胰岛素对大鼠心肌缺血再灌注损伤保护作用及机制研究

目的 探讨胰岛素对大鼠缺血再灌注损伤心肌的保护作用及其保护机制。方法 结扎SD大鼠左冠状动脉前降支（LAD）．建立大鼠缺血再灌注模型，将48只SD雄性大鼠随机分组为：缺血再灌注对照组（18只），假手术组（12只），胰岛素处理组（18只），分别给予生理盐水、冠脉穿线（不结扎）、胰岛素干预。在再灌注结束后，检测心肌组织中丙二醛（MDA）含量、血清中乳酸脱氢酶（LDH）活性、心肌梗死范围（IS／AAR％）及心肌细胞凋亡指数（AI），并进行组间比较。结果 与缺血再灌注对照组相比，胰岛素处理组可明显降低MDA（P〈0．05）、LDH值（P〈0．01），减少心肌IS／AAR％和AI（P〈0．01）。结论 胰岛素对大鼠再灌注心肌损伤具有保护作用，其保护机制可能与抑制细胞凋亡及抗氧自由基作用有关。     

温血逆灌对心肌缺血再灌注损伤的保护作用

本文对１３例风湿性心脏病换瓣手术患者用温血逆灌进行心肌保护，以高效液相色谱检测高能磷酸化合物及其某些降解产物，证明ＡＴＰ和ＰＣｒ含量均呈复跳２０分钟（Ⅳ）＜复跳立即（Ⅲ）＜缺血４０分钟（Ⅱ）＜停跳立即（Ⅰ）的趋势。ＡＤＰ、ＡＭＰ和ＨＹＰＯ具有与上述相反的变化趋势，而ＮＡＤ含量则稍有增高。上述实验结果表明：温血逆灌的心肌中，高能化合物（ＡＴＰ、ＰＣｒ）合成比作者以前用低温高钾稀释血灌注时（正灌＾（１     

褪黑素对大鼠心肌缺血再灌注损伤的保护作用和新机制

目的 观察褪黑素对大鼠心肌缺血再灌注损伤(IRI)的作用,并从细胞坏死方面探讨其可能机制.方法 将48只SD大鼠随机分为4组:假手术组、模型组、褪黑素低剂量(1 mg/kg)组、褪黑素高剂量(5 mg/kg)组,采用冠状动脉左前降支阻断法建立大鼠心肌梗死模型,缺血30 min后再灌注90 min,建立心肌IRI模型.用氯化三苯四唑(TTC)染色法检测心肌梗死面积,并测定左心室舒张末压(LVEDP)和左心室发展压(LVDP)以反映心脏功能.用Western blot检测受体相互作用蛋白激酶3(RIPK3)及磷酸化MLKL的表达水平.结果 心肌IRI后,心梗面积较假手术组显著增加,LVEDP值升高,而LVDP值降低,损伤区RIPK3及磷酸化MLKL蛋白表达水平显著增加(P＜0.01).与IRI组相比,褪黑素可剂量依赖性地减小梗死面积,降低LVEDP值,回升LVDP值,改善心功能,并抑制RIPK3及磷酸化MLKL蛋白的表达水平.结论 褪黑素对大鼠心肌IRI的保护作用与抑制程序性细胞坏死关键蛋白的表达相关.     

绞股蓝总皂甙对大鼠心肌缺血再灌注损伤的保护作用

结扎大鼠冠状动脉40分钟,解除结扎恢复血流再灌注20分钟,复制大鼠心肌缺血/再灌注损伤模型,观察绞股蓝总皂甙(GP)对心肌缺血/再灌注损伤的影响。结果,GP明显提高心肌组织GSH-Px活性,降低心肌MDA含量,使降低的线粒体膜流动性恢复,减轻再灌注导致心肌超微结构损伤。提示,GP对大鼠心肌缺血/再灌注损伤有保护作用,作用机理与抗氧化作用有关。     

牛磺酸对大鼠心脏模拟缺血再灌注损伤的保护作用

在离体大鼠心脏模拟缺血再灌注(I/R)损伤的模型上观察了牛磺酸的心肌保护作用。实验结果发现预先给大鼠牛磺酸灌胃(300mg/kg)三日或再灌注同时给药(20mmol/L),对心肌均有保护作用,明显减少心肌细胞内的Mb、LDH的漏出,降低心肌MDA的生成,减轻细胞内钙的聚集,促进心肌ATP含量的恢复。在本实验条件下预防应用牛磺酸较再灌注的同时应用更为有效,表现为更大程度地减少LDH漏出,抑制心肌MDA生成和钙聚集。结果证明牛磺酸具有心肌保护作用,对于防治心肌I/R损伤可能具有临床应用价值。     

冷钾稀释血逆灌对心肌缺血再灌注损伤的保护作用

本文对７例进行换瓣手术的风湿性心脏病患者，采用冷钾稀释血冠状静脉窦逆行灌注方法保护心肌，同时利用ＨＰＬＣ检测了手术不同时点心肌能量有关物质的变化，并以此为指标评价顺灌与逆灌的保护效果。结果提示，逆灌较顺灌保护效果好。表现为逆灌时，手术过程中各时点（除停跳立即外，缺血４０分钟，复跳立即，复跳２０分钟）ＰＣｒ检测表观值各时点比顺灌时高；ＡＴＰ检测表观值在复跳２０分钟时逆灌明显高于顺灌，ＡＤＰ和ＮＡＤ检     

胡黄连苷Ⅱ对心肌缺血再灌注损伤大鼠的保护作用

目的 观察胡黄连苷Ⅱ对大鼠心肌缺血再灌注损伤(MIRI)的保护作用,并探讨其作用机制.方法 取50只健康SD大鼠,随机分为对照组、I/R模型组、胡黄连苷Ⅱ低、中、高剂量组(2.5、5、10 mg/kg),10只/组,采用手术结扎法构建心肌缺血再灌注损伤模型.采用酶联免疫吸附法检测血清肿瘤坏死因子α(TNF-α)、白介素...     

Ca^2＋预处理对离体大鼠心肌缺血再灌注的保护作用

本文旨在探讨Ｃａ＾２＋预处理对离体大鼠心肌缺血再灌（即停灌复灌）的保护作用，实验应用Ｌａｎｇｅｎｄｏｒｆｆ灌流模型，经房室瓣向左心室内插入一导管球囊，用多导记录仪测量心功能指标。Ｃａ＾２＋预处理方案为３次３０ｓ无Ｃａ＾２＋继１０ｍｉｎ复Ｃａ＾２＋灌流。缺血处理方案为３次５ｍｉｎ停灌继５ｍｉｎ再灌，持续缺血方案为３０ｍｉｎ停灌继２０ｍｉｎ再灌，实验结果显示，对照组３０ｍｉｎ停灌后，再灌２０ｍｉｎ时支     

乙酰半胱氨酸对糖尿病大鼠心肌缺血再灌注损伤的保护作用及其机制

目的: 观察乙酰半胱氨酸对糖尿病大鼠心肌缺血/再灌注后导致的细胞凋亡的影响,探讨其机制.方法: 链尿佐菌素诱导糖尿病大鼠模型,随机分为假手术组、缺血/再灌注组和缺血/再灌注+乙酰半胱氨酸治疗组.组织匀浆检测心肌组织还原型谷胱甘肽(GSH)、氧化型谷胱甘肽(GSSG)含量和半胱氨酸天冬氨酸蛋白酶-3(Caspase-3)的活性;脱氧核糖核苷酸末端转移酶介导的缺口末端标记(TUNEL)和琼脂糖凝胶电泳检测DNA片段化两种方法检测心肌细胞凋亡并计算凋亡指数.结果: 缺血/再灌注后,糖尿病和非糖尿病组均出现明显的心肌细胞凋亡,同时伴有GSH含量降低,GSSG含量和Caspase-3的活性升高,上述变化糖尿病组比非糖尿病组更明显(P<0.05);乙酰半胱氨酸干预的糖尿病和非糖尿病大鼠的心肌细胞凋亡均减轻,同时伴有GSH含量上升,GSSG含量和Caspase-3的活性下降,上述变化非糖尿病组比糖尿病组更明显(P<0.05).结论: 乙酰半胱氨酸干预可以通过提高心肌GSH含量、降低Caspase-3的活性减轻糖尿病和非糖尿病大鼠缺血/再灌注引起的心肌细胞凋亡,对缺血/再灌注心肌有保护作用,但糖尿病组的疗效低于非糖尿病组.     

明胶酶在大鼠心肌缺血-再灌注损伤中的作用

目的：探讨明胶酶A（MMP-2）及明胶酶B（MMP-9）在大鼠心肌缺血-再灌注损伤（I/R）中的作用。方法：采用大鼠心肌缺血再灌注损伤模型，大鼠分7组：对照组（n=5），单纯缺血30 min组，缺血30 min再灌注1 min、5 min、10 min、20 min和30 min组（各组n=6）。利用Gelatin-PAGE观察外周血中MMP-2及MMP-9表达，并用免疫组织化学法观察MMP-2及MMP-9在心肌中表达情况。结果：单纯30 min缺血组（I_{30 min}）的MMP-2及MMP-9表达高于对照组（P<0.05）；在再灌注不同时间内，MMP-2表达不一：再灌注1 min（R_{1 min}）开始升高，再灌注5 min（R_{5 min}）达高峰，随后开始下降，再灌注30 min（R_{30 min}）为基线，其中R_{5 min}、R_{10 min}的MMP-2高于对照组及I_{30 min}组（P<0.05），而MMP-9在再灌注组间表达上则无显著差异（P>0.05）。免疫组织化学法显示明胶酶主要在细胞浆及细胞间质中表达，而且实验组强于对照组。结论：明胶酶的异常表达可能参与心肌缺血过程，其中MMP-2可能参与了大鼠心肌再灌注损伤的早期过程。     

前列地尔预处理对大鼠心肌缺血再灌注损伤的心脏超微结构的保护作用

目的　观察比较前列地尔预处理及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。方法　动物分为假手术对照组、缺血再灌注组、经典缺血预处理组、前列地尔预处理早期保护组及延迟保护组 ,透射电镜观察心肌超微结构的变化 ,同时用黄嘌呤氧化酶法测定心肌组织的超氧化物歧化酶 (SOD)活性和用硫代巴妥酸法测定丙二醛 (MDA)含量。结果　前列地尔预处理及经典缺血预处理均有保护心肌超微结构和抗氧化效应 ,与模型组相比 ,经典缺血预处理组、前列地尔预处理早期保护组及延迟保护组明显降低缺血再灌注后的心肌MDA含量 (P<0 .0 5 和升高T SOD (P<0 .0 5 水平。结论　前列地尔预处理对在体大鼠缺血 /再灌注心肌损伤具有保护效应 ,能模拟经典缺血预处理心肌保护效应。     

Expression of caveolin-1 is correlated with Akt-1 in colorectal cancer tissues

Caveolin is a major component of caveolae which is a plasma membrane microdomain. The emerging role of caveolin in tumorigenesis was based mainly on in vitro experiments with cancer cell lines. We performed semi-quantitative RT-PCR for caveolin, Akt and EGFR to understand the role of caveolins in colorectal tumor biology. Cancer tissue samples and the neighboring normal colon mucosa were obtained from 95 colorectal cancer patients who underwent operations at Ewha Womans University Mokdong Hospital. With these fresh tissues, semi-quantitative RT-PCR was performed by coamplification of the gene for caveolin-1, EGFR and Akt-1 with beta-actin. The average age was 60.21+/-13.33 years old, and sex ratio was 1.44:1. Caveolin-1 is more expressed in tumors than normal mucosa (P=0.025). The expression of caveolin-1 and Akt-1 had a definitive positive relationship (P=0.002). But, the expression of caveolin-1 and EGFR was not significantly related. We could not find correlations between caveolin-1 expression and clinical factors. In conclusion, caveolin-1 is more expressed in cancer tissues than normal colon and related with Akt-1, not with EGFR expression in colorectal cancer tissues, which suggests that signaling for caveolin-1 affects Akt-1 activation, but this reaction is not initiated by EGFR stimulation in colon cancer.     

前列地尔预处理对大鼠心肌缺血再灌注损伤的保护性作用

目的本实验采用酶组织化学法观察前列地尔预处理对大鼠心肌缺血再灌注损伤是否有保护性,并探讨其可能机理。方法选用275±25g的SD雄性大白鼠,随机分为6组,每组8只。假手术对照组(A),心肌缺血再灌注模型组(B),经典缺血预处理组(C),前列地尔脂肪乳剂早期保护组(D),前列地尔脂肪乳剂延迟保护组(E),前列地尔脂肪乳剂在缺血前72h应用组(F)。采用酶组织化学方法观察心肌过氧化氢酶及琥珀酸脱氢酶表达。结果与模型组相比,经典缺血预处理组、前列地尔预处理早期保护组及延迟保护组心肌过氧化氢酶及琥珀酸脱氢酶明显升高(p<0.05),且早期保护作用强于延迟作用。结论前列地尔预处理对大鼠心肌损伤具有早期和延迟保护作用。     

黄芪对大鼠肾缺血再灌注损伤的保护作用

目的 :研究中药黄芪注射液对大鼠肾缺血再灌注损伤的保护作用。方法 :复制大鼠肾缺血再灌注损伤模型 ,用药治疗 ,观察肾组织病理变化 ,测定血清和肾组织超氧化物歧化酶 (SOD )、丙二醛(MDA)含量。结果 :肾缺血 1h灌注 15min后 ,肾组织出现明显病理改变 ;血清和肾组织SOD活性下降 ,MDA含量升高。应用黄芪注射液治疗后 ,血清和肾组织SOD活性升高 ,MDA含量下降 ,肾组织病理变化有所改善。结论 :黄芪注射液具有减轻脂质过氧化反应、清除自由基的作用 ,这可能是黄芪注射液减轻肾缺血再灌注损伤的作用机制之一。     

Protective Effect of Ebselen on Ischemia-reperfusion Injury in Epigastric Skin Flaps in Rats

The purpose of this study was to determine the role of oxidized diacylglycerol (DAG) and the molecular mechanism underlying ischemia-reperfusion (I/R) injury in rat skin flaps. The protective effect of ebselen on the viability of rat skin flaps with I/R injury was investigated. Flaps were designed and raised in the left inguinal region. Then, a microvascular clamp was applied to the vascular pedicle and reperfused after 6 hr. After 7 days of I/R (I/R group), the skin flap survival area ratio was significantly reduced compared to the normal skin. The administration of ebselen significantly improved the ratio compared to the I/R group. The flap survival area ratio of the I/R + ebselen group was significantly improved compared to the I/R + vehicle group. In the I/R + ebselen group, the oxidized DAG content and intensity of phosphorylated PKCα and PKCδ were significantly lower compared to the I/R + vehicle group. Furthermore, the inflammatory response was suppressed in the I/R + ebselen group compared to the I/R + vehicle group. These results indicate that ebselen is useful as a preventive and therapeutic agent for skin flap necrosis caused by I/R, because of reduction and elimination of oxidized DAG.     

Age-related differences in the des IGF-I-mediated activation of Akt-1 and p70 S6K in mouse skeletal muscle

The ability of des IGF-I to activate Akt-1 and p70 S6K in skeletal muscle with or without acute endurance exercise was examined in young and old mice. Mice were sacrificed 12 h after a moderate intensity treadmill run following an interperitoneal injection of des-IGF-I or saline. Blood and skeletal muscle were collected and IGF-I receptor, Akt-1 and p70 S6K protein contents and their phosphorylation status were determined. Injection of des IGF-I similarly decreased plasma glucose concentration in both young (P<0.01) and old mice (P<0.01) whereas plasma insulin and total IGF-I levels of young and old mice were not significantly changed by des IGF-I. Total IGF-I receptor protein and IGF-1 receptor phosphorylation were lower in aged mice (P<0.05). Basal phosphorylation of Akt-1 was lower in aged skeletal muscle (P<0.01) and this was not caused by changes in Akt-1 protein. In both young (P<0.01) and aged (P<0.05) mice, des IGF-I significantly increased the phosphorylation of Akt-1 at Ser 473. However, a des IGF-I-mediated increase in the p70 S6K phosphorylation (P<0.01) was only seen in young mice. Prior exercise decreased the total plasma IGF-I level in the presence of des IGF-I in aged mice. Des IGF-I-mediated Akt-1 and p70 S6K phosphorylation was not changed by exercise in either young or old mice. It is concluded that there was an aging-related resistance at the p70 S6K level in mouse skeletal muscle that could not be restored by prior exercise and this resistance is associated with lower IGF-I receptor number and Akt-1 phosphorylation in the aged skeletal muscle.     

Effects of CXCR4 Gene Transfer on Cardiac Function After Ischemia-Reperfusion Injury

Acute coronary occlusion is the leading cause of death in the Western world. There is an unmet need for the development of treatments to limit the extent of myocardial infarction (MI) during the acute phase of occlusion. Recently, investigators have focused on the use of a chemokine, CXCL12, the only identified ligand for CXCR4, as a new therapeutic modality to recruit stem cells to individuals suffering from MI. Here, we examined the effects of overexpression of CXCR4 by gene transfer on MI. Adenoviruses carrying the CXCR4 gene were injected into the rat heart one week before ligation of the left anterior descending coronary artery followed by 24 hours reperfusion. Cardiac function was assessed by echocardiography couple with 2,3,5-Triphenyltetrazolium chloride staining to measure MI size. In comparison with control groups, rats receiving Ad-CXCR4 displayed an increase in infarct area (13.5% ± 4.1%) and decreased fractional shortening (38% ± 5%). Histological analysis revealed a significant increase in CXCL12 and tumor necrosis factor-α expression in ischemic area of CXCR4 overexpressed hearts. CXCR4 overexpression was associated with increased influx of inflammatory cells and enhanced cardiomyocyte apoptosis in the infarcted heart. These data suggest that in our model overexpressing CXCR4 appears to enhance ischemia/reperfusion injury possibly due to enhanced recruitment of inflammatory cells, increased tumor necrosis factor-α production, and activation of cell death/apoptotic pathways.Coronary artery disease is a leading cause of death in the United States. Acute myocardial infarction (MI) is a catastrophic manifestation of coronary artery disease that strikes nearly one million Americans each year.^1,2,3 The mainstay of current therapy in acute MI is the restoration of blood flow (reperfusion) to the affected area through thrombolytic therapy or angioplasty. This reperfusion, although key to myocyte survival, is also associated with myocardial injury.² One component of reperfusion is the influx of inflammatory cells into the heart. These inflammatory cells are believed to cause further damage to the heart by their release of a variety of enzymes and other factors.^4,5 However, in recent years, there has been an effort to maximize stem cell recruitment to speed repair of injured myocardium. Investigators have focused on the use of a chemokine, CXCL12 (also known as stromal cell–derived factor-1), which is the main functional ligand for CXCR4, as a new therapeutic modality. However, to date, several human clinical trials of stem cell therapy have shown limited cardiac benefit to individuals suffering from MI.⁶Chemokines are a super family of low-molecular-weight proteins (8 to 10 kDa) that have been subdivided into families on the basis of the position of their cysteine residues. There are currently 46 ligands that bind to 18 G protein–coupled receptors.⁷ Although chemokines are key regulators of leukocyte migration and host defense pathways, excessive production of chemokines has been implicated in the inflammatory components of numerous diseases including chronic heart failure and ischemia-induced myocardial injury.^8,9,10CXCR4 is a 37-kDa G protein–coupled receptor, located principally at the plasmalemma of cardiac myocytes. CXCL12, the predominant CXCR4 ligand, is constitutively expressed in myocardium, detectable in the serum, and is increased early post myocardial infarction.¹¹ Expression of CXCR4 is increased in the myocardium of patients with heart failure.⁹ Both CXCR4 and CXCL12 are expressed and functional in cardiomyocyte.¹² Whereas the significance of CXCR4 and CXCL12 in cardiac development has already been established,^13,14 there is a paucity of information regarding chemokine receptor signaling on adult cardiac myocytes. It was recently demonstrated that activation of CXCR4 results in a direct negative inotropic modulation of cardiac myocyte function in vitro implicating an important role for CXCR4 and its ligand, CXCL12, in heart function.¹⁵ In the present study, we explored the effects of CXCR4 gene transfer in a rat cardiac ischemia-reperfusion (IR) injury model. We hypothesized that overexpression of CXCR4 in the heart will increase the influx of inflammatory cells into ischemic tissue, enhance host response to oxygen free radicals, and impair the cardiac pump function. In support of this hypothesis, we examined the mechanistic role of CXCR4 in the pathophysiology of myocardial ischemic injury in vivo. Our data demonstrated that CXCR4 overexpression exacerbates the hemodynamic dysfunction and structural deterioration in a rat model of ischemic reperfusion injury. CXCR4 gene transfer increased the infarct size and decreased the cardiac pump function. Collectively, we show that overexpression of CXCR4 plays a potentially critical role dictating the outcome of ischemic reperfusion injury.     

石榴果浓缩物对大鼠免疫性结肠损伤的保护作用

目的:研究石榴果浓缩物对大鼠免疫性结肠损伤的保护作用。方法:建立大鼠免疫性结肠炎模型,采用石榴果浓缩物灌胃治疗并与阳性药物5-氨基水杨酸(5-ASA)及空白组对照。10天后,参照有关标准评价各组大鼠结肠粘膜损伤指数(CMDI),检测结肠髓过氧化物酶(MPO)、谷胱甘肽过氧化物酶(GSH-PX)、超氧化物歧化酶(SOD)活性,丙二醛(MDA)含量及肿瘤坏死因子(TNF)、血清白细胞介素-6(IL-6)、白细胞介素-10(IL-10)水平。结果:石榴果浓缩物300、500、1000mg/kg三种浓度和5-ASA均能不同程度降低结肠损伤大鼠CMDI、MPO活性、减少MDA含量,提高GSH-PX、SOD活性,使显著升高的TNF、IL-6水平下降、降低的IL-10水平升高,且呈一定量效关系。结论:石榴果浓缩物通过免疫调节及抗脂质过氧化对免疫性损伤结肠进行修复,抑制结肠炎症反应。     

Protective Effects of Acupuncture in Cardiopulmonary Bypass-Induced Lung Injury in Rats

Acute lung injury caused by cardiopulmonary bypass (CPB) increases the mortality after cardiac surgery. Our previous clinical study suggested that electroacupuncture (EAc) has a protective effect during CPB, but the mechanism was unclear. So, we design this study to investigate the effects of EAc on CPB-induced lung injury and the underlying mechanism. Male Sprague Dawley rats were randomly divided into control, CPB, and CPB + EAc groups. A lung injury model was created by CPB surgery to serve as the CPB group, and EAc (2/100 Hz) was used before CPB in the CPB + EAc group. Lung tissue was collected at 0.5, 1, and 2 h after CPB. Pulmonary malondialdehyde (MDA) concentrations as well as superoxide dismutase (SOD), myeloperoxidase (MPO), and caspase-3 activity were determined. c-Jun N-terminal kinase (JNK), ERK, p38 and cleaved caspase 3 in the lung were analyzed by western blotting. A549 cells were treated by rat serum from the CPB and CPB + EAc groups, and cleaved caspase-3 activity was detected by fluorescent immunohistochemistry. CPB significantly increased the MPO activity, MDA content, apoptosis, caspase-3 activity, and phosphorylated p38 but decreased SOD activity compared with the control group. EAc significantly increased SOD activity at 0.5 and 2 h (p < 0.01 vs CPB) and reduced CPB-induced histological changes, MPO activity at 1 and 2 h (p < 0.05 vs CPB), MDA content at 2 h (p < 0.05 vs CPB), caspase-3 activity at 1 h (p < 0.05 vs CPB), and phosphorylated p38 and JNK at 0.5 h after CPB. The serum from the CPB group increased more positive staining cells of cleaved caspase-3 than that from the CPB + EAc group. EAc reversed the CPB-induced lung inflammation, oxidative damage, and apoptosis; the mechanism may involve decreased phosphorylation of p38 along with caspase-3 activity and activation.