OBJECTIVE: To explore the possibility to bridge peripheral nerve defects by xenogeneic acellular nerve basal lamina scaffolds. METHODS: Thirty SD rats were randomly divided into 5 groups; in each group, the left sciatic nerves were bridged respectively by predegenerated or fresh xenogeneic acellular nerve basal lamina scaffolds, autogenous nerve grafting, fresh xenogeneic nerve grafting or without bridging. Two kinds of acellular nerve basal lamina scaffolds, extracted by 3% Triton X-100 and 4% deoxycholate sodium from either fresh rabbit tibial nerves or predegenerated ones for 2 weeks, were transplanted to bridge 15 mm rat sciatic nerve gaps. Six months after the grafting, the recovery of function was evaluated by gait analysis, pinch test, morphological and morphometric analysis. RESULTS: The sciatic nerve function indexes (SFI) were -30.7% +/- 6.8% in rats treated with xenogeneic acellular nerve, -36.2% +/- 9.7% with xenogeneic predegenerated acellular nerve, and -33.9% +/- 11.3% with autograft respectively (P gt; 0.05). The number of regenerative myelinated axons, diameter of myelinated fibers and thickness of myelin sheath in acellular xenograft were satisfactory when compared with that in autograft. Regenerated microfascicles distributed in the center of degenerated and acellular nerve group. The regenerated nerve fibers had normal morphological and structural characters under transmission electron microscope. The number and diameter of myelinated fibers in degenerated accellular nerve group was similar to that of autograft group (P gt; 0.05). Whereas the thickness of myelin sheath in degenerated accellular nerve group was significantly less than that of autograft group (P lt; 0.05). CONCLUSION: The above results indicate that xenogeneic acellular nerve basal lamina scaffolds extracted by chemical procedure can be successfully used to repair nerve defects without any immunosuppressants.
ObjectiveTo review the research progress of peripheral nerve mismatch regeneration, and to provide reference for its related basic research and clinical treatment.MethodsThe pathophysiology of peripheral nerve after injury, several main factors affecting the mismatch regeneration of peripheral nerve, and the fate of axon after mismatch regeneration were summarized by referring to the relevant literature at home and abroad in recent years.ResultsDistal pathways and target organs can selectively affect the mismatch regeneration of peripheral nerves; different phenotypes of Schwann cells have different effects on the mismatch regeneration of peripheral nerves; studying the mechanism of action of exosomes from different Schwann cells on different types of axons can provide a new direction for solving the mismatch regeneration of peripheral nerves.ConclusionPeripheral nerve mismatch regeneration is affected by various factors. However, the specific mechanism and characteristics of these factors remain to be further studied.
ObjectiveTo establish an efficient method of isolating and culturing high activity and high purity of Schwann cells, and to identify the cells at the levels of transcription and translation. MethodsThe sciatic nerves harvested from a 4-week-old Sprague Dawley rat were digested in the collagenase I for 15 minutes after dissecting, and then the explants were planted in culture flask directly. The cells were cultured and passaged in vitro, the growth state and morphological changes of the cells were observed under inverted phase contrast microscope. MTT assay was used to test the proliferation of cells and the cells growth curve was drawn. RT-PCR and immunohistochemistry staining were used to detect S100 and glial fibrillary acidic protein (GFAP) at the levels of transcription and translation, respectively. The purity of cells was caculated under microscope. ResultsAfter the digestion of collagenase I, fibroblast-like cells appeared around explants within 24 hours, with slender cell body and weak refraction. After tissues were transferred to another culture flask, a large number of dipolar or tripolar cells were seen after 48 hours, with slender ecphyma, plump cell body, and b refraction, and the cells formed colonies within 72 hours. The cells were covered with the bottom of culture flask within 48-72 hours after passaging at a ratio of 1∶2, and spiral colonies appeared. Cells showed vigorous growth and full cytoplasm after many passages. MTT assay results showed that the cells at passage 3 entered the logarithmic growth phase on the 3rd day, reached the plateau phase on the 7th day with cell proliferation, and the growth curve was “S” shape. RT-PCR results showed that the cells expressed S100 gene and GFAP gene, and immunohistochemistry staining showed that most of the cells were positively stained, indicating that the majority of cells expressing S100 protein and GFAP protein. The purity of Schwann cells was 98.37% ± 0.30%. ConclusionHigh activity and high purity of Schwann cells can be acquired rapidly by single-enzyme digestion and explant-culture method.
Objective Targeted adenoviral gene delivery from peripheral nerves was used to integrally analyse the characterization and time course of LacZ gene (AdLacZ) retrograde transfer to spinal cord and transgene product anterograde labeling ofperipheral nerve. Methods Recombinant replication-defective adenovirus containing AdLacZ was administrated to the cut proximal stumps of median and tibial nerves in Wister rats. Then the transected nerve was repaired with 10-0 nylon sutures. At different time point postinfection the spinal cords of C5 to T1 attached with DRGs and brachial plexuses, or L2 to L6 attached with DRGs and lumbosacralplexuses were removed. The removed spinal cord and DRGs were cut into 50 μm serialcoronal sections and processed for X-gal staining and immunohistochemical staining. The whole specimens of brachial or lumbosacral plexuses attaching with theirperipheral nerves were processed for X-gal staining. The number of X-gal stained neurons was counted and the initial detected time of retrograde labeling, peaktime and persisting period of gene expression in DRG sensory neurons, spinal cord motor neurons and peripheral nerves were studied. Results The gene transfer was specifically targeted to the particular segments of spinal cord andDRGs, and transgene expression was strictly unilaterally corresponding to the infected nerves. Within the same nerve models, the initial detected time of gene expression was earliest in DRG neurons, then in the motor neurons and latest in peripheral nerves. The persisting duration of β-gal staining was shortest in motor neurons, then in sensory neurons and longest in peripheral nerves. The initial detected time of β-gal staining in median nerve models was earlier in mediannerve models compared with that in the tibial nerve models. Although the initial detected time and the beginning of peak duration of β-gal staining were not same, the decreasing time of β-gal staining in motor and sensory neurons of thetwo nerve models were started at about the same day 8 post-infection. The labeled neurons were more in tibial nerve-models than that in median nerve models. Within the same models, the labeled sensory neurons of DRGs were morethan labeled motor neurons of ventral horn. The β-gal staining was tenser in median nerves than that in tibial nerves. However the persisting time of β-gal staining was longer in tibial nerve models. Conclusion The b gene expression in neurons and PNS renders this system particularly attractive for neuroanatomical tracing studies. Furthermore this gene delivery method allowing specific targeting of motor and sensory neurons without damaging the spinal cord might offer potentialities for the gene therapy of peripheral nerve injury.
OBJECTIVE Following the delayed repair of peripheral nerve injury, the cell number of anterior horn of the spinal cord and its ultrastructural changes, motorneuron and its electrophysiological changes were investigated. METHODS In 16 rabbits the common peroneal nerves of both sides being transected one year later were divided into four groups randomly: the degeneration group and regeneration of 1, 3 and 5 months groups. Another 4 rabbits were used for control. All transected common peroneal nerves underwent epineural suture except for the degeneration group the electrophysiological examination was carried out at 1, 3 and 5 months postoperatively. Retrograde labelling of the anterior horn cells was demonstrated and the cells were observed under light and electronmicroscope. RESULTS 1. The number of labelled anterior horn cell in the spinal cord was 45% of the normal population after denervation for one year (P lt; 0.01). The number of labelled cells increased steadily from 48% to 57% and 68% of normal values at 1, 3 and 5 months following delayed nerve repair (P lt; 0.01). 2. The ultrastructure of the anterior horn cells of the recover gradually after repair. 3. With the progress of regeneration the latency become shortened, the conduction velocity was increased, the amplitude of action potential was increased. CONCLUSION Following delayed repair of injury of peripheral nerve, the morphology of anterior horn cells of spinal cord and electrophysiological display all revealed evidence of regeneration, thus the late repair of injury of peripheral nerve was valid.
The sciatic nerves of adult rats were sectioned bilaterally and the ends of the nerves were placed in silicone tubes. One side of the distal nerve segment was inverted and that of the contralateral side was non-inverted. After 2, 4, 6 weeks, the rats were killed and the specimens were removed for macroscopic, histologic and morphometric analysis. The results showed that either the inverted or non-inverted distal nerve segments had no influence on the number of the myelinated axons in the regenerated nerves, but the number and density of the myelinated axons was markedly diminished in the inverted distal nerve segments.
Objective To observe the effect of comprehensive rehabilitation in patients with peripheral nerve injuries after the Wenchuan earthquake. Methods A total of 24 cases of peripheral nerve injuries who were admitted to the Rehabilitation Center for Earthquake Victims of West China Hospital of Sichuan University were treated with comprehensive rehabilitation, including exercise therapy, acupuncture therapy, functional electrical stimulation, and occupational therapy (mainly sensory training and wearing orthosis). After 30 treatment sessions, patient motor and sensory function, upper limb functional activity, and electrodiagnostic parameters were evaluated. Meanwhile, concomitant injuries were also recorded. Results As for the recovery of motor and sensory functions, the effective rate was 41.66%. The difference in the scores of upper limb functional activities was statistically significant before and after treatment (Plt;0.01). As assessed by electromyogram and nerve conduction velocity, the response rate was 87.50%. Patients with more concomitant injuries were likely to have slower recovery. Conclusion Comprehensive rehabilitation is appropriate and effective for patients with peripheral nerve injuries after the Wenchuan earthquake.
Objective To review researches of treatment of peripheral nerve injury with neuromuscular electrical stimulation (NMES) regarding mechanism, parameters, and cl inical appl ication at home and abroad. Methods The latest original l iterature concerning treatment of peri pheral nerve injury with NMES was extensively reviewed. Results NMES should be used under individual parameters and proper mode of stimulation at early stage of injury. It could promote nerve regeneration and prevent muscle atrophy. Conclusion NMES plays an important role in cl inical appl ication of treating peripheral nerve injury, and implantable stimulation will be the future.
ObjectiveTo summarize the regulatory role of long non-coding RNA (lncRNA) in peripheral nerve injury (PNI) and neural regeneration.MethodsThe characteristics and mechanisms of lncRNA were summarized and its regulatory role in PNI and neural regeneration were elaborated by referring to relevant domestic and foreign literature in recent years.ResultsNeuropathic pain and denervated muscle atrophy are common complications of PNI, affecting patients’ quality of life. Numerous lncRNAs are upregulated after PNI, which promote the progress of neuropathic pain by regulating nerve excitability and neuroinflammation. Several lncRNAs are found to promote the progress of denervated muscle atrophy. Importantly, peripheral nerve regeneration occurs after PNI. LncRNAs promote peripheral nerve regeneration through promoting neuronal axonal outgrowth and the proliferation and migration of Schwann cells.ConclusionAt present, the research on lncRNA regulating PNI and neural regeneration is still in its infancy. The specific mechanism remains to be further explored. How to achieve clinical translation of experimental results is also a major challenge for future research.
Objective To establish an animal model for repairing the sciatic nerve defect with a biodegradable poly D,L-lactic acid/nerve growth factor (PDLLA/NGF) that can control the release conduit in rats and to observe an effect of the conduit on the sciatic nerve regeneration. Methods The PDLLA conduit and the PDLLA/NGF-controlled release conduit (NGF 450 U per conduit) were madewith the solvent-volatilixation method. Forty male SD rats were randomly and equally divided into 4 groups. The middle segments (10 mm) of the sciatic nerves of the rats were excised and were then repaired with the sciatic nerve autograft(Group A), with the PDLLA conduit (Group B), with the PDLLA conduit and an injection of NGF (30 U) into the conduit (Group C), and with the PDLLA/NGF controlled-release conduit (Group D), respectively, with the 10-mm nerve defect left behind. Three months after operation, the morphologic parameters of the nerve regeneration were observed and evaluated under light microscope and electron microscope, and the image analysis was also made. Results Three months after operation, porous adherence between the conduit and the surrounding tissues could be observed. The conduit presented a partial biodegradation but still remainedintact in the outline and the proximal nerve regenerated through the conduit cavity. Based on the histological observation, the quantity, uniformity, and maturity of the nerve fiber regeneration in Groups A and D were better than those in Groups B and C. The image analysis indicated that there were no significant differences in the nerve fiber diameter, axon diameter or myelin thickness between Group A and Group D (P＞0.05). However, all the parameters in Groups A and D were better than those in Groups B and C (P＜0.05). Conclusion The PDLLA/NGF-controlled release conduit can effectively promote the sciatic nerve regeneration of rats. Its morphological index is similar to that of the nerve autograft.
