他克莫司后处理诱导缺血脊髓对再灌注损伤的耐受*

目的探讨他克莫司后处理能否诱导大鼠缺血脊髓对再灌注损伤的耐受。方法成年雄性SD大鼠30只,随机分为假手术（s0）组、缺血再灌注（IR）组和他克莫司后处理（TP）组,每组10只大鼠,采用经股动脉置管球囊扩张制备脊髓缺血模型,SO组仅行置管,IR组在脊髓缺血20分钟后行再灌注,TP组在脊髓缺血20分钟后再灌注,即刻经左颈总动脉一次性注射他克莫司0．5mg／kg。再灌注后7、14天采用Tarlov评分法检测大鼠后肢运动功能,脊髓组织切片HE染色观察病理学改变。结果SO组大鼠各时间点后肢Tarlov评分均为5分,形态学检测显示脊髓组织结构正常;IR组大鼠Tarlov评分明显降低,脊髓组织呈现出坏死、水肿、空腔形成等缺血再灌注损伤表现;TP组大鼠Tarlov评分结果显著优于IR组,脊髓组织病理变化较IR组为轻。结论建立大鼠脊髓缺血再灌注损伤模型,并初步证实他克莫司后处理能诱导缺血脊髓对再灌注损伤的耐受。     

己酮可可碱对抗兔肾脏缺血再灌注损伤的实验研究

目的: 研究己酮可可碱对抗兔肾脏缺血再灌注损伤作用。方法: 新西兰兔50只,随机分成5组:假手术组、缺血再灌注组(I/R)、I/R+己酮可可碱组、I/R+低温组、I/R+己酮可可碱+低温组。除假手术组外,其余4组均用动脉夹夹闭左侧肾动脉60min后恢复血流灌注,24h后取左肾分别检测肾组织匀浆的SOD、MDA和BUN、SCr水平的变化,并作病理观察。结果: I/R组肾小管出现水样变性、出血坏死,出血坏死组织中大量炎性细胞浸润,近曲小管上皮细胞线粒体高度肿胀,嵴极其紊乱、模糊、甚至消失;I/R+己酮可可碱组和I/R+低温组损伤减轻;I/R+己酮可可碱+低温组和假手术组形态正常。再灌注24h后I/R组BUN、SCr、MDA水平明显高于其它各组(P＜0.05),SOD活性明显低于其它各组(P＜0.05),I/R+低温组和I/R+己酮可可碱组BUN、SCr、MDA水平明显低于I/R组(P＜0.05),SOD活性明显高于I/R(P＜0.05),低温+己酮可可碱组的上述指标与假手术组无显著差异(P>0.05)。结论: 己酮可可碱有对抗兔肾脏缺血再灌注损伤的作用。     

大鼠脊髓缺血再灌注损伤后caspase-12表达与细胞凋亡

目的:观察大鼠脊髓缺血再灌注损伤过程中细胞凋亡、caspase-12的表达变化规律,以探讨其分子机制。方法:采用自制压迫装置制备脊髓压迫缺血再灌注模型。运用形态学、分子生物学等方法,分别于缺血再灌注后3、7、11、23和47h,观察脊髓缺血再灌注损伤后,脊髓的病理变化和内质网的形态学改变、细胞凋亡及caspase-12的表达变化的规律。结果:脊髓缺血再灌注3h后,出现不同程度的细胞肿胀,神经元退行性变及内质网结构变化;随着再灌注时间的延长,神经元和神经胶质细胞凋亡数明显增加,并伴有caspase-12的表达增强;capspase-12表达与细胞凋亡的时空变化规律相一致。结论:在脊髓缺血再灌注过程中神经细胞凋亡是引起脊髓继发性损伤的主要病理因素,caspase-12可能参与了脊髓缺血再灌注损伤所导致的细胞凋亡。     

外周血白细胞凋亡障碍与大鼠肠缺血-再灌注损伤的关系

目的： 探讨外周血白细胞和中性粒细胞凋亡障碍在肠缺血-再灌注（IR）损伤中的作用。方法：20只雄性SD大鼠随机分为肠IR组和假手术对照组,每组10只。肠IR组夹闭肠系膜上动脉（SMA）30 min后再灌注60 min;对照组只分离而不夹闭SMA。观察肠黏膜形态学变化;检测肠黏膜上皮细胞凋亡指数（TUNEL法）和caspase-3活性;Annexin-V/PI法检测外周血白细胞和中性粒细胞（PMN）凋亡比例;检测夹闭前、夹闭30 min、再灌注30 min、再灌注60 min外周血白细胞数量。结果：(1)光镜下,对照组未见肠黏膜损伤,而IR组肠黏膜损伤严重;（2）IR组肠黏膜上皮细胞凋亡指数和caspase-3活性比对照组明显增高（P<0.05）;（3）IR组外周血白细胞和PMN凋亡比例比对照组明显降低（P<0.05）;IR组外周血白细胞数量在缺血30min时明显增高,再灌注后进一步增高,与缺血前和对照组比都有显著差异（P<0.05）。(4)肠黏膜caspase-3活性与外周血白细胞凋亡比例有显著的负相关（r=-0.764, P<0.01）,与PMN凋亡比例也有显著的负相关（r=-0.845,P<0.01）;肠黏膜上皮细胞凋亡指数与PMN凋亡比例也有显著的负相关（r=-0.638, P<0.05）。结论：外周血白细胞数量增加及凋亡障碍与缺血-再灌注引起的肠黏膜细胞损伤密切相关。     

内质网分子伴侣GRP78在大鼠脊髓缺血再灌注损伤中的表达变化

目的观察在大鼠脊髓缺血再灌注损伤(SCII)过程中内质网分子伴侣GRP78的表达变化,并探讨其意义。方法健康成年Wistar大鼠55只,随机分为两组:(1)脊髓压迫缺血再灌注组50只,每个时间点10只,采用自制压迫装置制备脊髓压迫缺血再灌注模型;(2)假手术对照组5只,只做全椎板切除不做脊髓压迫。用免疫组化、West-ernblot和TUNEL等方法,分别于缺血再灌注后30min、3、7、11和23h,检测压迫段脊髓组织中GRP78的表达变化及细胞凋亡情况。结果再灌注30min后,GRP78在压迫段脊髓开始表达上调,7h达峰值,11h表达回落,23h显著减少。TUNEL染色显示,神经细胞的凋亡指数随着再灌注时间的延长而升高。结论GRP78在脊髓缺血再灌注损伤中呈现时序性的表达变化,这可能是脊髓内源性保护机制之一。     

乳果糖预处理减轻大鼠肠缺血再灌注损伤的机制研究

 目的： 探讨乳果糖预处理对大鼠肠缺血再灌注损伤的影响及其作用机制。方法： 随机将30只SD大鼠分成假手术组、缺血再灌注组和乳果糖预处理组。乳果糖预处理组在手术前7 d每天给予乳果糖灌胃,假手术组和缺血再灌注组在手术前7 d每天给予等量生理盐水灌胃。手术分离肠系膜上动脉,通过夹闭30 min、再灌注60 min诱导缺血再灌注损伤。收集血清检测白细胞介素6（IL-6）、肿瘤坏死因子α(TNF-α)和IL-1β水平。HE染色用来评估组织的损伤程度,TUNEL检测小肠上皮细胞的凋亡。部分小肠组织用来检测丙二醛、超氧化物歧化酶及激活型caspase-3的表达水平。结果： 乳果糖预处理显著减轻缺血再灌注引起的肠组织损伤和小肠上皮细胞凋亡,并显著抑制血清中细胞因子的水平和肠组织的脂质过氧化。结论： 乳果糖预处理可能通过抑制细胞凋亡和脂质过氧化减轻缺血再灌注引起的肠道损伤。     

动脉移植BMSCs对脊髓缺血再灌注损伤大鼠脊髓细胞凋亡和caspase-9基因的影响

目的 探讨肾下腹主动脉移植骨髓间充质干细胞(BMSCs)对缺血再灌注损伤脊髓细胞凋亡、caspase-9表达及功能恢复的影响.方法 将大鼠随机分为假手术组、缺血再灌注组、移植组,每组8只.假手术组仅行手术操作;缺血再灌注组阻断肾下腹主动脉120 min后开放,恢复脊髓再灌注5 min后经动脉留置管推注1 mL培养基;移植组恢复再灌注5 min后推注100万BMSCs悬液1 mL.术后1、3和7d对大鼠进行BBB评分;用RT-PCR、Western blot 检测术后7d大鼠缺血节段脊髓内caspase-9基因和蛋白表达,TUNEL观察细胞凋亡.结果 缺血再灌注组和移植组大鼠BBB评分于术后1、3和7d均显著低于假手术组(P＜0.01),移植组术后3、7 d BBB评分高于缺血再灌注组(P＜0.01);移植组和缺血再灌注组损伤脊髓caspase-9 mRNA和蛋白表达水平较假手术组增加(P＜0.01),缺血再灌注组增加更为显著(P＜0.01).缺血再灌注组和移植组损伤脊髓内出现大量凋亡细胞,而移植组凋亡细胞数少于缺血再灌注组(P＜0.01).结论 肾下腹主动脉移植BMSCs可通过抑制缺血再灌注损伤脊髓caspase-9表达,减轻脊髓局部细胞凋亡,改善其神经功能恢复.     

缺血预处理减轻脑皮质缺血再灌注损伤的研究

目的观察缺血预处理对脑皮质缺血再灌注期间神经元凋亡及磷酸化糖原合酶激酶-3β（GSK-3β）的影响,探讨其保护作用机制。结论雄性Wistar大鼠30只,随机分为假手术组（S）、缺血再灌注组（I/R）及预处理组（IPC）,每组各10只。采用4-VO法建立大鼠全脑缺血再灌注模型。IPC组分离双侧颈总动脉,夹闭10s,开放30s,反复3次,最后夹闭10min。于术后2d处死大鼠,取出脑组织,采用TUNEL法检测大鼠皮质神经元凋亡情况;TTC法检测大鼠脑部梗死面积;光谱法检测磷酸化的GSK-3β水平（p-GSK-3β）;采用Linear Regression分析GSK-3β活性与大鼠皮质神经元凋亡、脑部梗死面积的相关性。结果与S组相比,I/R组和IPC组皮质神经元凋亡和梗死面积显著增多（P〈0.01）,p-GSK-3β水平降低（P〈0.01）;与I/R组相比,IPC组皮质神经元凋亡和梗死面积显著减少（P〈0.01）,p-GSK-3β水平增高（P〈0.01）;p-GSK-3β与大鼠皮质神经元凋亡、脑部梗死面积之间具有高度相关性（P〈0.01）。结论缺血预处理使p-GSK-3β水平增高,脑皮质神经元凋亡和梗死面积减少,从而减轻脑缺血再灌注损伤。     

单纯缺血和缺血再灌注损伤大鼠小肠粘膜细胞凋亡的比较研究

目的比较单纯缺血及缺血再灌注损伤时大鼠小肠粘膜细胞凋亡的变化,并分析其可能机制.方法采用大鼠小肠缺血及缺血再灌注模型,取回肠段作连续切片,分别作HE染色和TUNEL、Bcl_2、Caspase_3免疫组化染色,观察单纯缺血及缺血再灌注时小肠粘膜损伤情况、粘膜细胞凋亡的变化以及Bcl-2和Caspase-3表达之间的关系.结果(1)随缺血时间延长,小肠粘膜损伤程度逐渐加重,缺血再灌注组引起的损伤较单纯缺血1h及缺血3h都更为严重.(2)TUNEL染色显示,随缺血时间延长,凋亡细胞数量增加,缺血再灌注组凋亡阳性细胞最多.(3)随缺血时间延长,caspases_3阳性细胞增多,缺血再灌注组阳性细胞最多;Bcl_2阳性细胞则呈现相反的变化.单纯缺血3h组和缺血1h再灌注2h组Bcl_2与Caspase_3蛋白的表达呈直线负相关(r1=-0.827,PP<0.05;r2=－0.998,P<0．01）。结论大鼠小肠单纯缺血及缺血再灌注都可造成粘膜的损伤，共同的表现为细胞坏死和凋亡，所不同的是单纯缺血所致的损伤以坏死为主，而缺血再灌注所致的损伤则以凋亡为主，凋亡原因之一是由于Bcl_2蛋白表达减少使Caspase-3大量激活。     

右美托咪定在大鼠脊髓缺血再灌注损伤中的 保护作用及机制研究

目的 探讨右美托咪定对大鼠脊髓缺血/再灌注损伤的保护作用及PI3K/Akt传导通路在其中的作用。方法 30只成年雄性大鼠随机分为假手术组、模型组和右美托咪定治疗组,每组10只。建立大鼠脊髓缺血/再灌注损伤模型,对再灌注损伤后6 h、12 h、24 h、48 h实验大鼠后肢运动功能进行评分,检测缺血脊髓前角组织中P-AKT的表达水平及神经元的凋亡指数。结果 右美托咪定可改善脊髓缺血/再灌注损伤后实验大鼠的后肢运动功能(P＜0.05);提高脊髓前角P-AKT的表达水平(P＜0.05),抑制缺血/再灌注损伤所致的脊髓神经元的凋亡(P＜0.05)。结论 右美托咪定对脊髓缺血/再灌注损伤有一定的保护作用,其机制可能与激活PI3K/Akt传导通路,从而抑制神经元的凋亡有关。     

Bradykinin preconditioning affects the number of degenerated neurons and the level of antioxidant enzymes in spinal cord ischemia in rabbits

Bradykinin preconditioning has been used for acquisition of tolerance after spinal cord ischemia. Rabbits were preconditioned intraperitoneally with bradykinin 48 h prior to 20 min of abdominal aorta ligation followed by 24 and 48 h of reperfusion. The activities of SOD and catalase were measured and Fluoro Jade B (FJB)-positive degenerated neurons were evaluated. The outcomes of Tarlov scoring system used to assess neurological functions showed significant improvement in bradykinin groups compared to the ischemic group. The number of FJB-positive degenerated neurons was decreased in ventral horns of both bradykinin groups. Significantly decreased activities of total SOD and mitochondrial Mn-SOD were also detected in both bradykinin groups versus ischemic group while CuZn-SOD and catalase activities were significantly decreased only in the bradykinin group after 24 h of reperfusion versus ischemic group. These findings suggest that one of the possibilities of the neuroprotective effect of delayed bradykinin preconditioning against spinal cord ischemic injury could be realized by mitochondrial protection and decreased synthesis of Mn-SOD as well as by promotion of neuronal survival.     

缺血预处理快速效应对兔急性缺血脊髓的保护作用

目的:探讨缺血预处理快速相对兔腹主动脉短暂阻断致缺血脊髓的保护作用。方法:36只雄性新西兰兔随机分成3组(n=12):即缺血再灌注损伤组(IR组)、缺血预处理组(IPC+IR组)及假手术组(Sham组)。IR组阻闭兔腹主动脉肾下段20min,复制兔脊髓缺血损伤模型;IPC+IR组预先阻闭腹主动脉肾下段6min,再灌注30min后再次阻闭腹主动脉肾下段20min;Sham组除不夹闭腹主动脉外,其余处理同IR组。再灌注后8h、12h、24h和48h分别对动物神经功能评分,然后,处死动物取脊髓(L_5-7),分别行组织病理学观察及测定脊髓组织中Na⁺,K⁺-ATP酶的活性。结果:Sham组及IPC+IR组神经功能评分各时点均明显高于IR组(P＜0.01);Sham组及IPC+IR组脊髓前角正常神经细胞数明显多于IR组(P＜0.01);Sham组及IPC+IR组脊髓组织中Na⁺,K⁺-ATP酶的活性明显高于IR组(P＜0.01)。结论:缺血预处理快速相对兔急性缺血脊髓有显著的保护作用,这种保护作用可能与稳定Na⁺,K⁺-ATP酶的活性有关。     

缺血后处理对兔缺血/再灌注损伤脊髓的保护作用可能与PI3K/Akt信号有关

目的 探讨缺血后处理对兔缺血/再灌注损伤脊髓的保护作用及PI3K/Akt传导通路在其中的作用.方法 42只日本大耳白兔(2-2.5kg),随机分为7组,分别为缺血组(Ⅰ组);缺血后处理组(PB组);PB+DMSO组(D组);PB+Ly294002 5μg组(PY5组);PB+LY294002 10μg组(PY10组);...     

Ischemic preconditioning suppresses apoptosis of rabbit spinal neurocytes by inhibiting ASK1-14-3-3 dissociation

The mechanism by which a brief episode of sublethal ischemia followed by reperfusion (ischemic preconditioning, IPC) prevents the lethal effects of subsequent periods of prolonged ischemia, are poorly understood. A completely randomized, controlled study was designed to study the effect of IPC using a rabbit model of ischemic spinal cord injury. Twenty-four white adult New England rabbits were randomly assigned to one of 3 groups (n=8 per group); the groups were assigned as follows: Group I: sham-operation group, Group II: ischemic reperfusion (I/R) group, and Group III: ischemic preconditioning group. Spinal cord ischemia was induced by introducing an infra renal aortic cross-clamp for 30min. Following injury, rabbits were subjected to 30min, 2h, or 8h of reperfusion in Group II. In Group III, subjects underwent three cycles, 5min each, of ischemia followed by 5min of reperfusion, before receiving 30min of ischemia. We previously reported that the association between ASK1 (apoptosis signal-regulating kinase 1) and 14-3-3 played an important role in regulating ischemia/reperfusion spinal cord injuries. To evaluate the effect of ischemic preconditioning in injured spinal cords, we examined alterations in spinal tissue morphology, activation of key members of the ASK1-mediated signaling pathway, and the association between ASK1 and 14-3-3. Changes in spinal cord morphology were observed with hematoxylin and eosin (H&E) staining and electron microscopy. The phosphorylation levels of ASK1, JNK, and p38 were assessed by immunoblot analysis. The association between ASK1 and 14-3-3 was analyzed by co-immunoprecipitation experiments. We observed that swelling of the neurocyte bodies and hemorrhage of the spinal cord were dramatically decreased in Group III compared to Group II. In addition, the degree of apoptosis among neurocytes was reduced in Group III compared to Group II. Finally, the phosphorylation of ASK1, JNK, p38 and the dissociation of ASK1 from 14-3-3 were dramatically decreased in Group III compared with Group II. These results indicate that ischemic preconditioning may have a protective affect against ASK1/14-3-3 dissociation-induced spinal cord injuries.     

带气囊导管构建脊髓缺血模拟再灌注与缺血分离模型

背景：采用带有气囊的导管急性压迫脊髓缺血模拟人类损伤可以造成再灌注与缺血分离的动物模型。 目的：应用免疫组化和生物化学分析方法观察不同缺血时间窗处理对损伤脊髓的影响。 方法：SD大鼠36只,随机分为假手术组,带气囊导管造成大鼠脊髓缺血10,30,45,60,90 min组。 结果与结论：再灌注48 h后,随着缺血时间的延长,脊髓前角神经元坏死和凋亡逐渐加重,丙二醛水平逐渐增加,超氧化物歧化酶活性逐渐下降,大鼠的神经行为学病症加重。提示用带气囊的导管建立缺血再灌注大鼠模型成功,再灌注后大鼠脊髓的损伤随缺血时间的延长而加重。     

Visualization of protein aggregation in nerve cells after ischemia/reperfusion by ubiquitin immunohistochemistry and impregnative Nauta method

Using ubiquitin immunohistochemistry and impregnative Nauta method we demonstrated that ubiquitin positivity and Nauta positivity in the neurons affected with ischemic injury in the lumbosacral spinal cord of rabbits and dogs may be of the same origin. Increased number of ubiquitin-positive aggregates was found in the cytoplasm of neurons in the intermediate zone and lamina IX of ventral horns of spinal cord in rabbits after 30 min of ischemia followed by 24 h lasting reperfusion. Nauta-positive, flocculent, intracytoplasmic, dark clusters appeared in the same localization in the canine lumbosacral spinal cord neurons after 30 min of ischemia and 24 h of reperfusion. Ubiquitin aggregates and Nauta-positive dark clusters in the injured spinal cord neurons could be the first light microscopic signs of slow neuronal death following spinal cord ischemia and reperfusion.     

脊髓缺血性再灌注损伤和预处理保护作用的实验研究

目的：探讨缺血预处理对家兔须缺血性损伤的保护作用。方法：家兔18只，随机分为Ⅰ组（假手术组）、Ⅱ组（缺血预处理组）和Ⅲ组（缺血再灌组），每组6只，Ⅰ组开腹后，在左肾动脉起点以下0．5cm处暴露并分离腹主动脉即关腹；Ⅲ组一次性阻断腹主动脉血流30min，松夹后关腹；Ⅱ组阻断腹主动脉血流5min，松夹后再灌注10min（如此反复2次），最后再持续夹闭腹主动脉30min，松夹后关腹。结果：Ⅰ组术后后肢运动功能全部正常，光镜和电镜检查显示组织结构变化甚微。Ⅲ组术后后肢运动功能发生严重障碍，脊髓组织严重损伤，与Ⅲ组比较，Ⅱ组术后后肢运动功能障碍较轻微，须组织损伤明显减轻，神经功能评价各组差异具有显著性（P12h=0.006和P36h=0.001)。结论：缺血预处理能够促进神经功能的恢复，减轻脊髓组织损伤，提示预处理对脊因再灌注损伤具有保护作用。