兔肺缺血预适应早期NOS活性及其基因表达的变化

缺血预适应(ischemic preconditioning, IPC)是一种能抵抗缺血再灌注损伤的内源性保护手段,在人或哺乳动物的多个脏器均存在这种现象.近来,学者们也开始发现肺脏也存在IPC效应,但对它产生的机制尚未明了.既往的研究表明,一氧化氮/一氧化氮合酶(nitro oxide/nitro oxide synthase, NO/NOS)在介导心肌IPC效应中起重要作用,但是否也介导肺脏的IPC还未见报道.本研究通过观察兔肺IPC早期NOS活力及基因表达来探讨NOS及其不同亚型在其中的作用.

缺血预处理对大鼠肝移植早期的保护作用

缺血预处理(ischemic preconditioning,IPC)可调动机体内源性保护机制对组织或器官提供保护作用,越来越多地引起人们的关注[1].本研究采用大鼠原位肝移植动物模型探讨IPC对肝脏及补体的作用.

远程缺血预处理对脊髓缺血再灌注损伤保护作用的研究进展

近年来,需要术中阻断胸腹主动脉的外科手术大大增加,由此引起的脊髓缺血性损伤会导致脊髓功能障碍,甚至截瘫[1];脊髓慢性压迫性疾病如颈椎病、椎管狭窄症、后纵韧带骨化症等在行减压手术后可发生脊髓损伤,即脊髓缺血再灌注损伤(spinal cord ischemic reperfusion injury,SCⅡ).对脊髓损伤目前尚缺乏确切有效的治疗方法,预防脊髓损伤和阻止脊髓继发性损伤是目前研究的重点.远程缺血预处理(remote ischemic preconditioning,RIPC)是指一个器官或组织经短暂缺血再灌注处理后通过释放生化信使到循环中或激活神经通路而对远隔器官产生保护作用.1997年,Matsuyama等[2]首先报道了脊髓RIPC对脊髓缺血再灌注损伤的保护作用,目前已成为脊髓缺血再灌注损伤研究的热点.现就RIPC对脊髓缺血再灌注损伤保护作用的研究进展综述如下.

远处缺血预处理减轻肾上腹主动脉阻断后肾脏损伤的实验研究

急性肾功能衰竭(acute renal failure,ARF)是腹主动脉瘤破裂修补术及肾上腹主动脉瘤术后的严重并发症.经典的缺血预处理(ischemic preconditioning,IPC)及远处缺血预处理(remote ischemic preconditioning,RIP)作为一种内源性抗缺血再灌注损伤(ischemia reperfusion inury,IRI)的保护机制,如果能适用于腹主动脉阻断引起的肾脏I/R损伤,那么对于提高腹主动脉瘤术后的生存率无疑是有价值的,实验拟通过对实验动物进行IPC和RIP,来了解其对肾脏I/R损伤的保护作用,并比较两者的效果.

Persimmon leaf flavonoid has been shown to enhance brain ischemic tolerance in mice, but its mechanism of action remains unclear. The bilateral common carotid arteries were occluded using a micro clip to block blood flow for 10 minutes. After 10 minutes of ischemic preconditioning, 200, 100, and 50 mg/kg persimmon leaf flavonoid or 20 mg/kg ginaton was intragastrical y administered per day for 5 days. At 1 hour after the final administration, ischemia/reperfusion models were estab-lished by blocking the middle cerebral artery for 2 hours. At 24 hours after model establishment, compared with cerebral ischemic rats without ischemic preconditioning or drug intervention, plasma endothelin, thrombomodulin and von Wil ebrand factor levels significantly decreased and intercel-lular adhesion molecule-1 expression markedly reduced in brain tissue from rats with ischemic pre-conditioning. Simultaneously, brain tissue injury reduced. Ischemic preconditioning combined with drug exposure noticeably improved the effects of the above-mentioned indices, and the effects of 200 mg/kg persimmon leaf flavonoid were similar to 20 mg/kg ginaton treatment. These results indicate that ischemic preconditioning produces tolerance to recurrent severe cerebral ischemia. However, persimmon leaf flavonoid can elevate ischemic tolerance by reducing inflammatory reactions and vascular endothelial injury. High-dose persimmon leaf flavonoid showed an identical effect to ginaton.

缺血预适应心肌保护机制研究

预先反复、短暂缺血可以减轻后续长期缺血所造成组织损伤的现象被称为缺血预适应(ischemic preconditioning,IPC),包括IPC后即刻出现并持续1～3小时的早期保护和IPC后24小时再度出现并持续72小时的延迟保护作用两个时相.本项目主要研究老年、病变心脏IPC保护特征与规律,研究心脏缺血预适应延迟保护的细胞核反应机制,并探讨具有临床应用前景的药物预适应的保护机制,为临床上缺血性心脏病的防治提供新的思路.

应重视缺血缺氧预处理的临床应用研究

缺血缺氧(缺血/氧)性损伤是指氧供下降或氧耗量增加引起的细胞代谢,继而使细胞功能和形态的改变.缺血与缺氧过程并不完全相同,但都具有缺氧的基本特征,因此我们在本文中提到的缺血/氧概指缺血与缺氧两种刺激.缺血/氧常发生于心脑血管意外、器官移植、胎儿宫内窘迫等,因此,对其病理生理及其保护措施的研究长期吸引着国内外医学工作者的关注.1986年,Murry等[1]首次提出"预处理"概念:在细胞或器官经历数次短暂亚致死性缺血/氧以后,再经历长时间的严重缺血/氧,可以明显减轻其损害作用.

阿片受体参与心肌缺血预适应的研究进展

阿片及各种阿片类活性碱用于临床止痛已有千余年的历史.阿片除具有独特的镇痛效应外,对心血管、呼吸、免疫等系统都有明显的调节作用.心肌缺血预适应(isch-emic preconditioning,IPC)是1986年Murry发现并命名的一种心肌保护现象[1],即心肌经历一次或多次短暂缺血后.对随后发生的长时间缺血有较好的耐受力,其机制可能与减轻组织损伤、减慢ATP消耗速度、减少再灌注心律失常的发生有关.

乌司他丁后处理及其联合预处理对体外循环下心脏瓣膜置换术患者心肌细胞凋亡的影响

Objective To evaluate the effects of ulinastatin postconditioning and combination of ulinastatin preconditioning and postconditioning on myocardial apoptosis in patients undergoing cardiac valve replacement with cardiopulmonary bypass (CPB).Methods Eighty New York Heart Association (NYHA) class Ⅱ or Ⅲ patients of both sexes,aged 21-59 years,scheduled for cardiac valve replacement with CPB,were randomly divided into four groups (n =20 each):normal saline control group (group C),ulinastatin preconditioning group (group U1),ulinastatin postconditioning group (group U2) and ulinastatin preconditioning plus postconditioning group (group U3).In group U1,uinastatin 20000 U/kg was infused via the central vein at 500-1000 U·kg-1 · min-1 after endotracheal intubation until 10 minutes before blocking the ascending aorta.In group U2,ulinastatin 10000 U/kg was infused via the aortic root at 4000-5000 U· kg-1 · min-1 at 5-7 minutes before opening the aorta.In group U3,ulinastatin preconditioning and postconditioning were performed as described in groups U1 and U2.In group C,the same volume of normal saline was infused instead of ulinastatin.Blood samples were taken from the radial artery at 10 minutes before blocking the ascending aorta,40 minutes after blocking the ascending aorta,45 minutes after opening the aorta and at the end of operation for determination of plasma concentrations of tumor necrosis factor-alpha (TNF-α) and soluble tumor necrosis factor receptor 1 (sTNF-R1).Myocardial tissues were obtained from the right atrial appendage at 45 minutes after opening the aorta for determination of the expression of TNF-α,bcl-2,bax,caspase-3,and apoptosis.The bcl-2/bax ratio and apoptotic index were calculated.Results Plasma concentrations of TNF-α and sTNF-R1 and the expression of TNF-α,bax,caspase-3 and apoptotic index were lower and the expression of bcl-2 and bcl-2/bax ratio were higher in groups U1,U2 and U3 than in group C and they were lower in group U3 than in groups U1 and U2 (P ＜ 0.05).Conclusion Ulinastatin postconditioning can inhibit myocardial apoptosis in patients undergoing cardiac valve replacement with CPB,and the efficacy of combination of ulinastatin preconditioning and postconditioning is stronger than that of ulinastatin postconditioning.The mechanism is involved in balancing the expression of bax and bcl-2 and down-regulating the expression of TNF-α and its receptor.

脑缺血耐受的研究进展

预先给动物轻微、短时、不致引起神经元死亡的脑缺血预处理(brain ischemic preconditioning,BIP),可以在后续较严重的脑缺血损伤中对神经元产生保护作用,这一现象被称为缺血耐受(ischemictolerance,IT)[1].BIP的保护作用实际上是短暂缺血启动机体内源性保护机制,提高组织对缺血的耐受性.IT的形成过程涉及热休克蛋白、兴奋性氨基酸、腺苷、凋亡相关基因,以及信号传导通路等的变化.

脑缺血药物预处理研究进展

脑缺血预处理(cerebal ischemic preconditioning,CIP)是指脑组织采用机械刺激,如一次或多次短暂性脑缺血再灌注后,诱导脑组织产生内源性保护机制,使其对以后较长时间的缺血性损伤产生显著的耐受.

心肌缺血预适应对急性心肌梗死患者心脏的保护作用

BACKGROUND:Ischemic preconditioning occur refers to the occurrence of many unstable angina pectoris before acute myocardial ischemia(AMI).It is generally recognized that ischemic preconditioning occur has protective effect on heart and can reduce infarction scope and improve contraction function of heart.Recently some authors thinks ischemic preconditioning occur will cause the exacerbation of patients' condition during the time of hospitalization and increase the incidence rate of angina and pectoris and death.

肢体缺血预处理对大鼠缺血再灌注海马HSP70表达的影响

热休克蛋白(heat shock proteins70,HSP70),是一种应激蛋白.研究显示,大鼠大脑中动脉阻断后,HSP70蛋白仅出现在梗死灶周围神经元,即在缺血半影区大量表达.在短暂缺血后死亡的海马CA1区锥体细胞中HSP70蓄积甚少,存活的齿状回颗粒细胞中有明显的HSP70积累.以上表明HSP70可能对脑缺血后神经细胞具有保护作用.我们以前研究结果证实肢体缺血预处理(limb ischemic preconditioning,LIP)可减轻脑缺血再灌注损伤.本实验运用免疫组化技术观察脑缺血再灌注前给予LIP海马HSP70的表达情况,探讨HSP70在LIP抗脑缺血再灌注损伤中的作用.

延迟预适应对缺血再灌注损伤冠状动脉内皮细胞的保护作用

心脏缺血再灌注(Ischemia/Reperfusion,I/R)损伤是临床上常见的病理生理现象.到目前为止,缺血预适应(Ischemic Preconditioning ,IPC)被认为是较有潜力的抗I/R的方法.预适应保护存在两个时间段[1]:早期预适应,也被称为经典预适应;另一个阶段是延迟期预适应,也被称为第二窗保护(SWOP).几项研究已表明:IPC减少心肌梗塞面积[2],同时也保护冠脉内皮的急性和慢性再灌注损伤[3].SWOP被证实存在于内皮细胞,但确切机制仍不清楚.本研究以SWOP对I/R冠状动脉内皮的保护作用为目的,观察I/R及IPC过程中一氧化氮(Nitric Oxide,NO)、丙二醛(Malondialehyde,MDA)及超氧化物歧化酶(Superoxide Dismutase,SOD)含量的变化,并通过免疫组化方法了解此过程中冠脉内皮细胞内皮型一氧化氮合成酶(Endothelial NO Synthase,eNOS)的表达情况.

AIM: To investigate the role of catecholamine, angiotensin converting enzyme(ACE) and adenosine triphosphatase in ischemic preconditioning in isolated rat hearts. METHODS: Isolated perfused rat heart was subjected to global ischemia for 40 min followed by reperfusion for 10 min (I/R). Preconditioning (PC) was induced by 5 min of ischemia and 10 min of reperfusion. The tissue concentrations in NE, and ACE, ATPase activities were determined in left ventricle in the PC and I/R groups by fluorometry and spectrophotometry. RESULTS: There were no significant difference in NE and ACE between PC and I/R groups. PC hearts showed improved recovery of the contractile function after 40 min ischemia/10 min reperfusion, but activities of the myocardial total ATPase, Mg2＋-ATPase, Na＋K＋-ATPase were inhibited markedly compared with I/R group. CONCLUSION: The inhibited myocardial ATPase may be involved in the mechanism of ischemic preconditioning protection in the isolated rat heart. Endogenous myocardial norepinephrine and ACE activation are not essential for ischemic preconditioning in the isolated rat heart.

自由基在肢体缺血预处理脑保护和p38 MAPK和ERK表达上调中的作用

目的：我们前期研究证实，肢体缺血预处理（ limb ischemic preconditioning， LIP）能诱导大鼠的脑缺血耐受并且上调海马CA1区p38 MAPK和ERK的表达。然而，进行缺血预处理的肢体与遭受缺血打击的大脑相隔较远，由LIP启动的内源性保护信号如何作用于大脑尚不完全清楚。本研究旨在探讨自由基在LIP诱导的大鼠脑缺血耐受和p38 MAPK和ERK表达上调中的作用。方法：采用大鼠全脑缺血模型，硫堇染色观察神经病理学变化，免疫组化和Western blot观察p38 MAPK和ERK的表达。结果：硫堇染色结果表明，自由基清除剂DMTU能部分逆转LIP的脑保护作用， DMTU也部分阻断了LIP引起的p38 MAPK和ERK表达的上调。结论：自由基在肢体缺血预处理脑保护及p38 MAPK和ERK表达上调中发挥着重要的作用。

MIPU1上调基质金属蛋白酶14促进血管新生

目的：探讨转录因子心肌缺血预处理上调蛋白1（ myocardial ischemic preconditioning upregulated protein 1， MIPU1）促进血管新生的分子机制。方法：mRNA测序分析MIPU1过表达人脐静脉内皮细胞（ HUVEC ）的mRNA差异表达；染色质免疫沉淀（chromatin immunoprecipitation， CHIP）检测MIPU1与基质金属蛋白酶14（matrix metalloproteinase 14， MMP14）启动子区结合情况；采用Matrigel、划痕和Transwell分析HUVEC管型形成和迁移；采用Western blot和定量PCR分别检测MIPU1和MMP14蛋白质和mRNA表达；采用LAD建立慢性心肌缺血小鼠模型，采用HE染色和CD31免疫组化分析缺血心肌组织形态学变化及微血管形成。结果：免疫组化和HE染色显示与假手术组相比，缺血心肌中组织损伤加重伴随有CD31＋微血管数目增加，同时心肌组织中MMP14和MIPU1蛋白和mRNA表达增加。 RNA测序显示与对照组相比MIPU1过表达HUVEC中MMP14 mR－NA增加约4倍。 MMP14特异性siRNA转染显著下调MMP14蛋白表达后，可抑制MIPU1促HUVEC管型形成和迁移作用；相反，MMP14过表达可增加MIPU1的上述作用。生物信息学分析显示MMP14启动子区含有2个MIPU1结合元件核心序列（“CTTA”），CHIP结果显示MIPU1与MMP14启动子区－217～－221 bp和－110～－106 bp处的“CTTA”有结合。结论：MIPU1通过上调MMP14促进HUVEC的管型形成和迁移作用，这一调节机制可能参与缺血心肌中微血管新生过程。

远端缺血预处理在脑梗死中应用的研究进展

目前无论是溶栓、抗血小板、抗凝、神经保护类药物,血管介入抑或是外科手术等针对脑梗死患者的治疗方式,都是相对被动作用于机体,并未能主动发挥机体内在能力,能否通过某种方法使机体产生内源性保护机制是近年研究的热点. 远端缺血预处理( remote ischemic preconditioning,RIPC)颇具研究前景[1-2]. 本文对国内外RIPC在脑梗死中的临床应用优势展开综述,探讨RIPC的临床使用价值.

缺血预处理对肾脏内源性保护作用的机制探讨

心肌细胞KATP通道与细胞骨架在缺血预适应中的作用

心肌缺血预适应(ischemic preconditioning,IP)的概念由Murry等[1]于1986年首先提出,是指经过1次或反复数次短暂缺血-再灌注后,使随后较长时间缺血的心肌得到保护.大量研究表明,反复短暂的缺血可能通过刺激心脏合成与释放内源性心肌保护物质,进而激活细胞内信号转导途径而发挥保护作用.