, the clinical and pathological features of sensory variant GBS are yet to be well characterized. The current study reports the case of a 43-year-old female that presented with acute, symmetric and monophasic sensory neuropathy, without motor weakness. Patient history, clinical examination, routine nerve conduction studies and sural nerve biopsy were reviewed. All the observations were consistent with a diagnosis of pure sensory GBS. In particular, the pathological features of the sural nerve biopsy revealed that the form of regenerated nerve fibers have complete structure of myelinated nerve fascicles, and these myelinated nerve fibers are thicker than other parts of the biopsy. The patient received small-dose (20 mg/day) prednisone initially, but without any benefit. Satisfactory improvements were observed with one course of intravenous immunoglobulin.

Transplantation of undifferentiated bone-marrow stromal cells into a vein graft accelerates sciatic nerve regeneration in streptozotocin induced diabetic rats.

Influence of undifferentiated bone marrow stromal cells (BMSCs) combined with vein graft on transected sciatic nerve repair was studied in diabetic rats. A nerve segment, 10 mm, was excised and a vein graft (VG) was used to bridge the gap. 10 microliter undifferentiated BMSCs (2 x 10(7) cells /mL) were administered into the graft in treatment group (VG/BMSC). Phosphate buffered saline was only administered into the graft in control group. The regenerated nerve fibers were studied in three time points of 4, 8 and 12 weeks after surgery. Evaluation of the repair process was based on behavioral, functional (Walking Track Analysis), electrophysiological, histomorphometrical and immunohistochemical criteria. The behavioral, functional and electrophysiological studies indicated that there was significant recovery in regeneration of axons in VG/BMSC group (P < 0.05). Morphometric evaluations showed that the number and diameter of myelinated fibers in VG /BMSC group were significantly higher than those in the control group (P < 0.05). This indicates the potential of using undifferentiated BMSCs combined with vein graft in peripheral nerve repair in diabetic rats with no restrictions of donor-site morbidity associated with isolation of Schwann cells. This technique is also cost saving because of decrease in interval from tissue harvest until administration of the cells and simplicity of laboratory techniques in comparison with undifferentiated BMSCs. It may have clinical implications for the surgical management of diabetic patients after nerve transection.

Behavioral and cellular consequences of high-electrode count Utah Arrays chronically implanted in rat sciatic nerve

Objective. Before peripheral nerve electrodes can be used for the restoration of sensory and motor functions in patients with neurological disorders, the behavioral and histological consequences of these devices must be investigated. These indices of biocompatibility can be defined in terms of desired functional outcomes; for example, a device may be considered for use as a therapeutic intervention if the implanted subject retains functional neurons post-implantation even in the presence of a foreign body response. The consequences of an indwelling device may remain localized to cellular responses at the device-tissue interface, such as fibrotic encapsulation of the device, or they may affect the animal more globally, such as impacting behavioral or sensorimotor functions. The objective of this study was to investigate the overall consequences of implantation of high-electrode count intrafascicular peripheral nerve arrays, High Density Utah Slanted Electrode Arrays (HD-USEAs; 25 electrodes mm−2). Approach. HD-USEAs were implanted in rat sciatic nerves for one and two month periods. We monitored wheel running, noxious sensory paw withdrawal reflexes, footprints, nerve morphology and macrophage presence at the tissue-device interface. In addition, we used a novel approach to contain the arrays in actively behaving animals that consisted of an organic nerve wrap. A total of 500 electrodes were implanted across all ten animals. Main results. The results demonstrated that chronic implantation (⩽8 weeks) of HD-USEAs into peripheral nerves can evoke behavioral deficits that recover over time. Morphology of the nerve distal to the implantation site showed variable signs of nerve fiber degeneration and regeneration. Cytology adjacent to the device-tissue interface also showed a variable response, with some electrodes having many macrophages surrounding the electrodes, while other electrodes had few or no macrophages present. This variability was also seen along the length of the electrodes. Axons remained within the proximity of the electrode tips at the distances required for theoretically effective stimulation and recording (⩽100 μm). Significance. We conclude from these studies that HD-USEAs do not cause overall global effects on the animals, at least up to the two-month period investigated here. These results demonstrate for the first time that the consequences of high-electrode count intrafascicular arrays compare with other peripheral nerve electrodes currently available for clinical or investigational neuromodulation.

Uncultured undifferentiated adipose-derived nucleated cell fractions combined with inside-out artery graft accelerate sciatic nerve regeneration and functional recovery

Effects of transplantation of adipose-derived nucleated cell fractions (ADNCs) on sciatic nerve regeneration were studied. A 10-mm sciatic nerve defect was bridged using artery graft filled with ADNCs. In control group, artery graft was filled with saline alone. Regenerated nerve fibres were studied for 12 weeks. In sham-operated group, sciatic nerve was only exposed and manipulated. Behavioural and functional studies confirmed faster recovery of regenerated axons in ADNCs transplanted animals than in control group (P<0.05). At the end of study period, animals in ADNCs transplanted group achieved a sciatic functional index (SFI) value of −31.6±−3.14, whereas in control group a value of −42.5±−3.7 was found. Gastrocnemius muscle mass in ADNCs transplanted animals was found to be significantly higher than that in control group (P=0.001). Morphometric indices of regenerated fibres showed the number and diameter of myelinated fibres to be significantly higher in ADNCs transplanted animals than in control group (P=0.001). On immunohistochemistry, there was more positive staining of S100 in the ADNCs transplanted animals than in control group. ADNCs transplantation into an artery graft could be considered a readily accessible technique that improves functional recovery of sciatic nerve.

Collagen scaffolds modified with CNTF and bFGF promote facial nerve regeneration in minipigs

Most experiments of peripheral nerve repair after injury have been conducted in the rodent model but the translation of findings from rodent studies to clinical practice is needed partly because the nerve regeneration must occur over much longer distances in humans than in rodents. The reconstruction of long distance nerve injuries still represents a great challenge to surgeons who is engaged in peripheral nerve surgery. Here we used the functional nerve conduit (collagen scaffolds incorporated with neurocytokines CNTF and bFGF) to bridge a 35 mm long facial nerve gap in minipig models. At 6 months after surgery, electrophysiology assessment and histological examination were conducted to evaluate the regeneration of peripheral facial nerves. Based on functional and histological observations, the results indicated that the functional collagen scaffolds promoted nerve reconstruction. The number and arrangement of regenerated nerve fibers, myelination, and nerve function reconstruction was better in the CNTF + bFGF conduit group than the single factor CNTF or bFGF conduit group. The functional composite conduit, which exhibited favorable mechanical properties, may promote facial nerve regeneration in minipigs effectively.

Repairing the ventral root is sufficient for simultaneous motor and sensory recovery in multiple complete cervical root transection injuries

AimIn multiple cervical root transection injuries, motor and sensory recovery has been demonstrated after repairing both dorsal and ventral roots with autologous grafts applied to the dorsal and ventral aspects, respectively. However, in clinical situations, autologous grafts may not be sufficient to repair both roots in this situation. In this study, the authors evaluated whether repairing ventral root alone is sufficient for simultaneous sensory and motor function recovery. Main methodsIn the transected group, the left 6th–8th cervical roots were pulled and transected at the spinal cord junction. In the repair group, the transected root was anastomosed to a single autologous nerve graft, which was inserted into the ventral horn through a pial incision. Acidic fibroblast growth factor mixed with fibrin glue was applied to the surgical area. Motor function, sensory function, cortical somatosensory evoked potentials (SSEPs), axon tracing, and CGRP+ fibers were evaluated. Key findingsThe repaired rats exhibited simultaneous sensory and motor function recovery. At the 16th weeks, SSEPs reappeared in all animals of the repair group, but not in the transected group. Retrograde axon tracing demonstrated an increased number of sensory neurons in the dorsal root ganglia and regenerating nerve fibers in the dorsal horn. CGRP+ fibers were significantly increased in the repair group and restricted to laminae I and II. SignificanceThis is the first report that in multiple root avulsions with insufficient grafts, repairing ventral roots alone leads to both sensory recovery and motor recovery. This finding may help patients with multiple cervical root avulsions.