磁刺激和碱性成纤维细胞生长因子对脊髓损伤早期的保护作用

目的探讨脊髓损伤后，应用磁刺激和外源性碱性成纤维细胞生长因子(bFGF)对损伤脊髓组织早期的保护作用。方法实验利用Allen WD(weight drop)技术，以致伤力(砝码质量10g，下落高度2．5cm)制成wistar大鼠T8脊髓损伤模型，治疗组分别于术后即刻、1h、2h、4h、24h分别予0．5HZ、70％输出强度的磁刺激，同时经蛛网膜下腔导管注入20ul bFGF，对照组不做处理。术后2h、6h、24h取治疗组、对照组动物损伤区脊髓组织作以下检测：用干湿法测水含量；用原子吸收光谱法测钙、镁离子含量；伤后5d取损伤脊髓组织，电镜观察脊髓结构。结果损伤区脊髓组织水含量增多，钙离子水平升高，镁离子水平下降，白质内髓鞘结构紊乱，囊性变严重；而应用磁刺激和bFGF可改善上述变化。结论脊髓损伤后应用磁刺激和bFGF可减轻脊髓损伤后的离子失衡，从而对继发性脊髓损伤具有保护作用。     

脊髓损伤后低剂量FK506对伤段组织电解质水含量失衡的早期保护作用

[目的]探讨脊髓损伤后早期应用低剂量抗移植排斥药物—FK506对伤段脊髓组织钙、镁离子及水含量的影响,明确其神经保护作用的可能机制。[方法]35只雄性Wistar大鼠随机分为对照组、损伤组和治疗组。采用Allen＇s打击法制作脊髓损伤模型,对照组仅做椎板切除术。治疗组在脊髓损伤后5min一次性经尾静脉注射FK506（0.3mg/kg）,其余两组以相同方法给予0.9%的生理盐水。术后6、12、24h取材,采用干湿法测定伤段脊髓组织水含量,以原子吸收光谱分析法测定钙、镁离子含量。[结果]伤段脊髓组织中水含量及钙离子水平升高,两者均于伤后12h达高峰,而镁离子水平降低,应用FK506可显著改善上述变化（P〈0.05,P〈0.01）。[结论]低剂量FK506可减轻伤段脊髓组织水肿和电解质失衡,对继发性脊髓损伤具有神经保护作用。     

兔脊髓损伤后钠钾钙镁含量变化及临床意义

目的研究脊髓损伤前后血清及脊髓内钠、钾、钙、镁含量的变化,为临床治疗脊髓损伤提供依据。方法３０只家兔用改良Ａｌｅｎ氏法造成脊髓损伤,６只家兔暴露脊髓不造成损伤。在伤前和伤后６ｈ、２４ｈ、４８ｈ、７２ｈ及６ｄ,用离子选择电极法和原子吸收光谱法测定血清和脊髓组织中离子钠、钾、钙、镁和总钠、钾、钙、镁含量。结果脊髓损伤后,血清中离子钙含量升高,总镁含量下降;脊髓组织中总钙、总钠含量升高,总镁、总钾含量下降。结论脊髓损伤后体内微量元素发生了不同程度的变化。     

甲基强的松龙与钙蛋白酶抑制剂对大鼠缺血再灌注损伤脊髓保护作用比较

[目的]观察脊髓缺血再灌注损伤后应用甲基强的松龙和钙蛋白酶抑制剂E-64-D,脊髓组织钙蛋白酶表达和活性的变化及对动物后肢功能的影响.[方法]纯种雄性成年SD大鼠,夹闭右肾动脉分支下腹主动脉30 min,造成动物脊髓缺血再灌注损伤(B组),再灌注后静脉应用钙蛋白酶特异性抑制剂E-64-D(C组)或甲基强的松龙(D组),观察3、24、72 h和7 d后脊髓损伤节段的钙蛋白酶的表达,及钙蛋白酶特异性底物68-KD NFP的降解和动物后肢功能情况.[结果]脊髓再灌注损伤后3 h,开始出现的钙蛋白酶阳性细胞,于再灌注后72 h最明显.68-KD NFP的降解产物也在再灌注损伤后3 h出现,并在72 h后达到高峰.应用E-64-D和甲基强的松龙后,钙蛋白酶的表达和68-KD NFP的降解得到抑制,而且E-64-D的抑制作用明显强于甲基强的松龙,结果具有显著性差异(P＜0.01).[结论]脊髓缺血再灌注损伤后两种治疗方法均可不同程度地保护脊髓组织和动物后肢的运动功能.     

甲基强的松龙对大鼠脊髓缺血再灌注损伤后钙蛋白酶表达的影响

目的观察大鼠脊髓缺血再灌注损伤后应用甲基强的松龙(MP)对脊髓组织钙蛋白酶表达的影响.方法用纯种雄性成年SD大鼠,夹闭右肾动脉分支下腹主动脉30min后恢复血供,缺血再灌注组(损伤组)不作任何治疗,造成动物脊髓缺血再灌注损伤模型,治疗组于恢复血供后即刻静脉应用MP(治疗组),观察再灌注后3h、24h、72h和7d时脊髓损伤节段钙蛋白酶Ⅰ的表达以及钙蛋白酶特异性底物68-KD NFP的降解.结果脊髓再灌注后3h出现钙蛋白酶Ⅰ阳性细胞和68-KD NFP的降解产物,随着时间的延长,阳性细胞数目逐渐增多,染色深度逐渐增加,再灌注后72h最明显,MP治疗组较损伤组明显降低(P＜0.01).结论脊髓再灌注损伤后静脉应用MP可以减少大鼠脊髓中calpain-Ⅰ阳性细胞的表达,对细胞骨架蛋白68-KD NFP具有明显保护作用.证实MP可以抑制钙蛋白酶的表达,可能是MP对脊髓损伤治疗的另一种机理.     

大鼠脊髓损伤后GDNFmRNA表达变化及意义

目的　探讨 GDNFm RNA在大鼠脊髓损伤后表达变化及其意义。方法　改良 Allen’s脊髓撞击 (10 g× 7.5 cm)致伤大鼠 T1 段脊髓 ,以 β- Actin为内参照物 ,应用半定量 RT- PCR方法 ,观察大鼠脊髓损伤前及损伤后不同时间 GDNFm RNA表达变化。结果　 GDNFm RNA在正常成年大鼠脊髓微量表达 ,脊髓损伤后 2 4h表达增加 5倍 ,72 h增加 2 0倍 ,7d增加 4倍 ,10 d仍高于正常水平。结论　脊髓损伤后早期 GDNFm RNA表达增加 ,是神经元自我保护作用的一种表现 ;损伤神经元修复需要大量 GDNF,应用 GDNF治疗脊髓损伤时应早期用药     

硫酸镁对继发性脊髓损伤保护作用的实验研究

目的：探讨硫酸镁对继发性脊髓损伤的保护作用及其作用机制。方法：选健康新西兰大白兔36只，随机分为3组：A组为正常组，仅行L1～L3椎板减压；B组和C组分别为对照组和治疗组，行L1～L3椎板减压后采用Allen’s重物打击法致伤脊髓．伤后30min时B组经腹腔注射蒸馏水600mg／kg，C组经腹腔注射硫酸镁600mg／kg。48h后切取伤段脊髓组织分别测定水、钙、镁含量，观察局部组织病理学改变、超微结构变化及单位面积凋亡细胞数。结果：与A组比较，B、C组伤段脊髓组织水、钙含量增多，镁含量减少，组织病理学改变及超微结构破坏严重，细胞凋亡数上升，且C组较对B组轻。结论：早期应用硫酸镁治疗可减轻脊髓损伤后的继发性损伤。     

碱性成纤维细胞生长因子对脊髓损伤早期保护作用的实验研究

目的　探讨碱性成纤维细胞生长因子（ｂ Ｆ Ｇ Ｆ）对脊髓损伤的早期保护作用。方法　选３４ 只 Ｓ Ｄ 大鼠,随机分为正常组、对照组和治疗组,采用 Ａｌｌｅｎ 氏技术,以１０ ｇ×２．５ ｃｍ 致伤力造成大鼠 Ｔ８ 急性脊髓损伤,并于损伤平面以下蛛网膜下腔置入细塑料管,治疗组给予ｂ Ｆ Ｇ Ｆ治疗,对照组同时注入生理盐水。术后切取损伤区脊髓组织进行形态学观察和生化指标测定。结果受损伤段脊髓组织水含量增多,钙离子水平升高,镁离子水平下降,白质内髓鞘结构紊乱,囊性变严重,而ｂ Ｆ Ｇ Ｆ可明显改变上述变化。结论　ｂ Ｆ Ｇ Ｆ对脊髓损伤早期的继发性损害有保护作用。     

bFGF对大鼠牵张性脊髓损伤后脊髓神经元影响的实验研究

目的探讨碱性成纤维细胞生长因子(bFGF)对牵张性脊髓损伤后神经元影响的作用。方法大鼠脊髓T13～L2经牵张损伤,CSEP监测P1～N1波幅下降至术前波幅70%后,于损伤平面以下经蛛网膜下腔置细导管,治疗组分别于术后即刻、1、2、3、4、8、12及24h经细导管注入bFGF溶液20μl(含bFGF20μg),对照组在相同时间注入等量生理盐水,然后于术后1d、4d、7d、14d及21d处死取材(n=4)。应用行为学及CSEP检查大鼠功能恢复情况,应用尼氏染色法观察神经元及尼氏体密度,并用计算机图像分析系统进行定量分析。结果bFGF治疗组大鼠的神经功能恢复与对照组相比差异有显著意义。尼氏染色的图像分析显示:bFGF治疗组的神经元截面积及尼氏体密度与对照组比较差异有显著意义(P<0.01)。结论bFGF对大鼠牵张性脊髓损伤后脊髓功能及神经元形态的恢复有明显的促进作用。     

钙蛋白酶抑制剂对缺血再灌注损伤脊髓的保护作用

目的 观察大鼠脊髓缺血再灌注损伤后应用钙蛋白酶特异性抑制剂E-64-D,对脊髓神经细胞组织学改变和凋亡的影响及对大鼠后肢运动功能的保护作用.方法 选用纯种雄性成年SD大鼠106只,夹闭右肾动脉分支下腹主动脉30 min,再灌注即刻静脉应用钙蛋白酶特异性抑制剂E-64-D,观察再灌注后3、24、72 h和7 d脊髓损伤节段神经细胞的凋亡及再灌注后24、72h组织病理学改变;对再灌注后72 h的大鼠后肢功能进行评分.结果 脊髓缺血再灌注24 h开始出现神经细胞凋亡现象,脊髓组织出现病理学改变,神经元死亡,胶质细胞增生.应用E-64-D后,凋亡现象和细胞坏死得到抑制,差异有统计学意义(P<0.01).再灌注后72 h后肢功能也得到一定程度的保护.结论 脊髓再灌注损伤后静脉应用E-64-D治疗,可以明显抑制脊髓神经细胞的凋亡,有利于神经元的存活,损伤后3 d大鼠后肢运动功能得到一定程度的改善.     

Effect of basic fibroblast growth factor on the expression of glial fibrillary acidic protein after tractive spinal cord injury in rats

Basicfibroblastgrowthfactor(bFGF) isanewneurotrophicfactor(NTF)andhasbeencloselystudiedinrecentyears.1 Itsneurotrophiceffectsincludepromotioninneuronalregenerationandsurvival. StudieshavefoundthatexogenousbFGFpumpedintothemarroworthesheathcandecreasetissu…     

The effect of fentanyl anesthesia and intrathecal naloxone on neurologic outcome following spinal cord injury in the rat

Whereas opiate receptor agonists have resulted in spinal cord damage; opiate receptor antagonists have demonstrated protection against spinal cord injury. Because opioids are used in clinical anesthesia, the effect of an opiate antagonist was evaluated on neurologic outcome in a rat model of spinal cord injury occurring during opioid anesthesia. One day prior to spinal cord injury, a catheter was inserted into the spinal subarachnoid space with the tip at T8. On the day of spinal cord injury a balloon tipped catheter was inserted in the epidural space with the tip at the thoracolumbar junction. Spinal cord injury was produced by balloon inflation during one of the following states: 1) group 1 (A/S), injury was produced in awake rats and saline was administered in the subarachnoid space immediately following injury; 2) group 2 (F/S), injury was produced during a fentanyl/nitrous oxide (N2O) anesthetic, and subarachnoid saline administered; and 3) group 3 (F/Nx), injury was produced during a fentanyl/N2O anesthetic, and subarachnoid naloxone (1 mg/kg) was administered immediately following injury. Dose-response curves describing the relationship between the duration of balloon inflation and the percentage of animals with a persistent neurologic deficit were constructed and compared for differences by use of a group t test. The duration of balloon inflation required to produce a neurologic deficit was greater in both the F/S and F/Nx groups than in the A/S group (P less than 0.05). There was no difference between the F/S and F/Nx groups. In summary, in rats receiving a fentanyl/N2O anesthetic, neurologic outcome was improved compared with the awake state.(ABSTRACT TRUNCATED AT 250 WORDS)     

硫酸软骨素酶ABC置管灌注治疗对大鼠脊髓损伤后神经功能恢复的影响

目的探讨硫酸软骨素酶ABC（ehondroitinase ABC,ChABC）置管灌注治疗对大鼠脊髓完全性横断伤后脊髓功能恢复的影响。方法采用大鼠胸段（T7-8）脊髓完全横断损伤模型,将SD大鼠随机分为4组：正常组（n=6）、假手术组（n=6）、单纯脊髓横断组（n=10）、ChABC置管灌注组（n=10）。正常组不进行任何干预处理;假手术组只切除T7-8椎板,不损伤硬脊膜;在横断节段下方蛛网膜下腔放置PE-10导管灌注,单纯脊髓横断组给予生理盐水10μl/d灌注,连续10 d;ChABC置管灌注组给予ChABC 6μl/次灌注,隔日1次,共5次。大鼠脊髓损伤术后1～8周,1周1次,12～24周,2周1次,进行行为学评估;24周时行大脑皮层诱发电位检测。结果（1）行为学评估：损伤后3周内,评分均在8分左右[单纯脊髓损伤组为（6.5±1.14）分,ChABC置管灌注组为（9.0±2.20分）],3周后ChABC置管灌注组的评分有明显提高,并于14～16周达到峰值,然后呈下降趋势,22～24周时稳定在10周时的水平。单纯脊髓横断组的最高评分为（11.0±1.47）分,ChABC置管灌注组的最高评分为（30.0±4.55）分,正常组的评分为53.5分。假手术组术后2周时的评分与正常组无明显差异,4周后ChABC置管灌注组的评分高于单纯脊髓横断组（P〈0.05）。（2）大脑皮层诱发电位检测：术后24周时,所有脊髓横断组中均未记录到体感诱发电位（somatosensory evoked potentia,SEP）波形。结论ChABC置管灌注治疗后,改善脊髓损伤区及两端的神经细胞功能,促进轴突再生,促进双下肢运动功能的恢复,动物行为学评分有明显提高。     

NGF、BDNF基因修饰嗅鞘细胞脊髓内移植对损伤脊髓细胞的保护作用

目的：观察神经生长因子(nerve growth factor，NGF)和脑源性神经营养因子(brain-derived neurotmphic fac-tor，BDNF)基因修饰的嗅神经鞘细胞(Olfactory ensheathing cells，OECs)移植对损伤脊髓组织的保护作用。方法：将脊髓半横断伤SD大鼠模型，随机分为：NGF、BDNF基因修饰的OECs移植组(A组)、OECs移植组(B组)、损伤对照组(C组)和正常对照组(D组)。24h后每组8只动物取伤段标本，测水离子含量。其余动物第6周和12周每组8只动物爬坡试验，评价下肢运动功能及运动诱发电位(MEP)检测。结果：脊髓损伤(SCI)后组织水肿，Na^ 、Ca^2 离子浓度升高，K^ 、Mg^2 离子浓度降低。NGF、BDNF、基因修饰的OECs脊髓内移植后显著改善这些变化，且使SCI后神经功能有显著恢复。结论：NGF、BDNF基因修饰的OECs脊髓内移植对SCI有保护作用。其机制可能与减少神经细胞离子失衡，改善细胞内环境有关。     

高渗盐水治疗脊髓急性压迫损伤的实验研究

目的观察高渗盐水对脊髓损伤的治疗作用,并探讨其作用机制.方法 36只SD大鼠造成T10节段脊髓急性压迫损伤后,随机分为三组:高渗盐水治疗组、生理盐水治疗组及对照组,每组观察损伤后1、4周两时间段;评价动物神经功能,观察各时间段脊髓病理改变,计算脊髓残留组织保留率.结果①高渗盐水治疗组动物神经功能恢复更快、更完全,与生理盐水组及对照组相比差异有显著意义(P＜0.05);②损伤后1周,高渗盐水治疗组脊髓组织炎症反应、水肿明显减轻;③损伤后4周,高渗盐水治疗组脊髓残留组织保留率显著增加,与其它两组相比差异有显著性意义(P＜0.01).结论高渗盐水能减轻脊髓组织病理改变,促进神经功能恢复;减轻损伤后脊髓组织的炎症反应及水肿是其作用机制之一.     

Excitotoxic model of post-traumatic syringomyelia in the rat

STUDY DESIGN: A rat model was developed to elucidate the role of excitatory amino acids and spinal subarachnoid block in the genesis of post-traumatic syringomyelia. This excitotoxic model produces intramedullary cavities rather than the dilation of the central canal (canalicular syringomyelia) created by previous animal models. OBJECTIVES: To produce extracanalicular cysts in the rat spinal cord with quisqualic acid, a potent agonist of multiple excitatory amino acid receptors, and to compare the effects of excitotoxic injury only with that of excitotoxic injury and subarachnoid block with kaolin. SUMMARY OF BACKGROUND DATA: In post-traumatic syringomyelia, primary injury and excitotoxic cell death secondary to elevated levels of excitatory amino acids may initiate a pathologic process leading to the formation of spinal cavities. Subarachnoid block by arachnoiditis may promote enlargement of the cavities. METHODS: Three control rats received a unilateral injection of normal saline into the spinal cord, and another five rats received an injection of kaolin into the spinal subarachnoid space. Quisqualic acid was injected unilaterally into the spinal cord of 20 rats, and 13 additional rats received a unilateral injection of quisqualic acid into the spinal cord after injection of kaolin into the subarachnoid space. Histologic and immunocytochemical assessments were undertaken. RESULTS: In the control groups, no parenchymal cyst developed in any of the animals. Spinal cord cyst formation was observed in 16 of 19 animals in the quisqualic acid groups, but no cysts exceeding two segments in the length of the spinal cord developed in any of the rats. Much larger cavities were seen in 9 of 11 animals in the group with quisqualic acid and kaolin, and cysts exceeding two segments developed in all 9 of these (9/11; 82%). CONCLUSIONS: In post-traumatic syringomyelia, excitotoxic cell death occurring secondarily to elevated levels of excitatory amino acids may contribute to the pathologic process leading to the formation of spinal cord cysts. Subarachnoid block by arachnoiditis is likely to cause enlargement of the cavity.     

Effects of nerve growth factor on neuronal nitric oxide production after spinal cord injury in rats

OBJECTIVE: To explore the protective effects of nerve growth factor (NGF) on injured spinal cord. METHODS: The spinal cord injury (SCI) model of Wistar rats was established by a 10 gx2.5 cm impact force on the T(8) spinal cord. NGF (60 microg/20 microl) was given to the rats of the treatment group immediately and at 2, 4, 8, 12, 24 hours after SCI. The level of neuronal constitutive nitric oxide synthase (ncNOS) and the expression of ncNOS mRNA in the spinal cord were detected by the immunohistochemistry assay and in situ hybridization method. RESULTS: Abnormal expression of ncNOS was detected in the spinal ventral horn motorneuron in injured rats. The levels of ncNOS protein in the NGF group were significantly lower than those in the normal saline group (P<0.05 ). The ncNOS mRNA expression was found in the spinal ventral horn motorneuron in injured rats and the expression in the NGF group was significantly decreased compared with that in the normal saline group (P<0.01). CONCLUSIONS: NGF can protect the injured tissue of the spinal cord by prohibiting abnormal expression of nitric oxide synthase and the neurotoxicity of nitric oxide.     

Effects of nerve growth factor on N-methyI-D-asparate receptor 1 after spinal cord injury in rats

To explore the effects of the nerve growth factor ( NGF ) on N-methyI-D-asparate receptor 1(NMDAR 1 ) after spinal cord injury. Methods: Spinal cord injury of Wistar rats was performed with Allen's method by a 10 g x 2.5 cm impact on the posterior T8 spinal cord. NGF was given to the rats of the treatment group via subarachnoid space tube at once,2, 4, 8, 12 and 24 hours after spinal cord injury,respectively. The expression of NMDAR1 mRNA in spinal cord was detected by in situ hybridization. Results: Rare expression sequence of NMDAR1 mRNA was found in rat spinal cord of the normal group. A strong expression sequence of NMDAR1 mRNA was found in rat spinal cord of the normal saline group. The expression of NMDAR1 mRNA in the NGF group was significantly decreased as compared with that in the normal saline group ( P ＝ 0.01 ). Conclusions: NGF can relieve damage of injured spinal cord by prohibiting the expression of NMDAR1 mRNA.