人脐血单个核细胞促进脊髓损伤后的轴突再生

[目的] 讨论人脐血单个核细胞(human cord blood mononuclear cells,HCMNCs)移植治疗大鼠脊髓损伤后损伤区域轴突再生情况和功能恢复.[方法] 利用 Impactor Model Ⅱ打击器制成30例T10脊髓损伤模型,分组为:实验对照组(DMEM细胞培养基),损伤后3 d HCMNCs移植组,损伤后14 d HCMNCs移植组,每组10例.以HE染色和免疫组化染色以及BDA顺行示踪染色观察脊髓损伤处轴突再生情况,结合对各组实验动物脊髓损伤后肢体功能的恢复情况进行行为学评分(BBB 评分),综合评估脊髓功能恢复程度.[结果] 与对照组比较,HCMNCs移植治疗能够明显促进神经轴突再生,改善功能恢复,损伤后14 d HCMNCs移植组优于损伤后3 d移植组,各组间疗效差异具有统计学意义(P<0.01).[结论] HCMNCs在体内向神经元及神经胶质细胞分化,促进神经轴突再生和功能恢复.损伤后14 d是移植的较为理想的时间.     

不同途径移植自体激活雪旺细胞修复大鼠脊髓损伤

目的 通过不同途径移植自体激活雪旺细胞(autologous activated Schwann cells,AASCs),评价各种移植途径在修复脊髓损伤中的作用.方法 结扎Wistar大鼠双侧隐神经,1周后取下结扎处远端神经,在体外分离、培养、传代、纯化和鉴定后获得供实验用AASCs.60只Wistar大鼠制成T_(10)脊髓损伤模型后随机分为三组,1周后将预先用Hoechst33342标记的AASCs移植到三组大鼠体内:Ⅰ组,尾静脉移植;Ⅱ组,鞘内移植(经蛛网膜下腔);Ⅲ组,局部损伤处移植.术后采用BBB评分评价大鼠功能恢复.3个月后行BDA皮质脊髓束顺行示踪标记.标记2周后处死动物,取出损伤处脊髓行快速冰冻切片,行Cy3荧光探针染色、神经丝蛋白200(NF200)和HE染色.结果 AASCs在体外可稳定传4代以上,并表达S-100抗原.从术后第4周开始,BBB评分在各组间差异有统计学意义.至实验结束时,HE染色显示Ⅲ组中损伤空洞明显小于其余两组,NF200免疫组化染色阳性面积占总面积百分比各组间差异有统计学意义.BDA神经示踪显示,Ⅲ组中有较多的再生轴突通过脊髓损伤区,横断面上再生轴突的免疫组化阳性面积各组间差异有统计学意义.结论 局部损伤处移植AASCs可以有效保证移植细胞的数量,AASCs通过分泌多种营养因子和桥接损伤轴突再生的作用促进大鼠脊髓损伤后的功能恢复.     

不同浓度人脐带间充质干细胞移植修复大鼠脊髓损伤的实验研究

[目的]比较不同浓度人脐带间充质干细胞(human umbilical cord mesenchymal stem cells,HUCMSCs)移植修复大鼠脊髓损伤(spinal cord injury,SCI)的疗效.[方法]利用NYU Impactor model-Ⅱ打击器制作大鼠T10 SCI模型,分组为:80只W istar大鼠随机分为DMEM实验对照组(A组)、1×1004 HUCM5C、移植组(B组)、1×105HUCMSC、移植组(C组)和1×106 HUCMSC,移植组(ll组),每组20只.对各组实验动物SCI后肢体功能恢复情况进行行为学评分(BBB评分),并以HF染色和免疫组化染色及生物素葡聚糖胺(BDA)顺行示踪皮质脊髓束( corticospinal tract,CST)染色观察SCI处轴突再生情况.[结果]与实验对照组相比,HUCMSCs移植能促进SCI后轴突再生,改善大鼠后肢功能恢复.D组优于其他组,各组问BBB评分差异有统计学意义(P<0.05); NF-200免疫荧光染色累积光密度各组间差异均有统计学意义(P<0.05).[结论]HUCMSC、在体内可向神经元及神经胶质细胞分化,促进SCI后轴突再生和肢体功能恢复.     

神经生物膜介导神经干细胞联合雪旺细胞移植治疗脊髓损伤

目的探讨以壳聚糖-胶原偶联生物膜为载体，联合移植雪旺细胞（SCs）与神经干细胞（NSCs）在治疗脊髓损伤中的作用，并评价该方法的疗效。方法大鼠孕鼠体内取出胎鼠分离获得原代NSCs进行体外培养，大鼠乳鼠坐骨神经中分离获得原代SCs进行体外培养，分别传代4代获得大量细胞。40只Wistar大鼠建立大鼠脊髓半横断动物模型并随机分为4组：空白对照组，SCs移植组，NSCs移植组，NSCs联合SCs移植组。将胎鼠NSCs和乳鼠SCs共同种植于胶原-壳聚糖偶联的神经生物膜上，移植入大鼠脊髓半横断模型的脊髓损伤部位，对动物进行BBB脊髓功能评分，BDA神经示踪标记，标记2周后处死动物取出动物脊髓组织进行Cy3荧光素染色，p75免疫荧光染色及脊髓组织苏木素-伊红（HE）染色。结果4组实验动物BBB评分组间比较差异有统计学意义（ANOVA，P〈0．05），p75免疫荧光染色阳性物面积比较各组之间差异有统计学意义（ANOVA，P〈0．05）。结论NSCs和SCs能够在胶原-壳聚糖偶联的神经生物膜上共同生长分化，并且SCs能够诱导NSCs产生轴突定向生长。壳聚糖-胶原生物膜介导的SCs联和NSCs移植治疗脊髓损伤可使神经部分再通。     

移植脐带间充质干细胞治疗脊髓损伤的实验研究

[目的]探讨人脐带间充质干细胞移植治疗脊髓损伤的疗效.[方法]50只Wistar大鼠成功制备脊髓打击模型,随机分成3组:DMEM移植组、细胞移植组、空白对照组.术后通过BBB评分来观察大鼠后肢功能恢复的情况,通过HE染色、嗜银染色观察损伤周围空洞形成以及神经轴突的再生情况,免疫组织化学观察hUC-MSCs在损伤局部存活、迁移、分化情况以及检测胶质纤维酸性蛋白(GFAP)来比较各组损伤局部胶质瘢痕形成的面积.[结果] BBB评分结果表明损伤后3周细胞移植组高于其他两组(P＜0.05),免疫荧光显示hUC-MSCs移植到大鼠体内后在损伤局部存活并向损伤局部迁移;但是并没有检测到向神经元、星形胶质细胞分化;细胞移植组损伤周围形成的胶质瘢痕面积少于其他两组(P＜0.05).[结论]移植hUC-MSCs能够促进大鼠脊髓损伤神经功能的恢复.     

人脐带间充质干细胞与自体激活雪旺细胞联合移植修复脊髓损伤的实验研究

目的 通过观察人脐带间充质干细胞(hUCMSCs)和大鼠自体激活雪旺细胞(AASCs)联合移植修复脊髓损伤的疗效,探讨AASCs对hUCMSCs体内存活、分化的影响.方法 分离、培养hUCMSCs和大鼠AASCs.通过IMPACTOR MODEL-Ⅱ型打击仪将80只Wistar成年雌性大鼠均制作成T10损伤模型,随机分为四组(n=20):DMEM移植对照组、hUCMSCs移植组、AASCs移植组、hUCMSCs与AASCs联合移植组.比较符组动物恢复情况,进行行为学评分(BBB评分),NF-200和GFAP染色观察细胞存活、分化情况,生物素葡聚糖胺示踪观察皮质脊髓束再生情况.结果 4周后各组间BBB评分差异有统计学意义(P<0.05),6周后联合移植组明显高于其他三组,差异有统计学意义(P<0.05).免疫组化染色示联合移植组的hUCMSCs存活数量,NF-200、GFAP阳性荧光面积均明显高于hUCMSCs移植组,差异有统计学意义(P<0.05),BDA顺行爪踪可见联合移植组于损伤区染色较多,部分纤维延续至损伤远端.结论 AASCs可支持移植的hUCMSCs在损伤部位存活并向神经方向分化,hUCMSCs与AASCs联合移植较二者单独移植能更有效地促进脊髓损伤后运动功能的恢复和轴突再生.     

乙交酯-丙交酯共聚物支架-细胞复合体移植对大鼠损伤脊髓的修复作用

目的 观察神经干细胞、雪旺细胞和组织工程材料乙交酯-丙交酯共聚物共移植后对大鼠损伤脊髓形态和功能的修复作用.方法 36只Wistar大鼠,随机数字法分为乙交酯-丙交酯共聚物移植组、神经干细胞/乙交酯-丙交酯共聚物绀和神经干细胞+雪旺细胞/乙交酯-丙交酯共聚物组.体外培养、鉴定胚胎脊髓源神经干细胞和雪旺细胞,制备和构建乙交酯-丙交酯共聚物支架细胞复合体并移植到大鼠脊髓T9半横断损伤部位,应用BBB行为评分和电生理技术在术后4、12周评价大鼠脊髓功能的恢复情况;应用透射电镜、HE染色和免疫组织化学染色方法在形态结构上观察轴突和髓鞘再生情况,以及神经干细胞在脊髓内的存活、迁移和分化情况.结果术后4、12周,细胞移植组的BBB评分较对照组明显提高(P＜0.05);细胞移植组的体感诱发电位和运动诱发电位波幅较对照组都有所好转.术后12周移植材料正中横断面透射电镜可见新生的无髓及有髓神经纤维;脊髓标本免疫组织化学染色显示移植的神经十细胞呵以在宿主脊髓内存活、迁移并分化成神经元和少枝胶质细胞,未分化成星形胶质细胞.结论 神经干细胞、雪旺细胞和组织工程材料乙交酯-丙交酯共聚物共移植可以促进半横断损伤的大鼠脊髓轴突再生,改善肢体的运动功能.     

活性巨噬细胞与周围神经联合移植治疗

目的脊髓损伤后轴突再生是脊髓功能恢复的基础，但再生轴突受神经自身条件及损伤微环境的限制。研究表明脊髓损伤后损伤区早期、大量的巨噬细胞聚积可改善局部微环境，减轻脊髓继发性损伤并促进其再生；而周围神经移植可为随后发生的再生轴突提供通道和营养物质，两者联合应用则为脊髓损伤的治疗提供一条有效的途径。方法将72只S—D大鼠采用随机的方法分为4组，A组大鼠在T。脊髓半切加洞性损伤；B组在上述基础上行肋间神经移植；C组行巨噬细胞移植；D组行巨噬细胞和肋间神经联合移植。术后1、3天和1、2、4、8周收集脊髓标本并冰冻切片、免疫组化染色，显微镜下巨噬细胞及神经纤维计数。结果D组大鼠术后4周以上时BBB运动功能评分平均提高1分，镜下观察见C、D组大鼠在伤后4周内巨噬细胞及再生轴突数目均高于A、B组。结论该方法可减轻脊髓损伤并促进其再生，可能是治疗脊髓损伤的一条有效途径。     

骨髓基质干细胞和神经生长因子悬液移植对脊髓损伤修复的影响

目的研究骨髓基质干细胞(BMSCs)移植联用神经生长因子(NGF)对脊髓损伤修复的治疗作用。方法用改良Allen法制成SD大鼠脊髓损伤动物模型(共32只),1周后分别将DMEM、BMSCs、NGF和BMSCs NGF移植入脊髓损伤部位即制成四组(每组8只),移植1、2个月后分别采用神经核蛋白(NeuN)抗体、胶质纤维酸性蛋白(GFAP)抗体和神经丝蛋白(NF)抗体进行免疫荧光染色观察移植的BMSCs的存活及分化情况、损伤部位神经纤维的再生情况。HE染色观察脊髓损伤处空洞面积的改变情况。同时采用BBB运动评分观察大鼠运动功能恢复情况。结果移植1、2个月后,部分移植细胞呈NeuN和GFAP阳性,同时实验组可见明显的神经纤维再生。脊髓损伤处的空洞面积明显减小,差异有显著性意义(P＜0．05),BBB评分结果比对照组均有明显增高,差异有显著性意义(P＜0．05)。在BMSCs NGF组上述改变更加显著。结论BMSCs可在脊髓损伤处分化为神经元和神经胶质细胞,BMSCs和NGF能够减小脊髓损伤处的空洞面积,促进受损轴突的再生和运动功能的恢复,两者联合应用在脊髓损伤修复治疗中具有协同作用。     

GDNF基因修饰的嗅鞘细胞移植联合IN-1注射修复大鼠急性脊髓损伤

目的 研究胶质细胞源性神经营养因子(GDNF)基因修饰的嗅鞘细胞(OECs)移植联合轴突生长抑制蛋白抗体(IN-1)局部持续注射对大鼠急性横断性脊髓损伤(SCI)的修复作用.方法 构建载有GDNF基因的慢病毒(Lentivirus)载体并体外转染OECs,Western Blot检测GDNF的表达.用50只成年雌性SD大鼠建立胸脊髓全横断损伤模型,随机分为A(对照组)、B(IN-1微泵注射组)、C(OECs组)、D(GDNF-OECs组)和E(GDNF-OECs+IN-1组)5组各10只.应用神经丝蛋白200(NF200)单抗免疫组化、生物素化的葡聚糖胺(BDA),顺行神经追踪对SCI区神经纤维再生进行形态学观察.采用BBB评分评估大鼠后肢功能恢复情况.结果 术后共有13只大鼠死亡.术后8周可观察到Hoechst标记的OECs在体内存活并在脊髓内迁移;E组和D组可见SCI区杂乱无序的再生轴突,有连续性神经纤维通过损伤区;C组可见少量无序的再生轴突,可疑连续性神经纤维通过损伤区;B组和A组脊髓残端萎缩,未见轴突再生.A、B、C、D和E组后肢功能运动平均BBB评分分别为7.70±0.24、7.89±0.15、10.50±0.25、11.43±0.23和12.81±0.40.结论 GDNF-OECs移植联合IN-1抗体注射可有效促进损伤脊髓神经轴突的存活、再生,促进损伤脊髓的修复.     

Adenovirus vector-mediated ex vivo gene transfer of brain-derived neurotrophic factor to bone marrow stromal cells promotes axonal regeneration after transplantation in completely transected adult rat spinal cord

The aim of this study was to evaluate the efficacy in adult rat completely transected spinal cord of adenovirus vector-mediated brain-derived neurotrophic factor (BDNF) ex vivo gene transfer to bone marrow stromal cells (BMSC). BMSC were infected with adenovirus vectors carrying β-galactosidase (AxCALacZ) or BDNF (AxCABDNF) genes. The T8 segment of spinal cord was removed and replaced by graft containing Matrigel alone (MG group) or Matrigel and BMSC infected by AxCALacZ (BMSC-LacZ group) or AxCABDNF (BMSC-BDNF group). Axons in the graft were evaluated by immunohistochemistry and functional recovery was assessed with BBB locomotor scale. In the BMSC-BDNF group, the number of fibers positive for growth associated protein-43, tyrosine hydroxylase, and calcitonin gene-related peptide was significantly larger than numbers found for the MG and BMSC-LacZ groups. Rats from BMSC-BDNF and BMSC-LacZ groups showed significant recovery of hind limb function compared with MG rats; however, there was no significant difference between groups in degree of functional recovery. These findings demonstrate that adenovirus vector-mediated ex vivo gene transfer of BDNF enhances the capacity of BMSC to promote axonal regeneration in this completely transected spinal cord model; however, BDNF failed to enhance hind limb functional recovery. Further investigation is needed to establish an optimal combination of cell therapy and neurotrophin gene transfer for cases of spinal cord injury.     

软骨素酶联合雪旺细胞移植促进脊髓损伤修复的研究

目的 观察软骨素酶联合雪旺细胞移植在治疗急性脊髓损伤中的作用.方法 Wistar大鼠80只,制作T10节段急性脊髓损伤模型(致伤力10g×4cm).随机分成4组:对照组、雪旺细胞移植组、硫酸软骨素酶治疗组和联合治疗组.采用脊髓运动功能评分(BBB法,总分21)、神经电生理(SEP&MEP)检查和生物素葡聚糖胺(BDA)神经示踪及标本NF-200免疫组织化学染色等比较各组疗效.结果 4周后BBB评分实验组较对照组明显提高,各组间差异有统计学意义(P<0.05)(12周时4组分别为9.11±1.41、11.22±1.59、11.77±1.76和14.22±1.92).术后4周起,神经电生理检查实验组动物较对照组差异有统计学意义(P<0.05),12周时4组MEP的波幅分别恢复至术前的28.8%、44.9%、49.0%和56.8%.BDA示踪显示联合组较对照组有较多的神经纤维穿过损伤部位.NF-200免疫组织化学染色吸光度(A)比较各组间差异有统计学意义(P<0.05),3个实验组纵切片A值与对照组的比值为1.44、1.55和2.78.结论 联合应用软骨素酶和雪旺细胞移植来治疗脊髓损伤,起到协同作用,效果好于单一方法,能明显促进脊髓损伤后的轴突再生和肢体功能恢复.     

Dissociated predegenerated peripheral nerve transplants for spinal cord injury repair: a comprehensive assessment of their effects on regeneration and functional recovery compared to schwann cell transplants

Abstract Several recent studies suggest that predegenerated nerves (PDNs) or dissociated PDNs (dPDNs) can improve behavioral and histological outcomes following transplantation into the injured rat spinal cord. In the current study we tested the efficacy of dPDN transplantation by grafting cells isolated from the sciatic nerve 7 days after crush. We did not replicate one study, but rather assessed what appeared, based on five published reports, to be a reported robust effect of dPDN grafts on corticospinal tract (CST) regeneration and locomotor recovery. Using a standardized rodent spinal cord injury model (200 kD IH contusion) and transplantation procedure (injection of GFP(+) cells 7 days post-SCI), we demonstrate that dPDN grafts survive within the injured spinal cord and promote the ingrowth of axons to a similar extent as purified Schwann cell (SC) grafts. We also demonstrate for the first time that while both dPDN and SC grafts promote the ingrowth of CGRP axons, neither graft results in mechanical or thermal hyperalgesia. Unlike previous studies, dPDN grafts did not promote long-distance axonal growth of CST axons, brainstem spinal axons, or ascending dorsal column sensory axons. Moreover, using a battery of locomotor tests (Basso Beattie Bresnahan [BBB] score, BBB subscore, inked footprint, Catwalk, and ladderwalk), we failed to detect any beneficial effects of dPDN transplantation on the recovery of locomotor function after SCI. We conclude that dPDN transplants are not sufficient to promote CST regeneration or locomotor recovery after SCI.     

Cationic liposome-mediated GDNF gene transfer after spinal cord injury

Glial cell line-derived neurotrophic factor (GDNF) has been shown to protect cranial and spinal motoneurons, which suggests potential uses of GDNF in the treatment of spinal cord injury (SCI) and motor neuron disease. We examined neuroprotective effect of cationic liposome-mediated GDNF gene transfer in vivo on axonal regeneration and locomotor function recovery after SCI in adult rats. The mixture of DC-Chol liposomes and recombinant plasmid pEGFP-GDNF cDNA was injected after SCI. RT-PCR confirmed the increased expression of GDNF mRNA in the injected areas at 7 days after injection. The expression of EGFP-GDNF was observed in the cells around the injection locus by fluorescence microscope at least 4 weeks after injection. Four weeks after GDNF gene transfer, regeneration of the corticospinal tracts was assessed using anterograde tract tracing. There are more HRP labeling of corticospinal tract axons across the lesion in GDNF group compared with control group. In GDNF group, the maximum distance these labeled axons extended varied in different animals and ranged from 5 mm to approximately 9 mm from the lesion. In control group, no HRP labeled axons extended caudal to the lesion. The locomotion function of hindlimbs of rats was evaluated using inclined plane test and BBB locomotor scores. The locomotion functional scores in GDNF group were higher than that in control group within 1-4 weeks after SCI (p < 0.05). These data demonstrate that in vivo transfer of GDNF cDNA can promote axonal regeneration and enhance locomotion functional recovery, suggesting that cationic liposome-mediated delivery of GDNF cDNA may be a practical gene transfer method for traumatic SCI treatment.     

Functional recovery after human umbilical cord blood cells transplantation with brain-derived neutrophic factor into the spinal cord injured rat

Summary There have been many efforts to recover neuronal function from spinal cord injuries, but there are some limitations in the treatment of spinal cord injuries.The neural stem cell has been noted for its pluripotency to differentiate into various neural cell types. The human umbilical cord blood cells (HUCBs) are more pluripotent and genetically flexible than bone marrow neural stem cells. The HUCBs could be more frequently used for spinal cord injury treatment in the future.Moderate degree spinal cord injured rats were classified into 3 subgroups, group A: media was injected into the cord injury site, group B: HUCBs were transplanted into the cord injury site, and group C: HUCBs with BDNF (Brain-derived neutrophic factor) were transplanted into the cord injury site. We checked the BBB scores to evaluate the functional recovery in each group at 8 weeks after transplantation. We then, finally checked the neural cell differentiation with double immunofluorescence staining, and we also analyzed the axonal regeneration with retrograde labelling of brain stem neurons by using fluorogold. The HUCBs transplanted group improved, more than the control group at every week after transplantation, and also, the BDNF enabled an improvement of the BBB locomotion scores since the 1 week after its application (P<0.05). 8 weeks after transplantation, the HUCBs with BDNF transplanted group had more greatly improved BBB scores, than the other groups (P<0.001). The transplanted HUCBs were differentiated into various neural cells, which were confirmed by double immunoflorescence staining of BrdU and GFAP & MAP-2 staining. The HUCBs and BDNF each have individual positive effects on axonal regeneration. The HUCBs can differentiate into neural cells and induce motor function improvement in the cord injured rat models. Especially, the BDNF has effectiveness for neurological function improvement due to axonal regeneration in the early cord injury stage. Thus the HUCBs and BDNF have recovery effects of a moderate degree for cord injured rats.     

Co-transplantation of neural stem cells and NT-3-overexpressing Schwann cells in transected spinal cord

Spinal cord transection results in severe neurological sequelae, and to date, there is no effective treatment. Because of the limited capacity for axonal regeneration in the spinal cord, recovery is minimal. Recently, efforts have been made to establish, by grafting neural tissue, a functional relay-station between the severed stumps of the injured cord. Previously, we used co-transplantation of neural stem cells (NSCs) and Schwann cells (SCs) to improve functional recovery of transected spinal cord. However, this effort has been partially impeded by limited neuronal differentiation of transplanted NSCs. To circumvent this problem, we have pre-differentiated NSCs toward neurons in vitro with the application of retinoic acid (RA) prior to cell grafting. Further, we genetically modified SCs to overexpress human neurotrophin-3 (hNT-3). When these cells were co-transplanted into the transected spinal cord of rats, injured animals had partial improvement (both functionally and structurally), including improved Basso, Beattie, and Bresnahan (BBB) scores, increased axonal regeneration/remyelination, and reduced neuronal loss. However, this pre-differentiation of NSCs in vitro only mildly improved neuronal differentiation of NSCs in vivo.     

Cotransplantation of human embryonic stem cell-derived neural progenitors and schwann cells in a rat spinal cord contusion injury model elicits a distinct neurogenesis and functional recovery

Cotransplantation of neural progenitors (NPs) with Schwann cells (SCs) might be a way to overcome low rate of neuronal differentiation of NPs following transplantation in spinal cord injury (SCI) and the improvement of locomotor recovery. In this study, we initially generated NPs from human embryonic stem cells (hESCs) and investigated their potential for neuronal differentiation and functional recovery when cocultured with SCs in vitro and cotransplanted in a rat acute model of contused SCI. Cocultivation results revealed that the presence of SCs provided a consistent status for hESC-NPs and recharged their neural differentiation toward a predominantly neuronal fate. Following transplantation, a significant functional recovery was observed in all engrafted groups (NPs, SCs, NPs + SCs) relative to the vehicle and control groups. We also observed that animals receiving cotransplants established a better state as assessed with the BBB functional test. Immunohistofluorescence evaluation 5 weeks after transplantation showed invigorated neuronal differentiation and limited proliferation in the cotransplanted group when compared to the individual hESC-NP-grafted group. These findings have demonstrated that the cotransplantation of SCs with hESC-NPs could offer a synergistic effect, promoting neuronal differentiation and functional recovery.     

Transplantation of preconditioned schwann cells in peripheral nerve grafts after contusion in the adult spinal cord. Improvement of recovery in a rat model

BACKGROUND: Recovery after injury to the peripheral nervous system is based on the pro-regenerative relationship between axons and the extracellular matrix, a relationship established by Schwann cells. As mechanical conditioning of Schwann cells has been shown to stimulate their regenerative behavior, we sought to determine whether transplantation of these cells to the central nervous system (i.e., the spinal cord), with its limited regenerative capacity after injury, would improve axonal regeneration and functional recovery. METHODS: A moderate contusion injury of the spinal cord was created with a force-directed impactor in forty-eight adult Sprague-Dawley rats, and, at one week postinjury, the spinal cords were reexposed in all animals. In twenty-four of these animals, peripheral nerve grafts with Schwann cells that had been obtained from the sciatic nerves of donor animals, and had been either untreated or subjected to mechanical conditioning, were transplanted to the contused area of the cords following resection of the glial scar. Another group of animals was treated with glial scar excision only, and a fourth group had the contusion injury but neither glial excision nor transplantation. Scores according to the Basso, Beattie, Bresnahan (BBB) Locomotor Rating Scale were assigned preoperatively and weekly thereafter. Tract tracing of descending and ascending spinal cord tracts was performed at six weeks postoperatively for quantitative histological evaluation of axonal regeneration. RESULTS: While the recovery following glial scar excision without peripheral nerve transplantation was significantly worse than the recovery in the other groups, both transplantation groups had significantly higher BBB scores than the controls (no transplantation) in the early postoperative period (p < 0.05). Moreover, histological analysis showed markedly increased axonal regeneration at the lesional sites in the animals treated with the mechanically conditioned grafts than in the other groups (p < 0.05). CONCLUSIONS: Functional recovery after spinal cord contusion improved following glial scar excision with transplantation of Schwann cells in peripheral nerve grafts to the contusion areas. Although recovery did not differ significantly between the transplantation groups, only the preconditioned grafts led to axonal regeneration at and past the lesional site. These grafts may further enhance functional recovery as the descending tracts eventually reach their target end-organs.