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1.
目的:建立离体大鼠心肌缺血/再灌注损伤模型,观察二氮嗪(diazoxide,D)后处理对缺血/再灌注损伤离体大鼠心功能及线粒体心磷脂的影响,并探讨ATP敏感性钾通道在二氮嗪后处理心肌保护中的作用。方法:采用Langendorff装置建立离体大鼠心肌缺血/再灌注损伤模型,将SD大鼠随机分为对照组(control)、缺血再灌注模型组(I/R)、二氮嗪后处理组(I/R+D)、5-羟葵酸拮抗二氮嗪后处理组(I/R+5-HD+D),每组8只,均先灌注平衡20 min。Control组:灌注平衡后续灌70 min;I/R组:缺血前灌注4℃ST.Thomas停跳液,全心缺血40 min,再灌30 min;I/R+D组:全心缺血40 min,缺血后给予含二氮嗪(50μmol/L)的K-H液灌注5 min后,再灌25 min;I/R+5-HD+D组:二氮嗪后处理前给予含5-羟葵酸(100μmol/L)的K-H液灌注5 min,再灌20 min。观察各组续(再)灌注末心率、冠脉流出液量、心功能、心肌酶学及心肌线粒体心磷脂的变化。结果:各组续(再)灌注末比较,I/R组较control组及I/R+D组心率减慢、冠脉流出液量降低,心功能明显受损,心肌酶增加,心磷酯含量减少,但与I/R+5-HD+D无明显差异。结论:二氮嗪后处理通过增加线粒体心磷脂含量,减少心肌酶的释放,改善心脏功能,减轻心肌的再灌注损伤,产生心肌保护作用。5-羟葵酸能够完全阻断二氮嗪的心肌保护作用。  相似文献   

2.
The aim of this study was to assess whether depression of cardiac Na+,K(+)-ATPase activity during ischemia/reperfusion (I/R) is associated with alterations in Na+,K(+)-ATPase isoforms, and if oxidative stress participates in these I/R-induced changes. Na+,K(+)-ATPase alpha1, alpha2, alpha3, beta1, beta2, and beta3 isoform contents were measured in isolated rat hearts subjected to I/R (30 min of global ischemia followed by 60 min of reperfusion) in the presence or absence of superoxide dismutase plus catalase (SOD+CAT). Effects of oxidative stress on Na+,K(+)-ATPase isoforms were also examined by perfusing the hearts for 20 min with 300 microM hydrogen peroxide or 2 mM xanthine plus 0.03 U/ml xanthine oxidase (XXO). I/R significantly reduced the protein levels of all alpha and beta isoforms. Treatment of I/R hearts with SOD+CAT preserved the levels of alpha2, alpha3, beta1, beta2, and beta3 isoforms, but not that of the alpha1 isoform. Perfusion of hearts with hydrogen peroxide and XXO depressed all Na+,K(+)-ATPase alpha and beta isoforms, except for alpha1. These results indicate that the I/R-induced decrease in Na+,K(+)-ATPase may be due to changes in Na+,K(+)-ATPase isoform expression and that oxidative stress plays a role in this alteration. Antioxidant treatment attenuated the I/R-induced changes in expression of all isoforms except alpha1, which appears to be more resistant to oxidative stress.  相似文献   

3.
4.
目的探讨丹参酮ⅡA对大鼠心肌缺血再灌注损伤的作用。方法雄性SD大鼠随机分为假手术组、模型组、丹参酮ⅡA预处理组,后两组进行冠状动脉左前降支结扎30min后再灌注120min。期间全程监测心率和血流动力学指标。实验结束后取心脏做Trc染色及HE染色,观察心肌梗死面积和组织学改变。结果模型组大鼠心脏功能明显下降并发生心肌梗死提示造模成功。与模型组比较,丹参酮ⅡA组在缺血30min,再灌注30、60、120min各时间点,左心室收缩末压、左室内压最大上升及下降速率明显增高、心率基本恢复正常。组织学染色显示,与模型组比较,丹参酮ⅡA组心肌梗死区面积降低、心肌细胞变性坏死程度明显减轻。结论丹参酮ⅡA预处理对大鼠心肌缺血再灌注损伤具有保护作用。  相似文献   

5.
We investigated the role of oxidative/nitrosative stress in the tolerance to ischemia/reperfusion (I/R) injury in BIO14.6 cardiomyopathy hamster hearts at 6 weeks of age. These hearts showed no significant morphologic change and left ventricular (LV) dysfunction. However, expression and activity of iNOS, nitrotyrosine (NT) formation, and protein kinase C (PKC)-epsilon activity were increased in these hearts. When the BIO14.6 hamster hearts were isolated and subjected to 40 min of global ischemia, they showed smaller myocardial necrosis and greater recovery of LV function during reperfusion compared with the control hamster heart. All of these effects were abrogated by prolonged treatment with the antioxidant, 2-mercaptopropionylglycine (MPG). Brief preischemic treatment with MPG or the iNOS inhibitor 1400W also abrogated NT formation and activation of PKC-epsilon and inhibited the tolerance to I/R injury in the BIO14.6 hamster heart. Brief preischemic treatment with the PKC inhibitor chelerythrine or the K(ATP) channel blockers, 5-hydroxydecanoate (5-HD) and glibenclamide, had no effect on iNOS activation and NT formation but inhibited the tolerance to I/R injury in the cardiomyopathic heart. These results suggest that oxidative/nitrosative stress plays a role in the tolerance to I/R injury in the cardiomyopathic heart through activation of PKC and the downstream effectors, K(ATP) channels.  相似文献   

6.
Changes in catecholamine ,angiotensin converting enzy me and adenosine triphosphatase in ischemic preconditioning rat hearts  相似文献   

7.
目的: 研究甘氨酰谷氨酰胺对缺血再灌注大鼠离体心脏的保护作用。方法:应用Langendorff离体心脏灌注系统建立心肌缺血再灌注模型。30只SD雄性大鼠随机分为正常对照组(control)、甘氨酰谷氨酰胺对照组(Gly-Gln)、缺血再灌注组(I/R)、缺血/再灌注+甘氨酰谷氨酰胺组(I/R+ Gly-Gln)。I/R组及I/R+ Gly-Gln组分别灌注30 min后,全心停灌20 min,再灌注40 min,I/R+ Gly-Gln组于再灌注时在灌流液中加入Gly-Gln;正常对照组连续灌流90 min,Gly-Gln对照组灌流液中加入Gly-Gln。记录各组灌注时,左室舒张末压(LVEDP)、左室发展压(LVDP)、左室压力最大变化速率(±dp/dtmax)、心率(HR)及心肌细胞单相动作电位(MAP);同时在相应的时点分别测定冠脉流出液中的乳酸脱氢酶(LDH)、肌酸激酶(CK)活性。结果:离体大鼠心脏缺血20min,再灌注40 min,导致严重的心功能抑制,表现为LVEDP升高,LVDP、±dp/dtmax降低;再灌注液中加入Gly-Gln后,LVEDP降低,LVDP、±dp/dtmax明显升高(P<0.01)。I/R+ Gly-Gln组冠脉流出液中LDH、CK活性明显低于I/R组(均P<0.01)。结论: Gly-Gln能有效减轻缺血再灌注引起的左室功能下降,减少心肌细胞LDH、CK的释出,表明Gly-Gln对缺血再灌注损伤的大鼠离体心脏具有保护作用。  相似文献   

8.

Purpose

Ethyl pyruvate has anti-inflammatory properties and protects organs from ischemia/reperfusion (I/R)-induced tissue injury. The aim of this study was to determine whether ethyl pyruvate decreases the inflammatory response after regional I/R injury and whether ethyl pyruvate protects against delayed regional I/R injury in an in vivo rat heart model after a 24 hours reperfusion.

Materials and Methods

Rats were randomized to receive lactated Ringer''s solution or ethyl pyruvate dissolved in Ringer''s solution, which was given by intraperitoneal injection 1 hour prior to ischemia. Rats were subjected to 30 min of ischemia followed by reperfusion of the left coronary artery territory. After a 2 hours reperfusion, nuclear factor κB, myocardial myeloperoxidase activity, and inflammatory cytokine levels were determined. After the 24 hours reperfusion, the hemodynamic function and myocardial infarct size were evaluated.

Results

At 2 hours after I/R injury, ethyl pyruvate attenuated I/R-induced nuclear factor κB translocation and reduced myeloperoxidase activity in myocardium. The plasma circulating levels of inflammatory cytokines decreased significantly in the ethyl pyruvate-treated group. At 24 hours after I/R injury, ethyl pyruvate significantly improved cardiac function and reduced infarct size after regional I/R injury.

Conclusion

Ethyl pyruvate has the ability to inhibit neutrophil activation, inflammatory cytokine release, and nuclear factor κB translocation. Ethyl pyruvate is associated with a delayed myocardial protective effect after regional I/R injury in an in vivo rat heart model.  相似文献   

9.
Isolated Langendorff-perfused hearts from sedentary and prolonged (24 weeks) treadmill-trained rats were subjected to 30 min of normoxic perfusion either alone or followed by 20 min of global ischaemia, or by 20 min of global ischaemia and 15 min of normoxic reperfusion. Pre-ischaemic values of antioxidant enzyme activities and ecto-5'-nucleotidase activity were not different in sedentary and trained hearts but a 5-fold increase of 72-kDa heat shock protein (HSP72) levels was detected in trained myocardium. After ischaemia and reperfusion (I/R), metabolic recovery was better in trained than in sedentary hearts as indicated by higher ATP and creatine phosphate levels. However, antioxidant enzymatic activities, glutathione reductase, and total and mitochondrial superoxide dismutase decreased in trained rats after I/R, whereas they remained unchanged in the sedentary ones. Ecto-5'-nucleotidase activity was modified by I/R in sedentary as well as in trained hearts while HSP72 content did not change. Ecto-5'-nucleotidase activity and HSP72 content increased in parallel by the 30-min perfusion period. In conclusion, the cardioprotection induced by long-term training could be mediated by the exercise-induced increase in HSP72 levels and is not related to enhanced antioxidant systems or ecto-5'-NT activity.  相似文献   

10.
目的 :研究巴曲酶 (BAT)对狗心脏缺血 /再灌注 (I/R)损伤过程中血栓素A2 (TXA2 )水平的影响。方法 :结扎狗左冠状动脉前降支 3 0min ,恢复血流 90min ,造成I/R模型 ,于缺血前或缺血后 15min静注BAT( 1U/kg) ,测定血浆、心肌TXB2 浓度以及血浆磷酸肌酸激酶 (CK)和乳酸脱氢酶 (LDH)活性 ,并检测心脏功能 ,观察病理学变化。结果 :I/R组心肌组织及血浆TXB2 水平明显升高 ,血浆CK及LDH活性明显降低 ,心功能受损。病理学发现心肌纤维水肿、排列紊乱、线粒体水肿、嵴明显断裂、细胞核皱缩。给予BAT后 ,动物死亡率、再灌期血浆及心肌TXB2 水平、血浆CK及LDH活性以及LVEDP明显低于I/R组 ,而±dp/dtmax明显高于I/R组 ,病理学检查无明显损伤。结论 :BAT能够降低血浆及心肌TXA2 水平减轻心肌组织I/R损伤。  相似文献   

11.
目的:研究巴曲酶(BAT)对狗心脏缺血/再灌注(I/R)损伤过程中血栓素A2(TXA2)水平的影响。方法:结扎狗左冠状动脉前降支30 min, 恢复血流90 min,造成I/R模型,于缺血前或缺血后15min静注BAT(1U/kg),测定血浆、心肌TXB2浓度以及血浆磷酸肌酸激酶(CK)和乳酸脱氢酶(LDH)活性,并检测心脏功能,观察病理学变化。结果: I/R组心肌组织及血浆TXB2水平明显升高, 血浆CK及LDH活性明显降低,心功能受损。病理学发现心肌纤维水肿、排列紊乱、线粒体水肿、嵴明显断裂、细胞核皱缩。给予BAT后,动物死亡率、再灌期血浆及心肌TXB2水平、血浆CK及LDH活性以及LVEDP明显低于I/R组,而±dp/dt max明显高于I/R组,病理学检查无明显损伤。结论:BAT能够降低血浆及心肌TXA2水平减轻心肌组织I/R损伤。  相似文献   

12.
目的:探讨亚甲蓝(methylene blue,MB)对大鼠离体心脏缺血/再灌注(ischemia/reperfusion,I/R)线粒体损伤的作用。方法:将Spragure-Dawley大鼠随机分为对照组(control组)、I/R模型组和MB治疗组(I/R+MB组),建立Langendorff离体心脏灌注模型(n=6)。手术前2 h,MB组大鼠按2 mg/kg腹腔注射MB。对照组持续灌注K-H液110 min,I/R组与I/R+MB组平衡灌注20 min后停灌30 min,再灌注60 min。实时记录心率(HR)、左室发展压(LVDP)、左室最大压力变化速率(±dp/dt_(max))和左室舒张末压(LVEDP)。测定冠脉流出液中肌酸激酶MB同工酶(CK-MB)和乳酸脱氢酶(LDH)活性。测定心肌组织中活性氧簇(ROS)、丙二醛(MDA)和三磷酸腺苷(ATP)含量以及超氧化物歧化酶(SOD)活性。苏木精-伊红染色观察组织病理学变化。分离心肌组织线粒体,测定线粒体肿胀程度和线粒体膜电位(MMP)。结果:与对照组相比,I/R组的心功能恶化,冠脉流出液中的CK-MB和LDH活性升高,心肌组织中的ROS和MDA增加,SOD活性降低,ATP减少,线粒体肿胀程度升高,MMP下降(P0.05);与I/R组相比,I/R+MB组的心功能改善,CK-MB和LDH的释放减少,组织中的ROS和MDA减少,SOD活性和ATP含量升高,线粒体肿胀程度降低,MMP升高(P0.05)。结论:MB通过减轻线粒体损伤对大鼠离体I/R心脏发挥保护作用。  相似文献   

13.
It is currently believed that reactive oxygen species are produced in the heart post-ischemia-reperfusion, causing pathophysiological disorders. Studies reported in the literature dealing with this subject have generated contradictory findings. The aim of this study was to assess the catalytic activity of the superoxide anion-producing enzyme xanthine oxidase, and the level of lipid peroxides in isolated rat heart muscle undergoing ischemia of varying duration and severity followed by reperfusion.Three levels of ischemia were investigated: total, and partial at either 0.10 or 0.35 ml/min (residual flow rate). Three different periods of ischemia were examined in each case. After each period of ischemia, followed by 10 min of reperfusion, the heart was frozen in liquid nitrogen. Xanthine oxidase activity and lipid peroxide levels were assayed in the cardiac homogenate and in the centrifuged supernatant, respectively. In the different experimental protocols studied here, both cardiac xanthine oxidase and lipid peroxide levels remained statistically unchanged compared to the continuously perfused control hearts. Moreover, in a recent study (Boucher et al., FEBS Lett. 203, 261–264, 1992), we were unable to detect reactive oxygen species in perfusate upon reperfusion of ischemic rat hearts.These results suggest that changes in xanthine oxidase activity during myocardial ischemia-reperfusion, and lipid peroxidation, as assessed by measuring thiobarbituric acid reactants and lipid hydroperoxides, are not predominant phenomena in ischemia-reperfusion-induced injury, at least in the experimental model used in this study. The significance of these results is discussed in the light of the popular point of view suggested first by McCord in 1985 concerning the conversion of xanthine dehydrogenase to xanthine oxidase in heart in the course of ischemia.  相似文献   

14.
Myocardial ischaemia followed by reperfusion (I/R) is associated with impaired endothelial function including diminished release and/or effects of nitric oxide (NO) which may contribute to the development of I/R injury. The aim of the present study was to investigate the role of the L-arginine/NO pathway in myocardial I/R injury. In isolated rat hearts subjected to global ischaemia followed by reperfusion L-arginine and the NO donor S-nitroso-N-acetyl-D,L-penicillamine (SNAP), but not D-arginine, significantly enhanced the recoveries of mycardial performance and coronary flow, and reduced the area of no-reflow and creatine kinase outflow. The NO synthase inhibitor NG-nitro-L-arginine (L-NNA) abolished the protective effects of L-arginine. Endothelium-dependent vasodilatation after I/R was preserved in L-arginine treated but not in vehicle hearts. Following I/R Ca2+-dependent NO synthase activity was reduced by 90% in comparison with non-ischaemic hearts. L-arginine but not D-arginine significantly increased NO synthase activity. In anaesthetized pigs, L-arginine given by local coronary venous retroinfusion reduced myocardial infarct size induced by 45 min of coronary artery ligation and 4 h of reperfusion to 35% of the area at risk from 76% in controls. The protective effect of L-arginine was blocked by L-NNA. Acetylcholine-induced coronary vasodilatation following I/R was attenuated in controls but not in L-arginine treated pigs. It is concluded that L-arginine or the NO donor SNAP reduces I/R-induced myocardial and endothelial injury. The protective effect of L-arginine seems to be mediated through maintained production of NO by preserving the function of Ca2+-dependent NO synthase in the heart.  相似文献   

15.
目的探讨尼可地尔对高胆固醇大鼠心肌缺血/再灌注损伤的影响及其可能机制。方法应用高胆固醇饮食喂养健康雄性Wistar大鼠8周建立高胆固醇大鼠模型,应用Langendorff灌流装置采用全心缺血30min和再灌注120min建立离体心脏缺血/再灌注(I/R)模型。在缺血前或再灌注即刻灌注含有尼可地尔的KH液10min以制备尼可地尔药物预处理(NIC-pre)与后处理(NIC-post)模型。通过TTC染色测量心肌梗死面积、TUNEL染色检测心肌细胞凋亡率,Western blot检测RISK通路p-Akt和p-Erk1/2蛋白表达水平。结果与I/R对照组相比,NIC-30pre组与NIC-30post组均可降低心肌梗死面积和心肌细胞凋亡率,并显著上调p-Akt和pErk1/2的表达水平。结论尼可地尔减轻高胆固醇大鼠心肌缺血/再灌注损伤,与其激活RISK通路相关。  相似文献   

16.
This study was to investigate whether polymerized human placenta hemoglobin (PolyPHb) given before ischemia protects in vivo rat heart function against ischemia/reperfusion (I/R) injury. Forty-five male Sprague-Dawley rats were randomly divided (n = 15 per group) into a sham group, control group (pretreatment with Lactated Ringer's solution), or PolyPHb group (pretreatment with 0.1 gHb/kg PolyPHb). Rat hearts were subjected to 30-min ischemia by occlusion of left anterior descending, followed by 2-hr reperfusion. As compared to the control group, PolyPHb preserved cardiac function and reduced cardiac troponin-I release and histopathological changes. Therefore, PolyPHb pretreatment provided a profound cardioprotective effect on the in vivo rat heart.  相似文献   

17.
The present study tested the hypothesis that prenatal cocaine exposure differentially regulates heart susceptibility to ischaemia–reperfusion (I/R) injury in adult offspring male and female rats. Pregnant rats were administered intraperitoneally either saline or cocaine (15 mg kg−1) twice daily from day 15 to day 21 of gestational age. There were no differences in maternal weight gain and birth weight between the two groups. Hearts were isolated from 2-month-old male and female offspring and were subjected to I/R (25 min/60 min) in a Langendorff preparation. Preischaemic values of left ventricular (LV) function were the same between the saline control and cocaine-treated hearts for both male and female rats. Prenatal cocaine exposure significantly increased I/R-induced myocardial apoptosis and infarct size, and significantly attenuated the postischaemic recovery of LV function in adult male offspring. In contrast, cocaine did not affect I/R-induced injury and postischaemic recovery of LV function in the female hearts. There was a significant decrease in PKCɛ and phospho-PKCɛ levels in LV in the male, but not female, offspring exposed to cocaine before birth. These results suggest that prenatal cocaine exposure causes a sex-specific increase in heart susceptibility to I/R injury in adult male offspring, and the decreased PKCɛ gene expression in the male heart may play an important role.  相似文献   

18.
目的:观察11,12-环氧二十碳三烯酸(11,12-EET)和缺血预处置对大鼠再灌注心肌组织磷酸化ERK1/ERK2和p38 MAPK表达的影响,了解大鼠心肌磷酸化ERK1/ERK2和p38 MAPK表达与预处置有否关系。方法: 使用雄性Wistar大鼠,通过结扎(60 min)和松开(30 min)冠状动脉左前降支,复制缺血/再灌注模型;采用缺血5 min,再灌注5 min两次造成缺血预处置。大鼠经手术并静脉给予6.24×10-8mol/L 11,12-EET,稳定20 min,结扎冠脉复制缺血/再灌注模型。实验分5组:①正常组(norm);②假手术组(sham);③缺血再灌注组(I/R);④短阵缺血预处置组(SI+I/R);⑤11,12-EET预处置缺血/再灌注组(EET+I/R)。采用Western blot法测定心肌细胞外调节的蛋白激酶(ERK1/2)和p38 MAPK的表达程度,并观察再灌注过程中心功能的变化。结果: 再灌注30 min时,I/R组+dp/dtmax%、-dp/dtmax%和LVDP均显著低于sham组、SI+I/R组和EET+I/R组(P<0.05);而I/R组大鼠心肌ERK1/2磷酸化表达明显高于sham组(P<0.05),明显低于SI+I/R组和EET+I/R组(P<0.05);I/R组大鼠心肌p38 MAPK磷酸化表达I/R组显著高于sham组、norm组、SI+I/R及EET+I/R组(P<0.05)。结论:6.24×10-8 11,12-EET mol/L具有保护心功能的作用,这种保护作用可能与大量激活磷酸化ERK1/2和抑制p38 MAPK有关。  相似文献   

19.
 目的:观察银杏达莫注射液预处理对大鼠离体心脏缺血/再灌注损伤的影响,并探讨其可能的作用机制。方法:SD雄性大鼠40只随机分成5组(n=8):正常对照(NC)组、缺血/再灌注(I/R)组、缺血预处理(IPC+I/R)组、银杏达莫注射液预处理(GD+I/R)组和银杏达莫+氯化镧预处理(GD+LaCl3+I/R)组。观察各组相同时点(预灌30 min稳定点,缺血30 min,再灌5 min、30 min、60 min)的心功能指标,包括心率(HR)、左室收缩压(LVSP)和室内压变化速率(±dp/dtmax),同时收集各时点冠脉流出液,检测其中乳酸脱氢酶(LDH)和肌酸激酶(CK)活性。实验结束后检测心肌线粒体Ca2+浓度和α-酮戊二酸脱氢酶(α-OGDH)含量。结果:与I/R组比较,IPC+I/R组和GD+I/R组在心脏再灌注期各项心功能指标均得到改善(P<0.05);心肌LDH和CK的释放量降低(P<0.01);线粒体内Ca2+超载降低(P<0.01),且线粒体内α-OGDH含量升高(P<0.05);而GD+I/R组中银杏达莫对心肌的保护作用被LaCl3抑制(P<0.05)。结论:银杏达莫可能通过抑制钙超载、增强线粒体酶活性以稳定线粒体能量代谢,从而缓解缺血/再灌注诱导的心肌细胞损伤。  相似文献   

20.
Sauchinone has been known to have anti-inflammatory and antioxidant effects. We determined whether sauchinone is beneficial in regional myocardial ischemia/reperfusion (I/R) injury. Rats were subjected to 20 min occlusion of the left anterior descending coronary artery, followed by 2 hr reperfusion. Sauchinone (10 mg/kg) was administered intraperitoneally 30 min before the onset of ischemia. The infarct size was measured 2 hr after resuming the perfusion. The expression of cell death kinases (p38 and JNK) and reperfusion injury salvage kinases (phosphatidylinositol-3-OH kinases-Akt, extra-cellular signal-regulated kinases [ERK1/2])/glycogen synthase kinase (GSK)-3β was determined 5 min after resuming the perfusion. Sauchinone significantly reduced the infarct size (29.0% ± 5.3% in the sauchinone group vs 44.4% ± 6.1% in the control, P < 0.05). Accordingly, the phosphorylation of JNK and p38 was significantly attenuated, while that of ERK1/2, Akt and GSK-3β was not affected. It is suggested that sauchinone protects against regional myocardial I/R injury through inhibition of phosphorylation of p38 and JNK death signaling pathways.  相似文献   

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