抑肽酶预处理对家兔脊髓缺血再灌注损伤后脊髓水电解质的影响

目的:观察抑肽酶预处理对家兔脊髓缺血再灌注损伤后脊髓水电解质的影响,为临床应用抑肽酶治疗脊髓缺血再灌注损伤提供实验依据。方法:60只家兔随机分为缺血再灌注损伤抑肽酶预处理组(A组)和生理盐水对照组(B组),每组30只。建立家兔脊髓腰骶段缺血模型,恢复血流再灌注7d。A组于缺血前10min一次性静脉注射抑肽酶3×107IU/kg,继而用微量泵持续注入1×107IU/(kg·h);B组缺血再灌注时间同A组,以等量生理盐水代替抑肽酶。缺血前、缺血再灌注后8h、24h、48h、72h和7d处死动物,取L4￣L5段脊髓做生化测定,L3￣L4段脊髓做组织病理学检查。结果:在缺血再灌注后检测的各时段,A组较B组脊髓含水量、Ca2+、Na+降低,Mg2+、K+升高(P<0.05)。组织病理学检查发现缺血再灌注后48h,A组脊髓前角运动神经元轻度肿胀,轮廓清楚,前索轴突分布较均匀;B组脊髓前角运动神经元固缩变小,前索轴突数量减少,分布紊乱。结论:抑肽酶具有降低脊髓缺血再灌注损伤后脊髓中含水量、Ca2+和Na+,增加Mg2+和K+含量作用;对脊髓缺血再灌注损伤具有保护作用。     

抑肽酶预处理对兔脊髓缺血再灌注损伤的影响

目的:观察抑肽酶预处理对兔脊髓缺血再灌注损伤的影响,为临床应用抑肽酶治疗脊髓缺血再灌注损伤提供实验依据.方法:6月龄国产大耳白兔39只,随机分为A组(15只)、B组(15只)和C组(9只).A、B组动物于左肾动脉下用主动脉环扎器环扎腹主动脉,缺血60min后开放,再灌注24h.A组于缺血前10min静脉注射抑肽酶3×107IU/kg,继而用Graseby 3500微量泵持续注入抑肽酶1×107IU/(kg·h)至处死动物时;B组用生理盐水代替A组的抑肽酶,其余同A组;C组只暴露不夹闭腹主动脉,不给药.A、B组缺血前,缺血5、10、20、60min及再灌注后8h、24h,C组相应时间点,测定各组皮层体感诱发电位(CSEP).A、B组缺血前,缺血再灌注后8h、24h,C组相应时间点,处死动物,取L2～L4脊髓行一氧化氮(NO)及一氧化氮合酶(NOS)测定,取L3～L4脊髓灰质切片进行组织学检查,观察神经无形态变化.结果:A、B两组缺血5min时CSEP的P1波和N1波潜伏期较缺血前延长、波幅降低(P<0.05),缺血20min时两波潜伏期及波幅消失,缺血冉灌注后8h两波潜伏期及波幅有所恢复,但较缺血前及缺血后5min、10min时明显延长和降低(P<0.01),缺血再灌注后24h两波潜伏期及波幅较前面各时间点延长和降低(P<0.01);缺血再灌注后8h、24h,A组较B组P1波和N1波潜伏期短、波峰高(P<0.05),而C组较A、B组潜伏期短、波峰高(P<0.01).A、B两组NO、总NOS及诱导型NOS(iNOS)在缺血再灌注后8h明显升高,24h时更高(P<0.05),在缺血再灌注后8h、24h时A组的NO、总NOS及iNOS较B组低(P<0.01).各时间点C组P1波和N1波潜伏期及波幅不变,NO、总NOS及iNOS量均不变(P>0.05).A、B组脊髓缺血再灌注后神经元均有损伤,但在再灌注后8h、24h时A组神经元损伤程度均较B组为轻:C组神经元正常.结论:抑肽酶预处理可以改善脊髓缺血再灌注早期的CSEP,减少NO含量,从而减少缺血再灌注损伤.     

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.     

三甲氧苄嗪对大鼠脊髓缺血-再灌注损伤的保护作用

目的评价三甲氧苄嗪(trimetazidine)对大鼠脊髓缺血-再灌注损伤的保护作用,并探讨其作用机制. 方法 45只SD大鼠采用随机数字表法分为3组,每组15只.建立大鼠脊髓缺血损伤模型,假手术组:行开腹手术,不阻断主动脉;对照组:剖腹后阻断主动脉20分钟;三甲氧苄嗪组:于主动脉阻断前10分钟静脉内注射三甲氧苄嗪(3mg/kg),其余处理与对照组相同.测定血浆丙二醛(MDA)含量,术后48小时按Tarlov评分标准评价动物后肢神经功能,取脊髓进行含水量、MDA含量测定及组织病理学检查.结果三甲氧苄嗪组血浆MDA含量明显低于对照组(P<0.05),动物后肢神经功能评分明显优于对照组(P<0.01),脊髓含水量、MDA含量明显低于对照组(P<0.01);三甲氧苄嗪组在光学显微镜下脊髓病理改变轻微,而对照组脊髓损伤较重,两组病理评分差别有显著性意义(P<0.01).结论三甲氧苄嗪对大鼠脊髓缺血-再灌注损伤具有明显的保护作用.     

甘草酸二铵对大鼠脊髓缺血再灌注损伤后运动神经元Caspase-3表达的影响

目的:观察甘草酸二铵(DG)对大鼠脊髓缺血再灌注损伤后脊髓前角运动神经元Caspase-3表达的影响.方法:60只大鼠随机分为3组,每组20只.两组采用手术夹闭大鼠左右肾动脉之间的腹主动脉30min致脊髓缺血,然后松开再灌注,其中一组在缺血前10min舌下静脉注射DG 20mg/kg(DG干预组),一组仅造成脊髓缺血损伤(损伤组);另一组打开腹腔后即关腹,不进行缺血再灌注(正常对照组).分别于术后3、24、72、168h处死大鼠取腰段脊髓行免疫组化染色,观察脊髓前角Caspase-3光密度变化情况;、168h处死动物前先采用Behrmann 5点评分法评定大鼠后肢功能.结果:损伤组与干预组72h时后肢功能评分分别为4.2±0.45分、5.8±1.1分:168h时分别为5±0分、6.2±1.3分,两组相同时间比较有显著性差异.Caspase-3表达位于脊髓前角运动神经元胞浆.术后3、24、72、168h,正常对照组前角运动神经元的平均光密度为0.13±0.04、0.15±0.06、0.13±0.06、0.15±0.06,损伤组为0.18±0.04、0.18±0.03、0.20±0.04、0.20±0.05,DG干预组为0.17±0.06、0.15±0.02、0.16±0.04、0.15±0.02,损伤组各时间点与对照比较均有显著性差异,DG干预组在24、72、168h与损伤组比较差异有显著性.结论:DG可下调凋亡信号转导通路中Caspase-3的表达水平,从而抑制脊髓前角神经元凋亡的发生.     

肢体缺血预处理对兔颈髓慢性缺血后再灌注损伤的影响

目的：探讨肢体缺血预处理对兔颈髓慢性缺血后再灌注损伤的影响及其机制。方法：建立兔颈髓慢性压迫损伤模型，随机分为实验组和对照组。实验组在脊髓减压再灌注前给予肢体缺血预处理，对照组不做预处理。两组兔在减压前和减压后2h、8h、24h，7d、21d分别进行后肢神经功能评分。在减压后即刻、0．5h、1h和以上时间点分别进行脊髓血流测定。处死动物取脊髓(C1～T1)进行组织病理学检查。结果：实验组于再灌注8h后神经功能评分明显好于对照组。实验组脊髓组织丙二醛含量于再灌注8h后显著低于对照组。两组再灌注后脊髓血流均显著下降，实验组优于对照组。病理学检查示对照组神经元呈缺血改变，白质水肿、脱髓鞘；实验组病理改变轻微。实验组热休克蛋白70表达阳性，对照组为阴性。结论：肢体缺血预处理对脊髓慢性缺血后的再灌注损伤具有明显保护作用。     

硫酸镁对兔脊髓缺血再灌注损伤保护作用的研究

目的:探讨硫酸镁对兔脊髓缺血再灌注损伤的保护效果。方法:27只新西兰大白兔,随机分为A组(硫酸镁处理组)、B组(生理盐水)和C组(假手术对照组)。A、B两组参照Tetik方法建立兔脊髓腰骶段缺血模型,比较三组动物不同时间点的体感诱发电位(SEP)、后肢运动功能评分及缺血再灌注后48h的病理学改变。结果:C组SEP没有明显变化,动物均完全康复。缺血30min时B组波形消失,A组波幅降为基线的(29.3±1.9)%。再灌注60min后A组、B组SEP波幅分别渐升致基线的(74.5±2.3)%和(49.2±2.1)%。A组N1、P1波峰潜伏期在缺血30min及再灌注60min时均明显优于B组(P<0.05);再灌注24h和48h后,A组的后肢运动功能评分均显著高于B组(P<0.05);再灌注48h后A组的脊髓前角神经细胞计数显著高于B组(P<0.01)。结论:硫酸镁具有减轻兔脊髓缺血再灌注损伤及保护神经功能的作用。     

辛伐他汀预先给药对大鼠脊髓缺血再灌注损伤的影响

目的 评价辛伐他汀预先给药对大鼠脊髓缺血再灌注损伤的影响.方法 雄性SD大鼠96只,体重220～280 g,随机分为3组(n=32):假手术组(S组)、缺血再灌注组(IR组)和辛伐他汀预先给药组(Si组).IR组和Si组采用夹闭腹主动脉45 min后开放的方法制备脊髓缺血再灌注模型,Si组制备模型前3 d开始以辛伐他汀20 mg·kg-1·d-1灌胃,连续3 d.分别于再灌注6、12、24 h时取8只大鼠,进行后肢运动功能评分.分别于再灌注2、6、12、24 h时取8只大鼠,采集静脉血样,测定血清脑型肌酸激酶同工酶(CK-BB)活性.取完血样后取大鼠脊髓组织,测定Toll样受体4(TLR4)mRNA表达、NF-κB活性、TNF-α含量和细胞间粘附分子-1(ICAM-1)含量,光镜下观察脊髓的病理学结果.结果 与S组比较,IR组和Si组后肢运动功能评分降低,血清CK-BB活性、脊髓TLR4mRNA表达、NF-κB活性、TNF-α和ICAM-1含量升高(P＜0.05或0.01).与IR组比较,Si组后肢运动功能评分升高,血清CK-BB活性、脊髓TLR4 mRNA表达、NF-κB活性、TNF-α和ICAM-1含量降低(P＜0.05或0.01).Si组脊髓病理学损伤程度轻于IR组.结论 辛伐他汀预先给药可减轻大鼠脊髓缺血再灌注损伤,其机制与下调TLR4表达、抑制NF-κB激活,从而减轻炎性反应有关.     

鼠后肢周围神经缺血再灌注对脊髓腰膨大前角运动神经元超微结构的影响

目的 探讨大鼠后肢周围神经缺血再灌注对脊髓腰膨大前角运动神经元超微结构的影响及其内在关系。方法 采用无损伤动脉夹暂时阻断大鼠一侧髂总、髂内、髂外及股动脉的大鼠周围神经缺血的实验模型，透射电镜下观察不同缺血再灌注时间脊髓腰膨大灰质前角细胞的超微结构改变。结果 对照组神经元的超微结构形态正常，缺血6h，8h，12h3组均出现暗神经元改变。缺血8h组，除暗神经元改变外，还出现明确的细胞坏死。缺血12h组，神经元暗细胞变与大片神经组织坏死并存，血脑屏障严重破坏。在缺血6h，8h，12h各组内，随着再灌注时间的延长(60h以内)，神经元的损害明显逐渐加重。结论 大鼠后肢周围神经缺血再灌注可相应地引起脊髓腰膨大前角运动神经元超微结构的改变，可引起神经元的暗细胞变和坏死。在同一缺血组内，随着再灌注时间的延长，神经元的损害逐渐加重。     

羟乙基淀粉行急性等容血液稀释对兔脊髓缺血-再灌注损伤的保护作用

目的 探讨用羟乙基淀粉(HES130/0.4)急性等容血液稀释(ANH)对兔脊髓缺血-再灌注损伤的保护作用.方法 24只新西兰雄性大白兔,随机均分成三组:HES组,生理盐水组(NS组),对照组(C组).HES组和NS组分别用HES130/0.4和生理盐水行ANH,使红细胞压积(Hct)达30%.ANH的方法为:15 min内经股动脉恒速放出计算的血量,同时利用微量输液泵经静脉输注与放血量等量的液体(HES组)或输注3倍于放血量的液体(NS组),放血和输液速度相等,维持术中大白兔的血压和心率恒定.稳定15 min后,行肾下腹主动脉(IRA)阻闭建立脊髓缺血-再灌注损伤模型.分别于稀释前、稀释后和腹主动脉开放后采集动脉血进行血气分析.评估再灌注后4、8、12、24及48 h后肢运动功能,并于48 h处死动物取脊髓(L5)制标本行病理组织学观察.结果 再灌注后48 h.HES组和NS组动物的后肢运动功能比C组明显改善(P＜0.05或P＜0.01);HES组和NS组动物脊髓前角正常运动神经元计数比C组显著增加(P＜0.05或P＜0.01),但两组间差异无统计学意义.结论 HES130/0.4行适度ANH对脊髓缺血-再灌注损伤具有显著地保护作用.     

Progressive cystic degeneration of the spinal cord following spinal cord injury

From a group of 520 spinal cord injury patients treated at Rancho Los Amigos Hospital, two cases of progressive myelopathy secondary to cystic degeneration of the spinal cord have been identified. The cyst may dissect proximately to produce progressive neurologic deficit. Surgical treatment with shunting can allow stabilization and improvement with return of newly lost function.     

Experimental study on spinal cord monitoring--changes in spinal cord evoked potentials during vertical direction distraction of the spinal cord

Experiments were carried out on 18 adult dogs ranging from 9.0 to 11.5 kg. The dogs were intubated and anesthetized with Halothene oxygen, and then mounted on a stereotaxic spinal apparatus. Facetectomies and a discectomy between L1 and L2 vertebrae were performed readily to give traction force to the spinal cord. Spinal cord function was monitored by the first and second negative deflections (I and II, respectively) of the descending spinal cord evoked potentials (descending SCEP) elicited at T7 and recorded at L4 through bipolar catheter electrodes. Both of them were inserted at the midline of the dorsal epidural space. The study was conducted in two parts. In the first part, the cyclic distraction-release program was carried out until motor function was impaired. Distraction was increased in increments of 5 mm, each time maintained for 10 minutes and then totally released for 10 minutes. If neurological deficits in the hind limbs were confirmed by the wake-up test, which was performed every 10 minutes after distraction and release, the 10 minutes' release period was extended for a total period of 30 minutes. The first change in the experimental protocol was transient augmentation of the amplitude of the II deflection which was always observed on a slight distraction, while the I deflection did not change in its amplitude and latency. Each distraction produced a reversible slight reduction of the amplitudes with delay of latencies of the I and II deflections before motor disturbance occurred. However, at a certain traction level paraparesis accompanied by irreversible decrease of amplitudes and delay of latencies was observed, which was confirmed by the wake-up test. At this point, which was designated as the critical point, SCEPs were so time dependent that only a slight amplitude reduction was noted immediately after distraction, but it decreased quickly in a short time during this traction level. Histopathology and microangiography did not show any hemorrhage in the spinal cord of any of the specimens, although there were formation of perivascular space, rupture of a part of nerve fibers in the white matter and findings of acute degeneration in the grey matter. In the second part of this study, a small amount of distraction was introduced until the amplitude of the II deflection depicted transient augmentation, which had a mean amplitude of 167.8 per cent as compared to the control. This enhancement returned approximately to the normal value within 10 minutes by total release.(ABSTRACT TRUNCATED AT 400 WORDS)     

A study of spinal cord ischemia during aortic cross-clamp--evoked spinal cord potential and histological analysis of the spinal cord

The relationship between the evoked spinal cord potential (ESP) and the histological findings of the spinal cord after thoracic aortic cross-clamp was studied. Thoracic aorta was cross-clamped in 23 dogs and ESP was monitored before, during, and after cross-clamping. Incidence of paraplegia and histological findings were studied after the dogs recovered from the procedure. Aortic cross-clamp was maintained for 60 minutes in 20 dogs (Group A). And cross-clamp was released 10 minutes after the amplitude of ESP became lower than 20% of control in 3 dogs. (Group B). In group A, three types of ESP changes were detected; ESP became lower or lost during cross-clamping in type 1 response, ESP remained unchanged in type 2 response, and ESP returned after transient loss during cross-clamping in type 3 response. Four of five dogs with type 1, none of nine with type 2, two of five with type 3 response showed paraplegia. One of the dogs with type 2 response showed paraparesis. ESP could not detected in one dog, in which traumatic spinal cord injury during laminectomy caused paraplegia. In Group B, all dogs showed type 1 response and paraplegia. Characteristic histological finding of the spinal cords of the dogs with paraplegia was the ischemic necrosis mainly in the gray matter. Necrotic foci were limited in the posterior horn in mild, in the anterior and posterior horn in moderate changes. And neurons were lost in entire gray matter in severe histological changes. In the spinal cords of the dogs with spastic paraplegia, severe histological changes were limited in the lower lumbar region.(ABSTRACT TRUNCATED AT 250 WORDS)     

大鼠脊髓损伤后巢蛋白在脊髓组织中的表达

目的探讨大鼠脊髓损伤后巢蛋白(nestin)的表达规律及其意义。方法30只Wister成年大鼠,随机分为正常对照组(A组)、损伤组(B组)。采用Allen打击模型(25g·cm),在T10段造成急性脊髓损伤,于损伤后1d、3d、1周、4周、8周进行取材,对距离损伤中心5mm处脊髓进行nestin免疫组化检测。应用图像分析软件进行nestin阳性区域面积侧算。结果A组脊髓室管膜细胞只可见极少数细胞胞浆内nestin表达,白质中几乎无表达。B组中nestin于损伤后24h表达于室管膜以及软膜,灰质和白质亦有少量表达,1周达到高峰(P<0.05),4周明显下降,8周时很少或几乎无表达。结论脊髓组织的许多部位可能存在具有分化和更新潜能的祖细胞,脊髓损伤后这些细胞被激活,在功能恢复中可能发挥着重要的作用。