高压氧预处理对大鼠急性脊髓损伤后神经细胞凋亡的影响

目的探讨高压氧预处理对急性脊髓损伤后不同时期神经细胞凋亡的影响及神经保护机制。方法将55只SD大鼠随机分为高压氧预处理组（25只）、正常损伤组（25只）及对照组（5只）。大鼠急性脊髓损伤模型制作采用改良Allen＇s法，分别于伤后1d、5d、7d、10d和14d在脊髓损伤部位取材，应用苏木精-伊红染色、原位缺口末端标记（TUNEL）方法检测大鼠脊髓损伤后的神经细胞凋亡情况。结果预处理组和单纯损伤组均见TUNEL阳性凋亡细胞，而预处理组凋亡细胞数减少；在各时间点预处理组与单纯损伤组差异均有统计学意义（P〈0．05）。结论高压氧预处理可减少继发性脊髓损伤细胞凋亡，因而可促进脊髓损伤后修复，对中枢神经系统损伤具有保护作用。     

脊髓损伤后神经元的再生与修复

由脊髓损伤所导致的神经功能缺失的不可逆转性，主要是因为损伤的神经元难以再生。中枢神经系统神经纤维再生的细胞生物学研究已成为当今的研究热点。随着对调节神经纤维再生机制的逐步了解，各种新技术如生物化学、分子生物学、细胞和组织培养技术以及神经解剖示踪方法的产生和应用，使我们对神经元的细微结构有了更深入的了解。近年来，学者把研究的焦点集中到影响神经组织的环境因素上。现已有大量事实证明，损伤的神经组织周围细胞环境的失衡是影响中枢神经组织再生的主要原因之一。本文对当今成熟脊髓神经细胞再生的研究现状做一综述。     

外源性血管内皮生长因子对大鼠损伤脊髓神经元的作用

目的研究外源性血管内皮生长因子(VEGF)局部应用对大鼠脊髓损伤(SCI)后脊髓灰质神经元的作用。方法采用改良Allen氏重量打击法建立大鼠急性SCI模型,将72只模型大鼠随机分为VEGF治疗组〔人工基底膜(Matrigel蛋白胶)10μL+重组人VEGF1650.2μg〕、基底膜对照组(Matrigel蛋白胶10μL)和空白对照组(生理盐水10μL)3组,分别经蛛网膜下腔给药。于SCI后1、2、3、4周分别观察模型鼠脊髓横切面灰质神经元数量、神经元截面积和尼氏体密度恢复情况。结果 SCI后1~4周VEGF治疗组脊髓横切面灰质神经元数量(分别为76.34±6.25、108.25±11.74、144.33±13.22、165.96±18.11)和神经元截面积〔分别为(177.87±14.42)(、229.63±21.74)(、340.55±32.66)(、390.30±46.19)μm2〕均高于同期基底膜对照组〔神经元数量分别为40.89±7.20、50.61±13.11、59.78±9.46、80.13±10.84,神经元截面积分别为(108.98±15.03)(、148.53±18.38)、(163.22±16.77)(、208.87±29.58)μm2〕和空白对照组〔神经元数量分别为37.66±6.69、52.36±5.17、60.58±9.13、78.56±13.56,神经元截面积分别为(114.55±14.22)(、139.24±15.17)、(157.11±20.26)(、185.23±21.65)μm2〕(P<0.01,P<0.05)。SCI后1周时VEGF治疗组神经元尼氏体密度(0.2089±0.0210)与基底膜对照组(0.2012±0.0145)、空白对照组(0.1982±0.0106)比较差异均无统计学意义(P>0.05),SCI后2、3、4周,VEGF治疗组尼氏体密度(分别为0.2489±0.0217、0.2908±0.0327、0.3508±0.0362)亦大于基底膜对照组(分别为0.2198±0.0214、0.2406±0.0198、0.2605±0.0322)和空白对照组(分别为0.2044±0.0231、0.2356±0.0311、0.2582±0.0245)(均P<0.05)。两对照组各指标均无统计学差异。结论局部应用外源性VEGF可能对SCI后大鼠脊髓灰质神经元具有保护作用。     

FTY720对大鼠急性脊髓损伤后caspase-3表达及细胞凋亡的影响

目的 探讨一种新型免疫抑制剂FTY720对大鼠急性脊髓损伤后caspase-3表达及细胞凋亡的影响。材料及方法 采用SD大鼠120只,随机分成A、B、C3组,每组40只,制作Allen’s胸9、10脊髓损伤模型。C组（FTY720治疗组）：以FTY720按3mg/kg生理盐水稀释至0.3ml灌胃。B组（对照组）：以等量生理盐水灌胃。A组（假手术组）：大鼠麻醉后仅切除胸9、10椎板,不打击脊髓,缝合后立即以等量生理盐水灌胃。分别于术后6小时、12小时、24小时、48小时、72小时处死大鼠,每次各组各8只,取损伤段脊髓超薄切片,行S-P免疫组化染色及Tunel染色,观察各组caspase-3表达及细胞凋亡情况,并计算各组免疫组化染色阳性细胞比值,进行统计学分析。结果A组各时间点几乎见不到Caspase-3和细胞凋亡表达阳性细胞。B组大鼠急性脊髓损伤后6小时出现caspase-3及细胞凋亡表达,伤后伤后12小时持续升高,到伤后24小时达高峰,伤后48小时开始减弱,伤后72小时进一步减弱,但仍维持较高水平; caspase-3表达及细胞凋亡同步,二者之间存在正相关（г=0.864,Ｐ＜０.０５）。而FTY720治疗组（C组）,虽然在caspase-3和细胞凋亡表达的周期上与损伤组相同,但caspase-3和细胞凋亡表达阳性的细胞数却显著低于对照组（B组）（Ｐ＜０.０５）。结论FTY720可以显著减少大鼠急性脊髓损伤后Caspase-3的表达及神经细胞凋亡,其具体机制还有待于进一步研究。     

脊髓损伤后细胞的凋亡及其药物治疗

细胞凋亡是脊髓损伤后引起神经功能障碍及影响疗效的主要原因。本文对引起脊髓细胞凋亡的原因及其药物治疗的研究进展进行了概述。     

依达拉奉对大鼠急性脊髓损伤后神经细胞凋亡的影响

目的:观察依达拉奉对大鼠急性脊髓损伤后细胞凋亡的影响,探讨脊髓保护的作用机制。方法:120只SD雄性大鼠,Allen法建立脊髓损伤模型,随机分为依达拉奉组、假手术组和对照组（均n=40）。依达拉奉组给予依达拉奉10mg·kg^-1,每日2次腹腔注射,连续6d;对照组给予等量同次数的生理盐水腹腔灌注;假手术组仅行椎板切除,不损伤脊髓,不给药。在伤后第1、7、14、28天观察各组大鼠活动情况行BBB评分,取受伤脊髓节段检测抑制羟自由基能力、caspase-3蛋白表达、原位脱氧糖核苷酸末端转移酶介导的原位末端标记法（TUNEL法）标记凋亡细胞。结果:依达拉奉组抑制羟自由基能力明显高于假手术组和对照组（P<0.05）;依达拉奉组caspase-3与对照组比各时间点的表达明显降低（P<0.05）;依达拉奉组与对照组比各时间点凋亡细胞显著减少（P<0.05）。结论:依达拉奉能减少急性脊髓损伤部位的羟自由基,下调caspase-3表达,抑制脊髓神经细胞凋亡,对继发性脊髓损伤有保护作用。     

大鼠急性脊髓损伤后细胞凋亡以及相关蛋白表达的实验研究

目的 观察脊髓损伤（spinalcordinjury，SCI）后细胞凋亡和相关调控基因（FasL和Caspase．3）的表达情况。方法 通过建立静压型SCI模型（30g的重量，压迫T10节段10min），并用TUNEL染色（terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling）和免疫组化染色方法，了解Sprague-Dawley大鼠SCI后（伤后6、12、24、48和72h以及伤后7、14、21d）细胞凋亡以及相关调控基因（FasL与Caspase-3）表达的情况。结果 大鼠SCI后损伤节段（T10节段）6h出现TUNEL阳性细胞数增加，12h达到高峰，持续3天～1周后显著减少；损伤相邻节段（T9、T11节段）伤后12h出现TUNEL阳性细胞，伤后3dTUNEL阳性细胞数达峰值；SCI后FasL与Cas-pase-3表达均有不同程度的增高。结论 大鼠脊髓损伤后多节段、长时间存在着大量的细胞凋亡；细胞凋亡可能与FasL-Caspase-3途径有关。     

女贞子对大鼠脊髓损伤后细胞凋亡及Bcl-2、Bax的表达影响

目的 通过观察女贞子对大鼠脊髓损伤后细胞凋亡及Bcl-2、Bax表达的影响,探讨其对脊髓损伤的保护作用.方法 选用90只SD大鼠随机分为假手术组、模型组和治疗组,制成脊髓损伤动物模型.治疗组取女贞子液3.0 g/(kg·d)腹腔注射,假手术组与模型组取等量生理盐水腹腔注射,于各时间点制成脊髓切片,行苏木素一伊红(HE)...     

脊髓损伤大鼠远端神经元及骨骼肌变化的基础研究

目的观察脊髓损伤大鼠远端神经元及骨骼肌变化情况。方法 20只大鼠随机分为2组,每组10只,分别为假手术组和脊髓损伤组,假手术组行椎板切除术,脊髓损伤组行胸10完全脊髓损伤,在制成模型后1、2、4、12、24周观察大鼠坐骨神经-运动终板-内侧腓肠肌形态变化情况。结果脊髓损伤组电镜下坐骨神经术后12周有髓神经纤维髓鞘崩解,其板层结构清晰,有髓神经纤维髓鞘于术后24周模糊、碎裂髓鞘变多,12周后无髓神经纤维及薄髓增多;术后12周腓肠肌光镜下局部肌细胞多数模糊,但边界清楚,结缔组织增生明显,肌细胞核相对聚集;肌细胞于术后24周融合,融合细胞间有空隙,细胞核密集,结缔组织增生明显;术后12周电镜下运动终板突触前后及皱褶膜不可分辨,肌纤维明暗带清晰,突触结构紊乱,z线不连续,高倍镜下突触前后膜不可辨,突触皱褶未见,可见类圆形细小颗粒及突触小泡,肌板结构清晰。结论大鼠脊髓损伤后在损伤平面以下周围神经、运动终板、骨骼肌在形态上会发生规律性变化,12周后显著变化,24周后则毁损性改变。     

阿托伐他汀对颅脑损伤大鼠神经元凋亡的抑制作用

目的 探讨阿托伐他汀对颅脑损伤（TBI）大鼠神经元凋亡的抑制作用及机制。方法 30只SD大鼠随机分为假手术组、模型组和阿托伐汀他组,各10只。采用液压打击法制作TBI模型,阿托伐他汀组连续灌胃阿托伐他汀2周（1 mg/kg/d）,假手术组、模型组灌胃等体积生理盐水。给药结束后第2天,参照Zea Longa 5分制标准进行神经功能评分。酶联免疫吸附法检测血清肿瘤坏死因子（TNF-α）、白介素（IL）-6和IL-1β水平;免疫印迹法检测损伤脑组织Toll样受体4（TLR4）、核转录因子（NF）-κB p65、p-IκB、cleaved Caspase-3蛋白表达;末端标记法检测神经元凋亡;HE染色观察脑组织病理变化。结果 与模型组相比,阿托伐他汀组大鼠神经功能缺损评分、细胞凋亡率、血清IL-6、TNF-α和IL-1β水平明显改善（P<0.05）,损伤脑组织TLR4、NF-KB p65、p-IκB、cleaved Caspase-3水平明显下调（P<0.05）;HE染色显示脑组织损伤程度明显减轻。结论 阿托伐他汀可能通过抑制TLR4/NF-кB信号通路,抑制TBI大鼠的神经元细胞凋亡,促进神经功能恢复。     

Senegenin inhibits neuronal apoptosis after spinal cord contusion injury

Senegenin has been shown to inhibit neuronal apoptosis, thereby exerting a neuroprotective effect. In the present study, we established a rat model of spinal cord contusion injury using the modiifed Allen’s method. Three hours after injury, senegenin (30 mg/g) was injected into the tail vein for 3 consecutive days. Senegenin reduced the size of syringomyelic cavities, and it substantially reduced the number of apop-totic cells in the spinal cord. At the site of injury, Bax and Caspase-3 mRNA and protein levels were decreased by senegenin, while Bcl-2 mRNA and protein levels were increased. Nerve ifber density was increased in the spinal cord proximal to the brain, and hindlimb motor function and electrophysiological properties of rat hindlimb were improved. Taken together, our results suggest that senegenin exerts a neuroprotective effect by suppressing neuronal apoptosis at the site of spinal cord injury.     

Tamoxifen reduces infiltration of inflammatory cells,apoptosis and inhibits IKK/NF-kB pathway after spinal cord injury in rats

In this study, neuroprotective effect of tamoxifen has been explored in spinal cord injury (SCI) in rats by examining factors influencing IKK/NF-kB pathway in SCI in rats. It has been shown in several studies that IKK/NF-kB signaling pathway plays a key role in pathophysiology of SCI. In this study, three groups of rats (n = 17 each) were selected that included, tamoxifen group (here tamoxifen was injected after SCI in rats), SCI group (here only dimethylsulfoxide was administered after inducing SCI in rats) and sham group (here only laminectomy was performed). The effect of tamoxifen (5 mg/kg) on various factors responsible for activation of IKK/NF-kB signaling pathway including NF-kB p65, phosphorylated I-kBα was studied through Western blotting as well as densitometry. The examination of expression of active caspase-3 and myeloperoxidase activity was also carried out through Western blot analysis and densitometry. A comparison of three groups of rats showed that administration of tamoxifen significantly reduced the expression of NF-kB p65 and phosphorylated I-kBα (P < 0.05) compared to control. It also attenuated the expression of active caspase-3 resulting in the reduction of apoptosis, and infiltration of leukocytes to the injury site was also greatly reduced in the group where tamoxifen was administered. Statistical analysis through SPSS 13.0 software showed a significant decrease in the expression of inflammatory factors in groups where tamoxifen was administered. We conclude that tamoxifen possesses the potential neuroprotective effects that can be explored further for future therapeutic techniques in treating spinal cord injuries.     

Role of tumor necrosis factor-alpha in neuronal and glial apoptosis after spinal cord injury

We investigated the role of tumor necrosis factor (TNF)-alpha in the onset of neuronal and glial apoptosis after traumatic spinal cord crush injury in rats. A few TUNEL-positive cells were first observed within and surrounding the lesion area 4 h after injury, with the largest number observed 24-48 h after injury. Double-labeling of cells using cell type-specific markers revealed that TUNEL-positive cells were either neurons or oligodendrocytes. One hour after injury, an intense immunoreactivity to TNF-alpha was observed in neurons and glial cells in the lesion area, but also seen in cells several mm from the lesion site rostrally and caudally. The level of nitric oxide (NO) also significantly increased in the spinal cord 4 h after injury. The injection of a neutralizing antibody against TNF-alpha into the lesion site several min after injury significantly reduced both the level of NO observed 4 h thereafter as well as the number of apoptotic cells observed 24 h after spinal cord trauma. An inhibitor of nitric oxide synthase (NOS), N(G)-monomethyl-l-arginine acetate (l-NMMA), also reduced the number of apoptotic cells. This reduction of apoptotic cells was associated with a decrease in DNA laddering on agarose gel electrophoresis. These results suggest that: (i) TNF-alpha may function as an external signal initiating apoptosis in neurons and oligodendrocytes after spinal cord injury; and (ii) TNF-alpha-initiated apoptosis may be mediated in part by NO as produced by a NOS expressed in response to TNF-alpha.     

Aldehyde dehydrogenase 2 overexpression inhibits neuronal apoptosis after spinal cord ischemia/reperfusion injury

Aldehyde dehydrogenase 2(ALDH_2)is an important factor in inhibiting oxidative stress and has been shown to protect against renal ischemia/reperfusion injury.Therefore,we hypothesized that ALDH_2 could reduce spinal cord ischemia/reperfusion injury.Spinal cord ischemia/reperfusion injury was induced in rats using the modified Zivin’s method of clamping the abdominal aorta.After successful model establishment,the agonist group was administered a daily consumption of 2.5%alcohol.At 7 days post-surgery,the Basso,Beattie,and Bresnahan score significantly increased in the agonist group compared with the spinal cord ischemia/reperfusion injury group.ALDH_2expression also significantly increased and the number of apoptotic cells significantly decreased in the agonist group than in the spinal cord ischemia/reperfusion injury group.Correlation analysis revealed that ALDH_2 expression negatively correlated with the percentage of TUNEL-positive cells(r=-0.485,P0.01).In summary,increased ALDH_2 expression protected the rat spinal cord against ischemia/reperfusion injury by inhibiting apoptosis.     

一氧化氮合酶对脑损伤后神经细胞凋亡的影响

目的探讨脑损伤后神经型一氧化氮合酶（nNOS）和诱生型一氧化氮合酶（iNOS）对神经细胞凋亡的影响及其相关机制。方法320只SD大鼠随机分成以下4组：假手术组、脑创伤组、7-硝基吲唑组（nNOS抑制剂）和氨基胍组（iNOS抑制剂），此4组分别划分为伤后3h、6h、12h、24h、2d、3d、7d、14d8个时相组，每个时相组均为10只大鼠，采用Marmarou法制造大鼠重型弥漫性颅脑创伤模型，运用末端脱氧核苷酸转移酶介导的生物素脱氧尿嘧啶核苷酸缺口标记法（TUNEL）和免疫组化法，观察4组不同时相点海马CA1区的神经细胞凋亡情况和Bcl-2、Fas的表达情况。结果①假手术组偶见TUNEL阳性凋亡细胞及Bcl-2、Fas阳性细胞；②脑创伤组，伤后各时相点均出现TUNEL阳性凋亡细胞及Bcl-2阳性细胞，先上升后下降；③7-硝基吲唑（7-NI）组，伤后6h、12h、24h凋亡细胞明显下降而Bcl-2阳性细胞却明显上升（同脑创伤组比较P〈0．05）；④氨基胍（AG）组，伤后2～7d，凋亡细胞及Fas阳性细胞明显下降（同脑创伤组比较P〈0．01）。结论在脑损伤的早期，nNOS能够通过抑制Bcl-2的表达来促进神经细胞的凋亡；在脑损伤的晚期，iNOS能够通过诱导Fas的表达来促进神经细胞的凋亡。     

Inhibitory effect of electro-acupuncture on apoptosis after spinal cord injury

INTRODUCTION Apoptosis is one of the most significant mechanisms in the patho- genesis of neuronal damage in secondary injury [1-3]. Some studies demonstrated that apoptosis is regulated mainly by the caspase fam- ily of cysteine proteases [4]. Activation…     

降纤酶对脊髓损伤后VEGF的表达及细胞凋亡的作用

目的 观察降纤酶对大鼠脊髓损伤后血管内皮生长因子(VEGF)的表达及细胞凋亡的影响.方法 SD大鼠随机分为假手术组、对照组、干预组,每组各30只.各组分别于伤后各个时间点进行运动功能(BBB)评分,并随机处死5只,损伤部位取材进行HE染色和免疫组化染色,在光镜下观察、计算VEGF阳性细胞数及凋亡细胞数.结果 假手术组的BBB评分为21分,对照组、干预组在各时间点评分明显降低,干预组在5d及之后的各时间点BBB评分明显高于对照组(P＜0.05),尤其7d、14 d、28 d时间点两组有显著性差异(P＜0.01).脊髓损伤后对照组VEGF在脊髓损伤及损伤周边区高表达,5d达高峰,7d、14d表达仍较明显,28 d见少量表达.干预组各时间点VEGF的表达和对照组相比明显增加(P＜0.05),其中3d、5d、7d、14 d时间点差异显著(P＜0.01).凋亡细胞在脊髓损伤后逐渐增多,1d达高峰,此后逐渐减少;干预组各个时间点凋亡细胞数较对照组明显减少(P＜0.05),其中3d、5d、7d时间点差异显著(P＜0.01).相关性分析发现对照组1～5d时间点VEGF阳性细胞数和细胞凋亡数呈负相关(r=-0.90052,P＜0.05).结论 降纤酶可能通过促进VEGF的表达减少细胞凋亡,从而对急性脊髓损伤起治疗作用.     

高压氧对大鼠脊髓损伤后血管内皮生长因子表达的影响

目的通过观察高压氧对成年大鼠脊髓损伤后不同时期血管内皮生长因子（VEGF）表达变化的影响,探讨高压氧对脊髓损伤的治疗作用机制。方法雌性SD大鼠55只,体质量250-300g。随机分为脊髓损伤组（对照组）、脊髓损伤＋高压氧治疗组各25只（n=5）,假手术组5只。采用改良A llen＇s法制作T8脊髓打击伤动物模型,各组分别于伤后1 d、1 w、2 w、4 w和8 w进行行为学观察,运动功能评分方法（BBB）评分后损伤部位取材,免疫组化染色及图像分析检测组织中VEGF的表达。结果假手术组的评分21分,治疗组和对照组与假手术组比较在各时间点评分明显降低,治疗组在各时间段BBB评分明显高于对照组（P〈0.05）。假手术组显示除脊髓中央管周围可见到极少量VEGF表达外,其它部位几乎不表达;对照组脊髓损伤1 d VEGF在大鼠脊髓损伤区及损伤周边区高表达,主要出现在软脊膜和脊髓灰、白质血管壁上的血管内皮细胞胞浆内,脊髓灰、白质内的神经胶质细胞和巨噬细胞胞浆内也出现表达,一般脊髓白质中更为多见,1 w后下调,而治疗组1 d至2 wVEGF的表达较对照组明显增加,差异有显著性（P〈0.05）,4 w、8 w时各组比较无统计学差异。结论急性脊髓损伤可上调VEGF在脊髓血管内皮细胞、胶质细胞和巨噬细胞内的表达,高压氧可能通过促进VEGF表达,促进血管内皮细胞生长从而对脊髓损伤起到治疗作用。