不同预处理后缺血再灌注损伤大鼠心肌αB晶状体蛋白的变化

目的 研究3种不同预处理对在体大鼠缺血再灌注心肌的保护作用及αB晶状体蛋白在不同预处理心肌细胞缺血再灌注损伤中的变化.方法 24只SD大鼠按完全随机法分成4组,每组6只,分别为缺血再灌注组、缺血预处理组、腺苷预处理组、远程预处理组.建立大鼠在体缺血再灌注损伤模型,观察各组缺血再灌注前后心功能变化,并检测冉灌注末血清肌钙蛋白T(cTnT)、丙二醛(MDA)、超氧化物歧化酶(SOD)的变化以及心肌组织αB品状体蛋白的表达.结果 心肌缺血再灌注120 min后,与缺血再灌注组比较,其余3组左心室室内压最大上升和下降速率(±dp/dt_(max))均明显升高(均P<0.05).缺血预处理组、腺苷预处理组、远程预处理组血清cTnT含量均低于缺血再灌注组[(12.898±2.887)、(5.049±4.387)、(7.049±4.387)μg/L比(22.902±3.146)μg/L,均P<0.05];MDA含量也均低于缺血再灌注组[(10.648±3.635)、(11.736±8.903)、(9.834±6.128)μmol/L比(16.083±10.423)μmol/L,均P<0.05];SOD含量均高于缺血再灌注组[(82.808±22.407)、(162.266±54.128)、(102.266±34.134)U/ml比(76.757±39.446)U/ml,均P<0.05].腺苷预处理组SOD含量高于缺血预处理组和远程预处理组;cTnT含量则低于缺血预处理组(均P<0.05).与缺血再灌注组比较,其余3组αB晶状体蛋白表达均显著增高(均P<0.05).结论 腺苷预处理、远程预处理均可以模拟缺血预处理的心肌保护作用.3种预处理可能通过上调αB晶状体蛋白表达从而减轻在体大鼠心肌缺血再灌注损伤.     

IRAK-4活性在脂多糖预处理减轻肝脏缺血再灌注损害中作用的实验研究

目的:观察脂多糖(LPS)预处理后白细胞介素-1受体相关激酶-4（IRAK-4）表达水平在大鼠肝脏缺血再灌注(I/R)早期的变化，探讨LPS预处理减轻肝脏缺血再灌注损害(I/RI)的相关机制。 方法:雄性SD大鼠，随机分为正常对照组，缺血再灌注组(I/R组)和LPS预处理组（LPS组）。正常对照组未予任何处理；LPS组第 1 d 经尾静脉给予脂多糖0.1mg·kg-1，第2、3、4、5 d给予0.5 mg·kg-1；I/R组给予等体积0.5 mL无菌PBS液。第 8 d，建立肝脏缺血再灌注模型。再灌注后0 min、60 min及180 min, 蛋白免疫印记法及逆转录-聚合酶链式反应测定肝组织的IRAK-4蛋白和mRNA表达水平；酶连免疫吸附法检测肝组织NF-κB活性及血清TNF-α含量。 结果:再灌注0 min, IRAK-4蛋白与mRNA表达水平依次为LPS组>I/R组>正常对照组(P<0.01), NF-κB活性以及TNF-α含量LPS组与I/R组差异无显著(P>0.05)，但均高于正常对照组(P<0.01)；再灌注后60 min及180 min，LPS组的IRAK-4蛋白与mRNA表达水平，NF-κB活性以及TNF-α含量却明显低于I/R组（P<0.01）。 结论:抑制IRAK-4表达是LPS预处理减轻肝脏I/RI的重要机制之一。     

缺血预处理通过抑制炎症反应减轻缺血性脑损伤

目的:探讨缺血预处理对缺血性脑损伤的神经保护作用及其可能的机制.方法:以成年雄性SD大鼠为研究对象,短暂夹闭双侧颈总动脉制备脑缺血预处理模型,线栓法阻塞大鼠大脑中动脉建立脑缺血模型,检测大鼠神经功能损伤评分和脑梗死体积,测量缺血脑组织髓过氧化物酶(MPO)的活性,免疫组织化学法检测核转录因子-κB(NF-κB)的转录活性,免疫印迹法检测环氧合酶-2(COX-2)的表达水平,ELISA法检测血清肿瘤坏死因子-α(TNF-α)的含量.结果:缺血预处理减轻神经功能损伤和脑梗死体积,减轻MPO活性,抑制NF-κB的转录活性、COX-2的表达和TNF-α的分泌.结论:缺血预处理减轻缺血性脑损伤,其神经保护作用可能与抑制炎症反应和炎症因子的表达有关.     

缺血预处理对脊髓缺血再灌注损伤HIF-1α表达的影响

目的探讨缺血预处理对大鼠脊髓缺血再灌注损伤后低氧诱导因子-1α(hypoxia-inducible factor-1α,HIF-1α)表达的影响。方法 Sprague-Dawley大鼠120只,随机分为4组:Sham组置入球囊导管但不阻断胸主动脉;I/R组球囊导管阻断胸主动脉12min造成脊髓缺血再灌注损伤;缺血预处理(Ischemic preconditioning,IPC)先短暂阻断胸主动脉3min,恢复灌注10 min实施缺血预处理,之后阻断胸主动脉造成脊髓缺血再灌注损伤;IPC+2ME2组缺血预处理前30min腹腔注射HIF-1α抑制剂2ME2(15 mg/kg),缺血预处理后阻断胸主动脉造成脊髓缺血再灌注损伤。分别于再灌注损伤后为4 h、12 h、24 h、3 d和7 d进行神经功能评分,并取脊髓L4-6缺血节段,脊髓组织病理学观察脊髓前角内健存运动神经元,Real time-PCR法检测HIF-1αmRNA表达。结果与Sham组比较,I/R组神经运动功能评分降低,脊髓灰质前角内健存运动神经元数量减少,HIF-1α表达增加(P<0.05)。与I/R组比较,IPC组神经运动功能评分增高,脊髓灰质前角内健存运动神经元数量增多,HIF-1α表达更多(P<0.05)。IPC+2ME2组HIF-1α表达上调受到抑制,神经运动功能评分降低,脊髓灰质前角内健存运动神经元数量减少(P<0.05)。结论缺血预处理可能通过上调HIF-1α表达减轻脊髓缺血再灌注损伤。     

丹参酮ⅡA磺酸钠对家兔缺血预处理心肌保护作用的影响

目的观察丹参酮ⅡA磺酸钠对家兔缺血预处理心肌保护作用及血浆和心肌组织NO代谢产物含量的影响。方法家兔24只 ,随机分为心肌缺血再灌注组 (IR ,n=8)、缺血预处理组 (IPC,n=8)和丹参酮ⅡA磺酸钠联合缺血预处理组 (DS-201 IPC,n=8) ;TTC染色测定梗塞面积 ;HE染色病理组织学观察。采用硝酸还原酶法检测缺血前、缺血后30min和再灌注30min三个时点血浆及心肌组织NO代谢物含量。结果 (1)TTC染色称重结果显示 ,IPC组心肌梗死面积 (梗死区重量/缺血区重量为9.54±5.79)明显小于IR组 (梗死区重量/缺血区重量为35.48±3.84Δ ,P<0.05) ,DS201 IPC组心肌梗死面积 (梗死区重量/缺血区重量为5.66±1.6)明显小于IPC组心肌梗死面积 (P<0.05)。病理学检测显示 ,与IR组相比 ,IPC组组织损伤程度明显减轻。与IPC组相比 ,DS201 IPC组组织损伤程度明显减轻。 (2)缺血30min和再灌注30minIR组血浆NO代谢产物[缺血30min(11.2±3.9)μmol/L,再灌注30min(11.6±5.6)μmol/L]和心肌组织NO代谢产物[再灌注30min末(23.0±5.3)μmol/mg]显著低于缺血前[血浆NO代谢产物为(28.5±6.8)μmol/L,心肌组织NO代谢产物为(49±18.3)μmol/mg](P<0.05) ;缺血30min和再灌注30minIPC组血浆NO代谢产物[缺血30min(19.5±2.5)μmol/L,再灌注30min(1     

腺苷预处理对大鼠脑缺血-再灌注损伤后脑内肿瘤坏死因子α和核因子κB表达的影响

目的 通过观察腺苷预处理对脑缺血-再灌注（IR）损伤后大鼠脑内肿瘤坏死因子α（TNF-α）和核因子κB（NF-κB）表达的影响,探讨腺苷对大鼠脑缺血-再灌注损伤的保护机制。方法 Sprague-Dawley大鼠60只随机分为假手术组（F组）、缺血-再灌注组（IR组）和腺苷预处理缺血-再灌注组（AP组）,每组动物按照缺血-再灌注后2 h、6 h、24 h及48 h这4个时间点随机分组,每组5只。采用大脑中动脉阻塞（MCAO）法制备大鼠大脑中动脉闭塞模型。通过对以上3组脑缺血 再灌注48 h后的大鼠脑组织行头颅MRI、HE染色以及对以上60只大鼠进行神经功能缺损评分,通过免疫组织化学方法观察大鼠脑组织中TNF-α和NF-κB的平均积分吸光度值进一步验证腺苷预处理对大鼠脑缺血-再灌注损伤的脑保护作用,探讨腺苷对大鼠脑缺血-再灌注损伤的保护机制。结果 F组大鼠术后无神经功能缺损体征,AP组和IR组大鼠术后均出现明显神经功能缺损体征。AP组和IR组大鼠神经功能缺损评分显著高于F组,AP组大鼠神经功能缺损评分显著低于IR组,差异均具有统计学意义（P＜0.05）。F组大鼠术后MRI中T1WI、T2WI均未见明显异常,AP组和IR组大鼠脑梗死体积显著高于F组,AP组大鼠脑梗死体积显著低于IR组,差异均具有统计学意义（P＜0.05）。AP组和IR组术后大鼠脑组织中TNF-α和NF-κB的表达显著高于F组,AP组术后大鼠脑组织中TNF-α和NF-κB的表达显著低于IR组,差异均具有统计学意义（P＜0.05）。结论 腺苷预处理可通过减少大鼠缺血-再灌注损伤后脑内TNF-α和NF-κB的表达而减轻神经细胞损伤,达到其脑保护作用。     

载脂蛋白M可能经NF-κB介导大鼠肾缺血再灌注损伤

目的 观察核因子-κB抑制剂——吡咯烷二硫代氨基甲酸盐(PDTC)对缺血再灌注(IRI)大鼠肾组织载脂蛋白M(APOM)表达的影响,探讨APOM参与肾IRI发病的机制.方法 75只雄性SD大鼠分为假手术(sham)组、IRI组和PDTC组.用real time PCR和Western blot法,检测不同时间点肾皮质APOM和核内NF-κB P65的表达.结果 IRI组各时间点核内NF-κB P65水平均较sham组明显增高(sham组1.0±0.2;IRI3h组4.1±0.5,P＜0.01),PDTC组表达明显低于IRI组(PDTC3h组2.0±0.2,P＜0.01),并呈双峰样改变,表达高峰分别在再灌注3和48 h.APOM mRNA水平在IRI组各时间点也较sham组明显增高(sham组0.9±0.1;IRI3h组6.6±2.3,P＜0.01),PDTC组的表达较IRI组降低(PDTC3h组3.3±0.8,P＜0.01),也呈双峰型表达趋势,表达高峰分别在再灌注3和48 h;APOM蛋白的表达模式与mRNA相同,但表达高峰较mRNA滞后.APOM mRNA与核内NF-κB P65的表达呈明显正相关.结论 APOM可能通过NF-κB介导肾IRI的发病.     

去甲肾上腺素和缺血预处理对大鼠缺血再灌注心肌细胞凋亡、Bcl-2、Bax蛋白表达的影响

目的:研究去甲肾上腺素预处理(NE-P)和缺血预处理(IP)对大鼠缺血再灌注(I/R)心肌细胞凋亡及相关基因Bcl-2和Bax蛋白表达的影响。方法:复制缺血再灌注损伤(IRI),采用末端标记技术(TUNEL)检测心肌细胞凋亡;应用免疫组化SABC法检测Bcl-2和Bax蛋白表达。结果:I/R组凋亡细胞较多,NE-P组及IP组凋亡细胞明显少于I/R组(P＜0.01)。在I/R组Bcl-2的表达少而Bax的表达较多,NE-P组及IP组Bcl-2的表达明显高于I/R组(P＜0.01),而Bax的表达明显低于I/R组(P＜0.01)。NE-P组与IP组各指标均无显著差异(P＞0.05)。结论:NE-P可抑制I/R诱发的心肌细胞凋亡,Bcl-2和Bax的蛋白表达在心肌凋亡的发生中起重要作用。NE-P与IP两者对心肌细胞凋亡及相关基因表达的影响的作用相近。     

钙卫蛋白在肾脏缺血再灌注损伤大鼠中的表达及其作用

目的:探讨钙卫蛋白(CALP)在肾脏缺血再灌注损伤(IRI)大鼠中的表达及其在炎症反应中的作用。方法:50只雄性SD大鼠随机分为IRI组和假手术组(sham组),每组25只。各组分别于缺血再灌注后6 h、12h、24 h、48 h和72 h观察肾脏病理改变,检测大鼠血清尿素氮(BUN)和肌酐(SCr)水平,ELISA法检测大鼠血清CALP、肿瘤坏死因子(TNF)-α和白细胞介素(IL)-6的含量,免疫组织化学法和Western blot法分别检测大鼠肾脏CALP、Toll样受体4(TLR4)和NF-κB p65蛋白表达水平。结果:IRI组大鼠肾脏呈现不同程度的肾小管上皮细胞和间质损伤,伴炎细胞浸润。血清BUN、SCr、CALP及促炎细胞因子TNF-α、IL-6的含量在各时点均显著高于sham组(P0.05)。CALP、TLR4和NF-κB p65主要表达于肾小管上皮细胞胞质中,在IRI组呈高表达,在各时点各因子的表达与sham组相比均显著增强(P0.05)。结论:肾脏IRI大鼠的血清CALP、TNF-α和IL-6水平升高,CALP、TLR4和NF-κB p65在肾组织中表达增强。CALP在大鼠肾脏IRI的炎症反应中可能起重要作用。     

NF-κB参与七氟烷预处理所致延迟性抗大鼠心肌缺血再灌注损伤

目的 观察七氟烷预处理对大鼠心肌缺血再灌注损伤的延迟性保护作用,探讨NF-κB参与保护作用的机制.方法 雄性SD大鼠随机分为:对照组(CON组);缺血再灌注组(I/R组);七氟烷延迟性组(SWOP组);七氟烷对照组(SEVO组);PTN(NF-κB特异性阻断剂)组;DMSO组以及PTN+ SWOP组.用TTC染色法测定心肌梗死范围;Western blot法检测NF-κB(P65,P50)蛋白表达.结果 与I/R组相比SWOP组梗死范围减小,且该作用可被PTN所阻断;SWOP组缺血前NF-κB(P65,P5O)蛋白表达(56±4,58±3)高于CON组(34±4,40 ±1);I/R和SWOP组再灌注后NF-κB(P65,P50)蛋白表达均上调,SWOP组蛋白上调幅度低于I/R组.结论 七氟烷预处理对大鼠心肌缺血再灌注损伤具有延迟性保护作用;NF-κB可能参与了其延迟性保护机制.     

高原习服与低氧预适应

高原低氧易导致急性高原反应,高原习服是机体为适应高原低氧环境发生的一系列代偿适应性变化。寻找加快高原习服的有效措施,提高机体高原习服能力,是预防和减轻急性高原反应的最好策略。低氧预适应是指机体经一次或多次短暂、非致死性低氧刺激后,机体获得的对后续更长时间或更严重低氧性损伤的耐受性。低氧预适应作为一种通过内源性保护机制来提高机体缺氧耐力的有效方法,是促进高原习服的重要措施。     

Isoflurane preconditioning inhibited isoflurane-induced neurotoxicity

The commonly used inhaled anesthetic isoflurane has been shown to be both neuroprotective and neurotoxic in various cell cultures and animal models. We hypothesize that, like cerebral ischemia, isoflurane is inherently neurotoxic. Limited exposure of isoflurane provides neuroprotection via induction of endogenous neuroprotective mechanisms (preconditioning), while prolonged exposure of isoflurane induces neurotoxicity directly by its inherent neurotoxic effects. To test this hypothesis, we treated rat primary cortical neurons at different days in vitro (DIV) and rat pheochromocytoma neurosecretory (PC12) cells with or without Alzheimer's mutated presenilin-1 (PS1) with 2.4% isoflurane for 24 h to induce cell damage determined by both MTT (3-(4,5-dimethyithiazol-2-yl)-2,5-diphenyl-tetrazolium bromide) reduction and LDH (lactate dehydrogenase) release assays. For isoflurane preconditioning, we treated the above cells with isoflurane at 0.6%, 1.2% and 2.4% for 60 min, 4 h prior to a prolonged exposure of 2.4% isoflurane for 24 h. One hour of preconditioning with isoflurane dose-dependently inhibited neurotoxicity induced by 2.4% isoflurane for 24 h in both primary cortical neurons and PC12 cells. This neuroprotection was most dramatically observed in matured cortical neurons (DIV 16) and PC12 cells with over expression of Alzheimer's mutated PS1 (L286V). Preconditioning L286V PC12 cells with equivalent two minimal alveolar concentrations (MAC) of halothane (1.5%), but not sevoflurane (4%), also abolished the neurotoxicity induced by 2.4% isoflurane for 24 h. Overall, these results suggest that isoflurane may be both neuroprotective and neurotoxic, depending on the exposure concentrations and duration.     

Fimbrial lesions and sensory preconditioning

The effects of fimbrial and cortical lesions on sensory preconditioning in the rabbit were examined. Damage to the cortex or the fimbria had no apparent effect on the acquisition of classically conditioned responses. However, fimbrial lesions virtually abolished the effects of preconditioning, whereas cortical lesions had no significant effect. Because fimbrial damage disrupts hippocampal output, these findings are interpreted to indicate that the hippocampus is vital to learning functions other than spatial cognition or working memory.     

Thioredoxin regulation of ischemic preconditioning

Thioredoxins are a class of small redox-regulating proteins that appear to play a crucial role in many oxidative stress-inducible degenerative diseases. A recent study demonstrated a reduction of thioredoxin-1 (Trx1) protein in the ischemic reperfused myocardium. When the same heart was adapted to ischemic stress by preconditioning with repeated cyclic episodes of small duration of ischemia and reperfusion, there was an increased induction of Trx1 expression. Inhibition of Trx1 expression resulted in reduced postischemic ventricular recovery and increased myocardial infarct size in the preconditioned heart. Corroborating these findings, transgenic mouse hearts overexpressing Trx1 were resistant to ischemic reperfusion injury as compared with the hearts from wild-type mice. Thus, it appears that thioredoxin plays a crucial role in cardioprotection induced by preconditioning.     

缺血预处理的抗心律失常作用

应用离体大鼠心脏Ｌａｎｇｅｎｄｏｒｆｆ灌流全心缺血模型，研究缺血预处理的抗收律失常作用及其作用的持续时间。发现ＩＰ可降低自搏心脏和人工起搏心脏的心率失常发生及严重程度，并引起心室颤动阈的升高；ＩＰ对随后的缺血－再灌过程中室性频率的改变无改善作用。     

Autophagy is involved in the ischemic preconditioning

Autophagy is a key pathway for the clearance of damaged organelles. Ischemic preconditioning (IPC) and autophagy are enhanced by mild hypoxic insults, but the association between autophagy and IPC remains unclear. We investigated the existence and role of autophagy in IPC. In an in vitro PC12 cell model, IPC increased generation and degradation of autophagosomes, as revealed by increased LC3-II bands, cathepsin D positive cells, lysosomal activity and autophagic vacuoles on electron microscopy. Autophagic activity was blocked using 3-methyladenine during IPC, and cell viabilities were measured using FASC and WST-1 assays. Inhibition of autophagy, especially during reperfusion or lethal oxygen-glucose deprivation periods ameliorated the neuroprotective effects of IPC. Moreover, inhibiting autophagy also attenuated Hsp70 upregulation induced by IPC. These findings imply that autophagy participates in IPC-induced neuroprotection, and that autophagy might provide a means of neuroprotection against cerebral ischemia.     

心肌肥厚预适应小鼠线粒体蛋白质组学分析

目的 使用线粒体蛋白质谱分析方法,探讨心肌肥厚预适应的分子保护机制。方法 14只雄性C57BL6/J小鼠随机分为假手术组（n=6）和心肌肥厚预适应组（n=8）,建立小鼠心肌肥厚预适应模型（主动脉弓缩窄3 d、解除缩窄4 d）,随机选假手术组3只、心肌肥厚预适应组4只小鼠做蛋白质组学分析,其余小鼠用于形态功能学实验。运用小鼠心脏超声及单个心肌细胞收缩检测技术检测心脏功能学变化,通过心脏常规病理切片及电子显微镜检测心肌组织形态学和线粒体超微结构变化,运用蛋白质组学技术及生物信息学方法,筛选出差异线粒体蛋白,并通过Western blotting验证关键蛋白表达水平变化。结果 心肌肥厚预适应组小鼠与假手术组小鼠相比,心脏功能及心肌组织形态学改变无显著性,但透射电子显微镜检测提示,线粒体嵴密度增加,后续利用线粒体蛋白质组学方法共筛选到20个差异表达蛋白（5个上调,15个下调）;随后生物信息学分析显示,差异蛋白主要与线粒体核糖体蛋白有关;关键蛋白的Western blotting验证结果与组学分析结果相一致。结论 心肌肥厚预适应激能够增强心肌线粒体功能,这可能与线粒体核糖体蛋白介导的线粒体氧化磷酸化复合体的转录加工、运输过程相关。     

Acidic preconditioning protects against ischemia-induced brain injury

Ischemic preconditioning protects against cerebral ischemia. Recent investigations indicated that acidic preconditioning (APC) protects against ischemia-induced cardiomyocytes injury. However, it is not clear whether APC can protect against cerebral ischemia. To address this issue, C57BL/6 mice were exposed 3 times at 10-min intervals to a normoxic atmosphere containing 20% CO(2) for 5 min before being further subjected to bilateral common carotid artery occlusion. APC reversed the ischemia-induced brain injury as revealed by improved performance in passive avoidance experiments and decreased neuron loss in the hippocampal CA1 region. Consistently, both APC-treated brain slices and primary cultured neurons were more resistant to oxygen-glucose-deprivation (OGD)-induced injury, in a pH- and time-dependent manner, as revealed by reversed cell/tissue viability. In addition, the APC treatment prevented OGD-induced mitochondrial transmembrane potential loss and apoptosis, which was inhibited by the mitochondrial permeability transport pore opener atractyloside. Taken together, these findings indicated that APC protects against ischemia-induced neuronal injury. The beneficial effects may be attributed, at least in part, to decreased mitochondria-dependent neuronal apoptosis.     

Prevention of experimental stroke by hypercapnic-hypoxic preconditioning

The effectiveness of hypercapnic hypoxic training in the prevention of acute disturbances in cerebral circulation was studied under experimental conditions. Hypercapnic hypoxic training was followed by a significant decrease in the severity of neurological deficit and locomotor and coordination disorders after cerebral ischemic injury. Translated from Byulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 146, No. 9, pp. 261–263, September, 2008