脊髓半切动物模型的制作及SEP和MEP监测

目的:研究可靠的脊髓半切动物模型的制作方法和损伤后SEP和MEP的变化。方法:选用30只SD雄性大鼠.随机分成3 组,正常对照组、假手术组和脊髓半切组各10只。脊髓半切在手术显微镜下进行。脊髓半切分3步:定位中线、脊髓横旋切和确认半切。脊髓半切后2 h进行SEP和MEP检查,动物完全清醒后进行患侧后肢运动功能评价。结果:所有动物均成功进行脊髓半切, 脊髓半切侧的下肢完全瘫痪,对侧下肢受影响不明显。动物清醒后能自行排尿,无腹胀、血尿等。完全半切侧检验不到MEP和SEP;而未损伤侧的MEP波幅稍有下降,但与正常对照组和假手术组相比差异无统计学意义;未损伤侧与正常组、假手术组之间的MEP潜伏期以及SEP潜伏期和波幅的差异也无统计学意义。结论:脊髓半切的"三步法"准确而完全,是制作该动物模型简单有效的方法。MEP可能比SEP更敏感和可靠,更适合用于脊髓半切后半切是否完全和准确以及脊髓功能的客观判定指标之一。     

电针联合骨髓基质细胞移植对脊髓损伤大鼠神经功能恢复的影响

背景：研究认为骨髓基质细胞在损伤、缺血的脑脊髓组织中定向神经分化与损伤局部的微环境变化有关,特别是神经营养因子的诱导作用。课题组前期实验已证实,针刺可以通过增加各种细胞因子及营养因子的表达,促进神经的再生及修复。 目的：观察电针联合骨髓基质细胞移植对脊髓损伤大鼠神经功能恢复的影响。 设计、时间及地点：随机对照动物实验,于2005-03/2006-07在哈尔滨医科大学细胞生物实验室完成。 材料：健康纯系SD大鼠80只,取8只用于骨髓基质细胞的分离培养,剩余72只随机分为4组：空白对照组、细胞移植组、电针组、联合组,18只/组。KWD-808II型脉冲电针仪由江苏武进第三无线电厂生产。 方法：取体外分离培养的第3代骨髓基质细胞,移植前72 h行BrdU标记,调整细胞浓度为1×1011 L-1备用。4组大鼠均建立脊髓损伤模型,造模后细胞移植组将骨髓基质细胞悬液缓慢注入到脊髓损伤临近区域的灰白质交界处,总细胞数6×105个;空白对照组同法注射等量磷酸盐缓冲液;电针组于造模成功后24 h采用脉冲电针仪进行夹脊电针治疗,在距损伤处上下端两个椎体的棘突间隙旁开距中线3.0~4.0 mm处取穴,针刺20 min,1次/d;联合组行骨髓基质细胞移植+夹脊电针治疗。 主要观察指标：移植后 3,7,14 d,应用联合行为评分评估大鼠脊髓损伤后神经功能的改善状况;免疫双标法检测BrdU标记的骨髓基质细胞胶质纤维酸性蛋白、神经元烯醇化酶的表达。 结果：损伤后3,7,14 d与空白对照组比较,细胞移植组、电针组、联合组联合行为评分均有显著性差异(P < 0.05,0.05,0.01);联合组神经功能恢复情况明显优于细胞移植组、电针组(P < 0.05);而细胞移植组、电针组之间比较无明显差异(P > 0.05)。与空白对照组相比,细胞移植组、电针组损伤区脊髓结构相对较完整,联合组脊髓结构更加完整,骨髓基质细胞移植的组织内可见 BrdU标记细胞在损伤区及其周边区明显聚集并存活;移植后14 d细胞移植组神经元烯醇化酶和胶质纤维酸性蛋白阳性细胞率分别分7.2%和1.5%,联合组阳性细胞率分别为7.9%和2.1%。 结论：骨髓基质细胞移植后可在宿主体内存活,电针可以促进骨髓基质细胞向神经细胞的分化,电针与骨髓基质细胞移植联合应用可以明显改善脊髓损伤大鼠的运动及感觉功能。     

骨髓间质干细胞移植对大鼠脊髓损伤神经功能恢复的影响

目的：观察成人骨髓间质干细胞（hBMSCs)移植对大鼠脊髓损伤神经功能恢复的影响.方法：Wistar大鼠90只，随机分为脊髓半切＋hBMSCs组、脊髓半切＋PBS组、单纯脊髓半切组和假手术组。脊髓半切＋hBMSCs组和PBS组又分别分为头侧注射、尾侧注射和头尾两侧注射三个亚组。移植后1、7、14、21、28d观察大鼠神经功能恢复情况，应用免疫组化和免疫荧光技术检测BrdU标记hBMSCs的胶质纤维酸性蛋白（GFAP）和神经元特异性核蛋白（NeuN)表达情况。结果：大鼠脊髓半切损害后，hBMSCs组动物较PBS组死亡率下降并有明显的神经功能恢复。移植的hBMSCs 在宿主脊髓中存活，从第7天开始即有NeuN和GFAP表达并向损伤部位及对侧迁移，第28天hBMSCs来源GFAP阳性细胞可见明显的树突生长。结论：hBMSCs可在宿主损伤脊髓中存活、向损伤部位迁移并向神经元和星形胶质细胞分化，并促进神经功能恢复，降低死亡率，成人骨髓间质干细胞作为一种独特的干细胞来源用于治疗脊髓损伤可能具有非常重要的价值。     

微囊化兔坐骨神经组织细胞移植对大鼠损伤脊髓核因子κB表达的影响

BACKGROUND： It has been reported that nuclear factor-kappa B （NF- κB）, activated after spinal cord injury in rats, plays a key role in inflammatory responses in the central nervous system. OBJECTIVE： To investigate the effects of transplantation of microencapsulated rabbit sciatic nerve on NF- κB expression and motor function after spinal cord injury in rats, and to compare the results with the transplantation of rabbit sciatic nerve alone. DESIGN, TIME AND SETTING： This completely randomized, controlled study was performed at the Department of Neurobiology, Medical College of Nanchang University between December 2007 and July 2008. MATERIALS： A rabbit anti-NF- κB P65 monoclonal antibody was made by the Santa Cruz Company, USA and a streptavidin peroxidase immunohistochemical kit was provided by the Sequoia Company, China. METHODS： Eight rabbits were used to prepare a sciatic nerve cell suspension that was divided into two parts： one stored for transplantation, and the other mixed with a 1.5% sodium alginate solution. One hundred and twenty adult Sprague Dawley rats weighing 220-250 g were randomly divided into four groups： the microencapsulated cell group （n = 36）, the non-encapsulated cell group （n = 36）, the saline group （n = 36） and the sham operation group （n = 12）. The first three groups underwent a right hemisection injury of the spinal cord at the T10 level, into which was transplanted a gelatin sponge soaked with 10 μL of a microencapsulated nerve tissue/cell suspension （microencapsulated cell group）, a tissue/cell suspension （non-encapsulated cell group） or physiological saline （saline group）. In the sham operation group the vertebrae were exposed, but the spinal cord was not injured, and no implantation was given. MAIN OUTCOME MEASURES： Pathological changes were detected using hematoxylin-eosin staining; NF- κB expression was quantified using immunohistochemical staining; motor function was assessed using the Basso, Beattie and Bresnahan （BBB） scale. RESULTS： Spinal cord injuries, such as neuronal death and inflammatory cell infiltration, were found in the microencapsulated cell group, the non-encapsulated cell group and the saline group. However, the damage in the microencapsulated cell group was milder than in the non-encapsulated cell or saline groups. NF- κB expression in the microencapsulated cell group, the non-encapsulated cell group and the saline group was increased after spinal cord injury; it reached a peak after 24 hours, gradually decreased after 3 days, and was close to normal levels after 7 days. NF- κB expression in the microencapsulated cell group was significantly lower than in the saline group and the non-encapsulated cell group （P 〈 0.05）. With time, the motor function of the animals in each group improved to a certain extent, but did not reach normal levels. There were no significant differences in BBB scores between the different groups on post-operative day 3; however, the BBB scores for the microencapsulated cell group and the non-encapsulated cell group were significantly higher than the saline group on post-operative day 7 （P 〈 0.05）. In addition, the motor function recovered better in the microencapsulated cell group than in the non-encapsulated cell group （P 〈 0.05）. CONCLUSION： The transplantation of microencapsulated rabbit sciatic nerve can inhibit NF- κB expression and inflammatory reactions and promote recovery of motor function after spinal cord injury in rats. The effects of microencapsulated cell transplantation are superior to those of transplantation of cells alone.     

人脐带间充质干细胞移植对大鼠脊髓损伤神经功能恢复的评价

目的 观察人脐带间充质干细胞（human umbilical cordmesenchymal stem cell，hUCMSC）移植对大鼠脊髓损伤神经功能恢复的影响。方法 SD大鼠70只，随机分为3组：脊髓半切＋hUCMSC组（n=30）、脊髓半切＋PBS组（n=30）和假手术组（n=10）。脊髓半切＋hUCMSC组和PBS组又分为头侧注射、尾侧注射和头尾两侧注射三个亚组。移植后1、7、14、21、28d观察大鼠神经功能恢复情况，应用免疫组化检测移植到脊髓的hUCMSC胶质纤维酸性蛋白（GFAP）和神经元特异性烯醇化酶（NSE）表达情况。结果 大鼠脊髓半切损害后，hUCMSC组动物较PBS组有明显的神经功能恢复。植入后28d在宿主脊髓中存活的hUCMSC细胞MABl281（mouse antiuman nuclei monoclonal antibody）染色阳性，免疫组化双标染色显示MABl28l阳性细胞亦分别有NSE或GFAP表达并向损伤部位迁移，hUCMSC来源的GFAP阳性细胞可见明显的树突生长。结论 hUCMSC移植到宿主损伤脊髓后可以存活、向损伤部位迁移，并向神经元样和星形胶质细胞分化，且可促进大鼠脊髓损伤后神经功能恢复。hUCMSC作为一种来源广泛的干细胞用于治疗脊髓损伤可能具有重要的价值。     

移植分泌神经营养素3的人胚神经干细胞在脊髓损伤大鼠体内存活及对运动功能的影响

BACKGROUND： Many methods have been attempted to repair nerves following spinal cord injury, including peripheral nerve transplantation, Schwann cell transplantation, olfactory ensheathing cell transplantation, and embryonic neural tissue transplantation. However, there is a need for improved outcomes.
OBJECTIVE： To investigate the repair feasibility for rat spinal cord injury using human neural stem cells （hNSCs） genetically modified by lentivirus to express neurotrophin-3.
DESIGN, TIME AND SETTING： In vitro cell biological experiment and in vivo randomized, controlled genetic engineering experiment were performed at the Third Military Medical University of Chinese PLA and First People＇s Hospital of Yibin, China from March 2006 to December 2007.
MATERIALS： A total of 64 adult, female, Wistar rats were used for the in vivo study. Of them, 48 rats were used to establish models of spinal cord hemisection, and were subsequently equally and randomly assigned to model, genetically modified hNSC, and normal hNSC groups. The remaining 16 rats served as normal controls.
METHODS： hNSCs were in vitro genetically modified by lentivirus to secrete both green fluorescence protein and neurotrophin-3. Neurotrophin-3 expression was measured by Western blot. Genetically modified hNSC or normal hNSC suspension （5 × 10^5） was injected into the rat spinal cord following T10 spinal cord hemisection. A total of 5μL Dulbecco＇s-modified Eagle＇s medium was infused into the rat spinal cord in the model grop. Transgene expression and survival of transplanted hNSCs were determined by immunohistochemistry. Motor function was evaluated using the Basso, Beattie, and Bresnahan （BBB） scale.
MAIN OUTCOME MEASURES： The following parameters were measured： expression of neurotrophin-3 produced by genetically modified hNSCs, transgene expression and survival of hNSCs in rats, motor function in rats.
RESULTS： hNSCs were successfully genetically modified by lentivirus to stably express neurotrophin-3. The transplanted hNSCs primarily gathered at, or around, the injection site two weeks following transplantation, and gradually migrated towards the surrounding tissue. Transplanted hNSCs were observed 7.0-8.0 mm away from the injection site. In addition, hNSCs were observed 10 weeks after transplantation. At week 4, BBB locomotor scores were significantly greater in the genetically modified hNSC and normal hNSC groups, compared with the model group （P 〈 0.05）, and scores were significantly greater in the genetically modified hNSC group compared with the normal hNSC group （P 〈 0.05）.
CONCLUSION： hNSCs were genetically modified with lentivirus to stably secrete neurotrophin-3. hNSCs improved motor function recovery in rats following spinal cord injury.     

嗅鞘细胞移植脊髓损伤大鼠Sema3A及其受体NP-1基因的表达

背景：嗅鞘细胞移植促进脊髓损伤修复机制中对神经生长抑制导向因子的研究较少。 目的：观察嗅鞘细胞移植对脊髓半横断损伤后神经生长抑制导向因子Sema3A及其受体NP-1在RNA水平表达的变化。 方法：17只SD大鼠随机分为嗅鞘细胞移植组、DMEM/F12 培养液移植组和正常对照组。制作T11~T12水平大鼠脊髓左侧半横断损伤模型,立刻分别注射嗅鞘细胞悬液或等量的DMEM/F12 培养液。 结果与结论：6周后取横断水平前后两个脊髓节段,用RT-PCR的方法对Sema3A、NP-1的mRNA进行半定量分析。①嗅鞘细胞在大鼠脊髓内仍有大量存活。②Sema3A及NP-1 mRNA的量,DMEM/F12 培养液移植组明显多于正常对照组(P < 0.05),嗅鞘细胞移植组与培养液移植组比较明显下调,且与正常对照组比较差异无显著性意义(P > 0.05)。③提示嗅鞘细胞移植有效减少了神经生长抑制导向因子Sema3A及其受体NP-1 mRNA的表达。     

Treatment of chronically injured spinal cord with neurotrophic factors stimulates betaII-tubulin and GAP-43 expression in rubrospinal tract neurons

Exogenous neurotrophic factors provided at a spinal cord injury site promote regeneration of chronically injured rubrospinal tract (RST) neurons into a peripheral nerve graft. The present study tested whether the response to neurotrophins is associated with changes in the expression of two regeneration-associated genes, betaII-tubulin and growth-associated protein (GAP)-43. Adult female rats were subjected to a right full hemisection lesion via aspiration of the C3 spinal cord. A second aspiration lesion was made 4 weeks later and gel foam saturated in brain-derived neurotrophic factor (BDNF), glial cell-line derived neurotrophic factor (GDNF), or phosphate-buffered saline (PBS) was applied to the lesion site for 60 min. Using in situ hybridization, RST neurons were examined for changes in mRNA levels of betaII-tubulin and GAP-43 at 1, 3, and 7 days after treatment. Based on analysis of gene expression in single cells, there was no effect of BDNF treatment on either betaII-tubulin or GAP-43 mRNA expression at any time point. betaII-Tubulin mRNA levels were enhanced significantly at 1 and 3 days in animals treated with GDNF relative to levels in animals treated with PBS. Treatment with GDNF did not affect GAP-43 mRNA levels at 1 and 3 days, but at 7 days there was a significant increase in mRNA expression. Interestingly, 7 days after GDNF treatment, the mean cell size of chronically injured RST neurons was increased significantly. Although GDNF and BDNF both promote axonal regeneration by chronically injured neurons, only GDNF treatment is associated with upregulation of betaII-tubulin or GAP-43 mRNA. It is not clear from the present study how exogenous BDNF stimulates regrowth of injured axons.     

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     

局部注射骨髓间充质干细胞治疗大鼠脊髓损伤：运动功能有改善吗？

背景：目前研究多为骨髓间充质干细胞的体外培养及细胞移植对颅内疾病的治疗,对植入细胞在损伤脊髓中的成活、分化、迁移、结构重建等了解有限。 目的：探讨局部骨髓间充质干细胞移植在脊髓损伤修复中的作用和骨髓间充质干细胞替代治疗的可行性。 方法：成年健康雌性SD大鼠随机分为细胞移植组和对照组,建立SD大鼠脊髓横断损伤模型,伤后即刻分别向损伤区局部移植大鼠骨髓间充质干细胞悬液或无钙镁磷酸缓冲液。在术前和术后1 d,1周,2周,3周,4周和8周进行BBB评分,观测大鼠的运动功能,并于移植后1周免疫组织化学染色法观察BrdU标记的骨髓间充质干细胞在脊髓损伤处的存活情况,移植后4周进行损伤脊髓的大体观察和组织学检测。 结果与结论：移植后第1~8周细胞移植组BBB评分均髙于对照组;术后1周免疫组织化学染色结果显示在细胞移植组大鼠脊髓远端检测到BrdU阳性细胞,术后4周脊髓损伤处发现有神经纤维。证实通过损伤后立即局部注射的方式将骨髓间充质干细胞移植进大鼠脊髓损伤区,细胞可在损伤区存活;存活的骨髓间充质干细胞可分化为神经元,在损伤局部形成神经元通路,从而促进脊髓神经纤维传导功能的恢复,并促进高位脊髓损伤后大鼠后肢运动功能恢复。     

嗅鞘细胞静脉移植治疗脊髓损伤

背景：嗅鞘细胞移植治疗脊髓损伤在众多疗法中效果较佳,成为最有前景的治疗方法之一。目前移植方法为局部移植,存在操作复杂、创伤大、重复移植治疗困难等缺点。寻找一种简单易行且疗效好的移植方法成为各国学者研究的热点。 目的：分析嗅鞘细胞静脉移植治疗脊髓损伤的可行性和疗效。 方法：制备Wistar大鼠脊髓半切模型,随机分4组：嗅鞘细胞髓内局部移植组、嗅鞘细胞静脉移植组、D/F12静脉移植组和空白对照组。定期行CBS功能评分及组织学检查,评价脊髓修复情况。 结果与结论：嗅鞘细胞髓内局部移植组、嗅鞘细胞静脉移植组的功能恢复和组织学改变优于D/F12静脉移植组和空白对照组,嗅鞘细胞髓内局部移植组、嗅鞘细胞静脉移植组间无显著差别。说明嗅鞘细胞静脉移植可向脊髓损伤部位迁移并修复脊髓损伤,其疗效与嗅鞘细胞髓内局部移植相当。     

Fibrin matrix provides a suitable scaffold for bone marrow stromal cells transplanted into injured spinal cord: A novel material for CNS tissue engineering

Recent basic experiments have strongly suggested that cell transplantation therapy may promote functional recovery in patients with spinal cord injury (SCI). However, a safe and efficient transplantation technique still remains undetermined. This study, therefore, was aimed to clarify whether fibrin matrix could be a useful scaffold in bone marrow stromal cell (BMSC) transplantation for the injured spinal cord. To clarify the issue, three‐dimensional structure of fibrin matrix was assessed and the green fluorescent protein (GFP)‐expressing BMSC were cultured in fibrin matrix. The rats were subjected to spinal cord hemisection at T8 level, and the vehicle, BMSC or BMSC‐fibrin matrix construct was implanted into the cavity. Neurologic function was serially evaluated. Using immunohistochemistry, we evaluated the survival, migration and differentiation of the transplanted cells at 4 weeks after transplantation. In the initial in vitro study, the BMSC could survive in fibrin matrix for 2 weeks. The animals treated with the BMSC‐fibrin matrix construct showed significantly more pronounced recovery of neurologic function than vehicle‐ or BMSC‐treated animals. Fibrin scaffold markedly improved the survival and migration of the transplanted cells. There was no significant difference in the percentage of cells doubly positive for GFP and microtubule‐associated protein 2 between the animals treated with BMSC‐fibrin matrix construct and those treated with BMSC, but a certain subpopulation of GFP‐positive cells morphologically simulated the neurons in the animals treated with BMSC‐fibrin matrix construct. These findings strongly suggest that fibrin matrix may be one of the promising candidates for a potential, minimally invasive scaffold for injured spinal cord, and that such strategy of tissue engineering could be a hopeful option in regeneration therapy for patients with SCI.     

Expression of GDNF in spinal cord injury and its repression by ONO-1714

ONO-1714 is a newly developed specific inhibitor for inducible nitric oxide synthase (iNOS). We have shown that ONO-1714 has some neuroprotective effects. In this report, we investigated the effects of ONO-1714 in injured spinal cords, and analyzed the expression of glial cell-line-derived neurotrophic factor (GDNF) after injury. Male Sprague-Dawley rats were subjected to contusive spinal cord injury and administrated 0.1 mg/kg ONO-1714. The injured spinal cords were isolated at appropriate time points and GDNF mRNA was determined by semi-quantitative RT-PCR. GDNF-positive cells were also counted after immunohistochemical stainings. ONO-1714 diminished the early stage production of GDNF after injury as well as it reduced the production of nitric oxide produced by iNOS and apoptotic cells.     

Distribution of serotonin 2A and 2C receptor mRNA expression in the cervical ventral horn and phrenic motoneurons following spinal cord hemisection

Cervical spinal cord injury leads to a disruption of bulbospinal innervation from medullary respiratory centers to phrenic motoneurons. Animal models utilizing cervical hemisection result in inhibition of ipsilateral phrenic nerve activity, leading to paralysis of the hemidiaphragm. We have previously demonstrated a role for serotonin (5-HT) as one potential modulator of respiratory recovery following cervical hemisection, a mechanism that likely occurs via 5-HT2A and/or 5-HT2C receptors. The present study was designed to specifically examine if 5-HT2A and/or 5-HT2C receptors are colocalized with phrenic motoneurons in both intact and spinal-hemisected rats. Adult female rats (250-350 g; n = 6 per group) received a left cervical (C2) hemisection and were injected with the fluorescent retrograde neuronal tracer Fluorogold into the left hemidiaphragm. Twenty-four hours later, animals were killed and spinal cords processed for in situ hybridization and immunohistochemistry. Using (35)S-labeled cRNA probes, cervical spinal cords were probed for 5-HT2A and 5-HT2C receptor mRNA expression and double-labeled using an antibody to Fluorogold to detect phrenic motoneurons. Expression of both 5-HT2A and 5-HT2C receptor mRNA was detected in motoneurons of the cervical ventral horn. Despite positive expression of both 5-HT2A and 5-HT2C receptor mRNA-hybridization signal over phrenic motoneurons, only 5-HT2A silver grains achieved a signal-to-noise ratio representative of colocalization. 5-HT2A mRNA levels in identified phrenic motoneurons were not significantly altered following cervical hemisection compared to sham-operated controls. Selective colocalization of 5-HT2A receptor mRNA with phrenic motoneurons may have implications for recently observed 5-HT2A receptor-mediated regulation of respiratory activity and/or recovery in both intact and injury-compromised states.     

Electrophysiological functional recovery in a rat model of spinal cord hemisection injury following bone marrow-derived mesenchymal stem cell transplantation under hypothermia

Following successful establishment of a rat model of spinal cord hemisection injury by resecting right spinal cord tissues, bone marrow stem cells were transplanted into the spinal cord lesions via the caudal vein while maintaining rectal temperature at 34 ± 0.5°C for 6 hours (mild hypothermia). Hematoxylin-eosin staining showed that astrocytes gathered around the injury site and formed scars at 4 weeks post-transplantation. Compared with rats transplanted with bone marrow stem cells under normal temperature, rats transplanted with bone marrow stem cells under hypothermia showed increased numbers of proliferating cells (bromodeoxyuridine-positive cells), better recovery of somatosensory-evoked and motor-evoked potentials, greater Basso, Beattie, and Bresnahan locomotor rating scores, and an increased degree of angle in the incline plate test. These findings suggested that hypothermia combined with bone marrow mesenchymal stem cells transplantation effectively promoted electrical conduction and nerve functional repair in a rat model of spinal cord hemisection injury.     

神经干细胞移植影响脊髓全横断大鼠大脑运动皮质相关凋亡基因的表达

背景：多项研究已证实神经干细胞能促进脊髓损伤大鼠神经功能的恢复,但其分子机制还不清楚。 目的：观察神经干细胞移植对脊髓全横断损伤大鼠大脑运动皮质相关凋亡基因Bax,Bcl-2和Caspase-3 mRNA表达的影响。 设计、时间及地点：随机对照动物实验,于2007-07/2008-12在昆明医学院神经科学研究所完成。 材料：孕14~15 d绿色荧光蛋白转基因鼠5只,取其胚胎用于神经干细胞培养。清洁级健康成年雌性SD大鼠88只,随机分成3组：假手术组8只、模型组40只、细胞移植组40只。 方法：模型组、细胞移植组大鼠建立T9脊髓全横断脊髓损伤模型,假手术组只行T8椎板切除。用DMEM/F12调整胎鼠神经干细胞密度为2×1010 L-1,吸取细胞悬液15 μL滴加到约2 mm3大小的明胶薄片上,细胞移植组将此明胶薄片植入大鼠脊髓两横断面之间的间隙处。分别于细胞移植后3,7,14,21,28 d取材进行指标检测。 主要观察指标：RT-PCR法检测大脑运动皮质Bax,Bcl-2和Caspase-3 mRNA表达的变化。 结果：与假手术组比较,模型组各时间点Bax的表达均无明显差异(P > 0.05),术后14,28 d Bcl-2的表达明显减少(P < 0.05),术后3 d Caspase-3的表达明显升高(P < 0.05)。与模型组比较,细胞移植组在神经干细胞移植后3 d Bax的表达明显减少(P < 0.05),移植后14,21 d Bcl-2的表达明显增高(P < 0.05),移植后3,7 d Caspase-3的表达明显减少(P < 0.05)。 结论：神经干细胞移植后,可能通过调控大脑运动皮质相关凋亡基因 Bax,Bcl-2和Caspase-3 mRNA的表达促进大鼠全横断脊髓损伤修复。     

嗅鞘细胞移植对脊髓全横断损伤大鼠大脑运动皮质胰岛素样生长因子1和睫状神经营养因子表达的影响

背景：多项研究已证实嗅鞘细胞能促进脊髓损伤大鼠神经功能的恢复,但其分子机制还不清楚。 目的：观察嗅鞘细胞移植对脊髓全横断大鼠大脑运动皮质神经营养因子胰岛素样生长因子1和睫状神经营养因子mRNA表达的影响。 设计、时间及地点：随机对照动物实验,于2007-07/2008-12在昆明医学院神经科学研究所完成。 材料：清洁级健康成年雌性SD大鼠88只,随机分成3组：假手术组8只、模型组40只、细胞移植组40只。另取新生一两天的GFP转基因小鼠5只用于分离培养嗅鞘细胞。 方法：模型组、细胞移植组大鼠建立T9脊髓全横断损伤模型,假手术组仅行T8椎板切除。造模后,细胞移植组吸取嗅鞘细胞悬液15 μL(约3×105个细胞)滴加到约2 mm3的明胶海绵上,将含有嗅鞘细胞的明胶海绵植入大鼠脊髓两横断面之间的间隙处。分别于移植后3,7,14,21,28 d取大脑运动皮质行RT-PCR检测。 主要观察指标：采用免疫细胞化学法对培养的嗅鞘细胞进行鉴定,RT-PCR法检测大脑运动皮质胰岛素样生长因子1和睫状神经营养因子mRNA的表达变化。 结果：培养的嗅鞘细胞p75-NGFR阳性率>90%,主要为双极细胞,突起较长。与假手术组比较,模型组术后3 d睫状神经营养因子表达明显升高,7,14,21 d降至无明显差异,至28 d明显降低(P < 0.05);术后各时间模型组胰岛素样生长因子1的表达无明显差异(P > 0.05)。与模型组比较,移植后14 d细胞移植组胰岛素样生长因子1表达明显增多(P < 0.05);移植后3 d睫状神经营养因子的表达明显减少(P < 0.05),但移植后7,14,21 d表达逐渐回升,至28 d明显高于模型组水平(P < 0.05)。 结论：嗅鞘细胞移植能够促进脊髓损伤修复,其机制可能与促进大脑运动皮质胰岛素样生长因子1 mRNA的表达上调,并在初期抑制睫状神经营养因子mRNA的表达有关。     

Functional recovery in chronic paraplegia after bone marrow stromal cells transplantation

Previous reports showed the therapeutic effect of transplants of bone marrow stromal cells (BMSC) after incomplete traumatic spinal cord lesions. We studied the effect of this form of therapy in chronically paraplegic Wistar rats due to severe spinal cord injury (SCI). Rats were subjected to weight-drop impact causing paraplegia, and BMSC or phosphate buffered saline (PBS) was injected into spinal cord 3 months after injury. Functional outcome was measured using the Basso-Beattie-Bresnehan score until sacrifice of the animals, 4 weeks after transplantation. At this time, samples of spinal cord tissue were studied histologically. The results showed a clear and progressive functional recovery of the animals treated with BMSC transplantation, compared to controls. Grafted BMSC survived into spinal cord tissue, forming cell bridges within the traumatic centromedullary cavity. In this tissue, cells expressing neuronal and astroglial markers can be seen, together with a marked ependymal proliferation, showing nestin-positivity. These findings suggest the utility of BMSC transplantation in chronically established paraplegia.     

Exercise-induced gene expression in soleus muscle is dependent on time after spinal cord injury in rats

Cycling exercise attenuates atrophy in hindlimb muscles and causes changes in spinal cord properties after spinal cord injury in rats. We hypothesized that exercising soleus muscle expresses genes that are potentially beneficial to the injured spinal cord. Rats underwent spinal cord injury at T10 and were exercised on a motor-driven bicycle. Soleus muscle and lumbar spinal cord tissue were used for messenger RNA (mRNA) analysis. Gene expression of brain-derived neurotrophic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF) was elevated 11- and 14-fold, respectively, in soleus muscle after one bout of exercise performed 5 days after spinal cord transection. Also, c-fos and heat shock protein-27 (HSP27) mRNA abundance were increased 11- and 7-fold, respectively. When exercise was started 2 days after the injury, the changes in gene expression were not observed. By contrast, at 2 but not at 5 days after transection, expression of the HSP27 gene was elevated sixfold in the lumbar spinal cord, independent of exercise. Electromyographic activity in soleus muscles was also decreased at 2 days, indicating that the spinal cord was less permissive to exercise at this early time. Long-term exercise for 4 weeks attenuated muscle atrophy equally well in rats started at 2 days or 5 days after injury. We conclude that BDNF and GDNF released from exercising muscle may be involved in exercise-induced plasticity of the spinal cord. Furthermore, the data suggest that the lumbar spinal cord undergoes time-dependent changes that temporarily impede the ability of the muscle to respond to exercise.