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。     

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。     

神经生长因子不同给药方式对坐骨神经吻合后修复与再生的影响*

背景：神经生长因子对神经损伤后的修复有促进作用,但目前对不同用药方式的优劣性尚有争议。 目的：观察鞘膜内与局部应用神经生长因子对兔坐骨神经吻合后修复与再生的影响。 方法：将24只新西兰大白兔坐骨神经切断后再缝合,分别向兔鞘膜内或损伤局部注射30 μg神经生长因子或等量生理盐水。 结果与结论：坐骨神经损伤后12周,鞘膜内注射神经生长因子组损伤坐骨神经鞘膜增厚,神经纤维排列较整齐,与正常神经纤维差异不大;且其神经干传导速度、有髓神经纤维数目、髓鞘厚度也明显高于其他组(P < 0.05),损伤局部注射神经生长因子组次之。说明神经生长因子具有促进外周神经吻合后修复与再生的功能,鞘膜内应用优于局部注射。     

新型仿生人工神经导管诱导犬周围神经再生过程的组织学观察**

背景：前期动物实验已经证明,精氨酸-甘氨酸-天冬氨酸多肽接枝聚(羟基乙酸-L-赖氨酸-乳酸)/β-磷酸三钙/神经生长因子导管可以修复大鼠坐骨神经10 mm缺损,该材料具有良好的生物相容性和细胞亲和性。 目的：观察精氨酸-甘氨酸-天冬氨酸多肽接枝聚(羟基乙酸-L-赖氨酸-乳酸)/聚乳酸/β-磷酸三钙/神经生长因子导管诱导犬周围神经再生过程的组织学变化。 方法：取健康成年杂种犬12只,建立30 mm腓总神经缺损模型,用精氨酸-甘氨酸-天冬氨酸多肽接枝聚(羟基乙酸-L-赖氨酸-乳酸)/聚乳酸/β-磷酸三钙/神经生长因子人工神经导管进行桥接修复。 结果与结论：修复后3个月时在神经远端即可发现新生神经纤维,随着时间的推移,再生神经轴突直径及髓鞘厚度不断增加,9个月时再生神经中可见较多发育成熟的有髓神经纤维。胫骨前肌损伤后出现逐渐萎缩,修复后6,9个月萎缩肌肉逐渐恢复。从组织学角度证实了精氨酸-甘氨酸-天冬氨酸多肽接枝聚(羟基乙酸-L-赖氨酸-乳酸)/聚乳酸/β-磷酸三钙/神经生长因子导管可修复大动物粗大神经缺损。      

PDLLA/NGF复合膜用于自体神经移植促进神经再生实验研究

目的：探讨外消旋聚乳酸／神经生长因子(PDLLA／NGF)复合膜用于自体神经移植是否具有促进神经再生作用。方法：雌性Wistar大白鼠16只，随机分为2组：A组(自体神经移植)8只；B组(自体神经移植并包绕PDLLA／NGF复合膜)8只。显露每只动物的右侧坐骨神经，A组将坐骨神经切除10mm长一段，以外膜缝合法行原位移植；B组与A组同样行神经原位移植并在远近两个神经缝接部位各包绕1块PDLLA／NGF复合膜(含NGF总量为400u)。6个月后观察比较两组神经再生情况。结果：B组的小腿三头肌湿重恢复率、运动神经传导速度、再生的有髓神经纤维数量、直径、轴突直径、髓鞘厚度均优于A组：结论：PDLLA／NGF复合膜包绕自体神经移植的神经缝接部位具有促进神经再生作用.     

Peripheral nerve repair of transplanted undifferentiated adipose tissue-derived stem cells in a biodegradable reinforced nerve conduit

This study proposes a biodegradable nerve conduit containing genipin-cross-linked gelatin annexed with tricalcium phosphate ceramic particles (genipin-gelatin-tricalcium phosphate, GGT) in peripheral nerve regeneration. Firstly, cytotoxicity tests revealed that the GGT-extracts were not toxic, and promoted the proliferation and neuronal differentiation of adipose tissue-derived stem cells (ADSCs). Secondly, the GGT composite film effectively supported ADSCs attachment and growth. Additionally, the GGT substrate was biocompatible with the neonatal rat sciatic nerve and produced a beneficial effect on peripheral nerve repair through in vitro tissue culture. Finally, the experiments in this study confirmed the effectiveness of a GGT/ADSCs nerve conduit as a guidance channel for repairing a 10-mm gap in a rat sciatic nerve. Eight weeks after implantation, the mean recovery index of compound muscle action potentials (CMAPs) was significantly different between the GGT/ADSCs and autografts groups (p < 0.05), both of which were significantly superior to the GGT group (p < 0.05). Furthermore, walking track analysis also showed a significantly higher sciatic function index (SFI) score (p < 0.05) and better toe spreading development in the GGT/ADSCs group than in the autograft group. Histological observations and immunohistochemistry revealed that the morphology and distribution patterns of nerve fibers in the GGT/ADSCs nerve conduits were similar to those of the autografts. The GGT nerve conduit offers a better scaffold for the incorporation of seeding undifferentiated ADSCs, and opens a new avenue to replace autologous nerve grafts for the rapid regeneration of damaged peripheral nerve tissues and an improved approach to patient care.     

Effects of nerve growth factor from genipin-crosslinked gelatin in polycaprolactone conduit on peripheral nerve regeneration--in vitro and in vivo

The gelatin solution crosslinked by genipin (0, 0.1, 0.5, 1.0, and 1.5% w/w) was studied as a nerve growth factor (NGF) carrier (GGp0, GGp0.1, GGp0.5, GGp1.0, and GGp1.5) in a polycaprolactone conduit in large-gap nerve regeneration. The GGp0 and GGp0.1 displayed the highest activity of PC12 cells and inhibited the reduction of 3-(4,5-dimethylthiazol-2-yl)2,5-diphenyl-tetrazolium bromide (MTT). No cytotoxicity was found in all groups by lactate dehydrogenase (LDH) release. The NGF-releasing characters were obtained by ELISA tests. A relatively fast release rate appeared during the first 10 days and then a subsequent slower release profile followed. NGF was higher in GGp0.1 than in GGp0 and GGp0.1 after 10 days. The bioactivity of the released NGF remains the same when measuring the neurite outgrowth of PC 12 cells. Finally, the controlled-release conduits were implanted into 12-mm long sciatic nerve gaps of rats. In addition, the best site of NGF carrier was determined either by filling carrier into the conduit lumen or by sucking carrier to the conduit wall. Four and 8 weeks after implantation, morphological analysis revealed that GGp0.1 conduits had markedly larger and more number of myelin axons in the midconduit and distal nerve. Further, sucking the carrier into the conduit wall was an efficient and convenient way to prevent the regeneration of axons and vessels from being impaired by the lumen's carrier. The genipin-crosslinked gelatin is a promising carrier in producing a high release concentration and a long release period of NGF to promote the regeneration over a large-gap nerve injury.     

Electrospun bio-composite P(LLA-CL)/collagen I/collagen III scaffolds for nerve tissue engineering

One of the biggest challenges in peripheral nerve tissue engineering is to create an artificial nerve graft that could mimic the extracellular matrix (ECM) and assist in nerve regeneration. Bio-composite nanofibrous scaffolds made from synthetic and natural polymeric blends provide suitable substrate for tissue engineering and it can be used as nerve guides eliminating the need of autologous nerve grafts. Nanotopography or orientation of the fibers within the scaffolds greatly influences the nerve cell morphology and outgrowth, and the alignment of the fibers ensures better contact guidance of the cells. In this study, poly (L-lactic acid)-co-poly(ε-caprolactone) or P(LLA-CL), collagen I and collagen III are utilized for the fabrication of nanofibers of different compositions and orientations (random and aligned) by electrospinning. The morphology, mechanical, physical, and chemical properties of the electrospun scaffolds along with their biocompatibility using C17.2 nerve stem cells are studied to identify the suitable material compositions and topography of the electrospun scaffolds required for peripheral nerve regeneration. Aligned P(LLA-CL)/collagen I/collagen III nanofibrous scaffolds with average diameter of 253 ± 102 nm were fabricated and characterized with a tensile strength of 11.59 ± 1.68 MPa. Cell proliferation studies showed 22% increase in cell proliferation on aligned P(LLA-CL)/collagen I/collagen III scaffolds compared with aligned pure P(LLA-CL) scaffolds. Results of our in vitro cell proliferation, cell-scaffold interaction, and neurofilament protein expression studies demonstrated that the electrospun aligned P(LLA-CL)/collagen I/collagen III nanofibrous scaffolds mimic more closely towards the ECM of nerve and have great potential as a substrate for accelerated regeneration of the nerve.     

Short- and long-term peripheral nerve regeneration using a poly-lactic-co-glycolic-acid scaffold containing nerve growth factor and glial cell line-derived neurotrophic factor releasing microspheres

Addition of neural growth factors to bioengineered scaffolds may improve peripheral nerve regeneration. The aim of this study is to evaluate the short- and long term effect of microsphere delivered nerve growth factor (NGF) and glial cell derived neurotrophic factor (GDNF) in the 10 mm rat sciatic nerve gap. Eighty-four rats were assigned to seven groups (n = 6) at two endpoints (6 and 16 weeks): saline, saline NGF, saline NGF-microspheres, saline GDNF, saline GDNF-microspheres, saline blank microspheres, and autologous nerve graft. Total fascicular area and total number of myelinated fibers at mid-tube increased in all conduit groups between 6 and 16 weeks. Autologous, saline NGF-microsphere and saline GDNF-microsphere groups reached maximal histomorphometric values by 6 weeks (p < 0.05). Compound muscle action potentials returned after 6 weeks for the autologous graft and continued to increase to a level of 3.6 ± 1.9 mV at endpoint. No significant differences were found between study groups as measured by ankle angle. These experiments show an initial beneficial effect of incorporation of NGF- or GDNF-microspheres in a PLGA 85/15 nerve conduit, since histomorphometric values reached their maximum by 6 weeks compared to control groups. These results do not yet extrapolate into improved electrophysiological or functional improvement.     

复合他克莫司聚乳酸-乙醇酸缓释导管修复大鼠胫神经缺损

背景：虽然单纯聚乳酸-乙醇酸导管修复大鼠神经缺损可部分恢复大鼠神经功能,但神经直径、再生纤维数量、髓鞘成熟度及功能恢复上均较自体神经移植差。 目的：观察复合他克莫司的聚乳酸-乙醇酸缓释导管修复大鼠胫神经缺损的可行性。 方法：制作SD大鼠右侧胫神经缺损模型,随机分为3组,分别植入自体胫神经、单纯聚乳酸-乙醇酸导管及复合他克莫司的聚乳酸-乙醇酸缓释导管修复。植入后3,6,12周行坐骨神经功能指数检查、电生理检查、组织学观测、腓肠肌湿质量测量。 结果与结论：植入后第6,12周复合他克莫司的聚乳酸-乙醇酸缓释导管组、自体胫神经组坐骨神经功能指数检查、电生理检查、组织学观测、腓肠肌湿质量测量结果优于单纯聚乳酸-乙醇酸导管组(P < 0.05),自体胫神经组、复合他克莫司的聚乳酸-乙醇酸缓释导管组比较差异无显著性意义。说明复合他克莫司的聚乳酸-乙醇酸缓释导管桥接修复大鼠胫神经缺损可明显促进断端神经的再生,在晚期功能恢复上取得接近自体神经移植的效果。 关键词：聚乳酸-乙醇酸;他克莫司;神经导管;大鼠;坐骨神经 doi:10.3969/j.issn.1673-8225.2012.12.003     

复合转化生长因子-β的组织工程化周围神经修复坐骨神经缺损

探讨了转化生长因子-β(Transforming growth factor-β,TGF-β)在周围神经缺损修复中的作用。将50 ng·ml-1 TGF-β加入体外培养的雪旺细胞(Sehwann cells,SC)中,MTT和流式细胞仪观测到TGF-β能够明显促进SC增殖;ELISA方法检测到TGF-β组上清神经生长因子(NGF)含量高于对照组(P<0．05);将牛去细胞基质(Bovine acellular matrix,BAM)、SC、血清和培养基按一定的比例混合,注入聚乳酸羟基乙酸共聚物(PLGA)神经导管去修复15 mm坐骨神经缺损。30只SD大鼠分为3组,实验组:PLGA导管 SC TGF-β;空白组PLGA导管 SC;和自体神经移植组。16周后通过电生理、透射电镜等检测方法显示各组坐骨神经均得到再生,修复效果实验组与自体神经移植组无显著性差异,均优于空白组。TGF-β一方面可以明显促进SC的增殖,另一方面可以增强SC分泌NGF的功能。因此周围神经修复过程中使用外源性的TGF-β对修复周围神经缺损有较好的疗效。     

载NGF海藻酸凝胶-聚乳酸复合导管修复兔面神经缺损实验研究

目的    观察载神经生长因子（nerve growth factors, NGF）海藻酸凝胶-聚乳酸复合导管修复面神经缺损的作用。  方法    建立白兔面神经缺损模型,将面神经断端植入制备好的载NGF海藻酸凝胶-聚乳酸复合导管内2 mm,使面神经两断端之间距离为10 mm,将导管两端与神经固定缝合皮肤。再随机将12只大白兔分为术后4、8、12周组。实验结束后切开大白兔面神经吻合部位,选取神经导管近、中和远端组织进行HE染色,观察神经生长及导管降解情况。  结果    实验白兔手术伤口Ⅰ期愈合,无局部坏死、移植物排出及全身不良反应。术后4周导管壁有巨噬细胞浸润,导管近端雪旺细胞、成纤维细胞增生,新生小血管丰富;8周可见导管壁变薄,有成纤维细胞附着,巨噬细胞浸润,导管内有神经束样结构,束间纤维分隔,外层纤维包膜增厚,新生小血管减少;12周可见神经导管壁进一步分解,胶原纤维增生,导管内神经纤维结构接近正常,轴突样结构增粗,外层纤维包膜变薄。  结论    载NGF海藻酸凝胶-聚乳酸复合导管能较好的引导面神经再生,具有良好的组织相容性。     

Sciatic nerve repair by reinforced nerve conduits made of gelatin-tricalcium phosphate composites

This study proposes a biodegradable GGT composite nerve guide conduit containing genipin-cross-linked gelatin and tricalcium phosphate (TCP) ceramic particles in peripheral nerve regeneration. The proposed genipin-cross-linked gelatin annexed with TCP ceramic particles (GGT) conduit was dark bluish and round with a rough and compact surface. Water uptake and swelling tests indicated that the hydrated GGT conduit exhibited increased stability with not collapsing or stenosis. The GGT conduit had higher mechanical properties than the genipin-cross-linked gelatin without TCP ceramic particles (GG) conduit and served as a better nerve guide conduit. Cytotoxicity tests revealed that the GGT conduit was not toxic and that it promoted the viability and growth of neural stem cells. The experiments in this study confirmed the effectiveness of the GGT conduit as a guidance channel for repairing a 10-mm gap in rat sciatic nerve. Walking track analysis showed a significantly higher sciatic function index score and better toe spreading development in the GGT group than in the silicone group 8 weeks after implantation. Gross examination revealed that the diameter of the intratubular newly formed nerve fibers in GGT conduits exceeded those in silicone tubes after the implantation period. Histological observations revealed that the morphology and distribution patterns of nerve fibers in the GGT conduits at 8 weeks after implantation were similar to those of normal nerves. The quantitative results indicated the superiority of the conduits over the silicone tubes. Motor functional and histomorphometric assessments demonstrate that the proposed GGT conduit is a suitable candidate for peripheral nerve repair.     

The effect of aligned core-shell nanofibres delivering NGF on the promotion of sciatic nerve regeneration

Recent bioengineering strategies for peripheral nerve regeneration have been focusing on the development of alternative treatments for nerve repair. In this study, we incorporated nerve growth factor (NGF) into aligned core-shell nanofibres by coaxial electrospinning, and reeled the scaffold into aligned fibrous nerve guidance conduits (NGCs) for nerve regeneration study. This aligned PLGA/NGF NGC combined physical guidance cues and biomolecular signals to closely mimic the native extracellular matrix (ECM). The effect of this aligned PLGA/NGF NGC on the promotion of nerve regeneration was evaluated in a 13-mm rat sciatic nerve defect using functional and morphological analysis. After 12 weeks implantation, the results of electrophysiological and muscle weight examination demonstrated that the functional recovery of the regenerated nerve in the PLGA/NGF NGC group was significantly better than that in the PLGA group, yet had no significant difference compared with the autograft group. The toluidine blue staining study showed that more nerve fibres were regenerated in the PLGA/NGF group, while the electron microscopy study indicated that the regenerated nerve in the PLGA/NGF group was more mature than that in the PLGA group. This study demonstrated that the aligned PLGA/NGF could greatly promote peripheral nerve regeneration and have a potential application in nerve regeneration.     

Affinity-based release of glial-derived neurotrophic factor from fibrin matrices enhances sciatic nerve regeneration

Glial-derived neurotrophic factor (GDNF) promotes both sensory and motor neuron survival. The delivery of GDNF to the peripheral nervous system has been shown to enhance regeneration following injury. In this study, we evaluated the effect of affinity-based delivery of GDNF from a fibrin matrix in a nerve guidance conduit on nerve regeneration in a 13 mm rat sciatic nerve defect. Seven experimental groups were evaluated which received GDNF or nerve growth factor (NGF) with the delivery system within the conduit, control groups excluding one or more components of the delivery system, and nerve isografts. Nerves were harvested 6 weeks after treatment for analysis by histomorphometry and electron microscopy. The use of the delivery system (DS) with either GDNF or NGF resulted in a higher frequency of nerve regeneration vs. control groups, as evidenced by a neural structure spanning the 13 mm gap. The GDNF DS and NGF DS groups were also similar to the nerve isograft group in measures of nerve fiber density, percent neural tissue and myelinated area measurements, but not in terms of total fiber counts. In addition, both groups contained a significantly greater percentage of larger diameter fibers, with GDNF DS having the largest in comparison to all groups, suggesting more mature neural content. The delivery of GDNF via the affinity-based delivery system can enhance peripheral nerve regeneration through a silicone conduit across a critical nerve gap and offers insight into potential future alternatives to the treatment of peripheral nerve injuries.     

Influence of nerve growth factor upon the injured peripheral nerve in the absence of its distal part

Transected peripheral nerve can be protected with different supplementations. One of them is implantation of dead-ended connective tissue chambers filled with fibrin and growth-promoting substances. The aim of this study was to find whether nerve growth factor (NGF) applied by means of such method exerts neuroprotective effect upon transected sciatic nerves. Study was performed on the adult male Wistar C rats. Connective tissue chambers grew around the silicone tubes implanted under their skin. Chambers were then filled with fibrin (control group) or fibrin with NGF solution (NGF group). Right sciatic nerve was cut, its distal stump was removed and its proximal stump was introduced into the chamber. Following 4 weeks DiI was applied to the free end of implant. The labeled motoneurons in the slices obtained from L3-L4 spinal cord segments and the number of myelinated nerve fibers present in the middle part of the chambers were counted. Acetylcholinesterase-positive fiber endings inside the chambers were also visualized. Our data showed that the number of motor neurons and their diameters as well as the number of myelinated fibers were higher in the NGF group when compared to the control group, but these differences were not significant. In both groups parallelly arranged acetylcholinesterase-positive nerve fibers were present. The obtained results show that NGF has no influence on regeneration of the motor component of the rat sciatic nerves in adult animals.     

巨噬细胞培养上清液促进大鼠坐骨神经损伤后修复的机制研究

目的 探讨巨噬细胞培养上清液促进大鼠坐骨神经损伤后修复的效果及机制.方法 SD雄性大鼠30只,体重200～250 g,随机分成对照组、观察组和模型组,每组10只,成功制作大鼠坐骨神经损伤离断模型后,对照组在吻合口间隙注射给予等量生理盐水,观察组注射巨噬细胞培养上清液,缝合后饲养12周处死。结果 观察组与对照组大鼠均无死亡。与对照组比,观察组大鼠坐骨神经电生理检测波幅[(0.16±0.04)V比(0.33±0.05)V,t=7.45,P=3.87E-05]和传导速度[(13.22±6.23)m/s比(24.54±6.36)m/s,t=4.02,P=3.01E-3)]显著提高,潜伏期[(0.74±0.06)ms比(0.53±0.04)ms,t=9.21,P=7.07E-06) ]缩短,差异有统计学意义.观察组坐骨神经形态学分析平均髓鞘厚度[(0.48±0.07)μm比(1.27±0.08)μm,t=23.50,P=2.18E-09) ]?神经纤维数量[(0.69±0.08)/HP比(3.22±0.06)/HP,t=80.01,P=3.77E-14) ]和有髓神经纤维平均直径[(1.08±0.39)μm比(3.63±0.42)μm,t=14.07,P=1.97E-07) ]显著增加,差异有统计学意义(P<0.05).观察组雪旺细胞表达的神经生长因子mRNA(NGF mRNA)[(0.13±0.04)比(0.42±0.05),t=14.32,P=1.68E-07) ]和层粘连蛋白mRNA[(0.07±0.03)比(0.38±0.06),t=14.61,P=1.41E-07) ]含量显著升高,差异有统计学意义(P<0.05).结论 巨噬细胞培养上清液可以有效促进大鼠坐骨神经损伤后修复,可能与促进雪旺细胞表达NGF和Laminin有关.     

Repair of peripheral nerve defects in rabbits using keratin hydrogel scaffolds

Entubulation of transected nerves using bioabsorbable conduits is a promising alternative to sural nerve autografting, but full functional recovery is rarely achieved. Numerous studies have suggested that scaffold-based conduit fillers may promote axon regeneration, but no neuroinductive biomaterial filler has been identified. We previously showed that a nerve guide filled with keratin hydrogel actively stimulates regeneration in a mouse model, and results in functional outcomes superior to empty conduits at early time points. The goal of the present study was to develop a peripheral nerve defect model in a rabbit and assess the effectiveness of a keratin hydrogel filler. Although repairs with keratin-filled conduits were not as consistently successful as autograft overall, the use of keratin resulted in a significant improvement in conduction delay compared to both empty conduits and autograft, as well as a significant improvement in amplitude recovery compared to empty conduits when measurable regeneration did occur. Taking into account all study animals (i.e., regenerated and nonregenerated), histological assessment showed that keratin-treated nerves had significantly greater myelin thickness than empty conduits. These data support the findings of our earlier study and suggest that keratin hydrogel fillers have the potential to be used clinically to improve conduit repair.     

Morphological analysis of peripheral nerve regenerated by means of vein grafts filled with fresh skeletal muscle

Clinical data have shown that a vein segment filled with fresh skeletal muscle can be considered a good autologous grafting conduit for the repair of peripheral nerve lesions. In this study, the long-term morphological organization of rat sciatic nerve fibers regenerated along a muscle-vein-combined graft conduit is further analysed by light and electron microscopy. Regenerated nerve fibers were organized into fascicles of various sizes that were clearly delimited by perineurial-like shells made by long and thin cytoplasmic processes of perineurial-like bipolar cells and by densely packed collagen fibrils. Grafted skeletal muscle fibers were still detectable among nerve fiber fascicles. However, in spite of the persistence of skeletal muscle along the graft, regenerated nerve fibers showed a good morphological pattern of regeneration, providing further evidence that the muscle-vein-combined grafting technique represents an effective surgical alternative to the classical fresh nerve autograft for the repair of peripheral nerve defects.     

Morphological analysis of peripheral nerve regenerated by means of vein grafts filled with fresh skeletal muscle

Clinical data have shown that a vein segment filled with fresh skeletal muscle can be considered a good autologous grafting conduit for the repair of peripheral nerve lesions. In this study, the long-term morphological organization of rat sciatic nerve fibers regenerated along a muscle-vein-combined graft conduit is further analysed by light and electron microscopy. Regenerated nerve fibers were organized into fascicles of various sizes that were clearly delimited by perineurial-like shells made by long and thin cytoplasmic processes of perineurial-like bipolar cells and by densely packed collagen fibrils. Grafted skeletal muscle fibers were still detectable among nerve fiber fascicles. However, in spite of the persistence of skeletal muscle along the graft, regenerated nerve fibers showed a good morphological pattern of regeneration, providing further evidence that the muscle-vein-combined grafting technique represents an effective surgical alternative to the classical fresh nerve autograft for the repair of peripheral nerve defects.