甲壳素神经导管修复大鼠坐骨神经10mm缺损的实验研究

探讨壳聚糖导管乙酰化反应而成的甲壳素神经导管修复周围神经缺损的效果.先将脱乙酰度92.5%的壳聚糖经溶解、冷冻、成形、中和、干燥等步骤制成壳聚糖导管,再经乙酰化反应制备成甲壳素神经导管.以该神经导管桥接大鼠坐骨神经10mm缺损.术后16周,通过电生理、组织形态学等方法评价神经导管修复坐骨神经缺损的效果.结果显示,术后16周再生神经已通过甲壳素神经导管长入远端.坐骨神经干重新恢复连续性,再生神经具有电传导功能,并实现对靶肌肉的再支配.缺损组则未观察到神经再生.实验表明,壳聚糖导管乙酰化而成的甲壳素神经导管能有效修复周围神经缺损.     

聚乳酸/神经生长因子缓释导管修复周围神经缺损实验研究

目的：观察聚乳酸／神经生长因子(PDLLA／NGF)缓释导管对大鼠坐骨神经缺损再生的促进作用及其性能、降解过程。方法：SD大鼠60只，随机分为4组：自体神经移植组(A组)，单纯PDLLA导管组(B组)，单纯导管加导管内一次性给药组(C组)，缓释导管组(D组)，每组15只。制作坐骨神经10mm缺损模型，分别用自体神经移植、单纯PDLLA导管、PDLLA／NGF缓释导管桥接修复。于第1、2、3月后行大体观察、三头肌湿重恢复率测量、电生理检测、组织学和图象分析对比。结果：同时间段组间比较，除三头肌恢复率低以外，D组再生神经取得了和A组相似的效果，明显比B组和C组恢复好。结论：PDLLA／NGF缓释导管桥接修复大鼠坐骨神经缺损，能够有效促进神经再生，效果接近自体神经移植。     

应用胶原-壳聚糖桥接管引导大鼠坐骨神经再生

目的:观察胶原-壳聚糖桥接管促进大鼠坐骨神经损伤后再生与修复的作用。方法:用壳聚糖和胶原蛋白按1∶3的比例采用冷冻干燥法制成胶原-壳聚糖复合导管;将20只雄性Wistar大鼠随机分为2组,胶原-壳聚糖导管组和硅胶管组,切断坐骨神经,建立10mm的缺损动物模型;分别用胶原-壳聚糖导管和硅胶管进行桥接。于术后不同时间对2组动物进行大体观察,并于术后14周进行电生理、组织学及逆行示踪检测,比较2组大鼠坐骨神经的再生和功能恢复情况。结果:术后14周2组动物坐骨神经再生和功能恢复情况的各项检测指标显示,胶原-壳聚糖桥接组明显优于硅胶管桥接组。结论:胶原-壳聚糖导管可用来桥接损伤神经,在周围神经缺损修复方面具有良好的应用前景。     

聚乳酸聚羟基乙酸共聚物三维神经导管修复周围神经缺损

背景:异体神经移植由于存在难以消除的宿主免疫排斥反应,限制了其使用,许多学者试图用其他组织替代来弥补以上不足,但效果均不满意。目前,尚没有研制出公认的效果满意的人工神经,自体神经移植至今仍被认为是最佳选择。目的:观察聚乳酸聚羟基乙酸共聚物(PLGA,85:15)三维神经导管修复大鼠周围神经缺损的可行性,及神经导管内微丝支架的作用和不同数量微丝对神经再生的影响。方法:40只成年SD大鼠随机数字表法分为4组,制作大鼠12mm的左侧坐骨神经缺损模型,用该导管桥接大鼠12mm的坐骨神经缺损。A组:PLGA神经导管组;B组:PLGA神经导管内纵形放入20根PLGA微丝;C组:PLGA神经导管内纵形放入40根PLGA微丝;D组:自体神经移植组。A、B、C组神经导管内均注入层粘蛋白+神经生长因子混合液。造模后动态观察大鼠肌肉萎缩、跛行情况,测量神经导管内再生神经的传导速度、小腿三头肌湿质量恢复率。对再生神经中1/3段行组织学观察及图像分析以评价神经修复的效果。结果与结论:造模后各组再生神经均已通过神经导管长入远端,B、D组再生神经较A、C组粗大;再生神经的运动神经传导速度B组和D组明显快于A组和C组(P0.05);A组、C组肌肉萎缩最明显,而B组、D组肌肉萎缩较轻且肌肉萎缩程度基本相当。病理图像分析神经纤维计数以D组最多,B组次之,而与A组、C组相比差异均有显著性意义(P0.05),B组与D组的再生神经纤维数量及成熟程度均要明显优于A组和C组。提示新型的PLGA三维神经导管能有效引导SD大鼠坐骨神经长过12mm的神经缺损,是一种较理想的神经导管;神经导管内微丝支架能有效引导神经再生,数量过多反而可能抑制神经再生。     

静电纺丝聚乳酸聚乙醇酸共聚物-丝素-胶原神经导管修复大鼠周围神经缺损

背景：周围神经缺损修复是临床上一大难题,由于自体神经移植有一定的局限性,人工神经修复材料是一种很有前途的选择。 目的：探讨静电纺丝聚乳酸聚乙醇酸共聚物(PLGA)-丝素-胶原纳米神经导管修复大鼠坐骨神经缺损的可能性。 方法：雌性SD大鼠36只,制备约10 mm的坐骨神经缺损,分别采用倒转自体神经、静电纺丝PLGA-丝素-胶原神经导管、单纯PLGA神经导管桥接,术后12周进行大体观察、神经电生理测定、光镜观察、透射电镜观察和图像分析对比,了解神经再生的情况。 结果与结论：静电纺丝法制备成的纳米神经导管管壁疏松多孔,能够模拟细胞外基质的结构。静电纺丝PLGA-丝 素-胶原神经导管组在促进坐骨神经再生、提高再生神经髓鞘化、加速再生神经功能重建等方面均优于单纯PLGA导管组,比自体神经移植组略差。     

PNGF导管复合骨髓间充质干细胞修复大鼠12 mm坐骨神经缺损

目的　观察RGD多肽接枝聚（乳酸-羟基乙酸-L-赖氨酸）/聚乳酸/β-磷酸三钙/神经生长因子（PRGD/PDLLA/β-TCP/NGF,PNGF）缓释导管复合骨髓间充质干细胞(Bone marrow derived mesenchymal stem cells, BMSCs)构建组织工程化人工神经,修复大鼠12 mm坐骨神经缺损的效果。  方法    雄性Wistar大鼠30只, 随机分为3组,每组10只,左后肢制作12 mm坐骨神经缺损模型,分别行单纯PNGF导管桥接（A）、PNGF导管复合BMSCs桥接（B）、自体神经移植（C）,所有大鼠左侧为实验侧,右侧为正常自身对照侧。术后3个月行大体观察、坐骨神经功能指数、电生理检测、小腿三头肌湿重恢复率测量、新生神经及靶肌肉组织学观察等检测坐骨神经功能恢复情况。  结果　术后3个月取材时见导管管壁变薄,表面血管化良好,管内有再生神经通过,直径较正常神经细。坐骨神经功能指数的检测结果显示PNGF导管复合BMSCs高于单纯PNGF导管组（P＜0.05）,PNGF导管复合BMSCs组神经传导速度恢复率、小腿三头肌湿重恢复率、有髓神经纤维数量和直径均优于单纯PNGF导管组（P＜0.01）,取得与自体神经移植组相似的效果。  结论　PNGF缓释导管复合BMSCs桥接修复大鼠坐骨神经缺损, 能够有效促进神经再生, 效果接近自体神经移植。     

异种神经脱细胞移植物修复周围神经缺损的实验研究

目的 探讨异种神经脱细胞移植物桥接大鼠坐骨神经缺损后的神经再生及其再生过程中免疫排斥反应. 方法用脱细胞兔周围神经作为移植物桥接大鼠坐骨神经1 cm缺损;术后3、5、8、11、15天检测血液中淋巴细胞占白细胞百分比;3个月后取移植物及腓肠肌,用甲苯胺蓝、乙酰胆碱酯酶（AchE）、琥珀酸脱氢酶（SDH）组化染色,光、电镜观察神经再生及腓肠肌运动终板的恢复情况. 结果术后大鼠血液中淋巴细胞占白细胞的百分比与正常大鼠相比较无显著性差异,3个月后大鼠术侧下肢足趾能分开,行走时后蹬动作有力,针刺足底有逃避反应,桥接物内见有大量再生的坐骨神经纤维,腓肠肌肌纤维上见有呈AchE阳性的运动终板和神经纤维.结论 异种神经脱细胞移植物桥接大鼠坐骨神经缺损具有促进其再生的作用.     

去细胞神经与自体神经移植桥接修复大鼠坐骨神经缺损的对比研究

目的观察同种异体去细胞神经与自体神经移植桥接修复大鼠坐骨神经缺损的神经再生情况。方法制备大鼠同种异体去细胞神经及大鼠坐骨神经缺损模型,修复12周后应用HE染色,Bielschowsky改良染色,Weil氏铁明矾苏木素染色,光镜下观察神经外膜上的微血管数和微血管面积百分比,计数单位面积的轴突数目,远端轴突密度/近端轴突密度为再生神经通过率,计数单位面积的有髓神经纤维数目和有髓神经纤维的直径。结果在坐骨神经纤维的再生神经纤维通过率、有髓神经纤维密度和直径、桥接体微血管的数目和微血管面积百分比等再生指标上,自体神经移植组略优于化学去细胞神经组。结论同种异体去细胞神经移植可促进神经再生,但仍然不如自体移植效果好。     

复合bFGF及肝素的外周神经桥接体在神经修复中的作用

目的：探讨bFGF和肝素与外周神经桥接体复合后在兔正中神经缺损修复中的作用。方法：成年雄性新西兰兔48只，建立左侧上臂正中神经30mm缺损。随机分为4组，分别用不同神经桥接体修复神经缺损，即A组为去细胞基膜管种植雪旺细胞并复合bFGF及肝素的桥接体、B组为去细胞基膜管种植雪旺细胞的桥接体、C组为去细胞基膜管复合bFGF及Hep桥接体、D组为自体神经作为对照。于术后1月、3月分别取材行HE及Masson’s三色染色，光镜观察神经再生、神经内胶原纤维形成及血管形成；3月检测各组桥接体运动神经传导速度，并行透射电镜检查，称量指浅屈肌肌肉湿重，观察神经功能恢复。结果：复合bFGF及肝素的桥接体组（A组、C组）神经再血管化及神经胶原形成与自体神经差异无统计学意义（P〉0.05），与B组比差异有显著统计学意义（P〈0．01）。A组神经再生数据（再生有髓神经纤维密度、平均髓鞘厚度、有髓纤维直径及运动神经传导速度、肌肉湿重恢复率）与自体神经移植（D组）比较，差异无统计学意义（P〉0.05）。结论：bFGF及肝素用于组织工程神经桥接体修复神经缺损，能提高神经桥接体再血管化水平，减少胶原纤维形成，促进轴突生长有利于神经再生质量的提高。     

人工组织神经移植物桥接修复缺损一月的大鼠坐骨神经

目的:用人工组织神经移植物桥接缺损1个月的大鼠坐骨神经,观察神经再生以及靶肌肉神经再支配的相关情况。方法:切除成年SD大鼠坐骨神经一段,造成1个月的神经缺损模型,用人工组织神经移植物进行桥接修复,3个月后进行神经及靶肌肉的观察。结果:术后3个月人工组织神经移植物组的复合肌动作电位、再生神经及腓肠肌的形态等和自体神经组接近,两组均明显优于缺损组。结论:人工组织神经移植物能在一定程度上修复缺损1个月的大鼠坐骨神经。     

神经导管修复周围神经损伤的研究进展

对神经导管在周围神经损伤的修复和再生的应用及研究进展作一综述。主要包括两方面内容：神经导管材料设计及导管内微环境构建。     

壳聚糖及相关材料用于神经修复的前景

壳聚糖（Chitosan）是一种具有优良的生物相容性的生物可降解材料,我们从壳聚糖的带正电性、吸附蛋白的能力、对神经细胞的特异性及表面的粗糙程度、孔径和表面形貌等方面叙述了壳聚糖的神经亲和性及壳聚糖与相关材料用于神经修复的进展和前景。     

Nerve in excitable state in microwave field

The study of electrical conductivity of excitable nerve membrane is made in the presence of microwave radiation. The behaviour of various ionic currents (such as sodium and potassium) of nerve in excitable state is predicted theoretically in the presence of microwave field. An electronic model is proposed and used to find the behaviour or nerve membrane. The curves of various ionic currents and membrane conductances are plotted for the squid, to show the various effects of microwave radiation field.     

壳聚糖和PHBHHx用作神经修复导管材料的研究

壳聚糖(Chitosan)和PHBHHx（羟基丁酸酯和羟基己酸酯共聚物）都是天然可降解材料。我们通过对这两种材料的亲水性、保持吸附蛋白有序结构的能力、胎鼠大脑皮层细胞在材料上生长情况以及两种材料的机械性能和后处理可加工性的研究，综合评价了它们作为神经修复导管材料的可行性。指出它们都有希望作为神经修复导管的材料。     

Fabrication Techniques of Nerve Guidance Conduits for Nerve Regeneration

Neuronal loss and axonal degeneration after spinal cord injury or peripheral injury result in the loss of sensory and motor functions. Nerve regeneration is a complicated and medical challenge that requires suitable guides to bridge nerve injury gaps and restore nerve function. Due to the hostility of the microenvironment in the lesion, multiple conditions should be fulfilled to achieve improved functional recovery. Many nerve conduits have been fabricated using various natural and synthetic polymers. The design and material of the nerve guide conduits were carefully reviewed. A detailed review was conducted on the fabrication method of the nerve guide conduit for nerve regeneration. The typical fabrication methods used to fabricate nerve conduits are dip coating, solvent casting, micropatterning, electrospinning, and additive manufacturing. The advantages and disadvantages of the fabrication methods were reported, and research to overcome these limitations was reviewed. Extensive reviews have focused on the biological functions and in vivo performance of polymeric nerve conduits. In this paper, we emphasize the fabrication method of nerve conduits by polymers and their properties. By learning from the existing candidates, we can advance the strategies for designing novel polymeric systems with better properties for nerve regeneration.     

Nerve guides manufactured from photocurable polymers to aid peripheral nerve repair

The peripheral nervous system has a limited innate capacity for self-repair following injury, and surgical intervention is often required. For injuries greater than a few millimeters autografting is standard practice although it is associated with donor site morbidity and is limited in its availability. Because of this, nerve guidance conduits (NGCs) can be viewed as an advantageous alternative, but currently have limited efficacy for short and large injury gaps in comparison to autograft. Current commercially available NGC designs rely on existing regulatory approved materials and traditional production methods, limiting improvement of their design. The aim of this study was to establish a novel method for NGC manufacture using a custom built laser-based microstereolithography (μSL) setup that incorporated a 405 nm laser source to produce 3D constructs with ∼50 μm resolution from a photocurable poly(ethylene glycol) resin. These were evaluated by SEM, in vitro neuronal, Schwann and dorsal root ganglion culture and in vivo using a thy-1-YFP-H mouse common fibular nerve injury model. NGCs with dimensions of 1 mm internal diameter × 5 mm length with a wall thickness of 250 μm were fabricated and capable of supporting re-innervation across a 3 mm injury gap after 21 days, with results close to that of an autograft control. The study provides a technology platform for the rapid microfabrication of biocompatible materials, a novel method for in vivo evaluation, and a benchmark for future development in more advanced NGC designs, biodegradable and larger device sizes, and longer-term implantation studies.     

Sympathetic Nerve Reconstruction for Compensatory Hyperhidrosis after Sympathetic Surgery for Primary Hyperhidrosis

We performed sympathetic nerve reconstruction using intercostal nerve in patients with severe compensatory hyperhidrosis after sympathetic surgery for primary hyperhidrosis, and analyzed the surgical results. From February 2004 to August 2007, sympathetic nerve reconstruction using intercostal nerve was performed in 19 patients. The subjected patients presented severe compensatory hyperhidrosis after thoracoscopic sympathetic surgery for primary hyperhidrosis. Reconstruction of sympathetic nerve was performed by thoracoscopic surgery except in 1 patient with severe pleural adhesion. The median interval between the initial sympathetic surgery and sympathetic nerve reconstruction was 47.2 (range: 3.5-110.7) months. Compensatory sweating after the reconstruction surgery improved in 9 patients, and 3 out of them had markedly improved symptoms. Sympathetic nerve reconstruction using intercostal nerve may be one of the useful surgical options for severe compensatory hyperhidrosis following sympathetic surgery for primary hyperhidrosis.     

Chronic Response of the Rat Sciatic Nerve to the Flat Interface Nerve Electrode

The chronic effects of a reshaping nerve electrode, the flat interface nerve electrode (FINE), on sciatic nerve physiology, histology, and blood–nerve barrier (BNB) are presented. The FINE electrode applies a small force to a nerve to reshape the nerve and fascicles into elongated ovals. This increases the interface between the nerve and electrode for selective stimulation and recording of peripheral nerve activity. The hypothesis of this study is that a small force applied noncircumferentially to a nerve can chronically reshape the nerve without effecting nerve physiology, histology, or the blood–nerve barrier permeability. Three FINE electrode designs were implanted on rat sciatic nerves to examine the nerve's response to small, moderate, and high reshaping forces. The chronic reshaping, physiology, and histology of the nerve were examined at 1, 7, and 28 days postimplant. All FINEs significantly reshape both the nerve and the fascicles compared to controls. FINEs that applied high forces caused a neurapraxia type injury characterized by changes in the animal's footprint, nerve histology, and the BNB permeability. The physiological changes were greatest at 7 days and fully recover to normal by 14 days postimplant. The moderate force FINE did not result in changes in the footprint or BNB permeability. Only a minor decrease in axon density without accompanying evidence of axon demyelination or regeneration was observe for the moderate force. The small force FINE does not cause any change in nerve physiology, histology, or BNB permeability compared to the sham treatment. An electrode that applies a small force that results in an estimated intrafascicular pressure of less than 30 mm Hg can reshape the nerve without significant changes in the nerve physiology or histology. These results support the conclusion that a small force chronically applied to the nerve reshapes the nerve without injury. © 2003 Biomedical Engineering Society. PAC2003: 8717Nn, 8719Nn, 8780Xa, 8719Uv     

高频电刀焦化处理神经残端预防痛性神经瘤的实验研究＊

目的研究高频电刀焦化处理神经残端预防痛性神经瘤形成的效果。方法取18只成年新西兰大白兔的左侧坐骨神经用高频电刀切断并焦化,右侧坐骨神经用锋利刀片切断处理,于术后2、4及8周各取大白兔6只观察神经残端大小并做组织切片进行比较,并采用SPSS13.0统计软件对标本大小进行分析。结果实验组与对照组的神经残端大小有显著差异,有统计学意义 组织学上对照组有明显的瘤体结构形成,而实验组只存在轻度的增生改变。结论利用高频电刀焦化处理神经预防残端神经瘤形成的是一种效果好,操作简单快捷的优良方法,本实验为临床应用提供了理论依据。     

修复周围神经缺损的组织工程研究

取有限的自体可牺牲的神经组织剥去外膜及束膜制成粗品雪旺氏细胞，并保留其中剖分基质，与２％壳聚糖凝胶制成混材料，加入外源性神经生长因子，注江表管内用以套接修复大鼠坐同有神经１００ｍｍ之缺损，术后１２周神经电生理测试及再生神经横面图像分析形态计量提示。