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.
To observe the change of morphology and neuropeptide in the spinal neurons in order to clarify the functional state after injury of peripheral nerves is especially in the late stage. Sciatic nerves were cut with their proximal segments in the preparation of a model of peripheral nerve injury. Combination of horseradish peroxidase retrograde tracing immunohistochemistry and computer image analysis the changes in the morphometry of the perikarya of ventral horn neurons of the spinal cord, the quantitative changes of substance P (SP). Calcitonin gene-related peptide (CGRP) in dorsal horn and CGRP and choline acetyransferase (CHAT) in ventral horn of the spinal cord were examed. The results showd: (1) At the 3rd week after injury, swollen perikarya of the ventral horn neurons were observed, subseauently the swelling of perikarya was decreased tile the 6th week the neurons recovered to their normal size. At the 12th week the neurons were generally stable in their size, shortening of the dendrites was seen in 27% of the neurons. (2) The dendrites of the neurons progressively contracted till at the 12th week 53% of them were degenerated. The results of the 24th week were similar to the that at the 12th week. (3) CGRP in the ventral horn of the spinal cord was elevated to the highest point after 1 week of injury, that lasting for 4 weeks and 8 weeks later, the lever of CGRP returned to normal. From 20th to 24th week, there was no obvious changes of CHAT in the ventral horn of the spinal cord during observation. (4) SP went to the lowest point in the dorsal horn during 2-6 weeks, then recovered slowly, and beiny normal again after 16 weeks, however, CGRP was changed slightly. The results indicated that although a series of degenerating changes occurred in the neurons of the spinal cord during the late peripheral nerve injury, but the functional activity of the central meurons still was maintained at a certain level.
Objective To explore effects of several immunosuppressants on cytokine expressions after repair for a sciatic nerve injury in a rat model. Methods The sciatic nerves of 42 rats were cut and suturedend to end. After operation, the rats were divided into 6 groups. Group A(n=9) was served as a control with no medicines given. Group B (n=9) was given methylprednisolone 20 mg/(kg·d) for 2 days. Groups C(n=9) and D(n=3) were given FK506 1 mg/(kg·d) for 2 weeks and 4 weeks respectively, and were given the same doses of methylprednisolone as Group B. Groups E and F were given CsA 2 mg/(kg·d) for 2 weeks and 4 weeks respectively, and were given the same doses of methylprednisolone as Group B. The sciaticnerves were sampled at 1, 2 and 4 weeks postoperatively. And immuneohistochemistry stainings of interleukin 1β(IL-1β)， tumor necrosis factor α(TNF-α), interferon γ(IFN-γ) and macrophage migration inhibitory factor(MIF) were performed. The staining results were compared and analyzed. Results The expression peaks of IL-1β and IFN-γ were found at the 1st week postoperatively in Group A. Then, the expression decreased rapidly at the 2nd week and disappeared at the 4th week. As for TNF-α and MIF, they were only found to have a low expression until the 1st week in Group A. In groups C-F, the expression peaks of IL-1β, TNF-α and IFN-γ were found at the 2nd week, while the expression peak of MIF was still at the 1st week, and the expression of all the cytokines extended to the 4th week. The expressions of these cytokines in Group B were just between the expression levels of Group A and Groups C-F. Conclusion Immunosuppressants can delay the expression peaks and significantly extend the expression time of IL-1β, TNF-α, IFN-γ and MIF after repair for a sciatic nerve injury in a rat model.
To evaluate the value of clinical application of examination of fibrillation potential amplitude, 110 patients, 97 males and 13 females, were examined and only the maximum fibrillation potential amplitudes were recorded in 420 muscles. The results showed that there was no significant difference between sexes, ages and sides. However, significant difference was evident between the groups of different frequency (1+ to 4+). The fibrillation potential amplitude was maximum at 3 to 4 months after denervation and still remained at relatively high level for years in certain patients. No significant difference was showed between the time groups in incomplete nerve injuries. Surgery did not affect the course of fibrillation potential amplitude change. It was suggested that the muscle cells sustained their property for years after denervation in some patients, thus it might explain that satisfactory result could be obtained from operative repair in some late cases. The changes of fibrillation potential amplitude might indicate that the changes from muscle denervation was still reversible and might be more accurate than traditional method of examination.
Peripheral nerve injury (PNI) is a common neurological dysfunction. In clinical practice, autologous nerve transplantation is used to solve problems related to PNI, such as limited donor resources, neuroma formation and high donor incidence rate. Therefore, searching for new nerve regeneration materials has become a hot research topic. The decellularized extracellular matrix (dECM) hydrogel provides a scaffold for nerve regeneration by removing the cellular components in biological tissues, preserving the extracellular matrix, and is a potential therapeutic material for nerve regeneration. This article reviews the research progress of dECM hydrogel for PNI and looks forward to the clinical prospects of this research direction.
OBJECTIVE: To investigate the protective effect of tumor necrosis factor-alpha(TNF-alpha) on spinal motor neurons after peripheral nerve injury. METHODS: Twenty Wistar rats were divided into two groups, the right sciatic nerves of 20 Wistar rats were transected, the proximal stumps were inserted into a single blind silicone tube. 16 microliters of normal saline(NS) and TNF-alpha(30 U/ml) were injected into the silicone tubes. After 2 weeks, the 4th, 5th lumbar spinal cord were taken for examination. Enzyme histochemical technique and image analysis were used to show acetylcholinesterase(AChE) and nitric oxide synthase(NOS) activity of spinal motor neurons. RESULTS: The number of AChE and NOS staining neurons were 8.65 +/- 1.98 and 5.92 +/- 1.36 in the experimental group and 6.37 +/- 1.42 and 8.67 +/- 1.45 in the control group respectively, there were significant difference between the two groups(P lt; 0.01). CONCLUSION: It suggests that TNF-alpha has protective effect on motor neurons after peripheral nerve injury.
ObjectiveTo investigate the effect of folic acid coated-crosslinked urethane-doped polyester elastomer (fCUPE) nerve conduit in repairing long distance peripheral nerve injury. MethodsThirty-six 3-month-old male Sprague Dawley rats weighing 180-220 g were randomly assigned to 3 groups, each consisting of 12 rats: CUPE nerve conduit transplantation group (group A), fCUPE nerve conduit transplantation group (group B), and autologous nerve transplantation group (group C), the contralateral healthy limb of group C served as the control group (group D). A 20-mm-long sciatic nerve defect model was established in rats, and corresponding materials were used to repair the nerve defect according to the group. The sciatic function index (SFI) of groups A-C was calculated using the Bain formula at 1, 2, and 3 months after operation. The nerve conduction velocity (NCV) of the affected side in groups A-D was assessed using neuroelectrophysiological techniques. At 3 months after operation, the regenerated nerve tissue was collected from groups A-C for S-100 immunohistochemical staining and Schwann cell count in groups A and B to compare the level of nerve repair and regeneration in each group. ResultsAt 3 months after operation, the nerve conduits in all groups partially degraded. There was no significant adhesion between the nerve and the conduit and the surrounding tissues, the conduit was well connected with the distal and proximal nerves, and the nerve-like tissues in the conduit could be observed when the nerve conduit stents were cut off. SFI in group A was significantly higher than that in group C at each time point after operation and was significantly higher than that in group B at 2 and 3 months after operation (P<0.05). There was no significant difference in SFI between groups B and C at each time point after operation (P>0.05). NCV in group A was significantly slower than that in the other 3 groups at each time point after operation (P<0.05). The NCV of groups B and C were slower than that of group D, but the difference was significant only at 1 month after operation (P<0.05). There was no significant difference between groups B and C at each time point after operation (P>0.05). Immunohistochemical staining showed that the nerve tissue of group A had an abnormal cavo-like structure, light tissue staining, and many non-Schwann cells. In group B, a large quantity of normal neural structures was observed, the staining was deeper than that in group A, and the distribution of dedifferentiated Schwann cells was obvious. In group C, the nerve bundles were arranged neatly, and the tissue staining was the deepest. The number of Schwann cells in group B was (727.50±57.60) cells/mm2, which was significantly more than that in group A [(298.33±153.12) cells/mm2] (t=6.139, P<0.001). ConclusionThe fCUPE nerve conduit is effective in repairing long-distance sciatic nerve defects and is comparable to autologous nerve grafts. It has the potential to be used as a substitute material for peripheral nerve defect transplantation.