甲基强的松龙和神经干细胞移植联合治疗大鼠脊髓损伤

目的：观察甲基强的松龙和神经干细胞移植对大鼠脊髓损伤后神经结构修复和功能恢复的治疗作用并探讨其作用机制。方法：制备大鼠胸10脊髓损伤模型，体外培养、诱导分化大鼠神经干细胞，定量评价甲基强的松龙和神经干细胞移植对脊髓损伤后神经结构修复和功能恢复的影响。结果：与对照组相比，移植组明显地增强了生长相关蛋白（GAP－43）mRNA的表达，促进了乙酰胆碱转移酶（ChAT)阳性脊髓运动神经元的再生、神经结构的修复和下肢运动功能的恢复（P＜0．05）。结论：甲基强的松龙和神经干细胞移植通过增强GAP－43 mRNA的表达、运动神经元的再生而促进了脊髓损伤后神经结构的修复和功能的恢复，是急性脊髓损伤的一种有效的治疗方案。     

神经干细胞移植治疗脊髓损伤

目的:探讨神经干细胞移植对脊髓损伤大鼠后肢运动功能修复的影响。方法:SD大鼠36只,制成T10脊髓全横断损伤模型。于造模成功后1周采用局部微量注射法移植。随机分三组：A损伤对照组（n=12）仅打开椎管暴露脊髓;B移植对照组（n=12）：注射10μl DMEM/F12培养液;C细胞移植组（n=12）：移植1.0?06/ml的神经干细胞悬液10μl。移植后通过不同时间点BBB行为评分、病理组织学、免疫荧光技术评价大鼠大鼠脊髓功能修复情况及移植细胞在体内的存活、迁移、分化。 结果:在体外成功建立SD大鼠海马源性神经干细胞培养体系;B、C两组大鼠随着时间延长BBB评分均不同程度提高,从移植后2W起C组大鼠评分明显高于B组,两组比较差异有统计学意义（P<0.05）;神经干细胞移植后能够在体内继续存活、迁移并且分化为NF-200、GFAP表达阳性的神经元及星形胶质细胞。 结论:神经干细胞移植治疗脊髓损伤是一种有效的方法。     

大鼠坐骨神经修复后重组睫状神经营养因子对相关神经元生长相关蛋白43、生长抑素表达的影响

目的观察周围神经修复后，重组睫状神经营养因子(CNTF)对相关神经元中生长相关蛋白表达的调控作用。方法用硅管套接切断的成年大鼠坐骨神经，在神经切断处给予重组CNTF，用免疫组织化学和原位杂交组织化学方法结合计算机图像分析观测L4脊髓和L4、L5脊神经节中生长相关蛋白43(GAP43)和生长抑素(SOM)mRNA的相对含量。结果在CNTF组修复侧脊髓前角外侧核，大、中型神经元胞质中神经元GAP43阳性物质的面积百分率显著高于生理盐水组，SOM mRNA杂交信号阳性的大、中型神经元的数量少于生理盐水组，但两组脊神经节的相应指标无显著差别。结论坐骨神经修复后，外加重组CNTF能上调相关运动神经元表达GAP43，下调其表达SOM mRNA，但对感觉神经元的相应作用不明显。     

HRP逆行示踪评价复合骨髓间充质干细胞的无细胞神经移植物

背景：作者前期将无细胞神经移植物与骨髓间充质干细胞复合培养,成功构建了组织工程人工神经。 目的：应用辣根过氧化物酶(HRP)神经逆行示踪技术对无细胞神经移植物复合骨髓间充质干细胞构建的神经移植复合体桥接大鼠坐骨神经缺损后运动神经元的保护作用进行评价。 方法：成年清洁级健康雄性SD大鼠,随机分成3组：①实验组：采用复合骨髓间充质干细胞的无细胞神经移植物桥接大鼠坐骨神经缺损。②空白对照组：采用无细胞神经移植物桥接大鼠坐骨神经缺损。③自体神经对照组：采用自体神经移植桥接大鼠坐骨神经缺损。术后12周应用辣根过氧化物酶神经逆行示踪技术对脊髓前角运动神经元的再生进行评价。 结果与结论：术后12周脊髓前角运动神经元再生评价结果显示：实验组优于无细胞神经移植物组,而与自体神经移植物组相比差异无显著性意义。证实无细胞神经移植物复合骨髓间充质干细胞构建组织工程人工神经修复大鼠坐骨神经缺损,对大鼠脊髓运动神经元具有保护作用,可能达到与自体神经移植相似的效果。 关键词：无细胞神经移植物;骨髓间充质干细胞;辣根过氧化物酶;神经移植;大鼠     

重组腺病毒载体AxCA-BDNF基因转染修复坐骨神经损伤*☆

背景：如何促进周围神经损伤修复与再生一直是基础与临床研究的热点。基因治疗有可能成为今后解决该问题的主要手段之一。 目的：观察携带小鼠脑源性神经营养因子(brain-derived neurotrophic factor,BDNF) cDNA表达片段的重组腺病毒载体AxCA-BDNF转染大鼠损伤坐骨神经后BDNF的表达,以及脊髓前角运动神经元的存活和神经生长情况。 方法：切除成年Wistar大鼠股中部10 mm长的坐骨神经,AxCA-BDNF转染组、BDNF组和对照组分别用硅胶管内置AxCA-BDNF原液,BDNF溶液或空白病毒稀释液桥接坐骨神经两断端。术后3,7,14 d,1,2,4个月应用原位杂交和免疫组织化学方法检测损伤坐骨神经及相应脊髓节段BDNF mRNA和蛋白的表达,并观察损伤坐骨神经的组织学及超微结构改变,再生的神经元及有髓神经纤维数目和髓鞘厚度。 结果与结论：术后3,7,14 d及1个月时,AxCA-BDNF转染组损伤坐骨神经近、远端神经干及脊髓(L3~6)中BDNF mRNA和蛋白水平明显高于BDNF组和对照组(P < 0.01)。光、电镜病理组织学检查和图像分析证实,BDNF基因转染后,脊髓前角运动神经元存活数量、新生神经纤维数目及其髓鞘厚度、神经联接的再形成均明显优于对照组(P < 0.01)。说明经腺病毒介导转染的BDNF基因可在大鼠坐骨神经内有效表达,并通过轴突逆行转运到了相应的脊髓神经元,不仅能促进损伤神经纤维再生,也能保护损伤的脊髓神经元。 关键词：坐骨神经损伤;重组腺病毒;脑源性神经营养因子;基因转染;免疫组织化学;原位分子杂交;神经再生     

骨髓间充质干细胞移植对大鼠脊髓损伤后脑神经生长因子表达影响的研究

背景: 近年来关于骨髓间充质干细胞移植对脊髓损伤修复方面的研究较多,但目前相关机制尚不清楚。 目的：观察间充质干细胞移植对大鼠脊髓损伤后脑源性神经营养因子表达的影响。 设计、时间及地点：随机对照动物实验,于2003-04/07在中国医科大学神经解剖学实验室完成。 材料：选取鼠龄3个月的SD大鼠64只,雌雄不拘,体质量250~300 g,随机抽取4只大鼠用于骨髓间充质干细胞的分离与培养,其余60只用于制备脊髓横断损伤模型。 方法：60只大鼠随机抽签法分为3组,细胞移植组(n=24)：脊髓损伤后第7天,无菌条件下以微量注射缓慢注入含骨髓间充质干细胞(1×109 L-1)的培养液5 μL至脊髓损伤区;PBS组(n=24)：注入等量(5 μL)磷酸盐缓冲液体;空白对照组(n=12)：注入生理盐水5 μL。 主要观察指标：分别于造模后7,14,28 d取材,观察骨髓间充质干细胞的形态变化;免疫组织化学法检测间充质干细胞移植后大鼠脊髓损伤区脑源性神经营养因子的表达。 结果：60只SD大鼠均进入结果分析。10代以后细胞增殖能力有所减弱,胞体变得扁平,若加入碱性成纤维细胞生长因子,则可维持其增殖能力和形态。大鼠脑源性神经营养因子在正常大鼠脊髓组织中有一定表达,细胞移植后第7,14,28天,细胞移植组脑源性神经营养因子表达均高于PBS组和空白对照组(P < 0.05);空白对照组与PBS组脑源性神经营养因子表达无明显差异(P > 0.05)。 结论：骨髓间充质干细胞在移植后通过上调脑源性神经营养因子的表达从而促进轴突的再生,可能是治疗脊髓损伤的重要机制。     

TLR4基因突变对小鼠坐骨神经损伤修复的影响

目的 探讨Toll样受体4（TLR4）基因突变达对小鼠坐骨神经损伤修复的影响。方法 取10只C3H/HeJ小鼠（TLR4基因突变作为突变组,20只C3H/HeN小鼠（TLR4基因正常）随机分为假手术组（n=10）和模型组（n=10）。突变组和模型组在暴露的坐骨神经中部用止血钳夹持60 s以建立小鼠坐骨神经损伤模型,假手术组仅暴露坐骨神经而不进行夹伤。造模后4周,采用坐骨神经功能指数（SFI）评分评定坐骨神经功能,然后每组取3只小鼠行HE染色观察坐骨神经病理改变,每组取3只小鼠采用RT-PCR检测坐骨神经组织白细胞介素-1β（IL-1β）、肿瘤坏死因子-α（TNF-α）、白细胞介素-6（IL-6）mRNA表达水平,每组取4只小鼠采用免疫印迹法检测坐骨神经组织生长相关蛋白43（GAP43）、p75神经营养素受体（p75NTR）蛋白表达水平。结果 与假手术组相比,模型组SFI评分显著降低（P<0.05）,HE染色显示细胞形态异常并出现大量嗜中性粒细胞和巨噬细胞,坐骨神经组织IL-1β、IL-6、TNF-α mRNA表达水平以及GAP43、p75NTR蛋白表达水平均显著增高（P<0.05）。与模型组相比,突变组SFI评分明显增高（P<0.05）,组织结构病理改变明显改善,IL-1β、IL-6、TNF-α mRNA表达水平以及GAP43、p75NTR蛋白表达水平显著降低（P<0.05）。结论 TLR4基因突变可促进小鼠坐骨神经损伤后修复,可能与降低IL-1β、IL-6、TNF-α等炎症因子水平有关。     

脊髓损伤模型大鼠神经胶质细胞增殖与胶质纤维酸性蛋白的表达

背景：星形胶质细胞可以通过细胞裂解释放各种神经营养因子,并可促进损伤脊髓的修复。 目的：观察脊髓损伤模型大鼠神经胶质纤维酸性蛋白的表达及对其后肢功能恢复的影响。 方法：将SD大鼠采用Allen's法撞击T9~10节段致脊髓损伤,造模成功后蛛网膜下腔移植骨形态发生蛋白7,并设置仅蛛网膜下腔移植His蛋白的正常SD大鼠做对照。用BBB评分法评估两组大鼠后肢的运动功能,用免疫组织化学染色法和Western-blot法观察各组神经胶质纤维酸性蛋白的表达。 结果与结论：BBB评分结果显示,模型组大鼠脊髓损伤后下肢功能自行恢复率达68%。模型组脊髓损伤3和7 d,损伤区域神经胶质纤维酸性蛋白表达逐渐增加(P < 0.05),随后逐渐下降,于脊髓损伤28 d后逐渐恢复到对照组水平(P > 0.05)。脊髓损伤后1~14 d两组胶质纤维酸性蛋白表达逐渐升高(P > 0.05)。结果证实,脊髓损伤后蛛网膜下腔移植骨形态发生蛋白7可诱导星形胶质细胞增殖,神经胶质纤维酸性蛋白的表达增强,进而促进脊髓损伤大鼠后肢功能的恢复。     

重复经颅磁刺激对急性脊髓损伤大鼠运动功能的影响

目的 探讨重复经颅磁刺激对急性脊髓损伤大鼠运动功能的影响. 方法 24只SD大鼠按照随机数字表法分为正常组、脊髓损伤对照组(对照组)、脊髓损伤高频磁刺激组(高频组)、脊髓损伤低频磁刺激组(低频组),每组6只.利用重物撞击法制作T10脊髓损伤模型.磁刺激组于手术后24 h开始给予刺激,高频组频率为10Hz,低频组频率为1 Hz,均为阈值刺激.500个脉冲,每天1次,连续4周,脊髓损伤对照组给予假刺激.各组大鼠分别于术后1 d、3d、7d、11 d、14d、21 d、28 d进行BBB行为学评分,于14、28 d时检测运动诱发电位(MEP),应用HE染色观察脊髓组织形态学变化,并应用免疫组织化学法检测神经丝蛋白(NF-200)表达变化. 结果 高频组、低频组大鼠BBB评分明显高于对照组,高频组BBB评分明显高于低频组,差异均有统计学意义(P<0.05).高频组、低频组运动诱发电位潜伏期较短,与对照组、正常组相比差异均有统计学意义(P<0.05);其中高频组较低频组短,差异有统计学意义(P<0.05).高频组、低频组NF-200表达较对照组明显升高,差异均有统计学意义(P<0.05);其中高频组较低频组高,差异有统计学意义(P<0.05).结论 重复经颅磁刺激可以促进脊髓损伤大鼠运动功能的恢复,其机制可能与促进轴突再生有关.高频组较低频组效果明显可能与调节大脑皮层兴奋性有关.     

胶质细胞源性神经营养因子缓释微球及NogoA, ChABC缓释微球联合应用损伤脊髓再生的形态学变化*☆

摘要 背景：促进轴突再生的原则是改善抑制再生的环境和提高轴突生长能力,措施主要有轴突生长抑制因子阻滞剂和神经营养因子应用。用可降解微球加载药物是一种在局部提供持续药物释放的方法。 目的：探讨胶质细胞源性神经营养因子、NogoA、ChABC 缓释微球联合应用促进大鼠损伤脊髓再生病理形态学修复的作用。 方法：建立SD大鼠T10 脊髓完全横断伤模型,分别在损伤局部给予生理盐水、胶质细胞源性神经营养因子、胶质细胞源性神经营养因子缓释微球、NogoA缓释微球、ChABC 缓释微球及3种微球联合治疗,并设立未造模的正常组及假手术组。损伤后10周,每组行四甲基若丹明葡聚糖胺顺行示踪,及神经丝蛋白200、生长相关蛋白43、胶质细胞源性神经营养因子免疫组化检查,并采用免疫组化图像分析系统进行定量分析。 结果与结论：胶质细胞源性神经营养因子、NogoA、ChABC 缓释微球联合能提高脊髓损伤局部神经丝蛋白200、生长相关蛋白43、胶质纤维酸性蛋白的表达水平,显示局部脊髓再生修复加强,其效果优于单用胶质细胞源性神经营养因子缓释微球。提示,胶质细胞源性神经营养因子缓释微球及NogoA,ChABC 缓释微球联合促大鼠损伤脊髓再生修复其效果优于单用胶质细胞源性神经营养因子缓释微球。 关键词：胶质细胞源性神经营养因子;微球;聚乳酸-聚羟基乙酸共聚物;脊髓损伤;神经再生 doi:10.3969/j.issn.1673-8225.2011.03.014     

7, 8-dihydroxycoumarin improves neurological function in a mouse model of sciatic nerve injury

In the present study, a mouse model of sciatic nerve injury was treated with intraperitoneal injection of 7, 8-dihydroxycoumarin (10, 5, or 2.5 mg/kg per day). Western blot and real-time PCR results showed that growth associated protein 43 expression was significantly increased in the L4-6 seg-ments of the spinal cord. The amplitude and velocity of motor nerve conduction in the sciatic nerve were significantly increased in model mice. In addition, the appearance of the myelin sheath in the injured sciatic nerve was regular, with an even thickness and clear outline, and the surrounding fi-broplasia was not obvious. Our results indicate that 7, 8-dihydroxycoumarin can promote the repair of injured nerve by upregulating growth associated protein 43 expression in the corresponding spinal cord segments of mice with sciatic nerve injury.     

纤维蛋白凝胶携载血管内皮生长因子对大鼠损伤坐骨神经运动功能的影响

背景：坐骨神经损伤后的修复方法多样,但由于坐骨神经解剖和功能上的特殊性,神经功能的恢复仍不理想。 目的：观察局部应用纤维蛋白凝胶携载血管内皮生长因子,对损伤坐骨神经组织神经功能恢复的疗效。 方法：将Wistar大鼠左侧坐骨神经切断,神经两断端原位缝合,制作大鼠坐骨神经损伤动物模型,然后随机分为2组,实验组于坐骨神经切断处外膜内、外注射纤维蛋白凝胶/血管内皮生长因子复合体;对照组于同处注射血管内皮生长因子165质粒。于用药后4,8,12周行大体观察、神经功能指数检测、电生理检测(测运动神经传导速度)。 结果与结论：两组动物伤口均为一期愈合。实验组用药后1周有6只出现足底溃疡伴肌萎缩;对照组有5只出现足底溃疡。实验组4周时,纤维蛋白凝胶基本被吸收;8周时完全吸收;12周时,神经外形基本正常。对照组4周时,神经轻度充血、水肿;8周时,神经无水肿,与周围组织见少量粘连;12周时,神经周围见瘢痕形成。实验组4,8周的神经功能指数、运动神经传导速度较对照组降低(P < 0.05),12周无显著性差异(P > 0.05)。提示纤维蛋白凝胶可以作为血管内皮生长因子的载体,纤维蛋白凝胶携载血管内皮生长因子给药可以促进损伤神经结构和功能的恢复。 关键词：坐骨神经;损伤;纤维蛋白凝胶;血管内皮生长因子;载体 doi:10.3969/j.issn.1673-8225.2010.29.015     

钙通道阻滞剂对大鼠坐骨神经损伤后c-fos表达及神经功能的影响

目的探讨钙通道阻滞剂(CCB)对周围神经损伤后c-fos表达及神经功能的影响。方法制作坐骨神经嵌压性损伤大鼠模型,给予模型大鼠分别腹腔注射氟桂利嗪1mg/kg(低剂量组)、2mg/kg(高剂量组),或生理盐水10ml/kg(模型组)。在坐骨神经嵌压后第1周、第4周时取大鼠坐骨神经,采用免疫组织化学、行为医学和电生理学的方法测定c-fos阳性细胞数及第4周时足趾间距、神经传导速度(NCV);并与正常大鼠比较。结果(1)损伤后1周时,模型组、氟桂利嗪低剂量组坐骨神经c-fos阳性细胞数显著多于正常对照组(均P<0.01);氟桂利嗪高剂量组c-fos阳性细胞数轻度增加,也显著多于正常对照组(P<0.05),但明显少于模型组和氟桂利嗪低剂量组(均P<0.01);损伤4周时各组c-fos阳性细胞数均无明显增高。(2)损伤后4周时,模型组和氟桂利嗪低剂量组、高剂量组坐骨神经NCV显著慢于正常对照组(均P<0.01),氟桂利嗪低剂量组、高剂量组的NCV快于模型组(P<0.05,P<0.01)。(3)损伤后4周时,模型组大鼠右后肢足趾间距明显小于其他3组(均P<0.01);氟桂利嗪高剂量组、低剂量组与正常对照组比较差异无统计学意义(均P>0.05)。结论CCB使周围神经损伤后早期c-fos表达下调,并使神经功能受损减轻。     

Combination therapy using evening primrose oil and electrical stimulation to improve nerve function following a crush injury of sciatic nerve in male rats

Peripheral nerve injuries with a poor prognosis are common. Evening primrose oil (EPO) has beneficial biological effects and immunomodulatory properties. Since electrical activity plays a major role in neural regeneration, the present study investigated the effects of electrical stimulation (ES), combined with evening primrose oil (EPO), on sciatic nerve function after a crush injury in rats. In anesthetized rats, the sciatic nerve was crushed using small haemostatic forceps followed by ES and/or EPO treatment for 4 weeks. Functional recovery of the sciatic nerve was assessed using the sciatic functional index. Histopathological changes of gas-trocnemius muscle atrophy were investigated by light microscopy. Electrophysiological changes were assessed by the nerve conduction velocity of sciatic nerves. Immunohistochemistry was used to determine the remy-elination of the sciatic nerve following the interventions. EPO + ES, EPO, and ES obviously improved sciatic nerve function assessed by the sciatic functional index and nerve conduction velocity of the sciatic nerve at 28 days after operation. Expression of the peripheral nerve remyelination marker, protein zero (P0), was in-creased in the treatment groups at 28 days after operation. Muscle atrophy severity was decreased significantly while the nerve conduction velocity was increased significantly in rats with sciatic nerve injury in the injury+ EPO + ES group than in the EPO or ES group. Totally speaking, the combined use of EPO and ES may pro-duce an improving effect on the function of sciatic nerves injured by a crush. The increased expression of P0 may have contributed to improving the functional effects of combination therapy with EPO and ES as well as the electrophysiological and histopathological features of the injured peripheral nerve.     

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.     

Electrical stimulation does not enhance nerve regeneration if delayed after sciatic nerve injury: the role of fibrosis

Electrical stimulation has been shown to accelerate and enhance nerve regeneration in sensory and motor neurons after injury, but there is little evidence that focuses on the varying degrees of fibrosis in the delayed repair of peripheral nerve tissue. In this study, a rat model of sciatic nerve transection injury was repaired with a biodegradable conduit at 1 day, 1 week, 1 month and 2 months after injury, when the rats were divided into two subgroups. In the experimental group, rats were treated with electrical stimuli of frequency of 20 Hz, pulse width 100 ms and direct current voltage of 3 V; while rats in the control group received no electrical stimulation after the conduit operation. Histological results showed that stained collagen fibers comprised less than 20% of the total operated area in the two groups after delayed repair at both 1 day and 1 week but after longer delays, the collagen fiber area increased with the time after injury. Immunohistochemical staining revealed that the expression level of transforming growth factor β(an indicator of tissue fibrosis) decreased at both 1 day and 1 week after delayed repair but increased at both 1 and 2 months after delayed repair. These findings indicate that if the biodegradable conduit repair combined with electrical stimulation is delayed, it results in a poor outcome following sciatic nerve injury. One month after injury, tissue degeneration and distal fibrosis are apparent and are probably the main reason why electrical stimulation fails to promote nerve regeneration after delayed repair.     

改善微循环对大鼠坐骨神经损害血管内皮细胞生长因子表达及病理改变的影响

目的:探讨改善微循环对周围神经嵌压性损害血管内皮细胞生长因子(VEGF)表达和病理改变的影响。方法:分别检测坐骨神经嵌压后12、72h和7d背根神经节细胞VEGF水平与第4周神经干、神经节病理变化、脊髓病变神经元计数等,并运用正常对照组、模型组、前列地尔组和丁咯地尔组采用SPSS10.0统计软件进行方差分析统计处理。结果:嵌压后72hVEGF水平达到高峰,与正常对照组比较,其余各组均显著增加(P<0.01,P<0.05);前列地尔组和丁咯地尔组较模型组为优(P<0.01,P<0.05);嵌压后4周前列地尔组和丁咯地尔组的神经干、神经节病理变化、脊髓病变神经元计数均优于模型组(P<0.05)。结论:对于周围神经嵌压性损害,改善微循环可增加VEGF的表达并减轻其病理损害,从而对周围神经嵌压性损害的修复具有促进作用。     

Vitamin B complex and vitamin B12 levels after peripheral nerve injury

The aim of the present study was to evaluate whether tissue levels of vitamin B complex and vitamin B12 were altered after crush-induced peripheral nerve injury in an experimental rat model. A total of 80 male Wistar rats were randomized into one control (n = 8) and six study groups (1, 6, 12, 24 hours, 3, and 7 days after experimental nerve injury;n = 12 for each group). Crush-induced peripheral nerve injury was per-formed on the sciatic nerves of rats in six study groups. Tissue samples from the sites of peripheral nerve injury were obtained at 1, 6, 12, 24 hours, 3 and 7 days after experimental nerve injury. Enzyme-linked immunosorbent assay results showed that tissue levels of vitamin B complex and vitamin B12 in the injured sciatic nerve were signiifcantly greater at 1 and 12 hours after experimental nerve injury, while they were signiifcantly lower at 7 days than in control group. Tissue level of vitamin B12 in the injured sciatic nerve was signiifcantly lower at 1, 6, 12 and 24 hours than in the control group. These results suggest that tissue levels of vitamin B complex and vitamin B12 vary with progression of crush-induced peripheral nerve injury, and supplementation of these vitamins in the acute period may be beneficial for acceleration of nerve regeneration.     

Immediate electrical stimulation enhances regeneration and reinnervation and modulates spinal plastic changes after sciatic nerve injury and repair

We have studied whether electrical stimulation immediately after nerve injury may enhance axonal regeneration and modulate plastic changes at the spinal cord level underlying the appearance of hyperreflexia. Two groups of adult rats were subjected to sciatic nerve section followed by suture repair. One group (ES) received electrical stimulation (3 V, 0.1 ms at 20 Hz) for 1 h after injury. A second group served as control (C). Nerve conduction, H reflex, motor evoked potentials, and algesimetry tests were performed at 1, 3, 5, 7 and 9 weeks after surgery, to assess muscle reinnervation and changes in excitability of spinal cord circuitry. The electrophysiological results showed higher levels of reinnervation, and histological results a significantly higher number of regenerated myelinated fibers in the distal tibial nerve in group ES in comparison with group C. The monosynaptic H reflex was facilitated in the injured limb, to a higher degree in group C than in group ES. The amplitudes of motor evoked potentials were similar in both groups, although the MEP/M ratio was increased in group C compared to group ES, indicating mild central motor hyperexcitability. Immunohistochemical labeling of sensory afferents in the spinal cord dorsal horn showed prevention of the reduction in expression of substance P at one month postlesion in group ES. In conclusion, brief electrical stimulation applied after sciatic nerve injury promotes axonal regeneration over a long distance and reduces facilitation of spinal motor responses.     

Effect of the combination of high-frequency repetitive magnetic stimulation and neurotropin on injured sciatic nerve regeneration in rats

Repetitive magnetic stimulation is effective for treating posttraumatic neuropathies following spinal or axonal injury.Neurotropin is a potential treatment for nerve injuries like demyelinating diseases.This study sought to observe the effects of high-frequency repetitive magnetic stimulation,neurotropin and their combined use in the treatment of peripheral nerve injury in 32 adult male Sprague-Dawley rats.To create a sciatic nerve injury model,a 10 mm-nerve segment of the left sciatic nerve was cut and rotated through 180°and each end restored continuously with interrupted sutures.The rats were randomly divided into four groups.The control group received only a reversed autograft in the left sciatic nerve with no treatment.In the high-frequency repetitive magnetic stimulation group,peripheral high-frequency repetitive magnetic stimulation treatment(20 Hz,20 min/d)was delivered for 10 consecutive days after auto-grafting.In the neurotropin group,neurotropin therapy(0.96 NU/kg per day)was administrated for 10 consecutive days after surgery.In the combined group,the combination of peripheral high-frequency repetitive magnetic stimulation(20 Hz,20 min/d)and neurotropin(0.96 NU/kg per day)was given for 10 consecutive days after the operation.The Basso-Beattie-Bresnahan locomotor rating scale was used to assess the behavioral recovery of the injured nerve.The sciatic functional index was used to evaluate the recovery of motor functions.Toluidine blue staining was performed to determine the number of myelinated fibers in the distal and proximal grafts.Immunohistochemistry staining was used to detect the length of axons marked by neurofilament 200.Our results reveal that the Basso-Beattie-Bresnahan locomotor rating scale scores,sciatic functional index,the number of myelinated fibers in distal and proximal grafts were higher and axon lengths were longer in the high-frequency repetitive magnetic stimulation,neurotropin and combined groups compared with the control group.These measures were not significantly different among the high-frequency repetitive magnetic stimulation,neurotropin and combined groups.Therefore,our results suggest that peripheral high-frequency repetitive magnetic stimulation or neurotropin can promote the repair of injured sciatic nerves,but their combined use seems to offer no significant advantage.This study was approved by the Animal Ethics Committee of the Affiliated Changzhou No.2 People’s Hospital of Nanjing Medical University,China on December 23,2014(approval No.2014keyan002-01).