心肌缺血再灌注损伤的钙信号调节

目的:综合分析钙离子的调节机制及钙超载与心肌缺血再灌注损伤的关系。资料来源:应用计算机检索Pubmed1994-01/2004-01有关钙离子的调节机制及钙超载与心肌缺血再灌注损伤关系的文献,检索词“myocardialischemia/reperfusioninjury,calciumoverload”,并限定文章语言种类为English。同时计算机检索CNKI数据库1996-01/2004-04有关钙离子的调节机制及钙超载与心肌缺血再灌注损伤关系的文献,检索词“心肌缺血,再灌注损伤,钙超载”,限定文章语言种类为中文。资料选择:对检索到的钙离子调节机制及钙超载与心肌缺血再灌注损伤关系的相关信息进行整理,选取针对性强的文章,同一领域的文献则选择近期发表或权威杂志的文章。资料提炼:共检索到154篇相关文献,其中18篇文章符合要求。资料综合:①胞内钙离子浓度维持在一定范围时,细胞维持正常生理功能。当钙离子浓度升高,会发生一系列生理、生化反应,如细胞结构的损伤、凋亡、死亡和细胞的退行性改变等。②心肌缺血再灌注损伤与能量代谢障碍、氧自由基产生、钙超载等因素有关,但钙超载在缺血再灌注损伤中起极其重要的作用。结论:调节细胞内钙离子的动态平衡对维持细胞正常的生理功能和信息传递十分重要。钙超载是心肌缺血再灌注不可逆损伤的最后通路,但其具体作用途径有待于进一步研究。     

糖调节蛋白78在缺血/再灌注损伤心肌中表达的意义

热休克蛋白70(HSP70)是广泛存在于原核和真核生物细胞内的一种蛋白质,其基本功能为帮助新生蛋白质的正确折叠、移位、维持,以及受损蛋白质的修复、移除、降解,对肾脏等组织器官缺血/再灌注(I/R)损伤具有保护作用[1].糖调节蛋白78(GRP78)也叫免疫球蛋白重链结合蛋白,因与HSP70家族具有高度同源性,而被认为是HSP70家族成员之一.GRP78能抑制细胞毒性,对抗细胞凋亡,是维持胚胎细胞生长和潜能细胞存活的必备物质基础[2].GRP78在多种组织I/R损伤中表达上调,对心肌细胞的存活具有重要的保护作用[3].目前国内关于缺血预处理(IP)对I/R损伤心肌中GRP78表达变化的影响尚未见报道,本实验旨在观察IP对GRP78表达的影响,以期为心肌I/R损伤的研究和临床干预性治疗提供实验依据.     

蛋白微泡声学造影剂在缺血再灌注心肌中排空现象及其机制的探讨

目的　探讨蛋白外壳含氟烷微泡声学造影剂在缺血再灌注 (I/R)心肌中的排空现象及其机制。方法　建立开胸犬I/R模型 ,再灌注前后采用氟烷微泡声学造影剂及间歇谐波技术行心肌声学造影 ,测定造影剂在心肌内的排空时间。光镜及电镜观察离体白细胞与蛋白微泡的粘附过程 ,流式细胞仪测定白细胞与微泡混合后 ,整合素对荧光强度的影响。结果　蛋白微泡声学造影剂流经I/R心肌时出现显著的延迟排空现象。蛋白微泡与佛波醇 (PMA )激活的白细胞接触后 5min大量结合到白细胞表面 ,未激活的白细胞表面少有微泡粘附 ( 2 0 .3± 2 .7对 4.5± 1.4,P <0 .0 1)。15min时微泡被吞噬入细胞内 ,并保持形态完整至 3 0min。两者的结合可被Mac 1mAb大部分阻止 ( P <0 .0 1) ,VLA 4mAb轻度阻止 ( P <0 .0 5 )。结论　蛋白微泡声学造影剂在I/R心肌延迟排空的可能机制是蛋白微泡经 β2 整合素Mac 1和VLA 4介导与I/R后激活的白细胞结合 ,并进入细胞内从而在炎症部位停留。     

人参皂甙Re抗大鼠急性缺血-再灌流心肌细胞凋亡及相关基因蛋白表达

目的　观察人参皂甙Re抗急性缺血再灌流心肌细胞凋亡及Bcl 2、Bax、Bad和Fas基因蛋白表达 ,探讨人参皂甙Re抑制心肌细胞凋亡的可能机制。方法　结扎Wistar大鼠左冠状动脉前降支 ,建立大鼠缺血 再灌流动物模型 ;采用透射电镜、缺口末端标记法检测心肌凋亡细胞 ,利用光学显微镜进行细胞计数 ;免疫组织化学检测Bcl 2、Bax、Bad和Fas基因蛋白的表达 ,并利用图像分析系统测量平均光密度值进行定量分析。结果　①假手术组未发现心肌凋亡细胞。缺血 再灌流组心肌凋亡细胞数为 (13 4 4 5± 4 5 61)个 /视野 ,Re治疗组 (90 66± 19 2 2 )个 /视野 ,两组间差异有显著性意义 (P <0 0 1)。②免疫组织化学检测发现缺血 再灌流组及Re治疗组Bcl 2、Bax、Bad和Fas基因蛋白的表达较假手术组明显增加 (P <0 0 5 ) ,Re治疗组Bcl 2的表达与缺血 再灌流组比较差异无显著性意义 (P >0 0 5 ) ,而Bax、Bad、Fas的表达明显下降 (P <0 0 5 ) ,人参皂甙Re治疗组Bcl 2 /Bad、Bcl 2 /Bad、Bcl 2 /Fas比值均较假手术组与缺血 再灌流组明显增大。结论　人参皂甙Re治疗可以抑制急性缺血再灌流诱导的心肌细胞凋亡 ,其作用机制可能是抑制了促凋亡基因Bax、Bad、Fas的表达 ,从而使Bcl 2 /Bax、Bcl 2 /Bad、Bcl 2 /Fas比值增大。     

缺血预处理及磺脲类降糖药物对在体大鼠缺血再灌注损伤心肌的作用

目的：观察经典缺血预处理对在体大鼠缺血再灌注心肌损伤的保护效应以及磺脲类降糖药物对其产生的影响。方法：将实验动物分为假手术组、缺血再灌注组、经典缺血预处理组和磺脲类降糖药物处理组，每组8只，观察经典缺血预处理和磺脲类降糖药物对心肌超微结构的影响，同时测定心肌组织丙二醛含量。结果：经典缺血预处理后缺血再灌注后的心肌丙二醛含量[(0．99&;#177;0．26)μmol／g]明显降低，与模型组[(1．68&;#177;0．33)μmol／g]比较，差异有显著性意义(P&;lt;0．05)，而且保护心肌超微结构；磺脲类药物预处理组心肌丙二醛含量[(1．71&;#177;0．26)μmol／g]与模型组比较，差异无显著性意义，且心肌超微结构明显破坏。结论：磺脲类药物预处理可以取消经典缺血预处理对在体大鼠缺血再灌注心肌损伤的保护效应。     

脊髓缺血再灌注损伤中热休克蛋白表达的研究

目的研究脊髓缺血再灌注损伤(SCII)后热休克蛋白(HSP70)表达的变化。方法制作SCII动物模型,采用光镜、激光多普勒超声、免疫组化等技术,研究SCII后HSP70表达的变化。结果(1)缺血30min,血灌流量平均下降85.37%,再灌流即刻血灌流量迅速升高,再灌流10min左右达到最高点。再灌流30min,血灌流量基本恢复到缺血前的基线水平,以后逐渐降低。(2)缺血后部分大鼠再灌注后出现“二次瘫痪”现象。(3)脊髓缺血30min再灌注60min后即有HSP70的表达增强,随着再灌注时间的延长,HSP70表达逐渐增多,在再灌注240min达到高峰。此后,HSP70表达逐渐减少,在再灌注24h基本消失。结论(1)脊髓缺血一定时间后恢复血液供应,可以发生再灌注损伤。(2)脊髓缺血再灌注后HSP70的表达增加。     

心型脂肪酸结合蛋白在瓣膜置换术后心肌损伤早期评价中的应用

目的:本研究旨在评价心型脂肪酸结合蛋白(H-FABP)能否作为体外循环下瓣膜置换术后心肌损伤的早期诊断指标。方法:对接受单瓣置换(A组)和双瓣置换(B组)手术的两组病人测定麻醉诱导后至主动脉开放后24h之间的H-FABP、心肌特异型肌钙蛋白Ⅰ(cTn-Ⅰ)和肌酸激酶同工酶MB(CK-MB)的血浆浓度变化。比较两组病例的临床资料和3种蛋白在不同时间的浓度,分析H-FABP峰值浓度与cTn-Ⅰ和CK-MB峰值浓度以及与主动脉阻断(ACC)时间和体外循环(CPB)时间的相关性。结果:主动脉开放后,3种蛋白血浆浓度很快上升,但B组始终高于A组,在峰值浓度时间点差异有显著性。H-FABP达到峰值浓度的时间明显早于cTn-Ⅰ和CK-MB,3种蛋白峰值浓度具有高度相关性且H-FABP峰值浓度与ACC时间和CPB时间具有良好的相关性。结论:心型脂肪酸结合蛋白能作为体外循环下瓣膜置换术后心肌损伤早期诊断的合适指标。     

脊髓缺血再灌注损伤中热休克蛋白表达的研究

目的：研究脊髓缺血再灌注损伤（SCⅡ）后热休克蛋白（HSP70）表达的变化。方法：制作SCⅡ动物模型，采用光镜，激光多普勒超声，免疫组化等技术，研究SCⅡ后HSP70表达的变化。结果：（1）缺血30min，血灌流量平均下降85．37％，再灌流即刻血灌流量迅速升高，再灌流10min左右达到最高点，再灌流30min，血灌流量基本恢复到缺血前的基线水平，以后逐渐降低。（2）缺血后部分大鼠再灌注后出现“二次瘫痪”现象。（3）脊髓缺血30min再灌注60min后即有HSP70的表达增强，随着再灌注时间的延长，HSP70表达逐渐增多，在再灌注240min达到高峰，此后，HSP70表达逐渐减少，在再灌注24h基本消失，结论：（1）脊髓缺血一定时间后恢复血液供应，可以发生再灌注损伤。（2）脊髓缺血灌注后HSP70的表达增加。     

DNA修复蛋白PARP基因在大鼠缺血脑组织中的表达

目的　探讨大鼠局灶性脑缺血再灌注后DNA修复蛋白PARP基因表达的时空改变及其与凋亡的关系。方法　采用大鼠大脑中动脉阻塞再灌注模型 (MCAO R) ,运用原位杂交技术观察缺血再灌注PARPmRNA的时空分布 ,结合TUNEL技术观察其与凋亡的关系。结果　脑缺血 30min再灌注 1hPARPmRNA表达增加 ,随缺血或再灌注时间的延长表达逐渐增强 (P <0 0 5 ) ,与凋亡的时间变化规律相似 ,但范围大于并涵盖凋亡的范围 ,凋亡分布区外侧的缺血区表达也明显增加。结论　脑缺血 /再灌注损伤可诱导神经细胞DNA修复蛋白PARP基因的转录增强 ,PARP可能参与脑缺血损伤后的DNA修复。     

山莨菪碱对心搏骤停猪氧化应激致心肌线粒体损伤的保护作用

目的 通过观察心搏骤停(CA)猪血浆和心肌氧化-抗氧化指标及心肌线粒体结构的变化,探讨山莨菪碱对氧化应激所致心肌缺血/再灌注(I/R)损伤的保护作用.方法 23头健康雄性家猪,按随机数字表法分为假手术组(n=5)、肾上腺素组(n=9)和山莨菪碱组(n=9),用交流电刺激法建立CA模型.在CA前、CA 8 min及自主循环恢复(ROSC)即刻、30 min、24 h留取血标本,ROSC 24 h处死动物留取心肌.采用分光光度法检测丙二醛(MDA)含量和超氧化物歧化酶(SOD)活性;高效液相色谱法测定心肌ATP含量;激光共聚焦显微镜下检测线粒体活性氧簇(ROS)水平;透射电镜下观察心肌组织超微结构,并对线粒体损伤程度进行评分.结果 山莨菪碱组ROSC 30 min和24 h时MDA含量(μmol/L)均较肾上腺素组明显减少(30 min:43.38±8.12比55.47±10.97,24 h:29.96±6.04比37.87±7.85,均P＜0.05);24h时心肌SOD活性(U/mg)及ATP含量(μmol/g)也均较肾上腺素组显著升高(SOD:1.35±0.50比0.54±0.19,ATP:4.17±1.06比2.95±0.94,P＜0.01和P＜0.05),线粒体ROS含量(RFU)水平降低(88.00±17.67比107.00±21.35,P＜0.05),心肌MDA(μmol/mg)含量有所减少,但差异无统计学意义(16.66±2.89比19.28±3.90,P＞0.05).透射电镜下观察显示,肾上腺素组心肌细胞排列紊乱,线粒体排列及形态与假手术组有明显差异[线粒体损伤评分(分):0.41±0.08比0.12±0.01,P＜0.01];山莨菪碱组线粒体损伤程度较肾上腺素组明显减轻(线粒体损伤评分:0.21±0.05比0.41±0.08,P＜ 0.05).结论 山莨菪碱可能通过调节氧自由基代谢,从而减轻氧化应激所致心肌线粒体结构和功能的损伤.     

乌司他丁预处理对心脏瓣膜置换患者心肌氧化应激损伤的保护作用

目的研究乌司他丁预处理对心脏瓣膜置换患者心肌氧化应激损伤的保护作用。方法将2012年5月至2014年5月在我院接受心脏瓣膜置换手术的70例患者纳入研究,根据麻醉诱导时的处理方法不同随机分为两组,观察组在麻醉诱导后接受乌司他丁预处理,对照组接受常规麻醉诱导,检测两组患者的心肌酶谱指标、氧化损伤指标以及炎症因子。结果 (1)心肌酶谱:观察组患者的血浆肌酸激酶同工酶(CK-MB)、心肌肌钙蛋白T(c Tn T)含量低于对照组;(2)氧化损伤指标:观察组血浆脂质过氧化物(LPO)含量低于对照组,还原型谷胱甘肽(GSH)、超氧化物歧化酶(SOD)含量高于对照组;(3)炎症因子:观察组患者的血浆TNF-α、IL-6含量低于对照组,IL-10含量高于对照组。结论乌司他丁预处理有助于减少心肌细胞损伤、缓解氧化反应和炎症反应,是心脏瓣膜置换术麻醉诱导时理想的处理方法。     

Platelets oxidative stress in Indian patients with ischemic heart disease

Background: Oxidative stress has been implicated in the development of atherosclerosis and vascular tissue injury. Both platelet activation and lipid peroxidation are known to play major role in ischemic heart disease. The purpose of this study was to investigate the status of platelets oxidative stress in Indian patients with ischemic heart disease. Methods: We measured platelets aggregation, malonyldialdehyde (MDA), plasma‐ionized Ca²⁺, and antioxidant enzymes, i.e., glutathione peroxidase and superoxide dismutase in healthy volunteers and patients with myocardial infarction, unstable and stable angina 40 subjects each. Results: Platelets aggregation, MDA, and plasma‐ionized Ca²⁺ have increased significantly across the patients groups compared with controls, this increase was accompanied by an overall decrease in the antioxidant enzymes activity; except for the slight increases in the glutathione peroxidase levels among the myocardial infarction patients. Conclusions: The current results suggest that platelet lipid peroxidation as marked by increased MDA level is augmented in ischemic heart diseases. The increased oxidative stress seen in these patients was accompanied by platelet activation and impaired antioxidant enzymes activity. J. Clin. Lab. Anal. 24:49–54, 2010. © 2010 Wiley‐Liss, Inc.     

Endoplasmic reticulum stress in ischemic and nephrotoxic acute kidney injury

Acute kidney injury (AKI) is a medical condition characterized by kidney damage with a rapid decline of renal function, which is associated with high mortality and morbidity. Recent research has further established an intimate relationship between AKI and chronic kidney disease. Perturbations of kidney cells in AKI result in the accumulation of unfolded and misfolded proteins in the endoplasmic reticulum (ER), leading to unfolded protein response (UPR) or ER stress. In this review, we analyze the role and regulation of ER stress in AKI triggered by renal ischemia-reperfusion and cisplatin nephrotoxicity. The balance between the two major components of UPR, the adaptive pathway and the apoptotic pathway, plays a critical role in determining the cell fate in ER stress. The adaptive pathway is evoked to attenuate translation, induce chaperones, maintain protein homeostasis and promote cell survival. Prolonged ER stress activates the apoptotic pathway, resulting in the elimination of dysfunctional cells. Therefore, regulating ER stress in kidney cells may provide a therapeutic target in AKI.

• KEY MESSAGES

• Perturbations of kidney cells in acute kidney injury result in the accumulation of unfolded and misfolded proteins in ER, leading to unfolded protein response (UPR) or ER stress.

• The balance between the adaptive pathway and the apoptotic pathway of UPR plays a critical role in determining the cell fate in ER stress.

• Modulation of ER stress in kidney cells may provide a therapeutic strategy for acute kidney injury.

     

Inhibition of endogenous thioredoxin in the heart increases oxidative stress and cardiac hypertrophy

Thioredoxin 1 (Trx1) has redox-sensitive cysteine residues and acts as an antioxidant in cells. However, the extent of Trx1 contribution to overall antioxidant mechanisms is unknown in any organs. We generated transgenic mice with cardiac-specific overexpression of a dominant negative (DN) mutant (C32S/C35S) of Trx1 (Tg-DN-Trx1 mice), in which the activity of endogenous Trx was diminished. Markers of oxidative stress were significantly increased in hearts from Tg-DN-Trx1 mice compared with those from nontransgenic (NTg) mice. Tg-DN-Trx1 mice exhibited cardiac hypertrophy with maintained cardiac function at baseline. Intraperitoneal injection of N-2-mercaptopropionyl glycine, an antioxidant, normalized cardiac hypertrophy in Tg-DN-Trx1 mice. Thoracic aortic banding caused greater increases in myocardial oxidative stress and enhanced hypertrophy in Tg-DN-Trx1 compared with NTg mice. In contrast, transgenic mice with cardiac-specific overexpression of wild-type Trx1 did not show cardiac hypertrophy at baseline but exhibited reduced levels of hypertrophy and oxidative stress in response to pressure overload. These results demonstrate that endogenous Trx1 is an essential component of the cellular antioxidant mechanisms and plays a critical role in regulating oxidative stress in the heart in vivo. Furthermore, inhibition of endogenous Trx1 in the heart primarily stimulates hypertrophy, both under basal conditions and in response to pressure overload through redox-sensitive mechanisms.     

促红细胞生成素对肾缺血再灌注氧化应激损伤的影响

目的：探讨重组人促红细胞生成素对肾缺血再灌注损伤的作用及机制。 方法：实验于2005—07／2006-01在泸州医学院中心实验室和病理生理实验室完成。选择雄性Wistar大鼠54只，建立右肾切除，左肾肾动脉夹闭45min后再灌注的动物模型，将54只大鼠随机数字表法分为左肾未缺血再灌注组18只，切除右肾，不夹闭左肾动脉。重组人促红细胞生成素干预组18只，在再灌注开始前5min静脉注射重组人促红细胞生成素（3000U／kg）。肾缺血再灌注损伤组18只，在再灌注开始前5min注射等量的生理盐水。各组再灌注达1，6，24h时间点检测肾功能（血肌酐，尿素氮），并观察肾组织中丙二醛含量、超氧化物歧化酶活性和组织形态学改变。 结果：纳入动物54只，均进入结果分析。①重组人促红细胞生成素干预组肾组织中丙二醛含量与肾缺血再灌注损伤组相比显著降低、超氧化物歧化酶活性显著升高[以再灌注6h为例，分别为（0．93&;#177;0.09），（1．19&;#177;0．08）μmol/g，（1919．55&;#177;126．52），（1338．10&;#177;5．50）μkat以，P〈0．05]。②重组人促红细胞生成素干预组血肌酐、尿素氮含量与肾缺血再灌注损伤组相比降低[以再灌注6h为例，分别为（87．53&;#177;1．22），（121．63&;#177;21．17）μmol/L，（252．06&;#177;4．59），（369．14&;#177;18．38）mg／L，P〈0．05]。③重组人促红细胞生成素干预组肾脏病变与肾缺血再灌注组比较明显减轻，肾小管上皮细胞轻度水肿，基底膜多完整，肾小管腔内见少量管型。 结论：重组人促红细胞生成素能减轻肾缺血再灌注损伤，其机制可能是抗氧自由基损伤．提高内源性抗氧化能力。     

促红细胞生成素对肾缺血再灌注氧化应激损伤的影响

目的:探讨重组人促红细胞生成素对肾缺血再灌注损伤的作用及机制。方法:实验于2005-07/2006-01在泸州医学院中心实验室和病理生理实验室完成。选择雄性Wistar大鼠54只,建立右肾切除,左肾肾动脉夹闭45min后再灌注的动物模型,将54只大鼠随机数字表法分为左肾未缺血再灌注组18只,切除右肾,不夹闭左肾动脉。重组人促红细胞生成素干预组18只,在再灌注开始前5min静脉注射重组人促红细胞生成素(3000U/kg)。肾缺血再灌注损伤组18只,在再灌注开始前5min注射等量的生理盐水。各组再灌注达1,6,24h时间点检测肾功能(血肌酐,尿素氮),并观察肾组织中丙二醛含量、超氧化物歧化酶活性和组织形态学改变。结果:纳入动物54只,均进入结果分析。①重组人促红细胞生成素干预组肾组织中丙二醛含量与肾缺血再灌注损伤组相比显著降低、超氧化物歧化酶活性显著升高[以再灌注6h为例,分别为(0.93±0.09),(1.19±0.08)μmol/g,(1919.55±126.52),(1338.10±5.50)μkat/g,P<0.05]。②重组人促红细胞生成素干预组血肌酐、尿素氮含量与肾缺血再灌注损伤组相比降低[以再灌注6h为例,分别为(87.53±1.22),(121.63±21.17)μmol/L,(252.06±4.59),(369.14±18.38)mg/L,P<0.05]。③重组人促红细胞生成素干预组肾脏病变与肾缺血再灌注组比较明显减轻,肾小管上皮细胞轻度水肿,基底膜多完整,肾小管腔内见少量管型。结论:重组人促红细胞生成素能减轻肾缺血再灌注损伤,其机制可能是抗氧自由基损伤,提高内源性抗氧化能力。     

Release kinetics of serum cardiac troponin i in ischemic myocardial injury

Objectives: The study was undertaken to evaluate the release kinetics of cardiac troponin I (c-cTn-I) in ischemic myocardial injury.

Design and Methods: The reference range for cTn-I was established by determination of cTn-I in sera and plasma obtained from 622 healthy volunteers (Group 1). cTn-I was compared to: (a) Creatine kinase (CK) MB mass and myoglobin in 12 patients with severe skeletal muscle damage (Group 2); (b) CK-MB activity in 48 patients with myocardial infarction (MI) receiving intravenous thrombolysis (Group 3) (in this group, an additional 43 patients with MI were analyzed separately to characterize cTn-I patterns in thrombolyzed and nonthrombolyzed populations); and in 44 patients with unstable angina (Group 4).

Results: In Groups 1 and 2, no positive results (0.1 μg/L) were obtained. In Group 3, the time-courses of cTn-I were mostly monophasic in form. A pathologic increase occurred earlier in cTn-I than in CK-MB activity (p = 0.0002); the period with increased cTn-I was longer (p = 0.001), the overall sensitivity of cTn-I (93.9%) was higher than that of CK-MB activity (p = 0.00001). cTn-I was more sensitive at admission (p = 0.0004). In additional patients, the cTn-I peak occurred and cTn-I disappeared significantly later in nonthrombolyzed than in the thrombolyzed group. In Group 4, positive tests results were detected in 45% of patients for cTn-I, 16% for CK-MB activity, and 32% for CK-MB mass.

Conclusions: The cTn-I assay appears to be ideally suited for the detection of ischemic myocardial injury in complex clinical situations because of its high specificity; cTn-I indicates myocardial tissue damage in patients with unstable angina and is superior to CK-MB activity and mass in this respect.