Acellular allogeneic nerve grafting combined with bone marrow mesenchymal stem cell transplantation for the repair of long-segment sciatic nerve defects:biomechanics and validation of mathematical models

We hypothesized that a chemically extracted acellular allogeneic nerve graft used in combination with bone marrow mesenchymal stem cell transplantation would be an effective treatment for long-segment sciatic nerve defects. To test this, we established rabbit models of 30 mm sciatic nerve defects, and treated them using either an autograft or a chemically decellularized allogeneic nerve graft with or without simultaneous transplantation of bone marrow mesenchymal stem cells. We compared the tensile properties, electrophysiological function and morphology of the damaged nerve in each group. Sciatic nerves repaired by the allogeneic nerve graft combined with stem cell trans-plantation showed better recovery than those repaired by the acellular allogeneic nerve graft alone, and produced similar results to those observed with the autograft. These ifndings conifrm that a chemically extracted acellular allogeneic nerve graft combined with transplanta-tion of bone marrow mesenchymal stem cells is an effective method of repairing long-segment sciatic nerve defects.     

Autogenous inside-out versus standard vein and skeletal muscle-combined grafting for facial nerve repair

BACKGROUND: In the repair of nerve defects, collapse of the venous wall, as a result of vein grafting alone, could impede nerve regeneration. Therefore, vein lumens filled with muscle and nerve segments have been used to bridge nerve defects. OBJECTIVE: To compare the effects of autogenous, inside-out, vein-skeletal, muscle-combined grafting versus standard, vein-skeletal, muscle-combined grafting for the repair of facial nerve defects. DESIGN, TIME AND SETTING: A randomized, controlled, neuroanatomical, animal study was erformed at the Animal Experimental Center and Laboratories of the Capital Medical University Xuanwu Hospital and the Peking Union Medical College Hospital from September 2007 to October 2008. MATERIALS: A total of 10 healthy, male, New Zealand rabbits, aged 6 months, were randomly assigned to inside-out, vein-skeletal, muscle-combined grafting and standard, vein-skeletal, muscle-combined grafting groups, with 5 rabbits in each group. METHODS: A 20-mm gap in the buccal branch of the right facial nerve was made in each animal, which was respectively repaired with inside-out, vein-skeletal, muscle-combined grafts or standard vein-skeletal muscle-combined grafts. MAIN OUTCOME MEASURES: At 6 months after implantation, evoked maximal compound muscle action potentials were recorded on bilateral facial nerves using electromyogram. Myelinated nerve fibers of the regenerating nerves were quantified using myelin sheath osmic acid staining. RESULTS: There was no significant difference between the groups in terms of ratios of bilateral amplitude and latency of compound muscle action potential (P> 0.05). Moreover, morphology of regenerating nerves and quantity of myelinated nerve fibers were similar between the groups (P > 0.05). CONCLUTION: Compared with standard vein grafting, the inside-out vein grafting did not significantly improve nerve regeneration. Therefore, it is not necessary to utilize inside-out vein grafting for the repair of nerve defects, in particular with the combined use of autogenous vein and skeletal muscle grafts.     

组织工程周围神经修复坐骨神经缺损应用研究

目的应用组织工程方法构建周围神经以修复坐骨神经缺损.方法体外培养的雪旺细胞(SC)与牛去细胞基质(BAM)、胎牛血清和培养液按一定的比例混合注入聚乳酸聚羟基己酸共聚物(PLGA)导管中,构建成组织工程周围神经.30只SD大鼠随机分为3组,实验组:使用组织工程周围神经修复坐骨神经缺损;对照组:用不含雪旺细胞的导管修复;自体神经组:自体神经移植.16周后通过免疫组化、电生理、透射电镜、辣根过氧化物酶(HRP)逆行示踪及坐骨神经功能指数(SFI)等方法检测神经再生及坐骨神经功能恢复情况.结果 PLGA导管至16周已基本吸收,再生神经已通过缺损区长至远端,组织工程周围神经的修复效果接近自体神经组,优于空白组.结论体外构建的组织工程周围神经可以修复周围神经缺损.     

Combining acellular nerve allografis with brain- derived neurotrophic factor transfected bone marrow mesenchymal stem cells restores sciatic nerve injury better than either intervention alone

In this study, we chemically extracted acellular nerve allografts from bilateral sciatic nerves, and repaired 10-mm sciatic nerve defects in rats using these grafts and brain-derived neurotrophic factor transfected bone marrow mesenchymal stem cells. Experiments were performed in three groups： the acellular nerve allograft bridging group, acellular nerve allograft ＋ bone marrow mesenchymal stem cells group, and the acellular nerve allograft ＋ brain-derived neurotrophic factor transfected bone marrow mesenchyrnal stem cells group. Results showed that at 8 weeks after bridging, sciatic functional index, triceps wet weight recovery rate, myelin thickness, and number of myelinated nerve fibers were significantly changed in the three groups. Variations were the largest in the acellular nerve allograft ＋ brain-derived neurotrophic factor transfected bone marrow mesenchymal stem cells group compared with the other two groups. Experimental findings suggest that chemically extracted acellular nerve allograft combined nerve factor and mesenchymal stem cells can promote the restoration of sciatic nerve defects. The repair effect seen is better than the single application of acellular nerve allograft or acellular nerve allograft combined mesenchymal stem cell transplantation.     

Effects of 660‐nm gallium–aluminum–arsenide low‐energy laser on nerve regeneration after acellular nerve allograft in rats

Purpose : The purpose of this study was to explore and discuss the effects of 660‐nm gallium–aluminum–arsenide low‐energy laser (GaAlAs LEL) irradiation on neural regeneration after acellular nerve allograft repair of the sciatic nerve gap in rats. Methods : Eight male and female Sprague–Dawley rats were used as nerve donors, and 32 healthy Wistar rats were randomly divided into four groups: normal control group, acellular rat sciatic nerve (ARSN) group, laser group, and autograft group. Twelve weeks after surgery, nerve conduction velocity, restoration rate of tibialis anterior wet muscle weight, myelinated nerve number, and calcitonin gene‐related peptide (CGRP) protein and mRNA expression of the spinal cord and muscle at the injury site were quantified and statistically analyzed. Results : Compared with the ARSN group, laser therapy significantly increased nerve conduction velocity, restoration rate of tibialis anterior wet muscle weight, myelinated nerve number, and CGRP protein and mRNA expression of the L₄ spinal cord at the injury site. Conclusions : These findings demonstrate that 660‐nm GaAlAs LEL therapy upregulates CGRP protein and mRNA expression of the L₄ spinal cord at the injury site and increases the rate of regeneration and target reinnervation after acellular nerve allograft repair of the sciatic nerve gap in rats. Low‐energy laser irradiation may be a useful, noninvasive adjunct for promoting nerve regeneration in surgically induced defects repaired with ARSN. Synapse 64:152–160, 2010. © 2009 Wiley‐Liss, Inc.     

Effects of FK506 on nerve regeneration and reinnervation after graft or tube repair of long nerve gaps.

We compared the effects of FK506 administration on regeneration and reinnervation after sciatic nerve resection and repair with an autologous graft or with a silicone tube leaving a 6-mm gap in the mouse. Functional reinnervation was assessed by noninvasive methods to determine recovery of motor, sensory, and sweating functions in the hindpaw over 4 months after operation. Morphometric analysis of the regenerated nerves was performed at the end of follow-up. The nerve graft allowed for faster and higher levels of reinnervation in the four functions tested than silicone tube repair. Treatment with FK506 (for the first 9 weeks only) resulted in a slight, although not significant, improvement of the onset of reinnervation and of the maximal degree of recovery achieved after autografting. The recovery of pain sensibility and of the compound nerve action potentials in the digital nerves, which directly depend on axonal regeneration, showed better progression with FK506 than reinnervation of muscles and sweat glands, which require reestablishment of synaptic contacts with target cells. The myelinated fibers in the regenerated nerve showed a more mature appearance in the FK506-treated rats. However, FK506 showed a marginal effect in situations in which regeneration was limited, as in a silicone tube bridging a 6-mm gap in the mouse sciatic nerve. In conclusion, treatment with FK506 improved the rate of functional recovery after nerve resection and autograft repair.     

Chemically extracted aceUular allogeneic nerve graft combined with ciliary neurotrophic factor promotes sciatic nerve repair

A chemically extracted acellular allogeneic nerve graft can reduce postoperative immune rejection, similar to an autologous nerve graft, and can guide neural regeneration. However, it remains poorly understood whether a chemically extracted acellular allogeneic nerve graft combined with neurotrophic factors provides a good local environment for neural regeneration. This study investigated the repair of injured rat sciatic nerve using a chemically extracted acellular allogeneic nerve graft combined with ciliary neurotrophic factor. An autologous nerve anastomosis group and a chemical acellular allogeneic nerve bridging group were prepared as controls. At 8 weeks after repair, sciatic functional index, evoked potential amplitude of the soleus muscle, triceps wet weight recovery rate, total number of myelinated nerve fibers and myelin sheath thickness were measured. For these indices, values in the three groups showed the autologous nerve anastomosis group 〉 chemically extracted acellular nerve graft ＋ ciliary neurotrophic factor group 〉 chemical acellular allogeneic nerve bridging group. These results suggest that chemically extracted acellular nerve grafts combined with ciliary neurotrophic factor can repair sciatic nerve defects, and that this repair is inferior to autologous nerve anastomosis, but superior to chemically extracted acellular allogeneic nerve bridging alone.     

Etifoxine provides benefits in nerve repair with acellular nerve grafts

Introduction: Acellular nerve grafts are good candidates for nerve repair, but the clinical outcome of grafting is not always satisfactory. We investigated whether etifoxine could enhance nerve regeneration. Methods: Seventy‐two Sprague‐Dawley rats were divided into 3 groups: (1) autograft; (2) acellular nerve graft; and (3) acellular nerve graft plus etifoxine. Histological and electrophysiological examinations were performed to evaluate the efficacy of nerve regeneration. Walking‐track analysis was used to examine functional recovery. Quantitative polymerase chain reaction was used to evaluate changes in mRNA level. Results: Etifoxine: (i) increased expression of neurofilaments in regenerated axons; (ii) improved sciatic nerve regeneration measured by histological examination; (iii) increased nerve conduction velocity; (iv) improved walking behavior as measured by footprint analysis; and (v) boosted expression of neurotrophins. Conclusions: These results show that etifoxine can enhance peripheral nerve regeneration across large nerve gaps repaired by acellular nerve grafts by increasing expression of neurotrophins. Muscle Nerve 50:235–243, 2014     

Sensory reinnervation of muscle spindles after repair of tibial nerve defects using autogenous vein gratis

Motor reinnervation after repair of tibial nerve defects using autologous vein grafts in rats has previously been reported, but sensory reinnervation after the same repair has not been fully investigated. In this study, partial sensory reinnervation of muscle spindles was observed after repair of lO-mm left tibial nerve defects using autologous vein grafts with end-to-end anasto- mosis in rats, and functional recovery was confirmed by electrophysiological studies. There were no significant differences in the number, size, or electrophysiological function of reinnervated muscle spindles between the two experimental groups. These findings suggest that repair of short nerve defects with autologous vein grafts provides comparable results to immediate end-to-end anastomosis in terms of sensory reinnervation of muscle spindles.     

Chitosan tube bridging autologous nerve segments for the repair of long-segmental sciatic nerve defects

BACKGROUND:Previous tissue-engineered nerve studies have focused on artificial nerve and nerve cell cultures.The effects of regeneration chambers with autologous nerve bridging for the repair of nerve defects remain unclear.OBJECTIVE:To explore the feasibility and advantages of chitosan tube bridging autologous nerve segments for repairing 12-mm sciatic nerve defects in rats.DESIGN,TIME AND SETTING:A randomized,controlled,animal study using nerve tissue engineering was performed at the Animal Laboratory and Laboratory of Histology and Embryology,Liaoning Medical University from June 2008 to March 2009.MATERIALS:Chitosan powder was purchased from Jinan Haidebei Marine Bioengineering,China.METHODS:A sciatic nerve segment of approximately 8 mm was excised from the posterior margin of the piriformis muscle of Sprague Dawley rats.The two nerve ends shrank to form a 12-mm defect,and the nerve defect was repaired using a chitosan tube bridging autologous nerve segment (bridge group),a chitosan tube-encapsulated autologous nerve segment (encapsulation group),and a chitosan tube alone (chitosan tube alone group),respectively.MAIN OUTCOME MEASURES:Histological and ultrastructural changes of the injured sciatic nerve;number of regenerated myelinated nerve fibers; nerve conduction velocity; leg muscle atrophy; and sciatic nerve functional index.RESULTS:At 4 months after implantation,the chitosan tube was absorbed.The tube was thin,but maintained the original shape,and vascular proliferation was observed around the tube.In the bridge group,regenerative myelinated nerve fibers were thick and orderly,with a thick myelin sheath and intact axonal structure.The number of myelinated nerve fibers and nerve conduction velocity were significantly greater compared with the other groups (P< 0.01).Moreover,nerve and muscle function was significantly improved following chitosan tube bridging autologous nerve segment treatment compared with the other groups (P< 0.05 or P < 0.01).CONCLUSION:Chitosan tube bridging autologous nerve segments exhibited better repair effects on nerve defects compared with chitosan tubeencapsulated autologous nerve segments and a chitosan tube alone.This method provided a simple and effective treatment for long-segmental nerve defects.     

Ganglioside promotes the bridging of sciatic nerve defects in cryopreserved peripheral nerve allografts

Previous studies have shown that exogenous gangliosides promote nervous system regeneration and synapse formation.In this study,10 mm sciatic nerve segments from New Zealand rabbits were thawed from cryopreservation and were used for the repair of left sciatic nerve defects through allograft bridging.Three days later,1 m L ganglioside solution(1 g/L) was subcutaneously injected into the right hind leg of rabbits.Compared with non-injected rats,muscle wet weight ratio was increased at 2–12 weeks after modeling.The quantity of myelinated fibers in regenerated sciatic nerve,myelin thickness and fiber diameter were elevated at 4–12 weeks after modeling.Sciatic nerve potential amplitude and conduction velocity were raised at 8 and 12 weeks,while conduction latencies were decreased at 12 weeks.Experimental findings indicate that ganglioside can promote the regeneration of sciatic nerve defects after repair with cryopreserved peripheral nerve allografts.     

富血小板血浆诱导骨髓间充质干细胞修复坐骨神经缺损：并与自体神经修复的效果相比较

目的：通过植入经PRP诱导的BMSCs结合化学萃取的去细胞神经修复坐骨神经缺损,观察其对周围神经的修复作用。 方法：32只新西兰大耳白兔,随机分成4组,即单纯的化学萃取的去细胞神经、BMSCs结合化学萃取的去细胞神经、经PRP诱导的BMSCs结合化学萃取的去细胞神和自体神经修复坐骨神经缺损,检测指标包括形态学观察、靶肌肉肌湿重恢复率、运动神经传导速度（MNCV）及轴突直径和髓鞘厚度等。 结果：结果显示,靶肌肉肌湿重恢复率、MNCV、轴突直径和髓鞘厚度和形态学观察在经PRP诱导的BMSCs结合化学萃取的去细胞神经组明显优于单纯的化学萃取的去细胞神经组和BMSCs结合化学萃取的去细胞神经组,而与自体神经修复组结果相似。 结论：经诱导后的BMSCs在体内具有SC的部分功能,可作为组织工程化外周神经的种子细胞,用于周围神经缺损的修复。     

A novel tissue engineered nerve graft constructed with autologous vein and nerve microtissue repairs a long-segment sciatic nerve defect

Veins are easy to obtain, have low immunogenicity, and induce a relatively weak inflammatory response. Therefore, veins have the potential to be used as conduits for nerve regeneration. However, because of the presence of venous valves and the great elasticity of the venous wall, the vein is not conducive to nerve regeneration. In this study, a novel tissue engineered nerve graft was constructed by combining normal dissected nerve microtissue with an autologous vein graft for repairing 10-mm peripheral nerve defects in rats. Compared with rats given the vein graft alone, rats given the tissue engineered nerve graft had an improved sciatic static index, and a higher amplitude and shorter latency of compound muscle action potentials. Furthermore, rats implanted with the microtissue graft had a higher density and thickness of myelinated nerve fibers and reduced gastrocnemius muscle atrophy compared with rats implanted with the vein alone. However, the tissue engineered nerve graft had a lower ability to repair the defect than autogenous nerve transplantation. In summary, although the tissue engineered nerve graft constructed with autologous vein and nerve microtissue is not as effective as autologous nerve transplantation for repairing long-segment sciatic nerve defects, it may nonetheless have therapeutic potential for the clinical repair of long sciatic nerve defects. This study was approved by the Experimental Animal Ethics Committee of Chinese PLA General Hospital (approval No. 2016-x9-07) on September 7, 2016.

Chinese Library Classification No. R456; R363; R741     

A novel bioactive nerve conduit for the repair of peripheral nerve injury

The use of a nerve conduit provides an opportunity to regulate cytokines, growth factors and neurotrophins in peripheral nerve regeneration and avoid autograft defects. We constructed a poly-D-L-lactide(PDLLA)-based nerve conduit that was modified using poly{(lactic acid)-co-[(glycolic acid)-alt-(L-lysine)]} and β-tricalcium phosphate. The effectiveness of this bioactive PDLLA-based nerve conduit was compared to that of PDLLA-only conduit in the nerve regeneration following a 10-mm sciatic nerve injury in rats. We observed the nerve morphology in the early period of regeneration, 35 days post injury, using hematoxylin-eosin and methylene blue staining. Compared with the PDLLA conduit, the nerve fibers in the PDLLA-based bioactive nerve conduit were thicker and more regular in size. Muscle fibers in the soleus muscle had greater diameters in the PDLLA bioactive group than in the PDLLA only group. The PDLLA-based bioactive nerve conduit is a promising strategy for repair after sciatic nerve injury.     

Nanofibrous nerve conduits for repair of 30-mm-long sciatic nerve defects*

It has been confirmed that nanofibrous poly(3-hydroxybutyrate-co-3-hydroxyvalerate) nerve conduit can promote peripheral nerve regeneration in rats. However, its efficiency in repair of over 30-mm-long sciatic nerve defects needs to be assessed. In this study, we used a nanofibrous poly(3-hydroxybutyrate-co-3-hydroxyvalerate) nerve conduit to bridge a 30-mm-long gap in the rat sciatic nerve. At 4 months after nerve conduit implantation, regenerated nerves were macroscopically observed and histologically assessed. In the nanofibrous graft, the rat sciatic nerve trunk had been reconstructed by restoration of nerve continuity and formation of myelinated nerve fiber. There were Schwann cells and glial cells in the regenerated nerves. Masson’s trichrome staining showed that there were no pathological changes in the size and structure of gastrocnemius muscle cells on the operated side of rats. These findings suggest that nanofibrous poly(3-hydroxybutyrate-co-3-hydroxyvalerate) nerve conduit is suitable for repair of long-segment sciatic nerve defects.     

自体神经片段串联再生室修复神经缺损

背景：周围神经缺损在现代生产生活中极为常见,自体神经移植被公认为是修复神经缺损的“金标准”;但是自体神经来源受限,且会导致供区感觉功能障碍,感觉神经细小,无法满足较粗神经缺损的需要,限制了其在临床上的广泛应用。因此,人们一直在努力寻找一种自体神经替代物来桥接神经缺损,同种异体神经﹑自体非神经组织、高分子人工合成材料以及二十世纪80年代兴起的组织工程学人工神经研究,用于修复周围神经缺损,但效果都不理想,临床应用还有很大距离距。 目的：本研究即不是风靡世界的人工神经研究,也不是各种神经细胞的培养,而是从另外一个新角度,使神经缺损很简便易行的转化成多个再生室用自体神经片段串联起来,完成修复。探讨对长距离神经缺损修复的一种新方法。 设计、时间及地点：市场购买成品壳聚糖粉、胶原、CNTF、成年SD大耳白兔。随机分组。在辽宁医学院组织胚胎实验室,附属第一医院动物实验室于2009年6月至2010年1月实验完成。 材料：日本大耳白兔28只,辽宁医学院实验动物中心提供。成品壳聚糖粉、胶原、CNTF、Sigma公司产品。 方法：健康日本大耳白兔28只（4周龄）, 雌雄不限,随机分为A、B、C、D四组,每组7只。麻醉下解剖大耳白兔坐骨神经,分别在梨状肌下缘6mm以远,造成右侧坐骨神经12mm、16 mm、30mm的缺损。A组采用30mm自体神经切取后,翻转180度进行桥接;B、C、D组分别采用10mm自体神经片段串联两个等长(6mm、8mm、10mm)壳聚糖-胶原-CNTF复合再生室桥接坐骨神经缺损。 主要观察指标：四通道肌电图仪、BH-2型光学显微镜及摄像系统、日本日立H/7500电镜检测神经传导速度和再生神经有髓纤维数目。 结果：术后24周A、B、C、D四组坐骨神经传导速度（41.99±2.10）m/s （39.79±2.20 ）m/s（27.94±1.67）m/s（19.89±1.57）m/s;最远端所取标本神经纤维数目（612.8±7.63）.（604.5±7.18）.（341.8±7.19）.（276.2±7.52）。以上指标A、B组比较差异无统计学意义(P >0.05);A组与D、 C组比较差异有统计学意义（ P<0.05）。 结论：1、壳聚糖-胶原-CNTF再生室具有良好的组织相容性,对大白兔坐骨神经缺损具有良好的桥梁作用和促进神经生长作用。 2、串联两个6mm壳聚糖-胶原-CNTF复合再生室修复坐骨神经12mm缺损的效果,近似自体神经移植效果。 3、串联再生室自体神经片段的雪旺细胞是可以分泌多种神经活性物质,在有效趋化距离内,神经活性物质可充分发挥其作用。     

Bridging sciatic nerve gap using tissue-engineered nerves constructed with neural tissue-committed stem cells derived from bone marrow

BACKGROUND: Schwann cells are the most commonly used cells for tissue-engineered nerves. However, autologous Schwann cells are of limited use in a clinical context, and allogeneic Schwann cells induce immunological rejections. Cells that do not induce immunological rejections and that are relatively easy to acquire are urgently needed for transplantation.OBJECTIVE: To bridge sciatic nerve defects using tissue engineered nerves constructed with neural tissue-committed stem cells (NTCSCs) derived from bone marrow; to observe morphology and function of rat nerves following bridging; to determine the effect of autologous nerve transplantation, which serves as the gold standard for evaluating efficacy of tissue-engineered nerves.DESIGN, TIME AND SETTING: This randomized, controlled, animal experiment was performed in the Anatomical laboratory and Biomedical Institute of the Second Military Medical University of Chinese PLA between September 2004 and April 2006.MATERIALS: Five Sprague Dawley rats, aged 1 month and weighing 100-150 g, were used for cell culture. Sixty Sprague Dawiey rats aged 3 months and weighing 220-250 g, were used to establish neurological defect models. Nestin, neuron-specific enolase (NSE), glial fibrillary acidic protein (GFAP), and S-100 antibodies were provided by Santa Cruz Biotechnology, Inc., USA. Acellular nerve grafts were derived from dogs.METHODS: All rats, each with 1-cm gap created in the right sciatic nerve, were randomly assigned to three groups. Each group comprised 20 rats. Autograft nerve transplantation group: the severed 1-cm length nerve segment was reverted, but with the two ends exchanged; the proximal segment was sutured to the distal sciatic nerve stump and the distal segment to the proximal stump. Blank nerve scaffold transplantation group: a 1-cm length acellular nerve graft was used to bridge the sciatic nerve gap. NTCSC engineered nerve transplantation group: a 1-cm length acellular nerve graft, in which NTCSCs were inoculated, was used to bridge the sciatic nerve gap.MAIN OUTCOME MEASURES: Following surgery, sciatic nerve functional index and electrophysiology functions were evaluated for nerve conduction function, including conduction latency, conduction velocity, and action potential peak. Horseradish peroxidase (HRP, 20%) was injected into the gastrocnemius muscle to retrogradely label the L4 and L5 nerve ganglions, as well as neurons in the anterior horn of the spinal cord, in the three groups. Positive expression of nestin, NSE, GFAP, and S-100 were determined using an immunofluorescence double-labeling method.RESULTS: NTCSCs differentiated into neuronal-like cells and glial-like cells within 12 weeks after NTCSC engineered nerve transplantation. HRP retrograde tracing displayed a large amount of HRP-labeted neurons in L4-5 nerve ganglions, as well as the anterior horn of the spinal cord, in both the autograft nerve transplantation and the NTCSC engineered nerve transplantation groups. However, few HRP-labeled neurons were detected in the blank nerve scaffold transplantation group. Nerve bridges in the autograft nerve transplantation and NTCSC engineered nerve transplantation groups exhibited similar morphology to normal nerves. Neither fractures or broken nerve bridges nor neuromas were found after bridging the sciatic nerve gap with NTCSCs-inoculated acellular nerve graft, indicating repair. Conduction latency, action potential, and conduction velocity in the NTCSC engineered nerve transplantation group were identical to the autograft nerve transplantation group (P>0.05), but significantly different from the blank nerve scaffold transplantation group (P<0.05). CONCLUSION: NTCSC tissue-engineered nerves were able to repair injured nerves and facilitated restoration of nerve conduction function, similar to autograff nerve transplantation.     

同种异体神经复合体修复兔周围神经缺损

背景：应用种植许旺细胞的去细胞同种异体神经复合体修复周围神经缺损,探索其对神经再生及功能恢复有更好的促进作用,并且免疫原性非常小。 目的：用种植胎兔许旺细胞的去细胞同种异体神经复合体修复兔缺损的坐骨神经,观察移植神经周围免疫细胞的变化及功能恢复。 　 方法：48只新西兰白兔随机分成实验组和对照组。两组动物均切除一段坐骨神经,造成2.0 cm长的缺损,实验组用种植胎兔许旺细胞的同种异体神经复合体修复坐骨神经;对照组仅用去细胞同种异体神经修复。移植后1,4,8周光镜观察移植段坐骨神经周围肌肉组织中免疫细胞的浸润情况,计数每个高倍视野免疫细胞的数量。移植后4,8,16周大体观察兔的足部溃疡形成及愈合情况,大体观察神经愈合情况;肌电图检查桥接段坐骨神经的传导速度。 结果与结论：手术区局部均未出现明显的排斥反应,实验组足部溃疡愈合情况优于对照组。移植后1周移植段坐骨神经周围肌肉组织中有大量淋巴细胞及巨噬细胞浸润,实验组明显多于对照组(P < 0.05);移植后4周,浸润的免疫细胞两组均较1周后明显减少,实验组减少更明显。移植后8周,浸润的免疫细胞更加减少,但两组间比较差异无显著性意义(P > 0.05)。移植后4周时,两组均未见明显的神经传导,8,16周神经传导速度实验组均优于对照组(P < 0.05)。提示,种植许旺细胞的去细胞同种异体神经复合体免疫原性非常小,对神经再生及功能恢复有更好的促进作用。     

Calcitonin pump improves nerve regeneration after transection injury and repair

Introduction: After nerve injury, excessive calcium impedes nerve regeneration. We previously showed that calcitonin improved nerve regeneration in crush injury. We aimed to validate the direct effect of calcitonin on transected and repaired nerve. Methods: Two rat groups (n = 8) underwent sciatic nerve transection followed by direct repair. In the calcitonin group, a calcitonin‐filled mini‐osmotic pump was implanted subcutaneously, with a catheter parallel to the repaired nerve. The control group underwent repair only, without a pump. Evaluation and comparison between the groups included: (1) compound muscle action potential recording of the extensor digitorum longus (EDL) muscle; (2) tetanic muscle force test of EDL; (3) nerve calcium concentration; and (4) nerve fiber count and calcified spot count. Results: The calcitonin pump group showed superior recovery. Conclusions: Calcitonin affects injured and repaired peripheral nerve directly. The calcitonin‐filled mini‐osmotic pump improved nerve functional recovery by accelerating calcium absorption from the repaired nerve. This finding has potential clinical applications. Muscle Nerve 51 : 229–234, 2015     

Platelet-rich plasma gel in combination with Schwann cells for repair of sciatic nerve injury

Bone marrow mesenchymal stem cells were isolated from New Zealand white rabbits, culture-expanded and differentiated into Schwann cell-like cells. Autologous platelet-rich plasma and Schwann cell-like cells were mixed in suspension at a density of 1 × 10 6 cells/mL, prior to introduction into a poly (lactic-co-glycolic acid) conduit. Fabricated tissue-engineered nerves were implanted into rabbits to bridge 10 mm sciatic nerve defects (platelet-rich plasma group). Controls were established using fibrin as the seeding matrix for Schwann cell-like cells at identical density to construct tissue-engineered nerves (fibrin group). Twelve weeks after implantation, toluidine blue staining and scanning electron microscopy were used to demonstrate an increase in the number of regenerating nerve fibers and thickness of the myelin sheath in the platelet-rich plasma group compared with the fibrin group. Fluoro-gold retrograde labeling revealed that the number of Fluo-ro-gold-positive neurons in the dorsal root ganglion and the spinal cord anterior horn was greater in the platelet-rich plasma group than in the fibrin group. Electrophysiological examination confirmed that compound muscle action potential and nerve conduction velocity were superior in the plate-let-rich plasma group compared with the fibrin group. These results indicate that autologous plate-let-rich plasma gel can effectively serve as a seeding matrix for Schwann cell-like cells to construct tissue-engineered nerves to promote peripheral nerve regeneration.