Humans ; Sciatic Neuropathy/etiology* ; Arthroplasty, Replacement, Hip/adverse effects* ; Peripheral Nerve Injuries/etiology* ; Sciatic Nerve/injuries*

No abstract available.
Animals ; Peripheral Nerve Injuries* ; Peripheral Nerves* ; Rats* ; Sciatic Nerve*

PURPOSE: Wallerian degeneration (WD) is an antegrade degenerative process distal to peripheral nerve injury. Numerous genes are differentially regulated in response to the process. However, the underlying mechanism is unclear, especially the early response. We aimed at investigating the effects of sciatic nerve injury on WD via CLDN 14/15 interactions in vivo and in vitro. METHODS: Using the methods of molecular biology and bioinformatics analysis, we investigated the molecular mechanism by which claudin 14/15 participate in WD. Our previous study showed that claudins 14 and 15 trigger the early signal flow and pathway in damaged sciatic nerves. Here, we report the effects of the interaction between claudin 14 and claudin 15 on nerve degeneration and regeneration during early WD. RESULTS: It was found that claudin 14/15 were upregulated in the sciatic nerve in WD. Claudin 14/15 promoted Schwann cell proliferation, migration and anti-apoptosis in vitro. PKCα, NT3, NF2, and bFGF were significantly upregulated in transfected Schwann cells. Moreover, the expression levels of the β-catenin, p-AKT/AKT, p-c-jun/c-jun, and p-ERK/ERK signaling pathways were also significantly altered. CONCLUSION Claudin 14/15 affect Schwann cell proliferation, migration, and anti-apoptosis via the β-catenin, p-AKT/AKT, p-c-jun/c-jun, and p-ERK/ERK pathways in vitro and in vivo. The results of this study may help elucidate the molecular mechanisms of the tight junction signaling pathway underlying peripheral nerve degeneration.
Animals ; Claudins ; Nerve Regeneration ; Peripheral Nerve Injuries ; Rats ; Schwann Cells/pathology* ; Sciatic Nerve ; Wallerian Degeneration/pathology*

OBJECTIVE: To verify the effect of low energy laser irradiation (LELI) on the regeneration of injured sciatic nerve of the rat by showing the functional improvement and the elevated immunoreactivities (IRs) of growth-associated protein 43 (GAP-43). METHOD: Twenty rats, which had standardized compression injuries to the sciatic nerves, received the calculated LELI therapy immediately after the nerve injury and four consecutive days. The functional status was evaluated by sciatic functional index (SFI), and GAP-43-IRs was evaluated by immunohistochemistry and RT-PCR. RESULTS: The SFI was recovered in LELI rats faster than in the control group. Although expression of GAP-43 in the injured sciatic nerve was increased both in the LELI and control groups, the intensities of GAP-43-IRs were much greater in LELI treated group at 1 and 3 weeks after nerve injury. Both SFI and GAP-43-IRs reached the same level at 5 weeks after the nerve injury. CONCLUSION: LELI enhanced the neural regeneration after experimentally induced sciatic nerve injury at the early stage of recovery. Considering the effect of LELI on nerve regeneration was not fully explained until now, this study could suggest the meaningful explanation on the mechanism of LELI effectiveness on neural regeneration.
Animals ; GAP-43 Protein ; Immunohistochemistry ; Nerve Regeneration ; Peripheral Nerve Injuries ; Rats* ; Regeneration* ; Sciatic Nerve*

Artificial nerve guidance conduits (NGCs) are synthetic nerve grafts that are capable of providing the structural and nutritional support for nerve regeneration. The ideal NGCs have plenty of requirements on biocompatibility, mechanical strength, topological structure, and conductivity. Therefore, it is necessary to continuously improve the design of NGCs and establish a better therapeutic strategy for peripheral nerve injury in order to meet clinical needs. Although current NGCs have made certain process in the treatment of peripheral nerve injury, their nerve regeneration and functional outcomes on repairing long-distance nerve injury remain unsatisfactory. Herein, we review the nerve conduit design from four aspects, namely raw material selection, structural design, therapeutic factor loading and self-powered component integration. Moreover, we summarize the research progress of NGCs in the treatment of peripheral nerve injury, in order to facilitate the iterative updating and clinical transformation of NGCs.
Humans ; Peripheral Nerve Injuries/therapy* ; Guided Tissue Regeneration ; Nerve Regeneration/physiology* ; Sciatic Nerve

OBJECTIVE: To provide useful information for selecting the most appropriate peripheral nerve injury model for different research purposes in nerve injury and repair studies, and to compare nerve regeneration capacity and characteristics between them. METHODS: Sixty adult SD rats were randomly divided into two groups and underwent crush injury alone (group A, n = 30) or transection injury followed by surgical repair (group B, n = 30) of the right hind paw. Each group was subjected to the CatWalk test, gastrocnemius muscle evaluation, pain threshold measurement, electrophysiological examination, retrograde neuronal labeling, and quantification of nerve regeneration before and 7, 14, 21, and 28 days after injury. RESULTS: Gait analysis showed that the recovery speed in group A was significantly faster than that in group B at 14 days. At 21 days, the compound muscle action potential of the gastrocnemius muscle in group A was significantly higher than that in group B, and the number of labeled motor neurons in group B was lower than that in group A. The number of new myelin sheaths and the g-ratio were higher in group A than in group B. There was a 7-day time difference in the regeneration rate between the two injury groups. CONCLUSION The regeneration of nerve fibers was rapid after crush nerve injury, whereas the transection injury was relatively slow, which provides some ideas for the selection of clinical research models.
Animals ; Rats ; Nerve Fibers ; Nerve Regeneration ; Rats, Sprague-Dawley ; Sciatic Nerve/injuries*

The effect of magnetic stimulation (MS) on sciatic nerve injury was observed. After sciatic nerve was crushed in 40 Sprague Dawley (SD) rats, one randomly selected group (group D) was subjected, from the 4th day post-operatively to 3 min of continuous 70% of maximum output of MS daily for 8 weeks. The other group (group E) served as a control group. The nerve regeneration and motor function recovery were evaluated by walking track analysis (sciatic function index, SFI; toe spreading reflex, TSR), electrophysiological, histological and acetylcholineesterase histochemistry. The SFI in the group D was greater than in the group E with the difference being statistically significant (P < 0.01). TSR reached its peak on the 4th day in the group D and on the 10th day in the group E respectively. The amplitude and velocity of MCAP and NCAP in the group D was greater than in the group E with the difference being statistically significant (P < 0.01), while the latency and duration of MCAP and NCAP in the group D were less than in the group E with the difference being also statistically significant (P < 0.01). Histological examination showed the mean axon count above the lesion for thick myelinated fibers (> 6.5 microns) in the group D was greater than in the control group with the difference being statistically significant (P < 0.01), while the mean axon count below the lesion for thick myelinated fibers was less than that in the group E with the difference being statistically significant (P < 0.01). The mean axon count above the lesion for thin myelinated fibers (2-6.5 microns) in the group D was greater than that in the group E with the difference being statistically significant (P < 0.05), while the mean axon count below the lesion for thin myelinated in the group D was greater than that in the group E with the difference being statistically significant (P < 0.01). Acetylcholine esterase examination showed that the MS could significantly increase the number of the motor neurons. There was no significant difference in the number of the motor neurons between the treatment side and the normal side (P > 0.05). It can be concluded that MS can enhance functional recovery and has a considerable effect in the treatment of the peripheral nerve injury.
Acetylcholinesterase/metabolism ; Electromagnetics ; Motor Neurons/physiology ; *Nerve Regeneration ; Random Allocation ; Rats, Sprague-Dawley ; Sciatic Nerve/*injuries ; Sciatic Nerve/*physiopathology ; Sciatic Neuropathy/rehabilitation

OBJECTIVETo observe the effect of tissue engineered nerves in repairing peripheral nerve defects (about 1.5 cm in length) in rats to provide data for clinical application.

METHODSGlycerinated sciatic nerves (2 cm in length) from 10 Sprague Dawley (SD) rats (aged 4 months) were used to prepare homologous dermal acellular matrix. Other 10 neonate SD rats (aged 5-7 days) were killed by neck dislocation. After removing the epineurium, the separated sciatic nerve tracts were cut into small pieces, then digested by 2.5 g/L trypsin and 625 U/ml collagenase and cultured in Dulbecco's modified Eagle's medium (DMEM) for 3 weeks. After proliferation, the Schwann cells (SCs) were identified and prepared for use. And other 40 female adult SD rats (weighing 200 g and aged 3 months) with sciatic nerve defects of 1.5 cm in length were randomly divided into four groups: the defects of 10 rats bridged with proliferated SCs and homologous dermal acellular matrix (the tissue engineered nerve group, Group A), 10 rats with no SCs but homologous dermal acellular matrix with internal scaffolds (Group B), 10 with autologous nerves (Group C), and the other 10 with nothing (the blank control group, Group D). The general status of the rats was observed, the wet weight of triceps muscle of calf was monitored, and the histological observation of the regenerated nerves were made at 12 weeks after operation.

RESULTSThe wounds of all 40 rats healed after operation and no death was found. No foot ulceration was found in Groups A, B and C, but 7 rats suffered from foot ulceration in Group D. The triceps muscles of calf were depauperated in the experimental sides in all the groups compared with the uninjured sides, which was much more obvious in Group D. The wet weight of triceps muscle of calf and nerve electrophysiologic monitoring showed no statistical difference between Group A and Group C, but statistical difference was found between Groups A and B and Groups B and D. And significant statistical difference was found between Group B and Group D. Obvious compound muscle (or motor) action potential (CMAP) could be evoked in Group A and Group C, but the evoked amplitude was very low in Group B and Group D. The axons of regenerated nerves penetrated through the whole graft in Group A and Group C, and partly penetrated through the graft in Group B, but did not penetrate in Group D. The two tips of the separated sciatic nerves of Groups A , B , and C were connected together, without formation of neuroma. But those of Group D were not connected together and neuroma formed in 6 rats.

CONCLUSIONSTissue engineered nerves can be used for repairing long defects of the peripheral nerves of rats and ideal repairing effects can be obtained.

Animals ; Animals, Newborn ; Female ; Nerve Regeneration ; Peripheral Nerve Injuries ; Rats ; Rats, Sprague-Dawley ; Sciatic Nerve ; injuries ; Tissue Engineering ; methods

PURPOSE: To determine the time of magnetic resonance(MR) signal intensity changes in denervated skeletal muscle and to compare MR imaging with electromyography(EMG) in the evaluation of peripheral nerve injury. MATERIALS AND METHODS: We evaluated MR imagings of denervated muscles after experimental transection of the sciatic nerve in five rabbits using 1.0T MR unit. MR imaging and EMG were performed 3 days and 1, 2 and 3 weeks after denervation. T1-weighted images(T1-WI), T2-WI and Short Tau Inversion Recovery(STIR) images were obtained. The signal intensity (SI) of muscles in the denervated and normal sides were visually and quantitatively compared. After measuring the SI of the normal and abnormal areas, the time of SI change was determined when there was significant difference (P<0.05) of SI between the normal and denervated sides. RESULTS: On STIR images, two of the five rabbits showed significant SI changes at the third day(P<0.05) and all showed significant changes(P<0.05)at the first week. On T2-WI, one rabbit showed significant SI changes at the third day, and all showed significant SI changes at the first week. On T1-WI, significant SI changes were seen in one rabbit at the second week and in one at the third. One week after denervation, all showed denervation potential on EMG. CONCLUSION: This study suggests that MR imaging using STIR images is a useful method in the evaluation of denervated muscle, and that MR signal changes of denervated muscle may precede EMG changes after denervation. To localize and to determine the severity of the peripheral nerve injury, future analysis of the distribution of abnormal MR SI in denervated muscles would be helpful.
Denervation ; Magnetic Resonance Imaging* ; Muscle, Skeletal* ; Muscles ; Peripheral Nerve Injuries ; Rabbits* ; Sciatic Nerve

There is close relationship between the morphologic changes of peripheral nerve after injury and its function recovery during regeneration. In our experiment, the sciatic nerve of rats was transected and bridge-connected with silicone tube, and the images of serial slices of different time and different injury parts were taken by micro-photograph system. The volume unit model was applied to rendering the three dimensional (3D) structure of degenerative and regenerative sciatic nerve fiber and its affiliated structure after injury. The 3D images showed that node of Ranvier had not formed and its array was turbulent, both the myelin sheath and the axis-cylinder were thinner, and the collagen fibres had proliferated.
Animals ; Male ; Nerve Regeneration ; physiology ; Rats ; Rats, Wistar ; Recovery of Function ; Sciatic Nerve ; injuries ; pathology ; physiopathology