Sciatic nerve derived exosomes in promotion of axon regeneration and functional recovery following peripheral nerve injury in rat / 中华显微外科杂志

Objective:To explore the effect of sciatic nerve derived exosomes(SN-EXO) on axon regeneration and functional recovery after peripheral nerve injury(PNI).Methods:From March 2021 to October 2022, the Department of Orthopedics of the First Affiliated Hospital of Zhengzhou University studied the effect of SN-EXO on the proliferation of Schwann cells(SCs) through EdU cell proliferation experiment. Twenty-one healthy male SD rats were randomly divided into 3 groups of sham operation, peripheral nerve injury(PNI) and SN-EXO treatment, with 7 rats in each group. The right sciatic nerves of rat models in sham group were exposed without injury. In the rat in PNI group and SN-EXO treatment group, PBS and SN-EXO were injected under the epineurium of right sciatic nerves following sciatic nerve crush. Sciatic nerve function index(SFI) was performed at 28 days after operation, and then sacrificed. Right sciatic nerves were removed for further exploration of nerve regeneration. The histopathological changes and axon arrangement of sciatic nerves were evaluated by HE staining. Regeneration efficiency of neurofilaments and SCs were obserred by NF200 and S100β double staining of sciatic nerve. The data obtained were statistically analyzed, and P<0.05 was statistically significant. Results:It was found that SN-EXO can significantly enhance the proliferation ability of SCs, with statistically significant difference( P<0.05). SFI in SN-EXO treatment group and PNI group were(-27.65±4.36) and(-57.33±7.49), respectively, and the difference was statistically significant( P<0.05). Axons in SN-EXO treatment group were arranged more closely and orderly than those in the PNI group at 28 days after operation, and there were less injury induced axon disintegration and vacuolation. Immunofluorescence assay indicated that NF200 and S100β fluorescence intensity in SN-EXO treatment group was significantly higher than that in the PNI group, and the difference was statistically significant( P<0.05). Conclusion:SN-EXO could enhance the proliferation of SCs to promote axon regeneration following peripheral nerve injury.

Effect of Buyang Huanwutang on Protein Expression of MAP-2， NF-M and GAP-43 After Sciatic Nerve Transection Anastomosis in Rats / 中国实验方剂学杂志

Objective:To investigate the effects of Buyang Huanwutang on the expression of microtubule-associated protein-2（MAP-2）， neurofilament-M（NF-M）， and growth associated protein-43（GAP-43）in rat sciatic nerve after sciatic nerve transection and anastomosis. To explore the mechanism of Buyang Huanwutang promoting peripheral nerve regeneration. Method:SD rats were selected as the experimental subjects， and sciatic nerve transection model was selected as the experimental model. They were randomly divided into model group， sham operation group， Buyang Huanwutang group high， medium and low dose （29.6， 14.8， 7.4 g·kg^-1）group， and mecobalamin （0.156 mg·kg^-1）group， the model group and the sham operation group were given distilled water intragastric administration. After successful modeling， each group was treated with relevant drugs for 4 weeks. After 4 weeks， sciatic nerve function index（SFI）， degree of inclined plate test and hematoxylin-eosin（HE）of sciatic nerve in each group were tested. The expression levels of MAP-2， NF-M， and GAP-43 at the sciatic nerve anastomosis site were detected by immunohistochemistry and Western blot. Result:Compared with sham operation group， the expression levels of SFI， inclined plate test， MAP-2， NF-M and GAP-43 in model group were significantly increased （<italic>P</italic><0.01）. Compared with model group， the expression levels of SFI， inclined plate test， MAP-2， NF-M and GAP-43 in Buyang Huanwutang high， medium and low-dose groups were significantly increased （<italic>P</italic><0.05，<italic>P</italic><0.01）. Conclusion:Buyang Huanwutang has a positive effect on nerve regeneration after sciatic nerve transection and anastomosis in rats.

Low-intensity pulsed ultrasound for regenerating peripheral nerves: Potential for penile nerve / 亚洲男科学杂志(英文版)

Peripheral nerve damage, such as that found after surgery or trauma, is a substantial clinical challenge. Much research continues in attempts to improve outcomes after peripheral nerve damage and to promote nerve repair after injury. In recent years, low-intensity pulsed ultrasound (LIPUS) has been studied as a potential method of stimulating peripheral nerve regeneration. In this review, the physiology of peripheral nerve regeneration is reviewed, and the experiments employing LIPUS to improve peripheral nerve regeneration are discussed. Application of LIPUS following nerve surgery may promote nerve regeneration and improve functional outcomes through a variety of proposed mechanisms. These include an increase of neurotrophic factors, Schwann cell (SC) activation, cellular signaling activations, and induction of mitosis. We searched PubMed for articles related to these topics in both in vitro and in vivo animal research models. We found numerous studies, suggesting that LIPUS following nerve surgery promotes nerve regeneration and improves functional outcomes. Based on these findings, LIPUS could be a novel and valuable treatment for nerve injury-induced erectile dysfunction.

Cell culture supernatant of olfactory ensheathing cells promotes nerve regeneration after peripheral nerve injury in rats / 中国组织工程研究

BACKGROUND: Previous studies have found that the culture supernatant of the olfactory ensheathing cells is capable of promoting axonal regeneration and functional recovery after spinal cord injury, but there is a lack of research in the field of peripheral nerve. OBJECTIVE: To investigate whether olfactory ensheathing cell culture supernatant is beneficial for nerve repair after peripheral nerve injury. METHODS: Olfactory ensheathing cells were isolated and purified, to prepare the supernatant. The olfactory ensheathing cell culture supernatant was applied to the dorsal root ganglion tissue block in vitro to observe the axon growth of the dorsal root ganglion. The olfactory ensheathing cell culture supernatant was applied to a rat sciatic nerve defect model in vivo to examine its effect on axonal regeneration and myelinization of the injured nerve. RESULTS AND CONCLUSION: The purity of olfactory ensheathing cells was (94.4±3.1)%. Compared with the blank control and low dose olfactory ensheathing cell culture groups, the average length of five longest axons in dorsal root ganglion tissue mass in the high dose olfactory ensheathing cells culture group was significantly increased (P < 0.05). Immunofluorescence showed that the regenerated nerve penetrated through the defect area and the regenerated nerve was arranged orderly in the olfactory ensheathing cell culture and the autologous nerve groups, which was significantly superior to that in the blank control group. Transmission electron microscope observed that the number of regenerated nerve axons and the thickness of myelin sheath in the olfactory ensheathing cell culture group were significantly higher than those in the blank control group (P < 0.05). These results indicate that the supernatant of the olfactory ensheathing cells can promote axonal regeneration after peripheral nerve injury and the myelination of the regenerated axons, which provides a new olfactory ensheathing cells-based acellular therapy for peripheral nerve injury.

Hericium erinaceus (Bull.: Fr.) Pers., a medicinal mushroom, activates peripheral nerve regeneration / 中国结合医学杂志

<p><b>OBJECTIVE</b>To study the ability of aqueous extract of Hericium erinaceus mushroom in the treatment of nerve injury following peroneal nerve crush in Sprague-Dawley rats.</p><p><b>METHODS</b>Aqueous extract of Hericium erinaceus was given by daily oral administration following peroneal nerve crush injury in Sprague-Dawley rats. The expression of protein kinase B (Akt) and mitogen-activated protein kinase (MAPK) signaling pathways; and c-Jun and c-Fos genes were studied in dorsal root ganglia (DRG) whereas the activity of protein synthesis was assessed in peroneal nerves by immunohistochemical method.</p><p><b>RESULTS</b>Peripheral nerve injury leads to changes at the axonal site of injury and remotely located DRG containing cell bodies of sensory afferent neurons. Immunofluorescence studies showed that DRG neurons ipsilateral to the crush injury in rats of treated groups expressed higher immunoreactivities for Akt, MAPK, c-Jun and c-Fos as compared with negative control group (P <0.05). The intensity of nuclear ribonucleoprotein in the distal segments of crushed nerves of treated groups was significantly higher than in the negative control group (P <0.05).</p><p><b>CONCLUSION</b>H. erinaceus is capable of promoting peripheral nerve regeneration after injury. Potential signaling pathways include Akt, MAPK, c-Jun, and c-Fos, and protein synthesis have been shown to be involved in its action.</p>

Rat Peripheral Nerve Regeneration Using Nerve Guidance Channel by Porcine Small Intestinal Submucosa

OBJECTIVE: In order to develop a novel nerve guidance channel using porcine small intestinal submucosa (SIS) for nerve regeneration, we investigated the possibility of SIS, a tissue consisting of acellular collagen material without cellular immunogenicity, and containing many kinds of growth factors, as a natural material with a new bioactive functionality. METHODS: Left sciatic nerves were cut 5 mm in length, in 14 Sprague-Dawley rats. Grafts between the cut nerve ends were performed with a silicone tube (Silicon group, n=7) and rolled porcine SIS (SIS group, n=7). All rats underwent a motor function test and an electromyography (EMG) study on 4 and 10 weeks after grafting. After last EMG studies, the grafts, including proximal and distal nerve segments, were retrieved for histological analysis. RESULTS: Foot ulcers, due to hypesthesia, were fewer in SIS group than in Silicon group. The run time tests for motor function study were 2.67 seconds in Silicon group and 5.92 seconds in SIS group. Rats in SIS group showed a better EMG response for distal motor latency and amplitude than in Silicon group. Histologically, all grafts contained some axons and myelination. However, the number of axons and the degree of myelination were significantly higher in SIS group than Silicon group. CONCLUSION: These results show that the porcine SIS was an excellent option as a natural biomaterial for peripheral nerve regeneration since this material contains many kinds of nerve growth factors. Furthermore, it could be used as a biocompatible barrier covering neural tissue.

Changes of ultrastructure of regenerative nerve fibers in response to application of sustained releasing agent FK506 / 中华创伤杂志

Objective To discuss the effect of the sustained releasing agent FK506 on the ultrastructure of the regenerative nerve fibers.Methods The new fusiform-shaped double channel nerve conduit was used for bridge the sciatic nerve defects for 10 mm in 32 Sprague-Dawley rats.The rats were divided into Group A(100μl chitin for both channels)and Group B(chitin plus FK506 for B1 and chitin plus normal saline for B2)according to different addition of the drugs.At 8 and 12 week after operation,the middle line of the regenerated nerve was observed under the transmission electron microscope.In the meantime,an analysis was done on the area of the regenerated nerve fibers(myelinated and unmyelinated),diameter and myelin thickness of the myelinated fiber axon at 8 and 16 months.Results There was not significant difference in aspects of type and number of the regenerative nerve fibers between two channels in Group A.However,the myelinated and unmyelinated fibers of the regenerative nerves were increased in Group B1,with larger area than Group B2(P ＜ 0.05).Conclusion FK506 can significantly promote the regeneration of both the myelinated and unmyelinated fibers.

Comparison of Processed Nerve Allograft and Laminin Derived Peptide Incorporated Nerve Conduit for Peripheral Nerve Regeneration / 대한정형외과학회잡지

PURPOSE: To compare a processed nerve allograft, laminin derived peptide incorporated nerve conduit, and autograft in terms of electrodiagnostic testing and nerve histomorphometry for peripheral nerve regeneration in a rabbit sciatic nerve defect model. MATERIALS AND METHODS: Thirty New Zealand white rabbits were divided into three groups, and a unilateral 15 mm sciatic nerve defect was made. Group I, II and III was repaired with a reversed autograft, a processed acellular nerve allograft, and a laminin derived peptide incorporated nerve conduit, respectively. At twelve weeks, the animals were evaluated with the compound muscle action potential, wet muscle weight, and nerve histomorphometric parameters such as nerve area, number of axons, and myelin thickness. RESULTS: At twelve weeks, the compound muscle action potential for group I, II and III was 54.1%, 38.2% and 26.4%, respectively. Significant differences were found between the three groups (p<0.001, group I vs II; p<0.001, group I vs III; p<0.001, group II vs III). The wet muscle weight for group I, II and III was 57.8%, 54.4% and 43.9%, respectively. Group I had significantly more muscle weight than group III (p<0.001), but the difference was not significant with group II (p=0.256). Group II and III showed a significant difference (p=0.002). The number of axons in group III decreased and the shape of the axon was irregular, even though the nerve area and myelin thickness were similar in the three groups. CONCLUSION: An autograft remains the gold standard to repair a segmental nerve defect. Processed allograft demonstrated superior nerve recovery compared to the laminin derived peptide incorporated nerve conduit.

Effect of nerve growth factor gene injection on the nerve regeneration in rat lingual nerve crush-injury model

Morphological study on the angiogenesis of peripheral nerve affected by nerve growth factor / 中国矫形外科杂志

[Objective]To discuss the effects of angiogenesis about nerve growth factor(NGF) during the peripheral nerve regeneration.[Method]Thirty-six Sprague-Dawley rats with 10mm gap of sciatic nerve were randomly divided into two groups which had been bridged with the new double channel nerve conduit of fusiform shape.Each group contained eighteen animals,in the first group,200 ?l of chitin for medical use was injected into the conduit,in the second group,the two branches of the conduit contained 100 ?l of the chitin and 5 ?l NGF or ciliary neurotrophic factor(CNTF).At four,eight or sixteen week after operation,the angiogenesis of NGF was evaluated with Hematoxylin and Eosin(HE) staining and electron microscope.[Result]There were not significant differences of the regenerative nerve fibres between two channels in the first groups,but in the second group,the regenerative nerve of NGF branch channel was red,crisp and the nerve of CNTF branch channel was yellow and tenacious.HE staining showed that there were much more new vessel in the regernerative nerve tract of NGF the branch channel,and the regernerative nerve fibre was disorder,there were much more fibroblasts and vessels observed under eletron microscope.[Conclusion]NGF can significantly promote the angiogenesis during the peripheral nerve regeneration,the mechanism may be related to fibroblast.

Experimental study of peripheral nerve regeneration by using non-tubular natural cellulose membrane nerve conduit

Styela clava, called non-native tunicate or sea squirt, is habitat which include bays and harbors in Korea and several sites in the sea faced world. We fabricate cellulose membrane nerve conduit (CMNC) from this native sea squirt skin, and evaluate the capacity of promoting peripheral nerve regeneration in the rat sciatic nerve defect model. After processing the pure cellulose membrane from the sea squirt skin as we already published before, CMNC was designed as a non-tubular sheet with 14 mm length and 4 mm width. Total eleven male Spraque-Dawley rats (12 weeks, weighing 250 to 300g) were divided into sham group (n=2), silicone tube grafted control group (n=3) and experimental group (n=6). Each CMNC grafted nerve was evaluated after 4, 8 and 12 weeks in the experimental group, and after 12 weeks, sciatic function was evaluated with sciatic function index (SFI) and gait analysis, and histomorphology of nerve conduit and the innervated tissues of sciatic nerve were all examined using image analyzer and electromicroscopic methods in the all groups. The regenerated axon and nerve sheath were found only in the inner surface of the CMNC after 4 weeks and became more thicker after 8 and 12 weeks. In the TEM study, CMNC grafted group showed more abundant organized myelinated nerve fibers with thickened extracellular matrix than silicone conduit grafted group after 12 weeks. The sciatic function index (SFI) and ankle stance angle (ASA) in the functional evaluation were -47.2+/-3.9, 35.5.+/-4.9.in CMNC grafted group (n=2) and -80.4+/-7.4, 29.2.+/-5.3.in silicone conduit grafted group (n=3), respectively. And the myelinated axon was 41.59% in CMNC group and 9.51% in silicone conduit group to the sham group. The development of a bioactive CMNC to replace autogenous nerve grafts offers a potential and available approach to improved peripheral nerve regeneration. As we already published before, small peptide fragment derived from the basement membrane matrix proteins of squirt skin, which is a kind of anchoring protein composed of glycocalyx, induced the effective axonal regeneration with rapid growth of Schwann cells beneath the inner surface of CMNC. So the possibilities of clinical application as a peripheral nerve regeneration will be able to be suggested.

Construction of hNGF-betarecombinant adenovirus and screening of its expression after transfection into various cell lines

A study of the effect of cultured bone marrow stromal cells on peripheral nerve regeneration

The role of cultured bone marrow stromal cells (BMSCs) in peripheral nerve regeneration was examined using an established rabbit peroneal nerve regeneration model. A 15-mm peroneal nerve defect was bridged with a vein filled with BMSCs (1 x 10(6)), which had been embedded in collagen gel. On the contralateral side, the defect was bridged with a vein filled with collagen gel alone. When the regenerated tissue was examined 4, 8 and 12 weeks after grafting, the number and diameter of the myelinated fibers in the side with the BMSCs were significantly higher than in the control side without the BMSCs. This demonstrates the potential of using cultured BMSCs in peripheral nerve regeneration.

Sciatic nerve regeneration using calcium phosphate coated conduit and brain-derived neurotrophic factor gene-transfected schwann cell in rat

PURPOSE OF STUDY: Peripheral nerve regeneration depends on neurotrophism of distal nerve stump, recovery potential of neuron, supporting cell like Schwann cell and neurotrophic factors such as BDNF. Peripheral nerve regeneration can be enhanced by the conduit which connects the both sides of transected nerve. The conduit maintains the effects of neurotrophism and BDNF produced by Schwann cells which can be made by gene therapy. In this study, we tried to enhance the peripheral nerve regeneration by using calcium phosphate coated porous conduit and BDNF-Adenovirus infected Schwann cells in sciatic nerve of rats. MATERIALS AND METHODS: Microporous filter which permits the tissue fluid essential for nerve regeneration and does not permit infiltration of fibroblasts, was made into 2mm diameter and 17mm length conduit. Then it was coated with calcium phosphate to improve the Schwann cell adhesion and survival. The coated filter was evaluated by SEM examination and MTT assay. For effective allogenic Schwann cell culture, dorsal root ganglia of 1-day old rat were extracted and treated with enzyme and antimitotic Ara-C. Human BDNF cDNA was obtained from cDNA library and amplified using PCR. BDNF gene was inserted into adenovirus shuttle vector pAACCMVpARS in which E1 was deleted. We infected the BDNF-Ad into 293 human mammary kidney cell-line and obtained the virus plaque 2 days later. RT-PCR was performed to evaluate the secretion of BDNF in infected Schwann cells. To determine the most optimal m.o.i of BDNF-Ad, we infected the Schwann cells with LacZ adenovirus in 1, 20, 50, 75, 100, 250 m.o.i for 2 hours and stained with beta-galactosidase. Rats(n=24) weighing around 300g were used. Total 14mm sciatic nerve defect was made and connected with calcium phosphate coated conduits. Schwann cells(1x10(6)) or BDNF-Ad infected Schwann cells(1x10(6)) were injected in conduit and only media(MEM) was injected in control group. Twelve weeks after surgery, degree of nerve regeneration was evaluated with gait analysis, electrophysiologic measurements and histomorphometric analysis. RESULTS: 1. Microporous Millipore filter was effective conduit which permitted the adhesion of Schwann cells and inhibited the adhesion of fibroblast. We could enhance the Schwann cell adhesion and survival by coating Millipore filter with calcium phosphate. 2. Schwann cell culture technique using repeated treatment of Ara-C and GDNF was established. The mean number of Schwann cells obtained 1 and 2 weeks after the culture were 1.54+/-4.0*10(6) and 9.66+/-9.6*10(6). 3. The mRNA of BDNF in BDNF-Ad infected Schwann cells was detected using RT-PCR. In Schwann cell 0.69 microgram/microliter of DNA was detected and in BDNF-Adenovirus transfected Schwann cell 0.795 microgram/microliter of DNA was detected. The most effective infection concentration was determined by LacZ Adenovirus and 75 m.o.i was found the most optimal. CONCLUSION: BDNF-Ad transfected Schwann cells successfully regenerated the 14mm nerve gap which was connected with calcium phosphate coated Millipore filter. The BDNF-Ad group showed better results compared with Schwann cells only group and control group in aspect to sciatic function index, electrophysiologic measurements and histomorphometric analysis.

Peripheral nerve regeneration using polyglycolic acid conduit and brain-derived neurotrophic factor gene transfected Schwann cells in rat sciatic nerve

PURPOSE: The essential triad for nerve regeneration is nerve conduit, supporting cell and neurotrophic factor. In order to improve the peripheral nerve regeneration, we used polyglycolic acid(PGA) tube and brain-derived neurotrophic factor(BDNF) gene transfected Schwann cells in sciatic nerve defects of SD rat. MATERIALS AND METHODS: Nerve conduits were made with PGA sheet and outer surface was coated with poly(lactic-co-glycolic acid) for mechanical strength and control the resorption rate. The diameter of conduit was 1.8mm and the length was 17mm. Schwann cells were harvested from dorsal root ganglion(DRG) of SD rat aged 1 day. Schwann cells were cultured on the PGA sheet to test the biocompatibility adhesion of Schwann cell. Human BDNF gene was obtained from cDNA library and amplified using PCR. BDNF gene was inserted into E1 deleted region of adenovirus shuttle vector, pAACCMVpARS. BDNF-adenovirus was multiplied in 293 cells and purified. The BDNF-Adenovirus was then infected to the cultured Schwann cells. Left sciatic nerve of SD rat (250g weighing) was exposed and 14mm defects were made. After bridging the defect with PGA conduit, culture medium(MEM), Schwann cells or BDNFAdenovirus infected Schwann cells were injected into the lumen of conduit, respectively. 12 weeks after operation, gait analysis for sciatic function index, electrophysiology and histomorphometry was performed. RESULTS: Cultured Schwann cells were well adhered to PGA sheet. Sciatic index of BDNF transfected group was -53.66+/-13.43 which was the best among three groups. The threshold of compound action potential was between 800 to 1000microA in experimental groups which is about 10 times higher than normal sciatic nerve. Conduction velocity and peak voltage of action potential of BDNF group was the highest among experimental groups. The myelin thickness and axonal density of BDNF group was significantly greater than the other groups. CONCLUSION: BDNF gene transfected Schwann cells could regenerate the sciatic nerve gap(14mm) of rat successfully.

Peripheral nerve regeneration using a three-dimensionally cultured schwann cell conduit

The use of artificial nerve conduit containing viable Schwann cells is one of the most promising strategies to repair the peripheral nerve injury. To fabricate an effective nerve conduit whose microstructure and internal environment are more favorable in the nerve regeneration than existing ones, a new three-dimensional Schwann cell culture technique using Matrigel(R) and dorsal root ganglion (DRG) was developed. Nerve conduit of three-dimensionally arranged Schwann cells was fabricated using direct seeding of freshly harvested DRG into a Matrigel(R) filled silicone tube (I.D. 1.98 mm, 14 mm length) and in vitro rafting culture for 2 weeks. The nerve regeneration efficacy of three-dimensionally cultured Schwann cell conduit (3D conduit group, n=6) was assessed using SD rat sciatic nerve defect of 10 mm, and compared with that of silicone conduit filled with Matrigel(R) and Schwann cells prepared from the conventional plain culture method (2D conduit group, n=6). After 12 weeks, sciatic function was evaluated with sciatic function index (SFI) and gait analysis, and histomorphology of nerve conduit and the innervated tissues of sciatic nerve were examined using image analyzer and electromicroscopic methods. The SFI and ankle stance angle (ASA) in the functional evaluation were -60.1+/-13.9, 37.9 degrees +/-5.4 degrees in 3D conduit group (n=5) and -87.0 +/-12.9, 32.2 degrees +/-4.8 degrees in 2D conduit group (n=4), respectively. And the myelinated axon was 44.91%+/-0.13% in 3D conduit group and 13.05%+/-1.95% in 2D conduit group to the sham group. In the TEM study, 3D conduit group showed more abundant myelinated nerve fibers with well organized and thickened extracellular collagen than 2D conduit group, and gastrocnemius muscle and biceps femoris tendon in 3D conduit group were less atrophied and showed decreased fibrosis with less fatty infiltration than 2D conduit group. In conclusion, new three-dimensional Schwann cell culture technique was established, and nerve conduit fabricated using this technique showed much improved nerve regeneration capacity than the silicone tube filled with Matrigel(R) and Schwann cells prepared from the conventional plain culture method.

THE EFFECTS OF ELECTRO-ACUPUNCTURE ON PERIPHERAL NERVE REGENERATION IN RATS / 体力科学

This study was undertaken to examine the effects of electro-acupuncture with direct current on peripheral nerve regeneration. Fifty-five 7 month old male rats were used in the present study. Sciatic nerve of each rat was crushed at the thigh, then the subject were divided into four groups as Cathode distal group (n=15), Anode distal group (n=14), Sham group (n=13), and Control group (n=13) . In the Cathode distal group, an insulated acupuncture needle which was inserted at lcm distal to the injured site was used as cathodal electrode, while a needle inserted at lcm proximal to the lesion was used as anodal electrode. In the Anode distal group, the needle at lcm distal and pro. ximal to the lesion were used as the anodal and the cathodal electrodes respectively. In the Sham group, no electrical stimulation were given to the insulated needle inserted at the same site as the aforementioned groups. In the Control group, no operation was given after crush injury. Regeneration of the sciatic nerve were evaluated with the number and the latency of the evoked EMG recorded at 12 sites in the foot, the behavioral test score (BTS) at 1, 2, 3, and 4 week after crush injury, weight ratio of the tibialis anterior and morphological study at 4 weeks after crush injury. Every kind of evaluation indicated that regeneration of the peripheral nerve was faster in the Cathode distal group than those in the other group. In the Anode distal group, the number of the evoked EMG and BTS were significantly lower than those in the Control group with tendency of longer latency and lesser muscle weight ratio. We suggested that electro-acupuncture with cathode distal orientation accelerated regeneration of the peripheral nerve after crush injury, while anode distal orientation delayed the regeneration. The electro-acupuncture with cathode distal orientation might be one of the useful treatment having advantage to perform deeper insertion with minimal invasion.

REGENERATION OF PERIPHERAL NERVE IN HETEROGENIC NERVE GRAFT / 解剖学报

Nerve segments were excised from the posterior limb of the adult dog and treated by repeated freezing and thawing for five times. A segment about 5 mm long was removed from the right tibial nerve proximal to the popliteal fossa of each experimental adult rabbit, and 8 mm of nerve segment from the dog prepared as above was transplanted in the gap. Both the proximal and distal ends of the tibial nerve of host rabbits were sutured to the graft nerve of the donor dog. The grafts were excised together with the sutured cut ends of the recipient tibial nerve at 3, 4, 5, 6, 7, 15, 18, and 31 weeks after transplantation. The regenerating nerve fibers were found by light microscope from the proximal end of the right tibial nerve to the graft, and from the graft to the distal part of the tibial nerve at 3, 4, 5, 6, 7, 15, 18 and 31 weeks. Under electron microscope regenerating myelinated and unmyelinated fibers were found to be separate or in fascicle in the graft and the distal segment of the tibial nerve at the above survival time after transplantation. Perineurium was seen surrounding the regenerating nerve fascicles. Neurotubules, neurofilaments and mitochondria were found in the regenerating axons. The diameter of the regenerating myelinated fibers with long survival time after transplatation was thicker than that with short survival time. Repeated freezing and thawing reduced the antigenicity of the heterogenic nerve that it was not rejected after transplantation, and induced the regenerating nerve fibers of the host grow into the graft nerve and extend distally.

EXPERIMENTAL STUDY ON THE RECONSTRUCTION OF THE NERVE-MUSCLE STRUCTURE AND FUNCTIONAL RECOVERY OF THE SCIATIC NERVE GAP BY ACELLULAR ALLOGRAFTS IN RAT / 解剖学报

Objective The experiment was designed to investigate the effect of acellular nerve allografts on the functional recovery and reconstruction of the nerve-muscle structure of the sciatic nerve defect in rats. Methods Acellular nerve allograft was transferred into the defected rat sciatic nerve with 10mm long.The wet weight of tibialis anterior was weighed at 12 and 24 weeks postoperatively compared with control group.The conducted velocity of regenerated nerve and the effect of regenerated nerve on tibialis anterior were investigated by electrophysiologic test,and silver staining combined with AChE histochemical methods were used in the experiment separately. Results The wet weight of tibialis anterior and the conducted velocity of regenerated nerve in experimental group were similar to those in control group in 12 and 24 weeks after transplantation.The positive acetylcholinesterase(AChE)histochemical reaction was observed in the tibialis anterior at 12 weeks with deeper staining and located in the middle of tibialis anterior tidily at 24 weeks after operation.The regenerated nerve bundles and nerve terminals were found to grow into the motor end-plate of the tibialis anterior in silver staining combined with AChE staining in experiment group.Electromyogram showed that the regenerated nerve has innervated tibialis anterior already.Conclusion The results indicated that extracted nerve allografts as a bridge can promote the motor functional recovery and reconstruction of the nerve-muscle structure of the defected rat sciatic nerve.