兔肢体缺血-再灌流对心肌细胞凋亡及心功能的影响

目的观察肢体缺血-再灌流时心功能的变化和心肌细胞凋亡状况。方法健康家兔30只,随机均分为假手术对照组(SC)、单纯缺血组(Ⅰ)和缺血再灌流组(JR)。免疫组化法检测心肌组织Bcl-2和Bax蛋白表达；原位缺口末端标记法(TUNEL)检测心肌细胞凋亡；比色法测定心肌组织超氧化物岐化酶(SOD)和髓过氧化物酶(MPO)活性-丙二醛(MDA)含量,测定血清乳酸脱氢酶(LDH)活性；通过生理记录仪观察心功能指标；光镜下观察心肌病变。结果IR组心肌组织细胞凋亡指数明显高于其它两组,Bax蛋白表达明显增多,同时IR组心肌组织SOD活性降低,MDA含量增高,血清LDH活性增高,左心室功能下降,且MDA含量与LDH活性、Bax蛋白表达和凋亡指数之间呈显著正相关,光镜下可见心肌病变。结论肢体缺血-再灌流可造成心肌损伤,心功能下降,与氧化损伤和细胞凋亡有关。     

生长激素对大鼠心肌缺血再灌注后心肌细胞凋亡的作用

目的:研究生长激素对大鼠心肌缺血再灌注(myocardialischemiareper-fusion,MIR)后心肌细胞凋亡及其机制的影响。方法:24只大鼠随机分为3组,假手术组(仅手术24h)、MIR组、生长激素组,每组8只。后两组均缺血30min,再灌注24h,其中生长激素组的每只大鼠每天皮下肌注生长激素1U/kg,连续7d。前两组每只大鼠相应皮下肌注生理盐水0.5mL/d。以TUNEL法检测心肌细胞凋亡情况,DAB免疫组化法检测心肌细胞核NF-κB蛋白、心肌细胞胰岛素样生长因子-1(insulin-likegrowthfactor-1,IGF-1)的表达并进行心肌组织病理学检查。结果:大鼠MIR24h后心肌细胞凋亡指数明显上升犤MIR组(16.17±5.02)%,假手术组为0犦(t=9.111,P<0.05)。心肌细胞核NF-κB蛋白表达呈阳性染色指数(positiveindex,PI)明显升高犤MIR组(18.60±7.21)%,假手术组为0犦(t=7.297,P<0.05)。心肌病理检查见心肌缺血区呈大小不一的坏死孔灶,缺血心肌间有炎症细胞浸润,心肌排列不整齐(HE染色),而生长激素组心肌细胞凋亡率及心肌细胞核NF-κB蛋白PI明显好于MIR组(t=4.302,2.943,P<0.05)。生长激素组IGF-1着色强度明显高于另外两组(χ2=12.443,9.167,P<0.05),心肌细胞间炎症细胞也明显减少,坏死灶也少于MIR组。结论:生长激素可以减少MIR后心肌细胞凋亡及细胞核NF-κB     

依达拉奉对大鼠缺血/再灌注心肌细胞凋亡的影响

目的：观察依达拉奉对心肌缺血／再灌注后心肌细胞凋亡的影响。方法：选择30只健康SD大鼠，采用结扎冠状动脉左前降支后再通的方法复制心肌缺血再灌注的动物模型，随机分为假手术组（n=10）、缺血／再灌注（I／R）组（n=10）和药物（依达拉秦）组（n=10）。检测各组3h后心肌组织的超氧化物歧化酶（SOD）和丙二醛（MDA）的含量。并用免疫组化法测定局部凋亡相关因子Bcl-2、Fas的表达，比较各组间差异。结果：与假手术组比较，I／R组中反映氧化损伤程度的MDA明显升高（P〈0．01），抗氧化酶SOD则明显减少（P〈0．01），Fas含量升高（P〈0、01），Bcl-2含量明显减少（P〈0、01）；药物组较I／R组MDA含量明显减少（P〈0．01），SOD活性显著增加（P〈0．01），Fas含量明显降低（P〈0，05），Bcl-2含量明显增加（P〈0．01）。结论：依达拉奉具有抗心肌缺血再灌注损伤作用，其机制可能是通过调节Bcl-2和Fas介导的细胞凋亡而实现     

二氮嗪对大鼠心肌缺血-再灌流损伤细胞凋亡的影响

目的观察二氮嗪对缺血-再灌流心肌细胞凋亡,以及对Bax、Bcl-2和Caspase-3表达的影响。方法21只SD大鼠随机分为假手术组(sham operation,SO),缺血-再灌流组(ischemia/reperfusion,IR)和二氮嗪处理组(Diazoxide,DI)。SO组和IR组静脉注射相应量溶媒,DI组12.5 mg/kg剂量静脉注射二氮嗪。10min后SO组不结扎前降支,4 h后取心脏,而IR组和DI组结扎前降支2 h,再灌流2 h。采用TUNEL法和免疫组化法检测缺血心肌细胞凋亡和Bax、Bcl-2、Caspase-3表达,及心肌梗死范围。结果与SO组相比,IR和DI组心肌细胞凋亡率显著增加(P<0.05),Bax、Bcl-2和Caspase-3蛋白阳性细胞指数明显升高(P<0.05);与IR组相比,DI组明显降低心肌细胞凋亡率(P<0.05)和Bax,Caspase-3蛋白阳性细胞指数(P<0.05),增加Bcl-2蛋白阳性细胞指数(P<0.05)。IR组心肌梗死范围为(36.9±2.3)%,DI组为(20.0±8)%,两组差异有显著性(P<0.05)。结论二氮嗪通过上调Bcl-2表达,下调Bax及Caspase-3表达而减少在体大鼠缺血-再灌流损伤心肌细胞凋亡。     

老年脑缺血/再灌注大鼠炎症级联反应变化及其意义

目的观察老年脑缺血／再灌注（I／R）大鼠肿瘤坏死因子-α（TNF—α）、细胞间黏附分子-1（ICAM-1）和血管内皮黏附分子-1（VCAM-1）及ICAMmRNA表达的变化，探讨老年脑I／R损伤的病理生理机制。方法36只青年（5～6月龄）SD大鼠和36只老年（20～21月龄）SD大鼠，均为雄性，采用随机方法将其分别分为青年假手术组、老年假手术组、青年模型组和老年模型组。两个模型组又各随机分为缺血3h（13h）和I／R1、3、6、12d时间点，每个时间点6只大鼠。采用大脑中动脉栓塞（MCAO）方法复制脑I／R损伤动物模型，观察各组大鼠各时间点神经功能障碍评分，脑组织含水量，脑组织病理学，TNF—α、VCAM-1、ICAM-1及ICAMmRNA表达的变化。结果老年假手术组TNF—α表达高于青年假手术组；青年模型组和老年模型组脑组织含水量（I／R1～6d）、神经功能障碍评分（I3h及I／R1～12d）、TNF—α（I3h及I／R1～6d）、VCAM-1（I3h及I／R1～12d）、ICAM-1（I3h及I／R1～6d）及ICAM-1mRNA（I3h及I／R1～12d）表达均高于同龄假手术组；老年模型组神经功能障碍评分（I3h、I／R6d）、TNF—α（I／R1d、3d）、VcAM-1（I／R 3d、6d）、ICAM-1（I3h、I／R1d）及IcAM-1 mRNA（I／R1～6d）表达均高于青年模型组。结论脑I／R损伤与TNF—α、VCAM-1、ICAM-1表达增加有关，老年脑I／R损伤严重可能为随着增龄TNF—α和黏附分子表达增强所致。     

老龄大鼠脑缺血-再灌注神经细胞凋亡变化规律研究

目的　比较研究青年与老龄大鼠脑缺血再灌注 (I/R)后超微结构与神经细胞凋亡特征。方法　采用线栓法建立急性局灶性脑缺血再灌注损伤模型 ,观察缺血 3h及再灌注 3、6、12、2 4和 72 h脑组织超微结构变化及细胞凋亡。结果　老龄大鼠脑缺血 3h和 I/R12 h脑梗死面积较青年大鼠增大。随着 I/R时间延长 ,脑组织细胞损伤逐步加重 ,老龄大鼠较青年大鼠严重。细胞凋亡随着 I/R时间延长而明显增加 ,老龄大鼠出现的早、持续时间长。结论　老年脑缺血再灌注脑梗死面积增大、超微结构损伤和细胞凋亡出现得早且严重。     

氢吗啡酮后处理经PI3K/Akt通路减轻大鼠心肌缺血-再灌注细胞凋亡

目的:探讨PI3K/Akt信号通路在氢吗啡酮后处理减轻大鼠心肌缺血-再灌注细胞凋亡中的作用。方法:健康雄性SD大鼠40只,按照随机数表法随机分为5组,每组8只,假手术组（Sham组）、缺血-再灌注组（I/R组）、缺血-再灌注+氢吗啡酮组（I/R+H组）、缺血-再灌注+PI3K抑制剂组（I/R+W组）、缺血-再灌注+氢吗啡酮+ PI3K抑制剂组（I/R+ H+ W组）。采用左冠状动脉前降支结扎30 min、再灌注120 min的方法建立心肌缺血-再灌注损伤模型。实验结束后,用TTC染色法测心肌梗死面积;用比色法检测血清乳酸脱氢酶（LDH）漏出量;末端标记法（TUNEL）测心肌细胞凋亡;Western blot法检测p-Akt、Bcl-2、Bax蛋白表达。采用SPSS 13.0软件行统计分析。采用单因素方差分析进行组间比较。结果:与Sham组比较,I/R组心肌梗死面积、血清LDH漏出量及心肌细胞凋亡增多,p-Akt表达和Bax表达上调,Bcl-2表达下调（ P<0.05）;与I/R组比较,I/R+H组心肌梗死面积、血清LDH漏出量及心肌细胞凋亡减少,心肌p-Akt及Bcl-2表达上调,Bax表达下调（ P<0.05）;与I/R+H组比较,I/R+H+W组心肌梗死面积、血清LDH漏出量及心肌细胞凋亡增多,p-Akt表达和Bcl-2表达下调,Bax表达上调（ P<0.05）。 结论:氢吗啡酮后处理可减轻心肌缺血-再灌注引起的心肌细胞凋亡,其心肌保护机制可能与激活PI3K/Akt信号通路有关。     

miR-486 attenuates cardiac ischemia/reperfusion injury and mediates the beneficial effect of exercise for myocardial protection

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MiR-486 attenuates cardiomyocyte apoptosis and cardiac ischemia/reperfusion (I/R) injury through targeting PTEN and FoxO1 and activating Akt/mTOR pathway, and mediates the beneficial effect of exercise for myocardial protection.     

Active site inhibited factor VIIa attenuates myocardial ischemia/reperfusion injury in mice

Summary.  Background:  Inhibition of specific coagulation pathways such as the factor VIIa-tissue factor complex has been shown to attenuate ischemia/reperfusion (I/R) injury, but the cellular mechanisms have not been explored. Objectives:  To determine the cellular mechanisms involved in the working mechanism of active site inhibited factor VIIa (ASIS) in the protection against myocardial I/R injury. Methods:  We investigated the effects of a specific mouse recombinant in a mouse model of myocardial I/R injury. One hour of ischemia was followed by 2, 6 or 24 h of reperfusion. Mouse ASIS or placebo was administered before and after induction of reperfusion. Results:  ASIS administration reduced myocardial I/R injury by more than 40% at three reperfusion times. Multiplex ligation dependent probe amplification (MLPA) analysis showed reduced mRNA expression in the ischemic myocardium of CD14, TLR-4, interleukin-1 (IL-1) receptor-associated kinase (IRAK) and IκBα upon ASIS administration, indicative of inhibition of toll-like receptor-4 (TLR-4) and subsequent nuclear factor-κB (NF-κB) mediated cell signaling. Levels of nuclear activated NF-κB and proteins influenced by the NF-κB pathway including tissue factor (TF) and IL-6 that were increased after I/R, were attenuated upon ASIS administration. After 6 and 24 h of reperfusion, neutrophil infiltration into the area of infarction was decreased upon ASIS administration. There was, however, no evidence of an effect of ASIS on apoptosis (Tunel staining and MLPA analysis). Conclusions:  We conclude that the diminished amount of myocardial I/R injury after ASIS administration is primarily due to attenuated inflammation-related lethal I/R injury, probably mediated through the NF-κB mechanism.     

Inhalation of NO during myocardial ischemia reduces infarct size and improves cardiac function

Purpose

Bioactive NO carriers in circulating blood formed during NO inhalation selectively distribute blood flow to areas in need, and may thus improve collateral perfusion to the area-at-risk in acute myocardial infarction (AMI). Here, we tested the hypothesis that NO inhalation during the ischemic phase of AMI may improve left ventricular function and reduce infarct size in rats.

Methods

Following left anterior descending coronary artery (LAD) occlusion, rats received 50?ppm NO for 2?h of ischemia, during subsequent 3?h of reperfusion, or for 5?h of ischemia and reperfusion. Effects of inhaled NO were compared to those of intravenous nitrite as a putative carrier formed during NO inhalation. Downstream signaling via soluble guanylate cyclase was tested by inhibition with 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ).

Results

NO inhalation during myocardial ischemia increased left ventricular systolic pressure, contractility, relaxation, and cardiac output, and reduced myocardial infarction size and area-at-risk as compared to untreated controls. NO inhalation during the reperfusion phase caused a comparable protective effect. Combined inhalation during ischemia and reperfusion did not further improve left ventricular hemodynamics, but had an additive protective effect on the myocardial area-at-risk. NO inhalation increased circulating nitrite levels, and mimicking of this effect by intravenous nitrite infusion achieved similar protection as NO inhalation during myocardial ischemia, while ODQ blocked the protective NO effect.

Conclusions

Inhalation of NO during myocardial ischemia improves left ventricular function and reduces infarct size by mechanisms that increase levels of circulating nitrite and involve soluble guanylate cyclase. NO inhalation may represent a promising early intervention in AMI.     

Growth hormone improves cardiac function in rats with experimental myocardial infarction

Accumulating evidence suggests from experimental and clinical studies beneficial effects of growth hormone (GH) on contractility, although concomitant cardiac hypertrophy, generally considered to be a cardiovascular risk factor, has also been reported. In the present study, we combine a rat model with impaired cardiac performance after myocardial infarction (MI) with echocardiographic evaluation of GH effects on cardiac structure and function. We have used a rat model with ligation of the left coronary artery in normal, growing male rats resulting in subsequent impaired cardiac performance. After 6 weeks' recovery, blind transthoracic echocardiography was performed to determine infarction size, cardiac geometry and performance. Rats with no signs of myocardial infarction were excluded from the study. After randomization, the rats were treated with daily s.c. injections of saline ( n  = 8) or recombinant human growth hormone (rhGH) ( n  = 6) at a dose of approximately 1 mg kg⁻¹ body weight for 1 week. A new blind echocardiography examination was performed after treatment demonstrating a 13% increase in ejection fraction (EF) and a 50% increase in cardiac index in GH-treated rats compared with control rats ( P  < 0.01). Moreover, GH caused a significant decrease in end-systolic volume. There were no significant changes in left ventricular (LV) or interventricular wall thickness, LV dimensions, heart rate or diastolic function. No effects were seen on LV weight, cardiac insulin-like growth factor (IGF) I, IGF-I receptor and GH receptor mRNA content. GH in a physiological dose improves systolic function in an experimental model of heart failure without signs of hypertrophy, suggesting a potential role as a therapeutic agent in the treatment of heart failure and merits further investigation.     

腺苷预处理对缺血/再灌注心肌细胞凋亡和凋亡蛋白Bcl-2/Bax的影响

目的 研究腺苷预处理对大鼠缺血/再灌注心肌细胞凋亡和凋亡蛋白Bcl-2/Bax的影响.方法 制备缺血/再灌注损伤(I/R)和腺苷预处理的大鼠模型,采用流式细胞仪检测心肌细胞凋亡率和凋亡蛋白Bcl-2和Bax.结果 ①缺血/再灌注组和腺苷组心肌细胞凋亡率均显著高于对照组(P<0.01),而腺苷组凋亡率显著低于缺血/再灌注组(P<0.01).②缺血/再灌注组抗凋亡蛋白Bcl-2表达与对照组比较无明显差别,而腺苷组Bcl-2显著高于缺血/再灌注组和对照组(P<0.01);缺血/再灌注组和腺苷组促凋亡蛋白Bax表达显著高于对照组(P<0.01),而腺苷组Bax低于缺血/再灌注组(P<0.01);缺血/再灌注组和腺苷组Bcl-2/Bax比值显著低于对照组(P<0.01),而腺苷组Bcl-2/Bax比值显著高于缺血/再灌注组(P<0.01).结论 腺苷预处理明显抑制大鼠缺血/再灌注后心肌细胞的凋亡,并使Bcl-2/Bax比值增加.     

Pretreatment with probucol attenuates cardiomyocyte apoptosis in a rabbit model of ischemia/reperfusion

Objective. Apoptosis plays an important role in ischemic reperfusion injury. Probucol is a hypolipidemic agent and has antioxidant activity, which may inhibit the oxidative modification of low‐density lipoprotein cholesterol. Studies have demonstrated that probucol improves left ventricular function, prevents left ventricular dilatation, and reduces cardiac fibrosis. However, the exact mechanism of probucol on the cardioprotective effect is not known. The objective of the present study was to examine the effect of probucol on ischemia/reperfusion‐induced cardiomyocyte apoptosis. Material and methods. Thirty male New Zealand White rabbits were randomly divided into sham, control, and treated groups, each group comprising 10 rabbits. Before establishment of the ischemia/reperfusion model, animals in the treated group were additionally fed daily with probucol (1000?mg per day) for 4 weeks. In the sham group, the heart was exposed after the chest had been opened, but the coronary artery was not ligated. The animals were killed 150?min after the procedure. In the other two groups, the rabbits were subjected to 30‐min of coronary occlusion followed by a 2‐h reperfusion. A blood sample was drawn from the right atrium before the animal was killed. The apoptotic myocytes were detected by terminal deoxynucleotidyl transferase‐mediated dUTP nick‐end labelling. Expression of caspase‐3 and mitochondrial cytochrome c release was detected by immunohistochemical analysis and Western blot analysis. The level of serum superoxide dismutase (SOD) was tested using the xanthine oxidase method, and the content of serum malondialdehyde (MDA) was measured by colorimetry. Results. As compared with the sham group, the control group had a significantly higher apoptotic index ((32.48±4.56)?% versus (0.56±0.18)?%, p<0.01) and serum MDA concentration (2.70±0.64 versus 1.06±0.46?µmol/L, p<0.01), and a significantly lower serum SOD level (144.27±21.69 versus 204.64±16.67?µU/L, p<0.01). Probucol pretreatment apparently caused a decrease in the apoptotic index ((21.64±3.08)?%, p<0.01 versus the sham or control group) and serum MDA concentration (1.95±0.51?µmol/L, p<0.01 versus the sham or control group), and increased the levels of serum SOD (162.61±16.13?µU/L, p<0.01 versus the sham group; p<0.05 versus the control group). The caspase‐3 activation and mitochondrial cytochrome c release in the control group were also higher than those in the treated group (p<0.01). Conclusions. The present study shows that probucol attenuates ischemia/reperfusion‐induced cardiomyocyte apoptosis. The protective effect of probucol on the myocardium may be partly due to its antioxidant activity.     

Pretreatment with probucol attenuates cardiomyocyte apoptosis in a rabbit model of ischemia/reperfusion

OBJECTIVE: Apoptosis plays an important role in ischemic reperfusion injury. Probucol is a hypolipidemic agent and has antioxidant activity, which may inhibit the oxidative modification of low-density lipoprotein cholesterol. Studies have demonstrated that probucol improves left ventricular function, prevents left ventricular dilatation, and reduces cardiac fibrosis. However, the exact mechanism of probucol on the cardioprotective effect is not known. The objective of the present study was to examine the effect of probucol on ischemia/reperfusion-induced cardiomyocyte apoptosis. MATERIAL AND METHODS: Thirty male New Zealand White rabbits were randomly divided into sham, control, and treated groups, each group comprising 10 rabbits. Before establishment of the ischemia/reperfusion model, animals in the treated group were additionally fed daily with probucol (1000 mg per day) for 4 weeks. In the sham group, the heart was exposed after the chest had been opened, but the coronary artery was not ligated. The animals were killed 150 min after the procedure. In the other two groups, the rabbits were subjected to 30-min of coronary occlusion followed by a 2-h reperfusion. A blood sample was drawn from the right atrium before the animal was killed. The apoptotic myocytes were detected by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling. Expression of caspase-3 and mitochondrial cytochrome c release was detected by immunohistochemical analysis and Western blot analysis. The level of serum superoxide dismutase (SOD) was tested using the xanthine oxidase method, and the content of serum malondialdehyde (MDA) was measured by colorimetry. RESULTS: As compared with the sham group, the control group had a significantly higher apoptotic index ((32.48 +/- 4.56) % versus (0.56 +/- 0.18) %, p < 0.01) and serum MDA concentration (2.70 +/- 0.64 versus 1.06 +/- 0.46 micromol/L, p < 0.01), and a significantly lower serum SOD level (144.27 +/- 21.69 versus 204.64 +/- 16.67 microU/L, p < 0.01). Probucol pretreatment apparently caused a decrease in the apoptotic index ((21.64 +/- 3.08) %, p < 0.01 versus the sham or control group) and serum MDA concentration (1.95 +/- 0.51 micromol/L, p < 0.01 versus the sham or control group), and increased the levels of serum SOD (162.61 +/- 16.13 microU/L, p < 0.01 versus the sham group; p < 0.05 versus the control group). The caspase-3 activation and mitochondrial cytochrome c release in the control group were also higher than those in the treated group (p < 0.01). CONCLUSIONS: The present study shows that probucol attenuates ischemia/reperfusion-induced cardiomyocyte apoptosis. The protective effect of probucol on the myocardium may be partly due to its antioxidant activity.     

Erythropoietin attenuates motor impairments induced by bilateral renal ischemia/reperfusion in rats

Neurologic sequelae remain a common and destructive problem in patients with acute kidney injury. The objective of this study was to evaluate the possible neuroprotective effect of erythropoietin (EPO) on motor impairments following bilateral renal ischemia (BRI) in two time points after reperfusion: short term (24 h) and long term (1 week). Male Wistar rats underwent BRI or sham surgery. EPO or saline administration was performed 30 min before surgery (1000 U/kg, i.p.). Explorative behaviors and motor function of the rats were evaluated by open field, rotarod, and wire grip tests. Plasma concentrations of blood urea nitrogen (BUN) and creatinine (Cr) were significantly enhanced in BRI rats 24 h after reperfusion. BRI group had only an increased level of BUN but not Cr 1 week after reperfusion. Impairment of balance function by BRI was not reversed by EPO 24 h after reperfusion, but counteracted 7 days after renal ischemia. Muscle strength had no significant differences between the groups. BRI group had a decrease in locomotor activity, and EPO could not reverse this reduction in both time points of the experiment. Although EPO could not be offered as a potential neuroprotective agent in the treatment of motor dysfunctions induced by BRI, it could be effective against balance dysfunction 1 week after renal ischemia.     

瑞芬太尼后处理对大鼠心肌缺血再灌注细胞凋亡的影响

目的：观察瑞芬太尼后处理对大鼠心肌缺血再灌注细胞凋亡的影响。方法建立60只大鼠心肌缺血再灌注损伤模型。随机分为假手术组（ sham组）、缺血再灌注对照组（ I-R组）和瑞芬太尼不同剂量后处理组（RPO1、RPO2、RPO3组）,RPO1、RPO2、RPO3组再灌注之初分别以2、4、6μg／kg静脉泵注5 min,停止5 min,重复进行三次。实验结束后留取左室心肌组织标本,光镜下观察心肌组织的病理变化;用原位末端转移酶标记法（ TUNEL）检测各组心肌细胞的凋亡指数（AI）;用蛋白免疫印迹（Western blot）法检测各组心肌细胞色素C（CytC）含量。结果①光镜观察：RPO组大鼠的心肌组织损伤程度明显低于I-R组。②RPO组心肌细胞AI明显低于I-R组（P＜0．05）,各RPO组之间心肌组织AI呈剂量依赖性（P＜0．05）。③RPO组心肌细胞胞浆中的CytC含量明显低于I-R组（ P＜0．05）。结论①瑞芬太尼后处理可以减轻大鼠心肌缺血再灌注损伤。②瑞芬太尼三种不同浓度后处理对减轻心肌组织损伤有明显的差别。③瑞芬太尼后处理减轻大鼠心肌缺血再灌注损伤的机制可能与抑制细胞凋亡有关。     

电针预处理对心肌缺血再灌注损伤大鼠线粒体介导的细胞凋亡的影响

目的:探讨电针预处理对心肌缺血再灌注损伤大鼠的线粒体膜电位(△Ψm)及其介导的细胞凋亡的影响。方法:将60只SPF级雄性Wistar大鼠随机分为假手术组(Sham)、缺血再灌注组(MIRI)和电针预处理组(EA),每组20只。Sham组、MIRI组均采用自制鼠衣捆绑,固定于自制鼠台7天,1次/天,20min/次,第8天,Sham组开胸暴露心脏50min后、MIRI组开胸缺血20min再灌注30min后取材。EA组,电针预处理"内关"(双侧)、"足三里"(双侧)、"关元"7天,1次/天,20min/次,第8天开胸缺血20min,再灌注30min后取材。采用TTC染色法测定缺血再灌注损伤后心肌梗死的面积和重量,采用JC-1染色法检测△Ψm的水平,采用实时荧光定量PCR法检测第二个线粒体衍生的半胱氨酸蛋白酶激活剂(Smac/Diablo)、天冬氨酸特异性半胱氨酸蛋白酶-7(Caspase-7)、天冬氨酸特异性半胱氨酸蛋白酶-9(Caspase-9)基因表达水平。结果:(1)心肌梗死面积和重量:与Sham组相比,MIRI组和EA组的梗死面积和重量均增加(均P0.05),且EA组的梗死面积和重量低于MIRI组(均P0.01)。(2)线粒体膜电位:与Sham组相比,MIRI组和EA组的红/绿荧光比值均明显下降(均P0.01);与MIRI组比较,EA组红/绿荧光比值明显升高(P0.01)。(3)Smac/Diablo基因表达水平:与Sham组相比,MIRI组和EA组的Smac/Diablo、Caspase-7、Caspase-9的基因表达水平显著升高(均P0.01);与MIRI组相比,EA组的Smac/Diablo、Caspase-7、Caspase-9基因表达明显下降(均P0.01)。结论:电针预处理可有效缩小心肌梗死范围,提高线粒体膜电位水平,下调促凋亡基因Smac/Diablo、Caspase-7、Caspase-9的表达,电针预处理的保护作用可能是基于改善线粒体膜电位水平、抑制Smac/Diablo介导的线粒体Caspase凋亡通路产生的。     

心肌缺血再灌注过程中氟烷、异氟醚和恩氟烷对心脏功能的影响

目的:研究氟烷、异氟烷和恩氟烷对缺血再灌注心肌功能、代谢自由基的影响。方法:SD大鼠104只,随机数字表法分为13小组,每组8只。采用Lan-gendorff离体大鼠心脏模型。按给药方式又分为对照、氟烷、恩氟烷、异氟烷4大组。①对照组(含4小组):平衡15min组,平衡后续灌15min组,平衡续灌后缺血10min组,平衡续灌缺血25min后复灌30min组。②氟烷组(含3小组):平衡15min后,灌注含1.5肺泡气最低有效浓度(minimalalveolarconcentration,MAC)氟烷灌注液15min组,平衡续灌后缺血10min组,平衡续灌缺血25min复灌含1.5MAC氟烷的灌注液30min组。③恩氟烷和异氟烷组,各包括3小组,情况同氟烷组。各组记录平衡后,给药(或续灌15min)复灌30min左心室收缩压、左心室舒张末期压(leftventriculardiastolicpressure,LVEDP)、左心室发展压、左心室压力升高或降低最大速率、心率、冠状动脉流量(coronaryflow,CF)。实验结束后测定心肌超氧化物歧化酶(superoxidedismutase,SOD)活性、心肌丙二醛含量、高能磷酸盐(ATP)含量。结果:①恩氟烷、异氟烷具有明显扩张冠状动脉的作用。恩氟烷能促进缺血再灌注心肌冠脉流量的恢复。②各用药组明显降低左心室发展压、左心室压力升高速率,升高LVEDP(P均<0.05);缺血再灌注后,氟烷、恩氟烷、异氟烷组的     

血管生成素1基因治疗抑制大鼠急性心肌梗死后心肌细胞凋亡和改善心脏功能

目的:观察心肌内直接注射血管生成素1基因对急性心肌梗死大鼠心肌细胞凋亡的影响,并进一步探讨血管生成素1基因治疗对急性心肌梗死后心室重构的影响。方法:实验于2004-09/2005-09在北京大学医学部生物化学与分子生物学基因组实验室完成。①选用SPF级近交系SD雄性大鼠95只,鼠龄6周,体质量(250±26)g。按随机抽签法将大鼠分为4组:假手术组(n=20)、模型组(n=28)、载体治疗组(n=24)、基因治疗组(n=23)。②结扎大鼠冠状动脉左前降支制备心肌梗死模型。假手术组:只进行前降支下穿线而未进行结扎。模型组:模型制备后于心肌梗死组织周围多点注射磷酸盐缓冲溶液。载体治疗组:模型制备后于心肌梗死组织周围多点注射载体质粒50μg。基因治疗组:模型制备后于心肌梗死组织周围多点注射50μg血管生成素1质粒。③术后3,7,14,28d进行心脏超声心动图检查。采用聚合酶链反应半定量分析外源血管生成素1mRNA和蛋白激酶B的mRNA表达水平。采用DNA片段原位末端标记法观察心肌细胞凋亡情况。④计量资料间差异比较采用单因素方差分析。结果:实验中因死亡等原因脱失15只,共有80只进入结果分析,各检测时间点各组分别为5只。①心肌组织内外源血管生成素1mRNA表达:术后3,7,14,28d,假手术组、模型组、载体治疗组均未见表达,基因治疗组均有表达,并维持在较高水平,注射后28d仍有表达。②心肌细胞凋亡数量:术后3,7,14,28d,基因治疗组心肌细胞凋亡数量均明显少于模型组和载体治疗组(P<0.05)。③心肌组织内蛋白激酶BmRNA表达:术后3,7,14和28d,基因治疗组明显高于模型组和载体治疗组(P<0.01),而模型组和载体治疗组差异不明显(P>0.05)。④心脏功能:术后7,14,28d模型组和载体治疗组的左心室舒张及收缩末期内径均明显大于假手术组和基因治疗组(P<0.05～0.01)。而基因治疗组术后7,14和28d心脏射血分数和左心室短轴缩短率明显高于模型组和载体治疗组(P<0.05)。结论:血管生成素1基因心肌内注射可能通过直接抑制心肌缺血时心肌细胞的凋亡,促进心肌细胞存活,延缓心肌梗死后的心室重构和心力衰竭的进展。     

血管生成素1基因治疗抑制大鼠急性心肌梗死后心肌细胞凋亡和改善心脏功能

目的：观察心肌内直接注射血管生成素1基因对急性心肌梗死大鼠心肌细胞凋亡的影响，并进一步探讨血管生成素1基因治疗对急性心肌梗死后心室重构的影响。方法：实验于2004-09／2005-09在北京大学医学部生物化学与分子生物学基因组实验室完成。①选用SPF级近交系SD雄性大鼠95只，鼠龄6周，体质量（250&;#177;26）g。按随机抽签法将大鼠分为4组：假手术组（n=20）、模型组（n=28）、载体治疗组（n=24）、基因治疗组（n=23）。②结扎大鼠冠状动脉左前降支制备心肌梗死模型。假手术组：只进行前降支下穿线而未进行结扎。模型组：模型制备后于心肌梗死组织周围多点注射磷酸盐缓冲溶液。载体治疗组：模型制备后于心肌梗死组织周围多点注射载体质粒50μg。基因治疗组：模型制备后于心肌梗死组织周围多点注射50μg血管生成素1质粒。③术后3，7，14，28d进行心脏超声心动图检查。采用聚合酶链反应半定量分析外源血管生成素1mRNA和蛋白激酶B的mRNA表达水平。采用DNA片段原位末端标记法观察心肌细胞凋亡情况。④计量资料间差异比较采用单因素方差分析。结果：实验中因死亡等原因脱失15只，共有80只进入结果分析，各检测时间点各组分别为5只。①心肌组织内外源血管生成素1mRNA表达：术后3，7，14，28d，假手术组、模型组、载体治疗组均未见表达，基因治疗组均有表达，并维持在较高水平，注射后28d仍有表达。②心肌细胞凋亡数量：术后3，7，14，28d，基因治疗组心肌细胞凋亡数量均明显少于模型组和载体治疗组（P〈0．05）。③心肌组织内蛋白激酶BmRNA表达：术后3，7，14和28d，基因治疗组明显高于模型组和载体治疗组（P〈0．01），而模型组和载体治疗组差异不明显（P〉0．05）。④心脏功能：术后7，14，28d模型组和载体治疗组的左心室舒张及收缩末期内径均明显大于假手术组和基因治疗组（P〈0．05～0．01）。而基因治疗组术后7，14和28d心脏射血分数和左心室短轴缩短率明显高于模型组和载体治疗组（P〈0．05）。结论：血管生成素1基因心肌内注射可能通过直接抑制心肌缺血时心肌细胞的凋亡，促进心肌细胞存活，延缓心肌梗死后的心室重构和心力衰竭的进展。