Functional collagen conduits combined with human mesenchymal stem cells promote regeneration after sciatic nerve transection in dogs

Numerous studies have focused on the development of novel and innovative approaches for the treatment of peripheral nerve injury using artificial nerve guide conduits. In this study, we attempted to bridge 3.5‐cm defects of the sciatic nerve with a longitudinally oriented collagen conduit (LOCC) loaded with human umbilical cord mesenchymal stem cells (hUC‐MSCs). The LOCC contains a bundle of longitudinally aligned collagenous fibres enclosed in a hollow collagen tube. Our previous studies showed that an LOCC combined with neurotrophic factors enhances peripheral nerve regeneration. However, it remained unknown whether an LOCC seeded with hUC‐MSCs could also promote regeneration. In this study, using various histological and electrophysiological analyses, we found that an LOCC provides mechanical support to newly growing nerves and functions as a structural scaffold for cells, thereby stimulating sciatic nerve regeneration. The LOCC and hUC‐MSCs synergistically promoted regeneration and improved the functional recovery in a dog model of sciatic nerve injury. Therefore, the combined use of an LOCC and hUC‐MSCs might have therapeutic potential for the treatment of peripheral nerve injury.     

负压吸引与大鼠损伤坐骨神经的修复和再生

背景：外周神经缺损的修复是目前创伤外科及修复重建外科临床上的一个难题,常用的神经移植、神经延长、神经桥接和组织工程等方法有局限性。目的：比较不同负压对大鼠损伤坐骨神经的修复和再生。方法：健康成年SD大鼠分别以6.65,13.30,19.95kPa压力对大鼠右侧离断坐骨神经近端行负压吸引。负压每吸引60min,休息30min,交替进行,连续4周。结果与结论：术后1个月,6.65,13.30,19.95kPa负压吸引的大鼠坐骨神经实验侧近端均有不同程度生长,且13.30kPa压力组生长长度明显优于6.65和19.95kPa组;对延长的神经进行组织学观察,发现延长神经的近侧部分轴突轴索较直,弯曲度较小,粗细均匀,髓鞘连续性良好,再生神经生长较好;中段部分神经纤维致密,成簇状排列,神经延长末端髓鞘成分减少,许旺细胞增殖明显。说明负压吸引可以促进大鼠坐骨神经的再生,且13.30kPa压力下更有利于神经再生。     

负压吸引与大鼠损伤坐骨神经的修复和再生

背景:外周神经缺损的修复是目前创伤外科及修复重建外科临床上的一个难题,常用的神经移植、神经延长、神经桥接和组织工程等方法有局限性。目的:比较不同负压对大鼠损伤坐骨神经的修复和再生。方法:健康成年SD大鼠分别以6.65,13.30,19.95kPa压力对大鼠右侧离断坐骨神经近端行负压吸引。负压每吸引60min,休息30min,交替进行,连续4周。结果与结论:术后1个月,6.65,13.30,19.95kPa负压吸引的大鼠坐骨神经实验侧近端均有不同程度生长,且13.30kPa压力组生长长度明显优于6.65和19.95kPa组;对延长的神经进行组织学观察,发现延长神经的近侧部分轴突轴索较直,弯曲度较小,粗细均匀,髓鞘连续性良好,再生神经生长较好;中段部分神经纤维致密,成簇状排列,神经延长末端髓鞘成分减少,许旺细胞增殖明显。说明负压吸引可以促进大鼠坐骨神经的再生,且13.30kPa压力下更有利于神经再生。     

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30μg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。     

Enhancement of nerve regeneration with nimodipine treatment after sciatic nerve injury

Peripheral nerve injuries (PNI/s) are common orthopedic conditions, characterized by motor and sensory deficits in the damaged region. There is growing evidence that the L-type calcium channel antagonist nimodipine has neuroprotective and neuroregenerative effects in animal models of neurological disorders. The efficacy of nimodipine on improving motor function and sensation following a sciatic nerve crush model was investigated in male Wistar rats as a model of PNI. At different time periods following damage, we evaluated motor function, sensory recovery, electrophysiology, histomorphometry, and gene expression. Moreover, we used histological and mass ratio analysis of the gastrocnemius muscle to assess atrophy. Our findings suggest that the nimodipine improves motor and sensory function more quickly in the damaged region 2, 4, and 6 weeks after 1 week of treatment. Nimodipine treatment also increased the number of myelinated fibers while decreasing their thickness, as shown by histomorphometry. Additionally, nimodipine treatment increases the mRNA levels of neurotrophic factors (BDNF and NGF), which are known to contribute to the regeneration of injured neurons. The impact of nimodipine in PNI recovery may be due to its stimulation of the CREB signaling pathway and suppression of pro-inflammatory factor production.     

丙戊酸钠对大鼠坐骨神经修复与再生的影响

目的:通过对坐骨神经损伤模型的药物实验研究,观察丙戊酸钠对大鼠周围神经损伤的修复作用。方法:实验于2004-07/11在武汉大学医学院动物实验中心进行。采用清洁级SD大鼠36只,行右坐骨神经横形切断后即刻原位吻合术,制成周围神经损伤模型后,随机分为丙戊酸钠组、对照组、维生素组。分别在给药后4,8,12周以坐骨神经功能指数(sciaticnervefunctionindex,SFI)、坐骨神经传导速度(nerveconductionvelocity,NCV)和坐骨神经轴突计数(sciaticnerveaxoncounting,NAC)为观测指标,判断神经功能的修复情况。结果:①术后4,8,12周坐骨神经功能指数检测结果:丙戊酸钠组分别为-74.75±1.55,-67.41±2.21,-55.29±0.82,明显好于对照组-84.60±2.00,-79.43±0.72,-73.41±0.94和维生素组-77.15±0.90,-73.55±0.92,-63.48±0.57(P均<0.05)。②再生神经运动诱发电位潜伏期检测结果:丙戊酸钠组分别为(2.19±0.13),(1.97±0.28),(1.61±0.73)ms,明显好于对照组(3.10±2.11),(2.62±1.79),(2.58±0.16)ms和维生素组(2.64±1.94),(2.59±0.67),(2.54±0.09)ms(P均<0.05)。③术后12周单位视野有髓神经纤维计数结果:丙戊酸钠用药组(152.33±7.88)个/视野优于对照组(116.08±12.63)个/视野和维生素组(136.42±11.41)个/视野(P均<0.     

电针对大鼠损伤坐骨神经再生的影响

目的:探讨电针对受损伤的周围神经功能恢复的影响。方法:Wistar大鼠60只切断左侧坐骨神经并缝合,随机分成电针组与模型组。电针组每天穴位电针20min。分别于术后2,4及8周动态观察髓纤维形态学变化、坐骨神经动作电位幅值的变化。模型组不作任何处理。结果:电针组坐骨神经动作电位幅值恢复率2,4及8周时分别为(11.98±4.12)%,(45.03±7.21)%,(82.41±15.97)%时优于模型组(9.46±4.17)%,(15.02±16.98)%,(33.97±7.46)%(P<0.05);有髓神经纤维数、有髓神经纤维直径及截面积在术后各观察点电针组明显多于模型组(P<0.01)。结论:穴位电针对损伤神经的再生和功能恢复有促进作用。     

Flunarizine selectively blocks transient calcium channel currents in N1E-115 cells.

The sensitivities of two types of voltage-dependent calcium channel currents in N1E-115 neuroblastoma cells to various agents were studied using the whole cell version of the patch clamp technique. Cells cultured in normal media expressed predominantly transient (T) currents whereas cells cultured in media with dimethylsulfoxide for 1 month expressed predominantly long-lasting (L) currents. Furthermore, by selecting cells with one or two short neurites it was possible to obtain cells which expressed only L channels. The dihydropyridine agonist, Bay K-8644 (5 microM), increased the amplitude of L channel currents by a factor of nearly two, whereas T channel currents were unaffected. Nifedipine (0.1 mM) significantly inhibited L channel currents, whereas T channel currents were insensitive to this treatment. Flunarizine, a diphenylpiperazine, had no effect on L channel currents but selectively inhibited T channel currents in a dose-dependent manner, with a significant effect at a concentration of 1 microM. However, flunarizine did not change the I-V relationships of T channel currents. Furthermore, the voltage dependence of T channel inactivation was shifted toward more negative potential by flunarizine. The present study provides direct evidence of the selective inhibition of T channel currents by flunarizine in N1E-115 neuroblastoma cells.     

Effects of ozone on sciatic nerve in rat

This study evaluated the influence of ozone on rat sciatic nerve structure and function. Thirty Wistar rats were randomly divided into six groups (n = 5). In groups I to IV, 1ml of ozone (O(3)) 10 μg/ml, 30 μg/ml, 50 μg/ml, 8 0 μg/ml was injected at the junction of gluteus maximus margin and lateral edge of the long head of biceps femoris respectively, in group V, 1 ml of pure O(2) was injected at the same point, and group V had puncture without any injection. Ozone was manufactured by an ozone generator (Ozone Line Co, Italy). The rats were investigated by both gross measurement and behavioral changes. One day, one week and three weeks after injection, rat hindlimb footprints were measured and the sciatic nerve function index (SFI) was calculated, and after three weeks, all right sciatic nerves were exposed under anesthesia. Near neural stimulation of the rat sciatic nerve was calculated and nerve conduction velocity, latency and maximum amplitude recorded. Animals were sacrificed for pathology, and ipsilateral triceps surae were taken for wet weight. No serious behavioral abnormalities were observed in any animal. SFI comparison in the various times and various groups showed no significant differences (p<0.05), and nerve conduction velocity, latency and maximum amplitude difference amongst the groups was not significant (p<0.05). There were no abnormalities in peripheral nerves pathologically after injection. Our initial study suggests that ozone concentrations from 10 μg/ml to 80 μg/ml injected around rat's peripheral nerve will not cause serious sequelae or serious damage to the structure and function of peripheral nerve. This finding provides evidence of the safety of ozone injected around the peripheral nerve.     

冷冻保存的雪旺细胞对损伤后坐骨神经再生影响的实验研究

目的比较原代培养雪旺细胞(Schwann cells,SCs)和冷冻保存的 SCs移植对损伤后坐骨神经再生的作用.方法原代培养和液氮保存的 SCs分别移植到桥接缺损坐骨神经的硅胶管内.在移植后不同时间,硅胶管远端神经干内注射 HRP,逆行追踪背根神经节和脊髓前角的标记神经元数量;测量再生神经纤维的复合动作电位传导速度;电镜观察再生神经纤维的髓鞘形成.结果原代培养和冷冻保存 SCs在移植后不同时间其背根神经节(术后 6周 3967.41± 305.91与 3890.55± 315.63, t=0.55, P > 0.05;术后 8周 4029.33± 313.80与 4184.90± 305.75, t=1.11, P > 0.05)和脊髓前角神经元 HRP标记细胞数量(术后 6周 404.87± 40.05与 429.77± 43.40, t=1.33,P > 0.05; 术后 8周 474.49± 42.74与 470.99± 38.82,t=0.19,P > 0.05)、再生神经纤维的复合动作电位传导速度 (m/s)基本一致(术后 6周 32.28± 1.96与 32.05± 2.31,t=0.24,P > 0.05; 术后 8周 43.60± 1.88与 43.84± 2.19,t=0.26,P > 0.05; 术后 12周 43.78± 1.71与 43.83± 1.75,t=0.06,P > 0.05),再生神经纤维髓鞘的形成未见明显差别.结论冷冻保存的 SCs仍具有促进损伤后周围神经再生的能力.     

神经生长因子对大鼠坐骨神经损伤修复的影响

以坐骨神经损伤的大鼠为动物模型，采用形态学方法，研究了外源性短暂给予较大剂量神经生长因子后，对大鼠周围神经损伤修复的影响。结果表明，神经生长因子可促进周围神经损伤的修复，该促进作用在早期较为明显，晚期则不明显，可能与神经生长因子进入体内的途径、方式、活性持续时间有关；损伤神经近侧端的再生修复好于远侧端，可能与其有利于接受胞体对再生修复的调节有关。     

De- and regeneration of axons after minor lesions in the rat sciatic nerve. Effects of microneurography electrode penetrations

The structural effects of microneurography electrode penetrations were examined in the rat sciatic nerve. Such penetrations always produced restricted peri- and endoneurial lesions, resulting in degeneration of myelinated and unmyelinated axons, as well as in demyelination. The regenerative response was vigorous, and the regenerating axons usually formed a separate region of fascicle. However, restitution was not complete after 9 weeks survival, and in some cases not even after 16 weeks.     

鼠肢芽提取液及运动对坐骨神经损伤修复的比较

目的:观察鼠肢芽提取液及运动对坐骨神经损伤修复的作用。方法:实验于2005-09/2006-09在湛江师范学院重点学科实验室完成。①实验分组:用成年Wistar怀孕大鼠肢芽制备提取液。出生3d Wistar乳鼠40只,行右侧坐骨神经切断术,按随机数字表法分为肢芽提取液非运动组、肢芽提取液运动组、生理盐水非运动组、生理盐水运动组,每组10只。肢芽提取液非运动组、肢芽提取液运动组损伤局部用鼠肢芽提取液每隔2d注射1次。肢芽提取液运动组乳鼠每天进行零坡度跑台运动训练,每周递增速度,25,30,35,40m/min。生理盐水非运动组、生理盐水运动组损伤局部注射等量的生理盐水。生理盐水运动组乳鼠运动时间和程度同上。②实验评估:术后30d肉眼观察坐骨神经失神经后有无水肿、充血、坏死,新生轴突长度、粗细等情况;光镜检查脊髓前角神经元胞体状况,尼氏染色Nissl小体状况(包括核、核仁)神经元有无浓缩、破碎、胶质细胞数量;运动神经元计数检查尼氏染色切片上双侧前角运动神经元数目,标准为能辨认出细胞核的神经元轮廓。结果:①肉眼观察坐骨神经失神经后状况:失神经后,局部有轻微水肿、充血、坏死,有新生轴突,肢芽提取液运动组新生轴突较粗较长,生理盐水非运动组局部严重水肿、充血、坏死,新生轴突,较细较短。②光镜下观察神经元情况:生理盐水非运动组神经元无浓缩、破碎不明显、胶质细胞数量稍有改变。肢芽提取液非运动组有些神经元浓缩、破碎、胶质细胞数量增多。肢芽提取液运动组神经元无浓缩、轻微破碎、胶质细胞数量增加。③运动神经元数目:术后30d肢芽提取液非运动组损伤侧神经元数目高于生理盐水非运动组,差异有显著性意义(t=2.85,P<0.005)。肢芽提取液运动组损伤侧神经元数目高于肢芽提取液非运动组,生理盐水运动组损伤侧神经元数目高于生理盐水非运动组,差异均有显著性意义(t=2.38,2.48,P<0.005)。④运动神经元存活率:乳鼠坐骨神经切断术后局部注射肢芽提取液,术后30d,运动乳鼠可维持损伤侧脊髓前角运动神经元存活率77.96%,非运动乳鼠存活率59.75%;局部注射生理盐水,运动乳鼠可维持损伤侧脊髓前角运动神经元存活率33.45%,非运动乳鼠存活率28.62%。结论:鼠肢芽提取液对坐骨神经损伤的修复作用显著,加入运动干预后恢复效果更佳。     

神经生长因子对挤压伤坐骨神经再生的促进作用

背景神经生长因子(nerve growth factor,NGF)不仅是维持促进中枢神经系统发育、分化、存活的基本的生长因子,而且在外周神经损伤的修复中也起着重要的作用.目的观察NGF肌注对大鼠坐骨神经挤压伤后神经再生恢复以及功能的影响.设计以实验动物为研究对象,随机对照的重复观察测量,探索性研究.单位一所军医大学的新药评价中心.材料实验于1999-07/2000-03在第二军医大学基础部新药评价中心完成.SD大鼠40只,雌雄各半,体质量200～250 g,上海西普尔-必凯实验动物有限公司提供.方法将40只大鼠随机分成NGF高、中、低剂量组,正常对照和模型对照组.距坐骨切迹远端6 mm处钳夹坐骨神经,使产生-4 mm宽的挤压伤.NGF高、中、低剂量组分别给予NGF 8,4和2μg/kg(1.6×103,8×102和4×102 IU/kg)药物,肌注1次/d,连续56 d.主要观察指标①手术后的不同时间神经传导速度(nerve conduction ve1ocities,NCV)和坐骨神经功能指数(sciatic functional index,SFI).②组织形态学评价.结果与模型对照组相比,高剂量组在35,56 d,中剂量组在35 d的NCV均显著加快(t=2.32～5.14,P＜0.05～0.01);高、中、低3个剂量组在手术14 d后的SFI与模型组相比,差异均有显著性意义(t=2.29～6.28,P＜0.05～0.01),且高剂量组恢复较明显,至56 d各剂量组SFI各组差异均无显著性意义;组织形态学显示,NGF治疗组神经髓鞘、轴索与正常对照组相比,差异无显著性意义;而模型组髓鞘出现脱失,细微结构不清晰,许旺细胞变性坏死.结论NGF对大鼠坐骨神经受损部位的神经髓鞘及轴索有明显的改善作用,能促进其神经纤维的再生及神经功能的恢复.     

毛囊干细胞对坐骨神经损伤修复的影响

背景:毛囊干细胞具有多分化潜能,可分化成神经细胞,极有希望成为治疗周围神经损伤的种子细胞。目的:观察毛囊干细胞对坐骨神经损伤修复的影响。方法:体外分离培养SD大鼠乳鼠胡须处的毛囊干细胞,经鉴定备用。36只SD大鼠随机分为实验组和对照组,建立坐骨神经损伤模型后,实验组于坐骨神经损伤处的上方注入浓度约106L-1的毛囊干细胞50μL,对照组注射等量的磷酸盐缓冲液。结果与结论:各组坐骨神经功能指数均随观察时间进行性增加,其中实验组大鼠神经功能恢复早于对照组;免疫组织化学检测移植后的毛囊干细胞大量存活并分化成神经细胞。结果提示毛囊干细胞能够有效的促进损伤的坐骨神经修复。     

不同剂量睫状神经营养因子对大鼠坐骨神经损伤后再生的影响

目的:探讨不同剂量睫状神经营养因子(ciliaryneurotrophicfactor,CNTF)对大鼠坐骨神经损伤后桥接再生影响。方法:选用30只大鼠分5组,每组6只,切除左侧坐骨神经6mm,用硅胶管10mm桥接坐骨神经的两个断端。其中治疗组CNTF一次给药量分别为500,300,100,50ng,对照组给生理盐水5μL。术后1个月活杀动物,观察坐骨神经近、远心端,新生神经纤维,脊髓,运动终板的变化。结果:电镜结果显示300和500ng治疗组,新生雪旺细胞及神经纤维较多。单个雪旺细胞内夹有神经纤维,髓鞘厚度均匀。其他各组有少许髓鞘样结构。新生神经纤维细小。光镜观察发现:300,500ng治疗组新生神经纤维较成熟,排列整齐。对照组新生的坐骨神经细小,远端有变性改变。结论:CNTF对坐骨神经损伤有促进再生作用,用量最好是300～500ng。     

丙烯酰胺对小鼠坐骨神经捻挫损伤后有髓纤维变性和再生的影响

背景:Ola鼠是一种基因变异鼠,其周围神经轴突损伤后华勒氏变性速度比正常的6J鼠缓慢,增加损伤因素可能有助于了解Ola鼠的特性。目的:观察丙烯酰胺对捻挫损伤后C57BL/Ola(Ola)鼠和C57BL/6J(6J)鼠坐骨神经有髓纤维变性和再生的不同病理过程。设计:随机对照实验。单位:深圳市第二人民医院神经内科和吉林大学第一医院神经内科。材料:实验于1996-01/06在日本产业医科大学神经内科进行。选择成年Ola鼠和6J鼠各12只,Ola鼠和6J鼠各6只为实验组,其余各6只为对照组。方法:全部动物麻醉状态下暴露坐骨神经上段,用止血钳捻挫神经近端10s后缝合。实验组动物注射总剂量为350mg的丙烯酰胺,对照组动物同时腹腔注射等量生理盐水。坐骨神经捻挫损伤后14d,全部动物再次麻醉,取捻挫部位远端坐骨神经制备切片,测量并计算神经横截面积,有髓纤维密度和有髓纤维大小频率分布和每根神经的有髓纤维数目。主要观察指标:两组中01a鼠和6J鼠坐骨神经的有髓纤维密度、有髓纤维数目、有髓纤维最大直径、有髓纤维平均直径。结果:参加实验Ola鼠和6J鼠各12只全部进入结果分析。①Ola鼠没有发生华勒氏变性;而6J鼠可见有髓纤维变性和许多变性后新生小径有髓纤维。②实验组6J鼠坐骨神经总有髓纤维密度低于Ola鼠(P<0.05);总有髓纤维数目少于Ola鼠(P<0.01),以大径纤维数目减少明显(P<0.01);有髓纤维平均直径也明显小于01a鼠(P<0.01)。结论:Ola鼠捻挫伤后华勒氏变性速度极其缓慢,丙烯酰胺对这一特征没有影响;丙烯酰胺对6J鼠捻挫损伤后轴突的再生过程有抑制作用。     

丙烯酰胺对小鼠坐骨神经捻挫损伤后有髓纤维变性和再生的影响

背景：Ola鼠是一种基因变异鼠，其周围神经轴突损伤后华勒氏变性速度比正常的6J鼠缓慢，增加损伤因素可能有助于了解Ola鼠的特性。目的：观察丙烯酰胺对捻挫损伤后C57BL／Ola（Ola）鼠和C57BL／6J（6D鼠坐骨神经有髓纤维变性和再生的不同病理过程。’设计：随机对照实验。单位：深圳市第二人民医院神经内科和吉林大学第一医院神经内科。材料：实验于1996-01／06在日本产业医科大学神经内科进行。选择成年Ola鼠和6J鼠各12只，Ola鼠和6J鼠各6只为实验组，其余各6只为对照组。方法：全部动物麻醉状态下暴露坐骨神经上段，用止血钳捻挫神经近端10s后缝合。实验组动物注射总剂量为350mg的丙烯酰胺，对照组动物同时腹腔注射等量生理盐水。坐骨神经捻挫损伤后14d，全部动物再次麻醉，取捻挫部位远端坐骨神经制备切片，测量并计算神经横截面积，有髓纤维密度和有髓纤维大小频率分布和每根神经的有髓纤维数目。主要观察指标：两组中Ola鼠和6J鼠坐骨神经的有髓纤维密度、有髓纤维数目、有髓纤维最大直径、有髓纤维平均直径。结果：参加实验Ola鼠和6J鼠各12只全部进入结果分析。①Ola鼠没有发生华勒氏变性；而6J鼠可见有髓纤维变性和许多变性后新生小径有髓纤维。②实验组6J鼠坐骨神经总有髓纤维密度低于Ola鼠（P〈0．05）；总有髓纤维数目少于Ola鼠（P〈0．01），以大径纤维数目减少明显（P〈0．01）；有髓纤维平均直径也明显小于Ola鼠（P〈0．01）。结论：Ola鼠捻挫伤后华勒氏变性速度极其缓慢，丙烯酰胺对这一特征没有影响；丙烯酰胺对6J鼠捻挫损伤后轴突的再生过程有抑制作用。     

骨骼肌卫星细胞异体移植对周围神经缺损后再生的影响

背景:有研究表明肌卫星细胞不仅在体外具有较强的增殖能力及适应能力,而且在异体内免疫原性低,免疫排斥反应低,移植后存活时间长.因此设想肌卫星细胞异体移植在促进缺损神经再生等方面可能具有良好的研究和应用前景.目的:探讨骨骼肌卫星细胞移植对周围神经缺损后再生修复的影响.方法:将16只Wistar大鼠随机分成移植组与对照组,每组8只,均切断右后肢坐骨神经,并通过生物可降解膜包裹缺损神经断端形成神经再生室.用微量注射器抽取己配制成的肌干细胞悬液0.2 mL注入移植组的神经再生室内.对照组注入等量的生理盐水.术后4,8和12周进行大鼠行步态测定,并用锇酸染色法制片观察缺损神经再生情况.观测大鼠坐骨神经功能指数、腓肠肌湿质量恢复率、再生的有髓神经纤维数量和直径及髓鞘厚度的变化.结果与结论:大鼠经肌卫星细胞移植后腓肠肌湿质量残存率、再生的有髓神经纤维数目、直径及髓鞘厚度等项检测指标与对照组相比均差异有显著性意义(P<0.05).术后8和12周,移植组坐骨神经功能指数恢复情况明显优于对照组(P<0.05).实验结果提示在神经再生室中加入肌卫星细胞能促进缺损神经纤维的再生及其结构的成熟.     

Histamine-induced intracellular free Ca++, inositol phosphates and electrical changes in murine N1E-115 neuroblastoma cells

Apparent intracellular free Ca++ concentration [(Ca++]i) was measured in differentiated N1E-115 neuroblastoma by microinjecting cells with aequorin (estimated intracellular concentration, 4 microM) and measuring light emission. Histamine produced a transient, dose-dependent increase in [Ca++]i. Pyrilamine blocked completely the response to histamine whereas cimetidine had no effect. Omitting Ca++ from the external medium reversibly blocked the response. As well as a rise in [Ca++]i, histamine caused a concomitant cell hyperpolarization that was not blocked by ouabain, low Cl-, tetraethylammonium chloride/tetradotoxin or metiamide but was blocked by apamin and pyrilamine. A secondary small depolarization caused by histamine was also blocked by apamin but not by ouabain, low Cl- or tetraethylammonium chloride/tetrodotoxin. Direct iontophoretic injection of Ca++ into cells caused only hyperpolarization. Injection of inositol 1,4,5-trisphosphate [IP3(1,4,5)] caused an increase in [Ca++]i and rapid hyperpolarization. Inositol 1,3,4-trisphosphate [IP3(1,3,4)] caused an increase in [Ca++]i, rapid hyperpolarization and a slower depolarization. Repeated injections of IP3(1,3,4) led to a diminished [Ca++]i response and decreased hyperpolarization but had no effect on depolarization. Inositol 1,3,4,5-tetrakisphosphate was without effect on [Ca++]i or on cellular membrane potential. The results suggest that histamine causes an H1 receptor-dependent increase in [Ca++]i, probably by the increased entry of extracellular Ca++, although there may be a contribution from intracellular Ca++ released by IP3(1,4,5). The increase in [Ca++]i activates K+ channels leading to cell hyperpolarization. IP3(1,3,4) formed from inositol 1,3,4,5-tetrakisphosphate, which is itself a product of IP3(1,4,5), causes a slower depolarization by a mechanism that does not involve Na+ channels or an increase in [Ca++]i.