山楂提取物对心肌缺血/再灌注损伤的保护作用

目的探讨山楂提取物对大鼠心肌缺血/再灌注损伤（IR I）的保护作用。方法建立大鼠心肌缺血/再灌注模型,在缺血前给予山楂提取物处理,观察动脉压和心律失常的改变,测定血液中乳酸脱氢酶（LDH）、超氧化物歧化酶（SOD）和丙二醛（MDA）的变化。结果预先给予山楂提取物可降低血液中LDH和MDA含量,提高SOD活性,降低血压,有抗心律失常作用。结论山楂提取物对大鼠心肌IR I具有一定的保护作用。     

环孢菌素A拮抗心肌缺血／再灌注损伤的作用

目的：研究环孢菌素A（CsA）拮抗小型猪心肌缺血／再灌注损伤（MI／RI）的作用及可能的机制。方法：经皮球囊封堵冠状动脉左前降支制备小型猪MI／RI模型。将存活的动物随机分为3组：即对照组（n=4）、CsA组（n=6）及他可英司（FK-506）组（n=6）,分别静滴生理盐水100ml、25mg／kgCsA及1mg／kgFK-506。所有动物均经90rain缺血和3h再灌注。通过病理检查评估心肌梗死（MI）面积。用免疫组化染色法检测心肌细胞凋亡。用透射电子显微镜观察各组心肌细胞线粒体的形态。结果：CsA组MI的面积比对照组[（7．5±0．6）cm。粥．（10．5±2．6）cm。]和FK-506组[（7．5±0．6）cm。掷．（9．6±2．7）cm。]明显减少（P〈0．01）;CsA组心肌细胞的凋亡率（％）比对照组[（11．9±1．88）％郴．（22．3±1．66）％]和FK-506组[（11．9±1．88）％郴．（19．2±1．82）％]明显下降（JP〈0．01）。透射电子显微镜检查显示,CsA组能维持线粒体的形态,线粒体坍塌的百分率为（20％±7％）,比对照组（53％±12％）和FK-506组（47％±9％）明显减少（P〈0．01）。结论：CsA可能对MI／RI具有拮抗作用,其机制可能是通过抑制线粒体膜通透性转换孔（mPTP）,保持线粒体形态完整而实现,此种效应不依赖于钙调磷酸酶抑制途径。     

环孢菌素A拮抗心肌缺血/再灌注损伤的作用

目的:研究环孢菌素A(CsA)拮抗小型猪心肌缺血/再灌注损伤(MI/RI)的作用及可能的机制。方法:经皮球囊封堵冠状动脉左前降支制备小型猪MI/RI模型。将存活的动物随机分为3组:即对照组(n=4)、CsA组(n=6)及他可英司(FK-506)组(n=6),分别静滴生理盐水100 ml、25 mg/kg CsA及1 mg/kg FK-506。所有动物均经90 min缺血和3 h再灌注。通过病理检查评估心肌梗死(MI)面积。用免疫组化染色法检测心肌细胞凋亡。用透射电子显微镜观察各组心肌细胞线粒体的形态。结果:CsA组MI的面积比对照组[(7.5±0.6)cm2vs.(10.5±2.6)cm2]和FK-506组[(7.5±0.6)cm2vs.(9.6±2.7)cm2]明显减少(P0.01);CsA组心肌细胞的凋亡率(%)比对照组[(11.9±1.88)%vs.(22.3±1.66)%]和FK-506组[(11.9±1.88)%vs.(19.2±1.82)%]明显下降(P0.01)。透射电子显微镜检查显示,CsA组能维持线粒体的形态,线粒体坍塌的百分率为(20%±7%),比对照组(53%±12%)和FK-506组(47%±9%)明显减少(P0.01)。结论:CsA可能对MI/RI具有拮抗作用,其机制可能是通过抑制线粒体膜通透性转换孔(mPTP),保持线粒体形态完整而实现,此种效应不依赖于钙调磷酸酶抑制途径。     

减阻剂减轻大鼠离体心脏缺血/再灌注损伤的作用

目的 应用减阻剂聚氧化乙烯（polyethylene oxide,PEO）减轻大鼠离体心脏缺血/再灌注（I/R）损伤的作用。方法 Wistar大鼠50只随机分为5组,制备Langendorff离体心脏I/R模型,分为对照组、I/R组、缺血-低剂量PEO再灌注组（低剂量组）、缺血-中剂量PEO再灌注组（中剂量组）、缺血-高剂量PEO再灌注组（高剂量组）。通过多导生理记录仪记录灌注心脏的左心室最大收缩压峰值（LVPSP）、左室舒张末压峰值（LVEDP）、左室内压等容相最大上升及下降速率（+dp/dtmax,-dp/dtmax）、心率、冠脉流量。检测冠脉流出液的乳酸脱氢酶（lactate dehydrogenase,LDH）的含量。结果 再灌注30 min及60 min后,中剂量及高剂量的PEO对I/R心肌的LVPSP、LVEDP、+dp/dtmax、-dp/dtmax均有明显改善作用（P<0.05）。中剂量及高剂量PEO在维持离体心脏的心率方面优于低剂量组和I/R组（P<0.05）,冠脉流出液的容积增加（P<0.05）。应用中剂量及高剂量的PEO灌注后,冠脉流出液中LDH含量明显下降（P<0.05）。结论 PEO作为减阻剂,减低Langendorff离体心脏I/R系统的流体阻力,改善离体心脏的收缩及舒张功能,增加冠脉流出液量,减少心肌细胞损伤,抑制心肌细胞凋亡,对心肌I/R损伤的治疗提供新的研究思路。     

卡维地洛和庚醇对心肌缺血再灌注损伤的保护作用

目的研究卡维地洛（CVD）、庚醇（HT）在缺血再灌注心肌损伤中作用。方法通过建立的心脏缺血再灌注模型，采用2％氯化三苯四唑（TTC）染色测量心肌梗死的重量，监测心肌型肌酸激酶同功酶（CK—MB）、乳酸脱氢酶（LDH）、丙二醛（MDA）和一氧化氮（NO）等的变化。观察CVD、HT对心肌梗死的影响。结果在缺血30min，再灌注6h后，CVD减少CK—MB、LDH及MDA的释放，稳定NO的分泌。HT组在一定程度上也减少了LDH、CK—MB的释放，但对NO、MDA的释放似乎没有太大影响。CVD组的大鼠梗死心肌仅占左心室心肌重量的（6．2±1.1）％，比对照组减少了51.6％。HT组梗死心肌占左心室心肌重量的（7．4±1.0）％，比对照组减少了42．2％。HE常规染色发现CVD组心肌细胞损伤程度明显减轻，粒细胞浸润也明显减少，大部分仅表现肌纤维肿胀和断裂。CVD可以防止内皮型一氧化氮合酶的减少。电镜下，CVD组和HT组心肌润盘肌丝、线粒体等损伤较轻。结论CVD通过B受体拮抗、抗氧化等方面的作用来保护心肌。HT可能是使缝隙连接可逆性解藕联产生心肌保护作用。     

梓醇减轻心肌缺血/再灌注损伤及机制

目的:观察梓醇是否可减轻急性心肌缺血/再灌注（MI/R）损伤。方法:建立大鼠MI/R模型,随机给予生理盐水和梓醇预处理,全程检测大鼠的心脏功能。再灌注末检测大鼠心肌梗死(MI)面积、心肌细胞凋亡指数、血清肌酸激酶和乳酸脱氢酶的活性、心肌组织过氧亚硝基阴离子（ONOO-）、一氧化氮（NO）、超氧化物及超氧化物歧化酶（SOD）的含量。结果:梓醇预处理可明显改善心脏功能,减少心肌梗死面积和心肌细胞的凋亡与坏死（均P<0.05）。同时,ONOO-和超氧化物的产生也显著减少（P<0.05）;NO和SOD的含量显著增加（均P<0.05）。缺血前给予ONOO-清除剂尿酸（UA）显著减少ONOO-生成及MI范围（P<0.05）,但不能额外增强梓醇降低ONOO-及减小MI范围的效应（MI/R+梓醇+UA组 vs. MI/R+梓醇组）。结论:梓醇可抑制ONOO-形成,从而减轻MI/R损伤,其机制可能与增加NO水平及减少超氧化物生成有关。     

丙酮酸对缺血/再灌注大鼠心肌的保护作用

目的:探讨丙酮酸(Pyr)对缺血/再灌注(I/R)大鼠心肌的影响及其可能的机制。方法:30只SD成年大鼠随机分为假手术(Sham)组、I/R组及I/R+Pyr组,每组10只。I/R+Pyr组大鼠于再灌前5 min,开始持续性静脉灌注Pyr 2 h[25 mg/(kg·h)]。再灌注2 h后,利用多道生理记录仪检测大鼠在体血流动力学指标:平均动脉压(MABP)、左室收缩压(LVSP)及左室最大收缩、舒张末压微分(±LV dP/dt max)。采用Western blot方法检测磷酸化-JNK(p-JNK)和总的JNK(t-JNK)表达。用原位缺口末端标记法(TUNEL)评价心肌细胞的凋亡。结果:I/R组的MABP、LVSP、±LV dP/dt max显著低于Sham组(P0.01),Pyr干预可增加I/R后MABP、LVSP及±LV dP/dt max的水平(P0.05)。与Sham组相比,I/R组大鼠左心室p-JNK的水平明显增高(P0.01);而Pyr可降低大鼠左心室p-JNK的水平(P0.01),并抑制心肌细胞凋亡(P0.05)。结论:Pyr可改善I/R大鼠心肌的功能,抑制心肌细胞凋亡,其机制可能与抑制JNK信号的激活有关。     

Metalloproteinase-9 deficiency protects against hepatic ischemia/reperfusion injury

Leukocyte transmigration across endothelial and extracellular matrix protein barriers is dependent on adhesion and focal matrix degradation events. In the present study we investigated the role of metalloproteinase-9 (MMP-9/gelatinase B) in liver ischemia/reperfusion (I/R) injury using MMP-9-deficient (MMP-9(-/-)) animals and mice treated with a specific anti-MMP-9 neutralizing antibody or with a broad gelatinase inhibitor for both MMP-9 and metalloproteinase-2 (MMP-2/gelatinase A). Compared to wild-type mice, MMP-9(-/-) mice and mice treated with an anti-MMP-9 antibody showed significantly reduced liver damage. In contrast, mice treated with a broad gelatinase inhibitor showed rather inferior protection against I/R injury and were characterized by persistent ongoing liver inflammation, suggesting that MMP-2 and MMP-9 may have distinct roles in this type of injury. MMP-9 was mostly detected in Ly-6G and macrophage antigen-1 leukocytes adherent to the vessel walls and infiltrating the damaged livers of wild-type mice after liver I/R injury. Leukocyte traffic and cytokine expression were markedly impaired in livers of MMP-9(-/-) animals and in livers of mice treated with anti-MMP-9 antibody after I/R injury; however, initiation of the endothelial adhesion cascades was similar in both MMP-9(-/-) and control livers. We also showed that MMP-9-specific inhibition disrupted neutrophil migration across fibronectin in transwell filters and depressed myeloperoxidase (MPO) activation in vitro. CONCLUSION: These results support critical functions for MMP-9 in leukocyte recruitment and activation leading to liver damage. Moreover, they provide the rationale for identifying inhibitors to specifically target MMP-9 in vivo as a potential therapeutic approach in liver I/R injury.     

Gentamicin effects on renal ischemia/reperfusion injury.

This study assessed gentamicin's effects on ischemia/reperfusion renal injury to better understand when and how it worsens postischemic acute renal failure. Rats were subjected to 25 minutes of renal pedicle occlusion with and without preischemic (15-minute) or postischemic (15-minute or 8-hour) gentamicin treatment (100 mg/kg, by itself a subtoxic dose). Gentamicin's impact on hypoxia/reoxygenation injury to isolated rat proximal tubular segments was also assessed. Preischemic and postischemic gentamicin worsened the severity of acute renal failure to the same degree, suggesting that pretreatment induces its effect in the reperfusion period. Gentamicin paradoxically lessened hypoxic damage to proximal tubular segments (assessed by lactate dehydrogenase release), again implying no adverse impact on oxygen deprivation-induced tubular injury. From 0-4 hours of reperfusion, gentamicin approximately halved ATP/ADP ratios (due to increased ADP), indicating a drug-induced defect in cellular energetics. This abnormality temporally correlated with evolving morphological damage. Although antioxidants (deferoxamine and sodium benzoate) have been reported to protect against pure aminoglycoside nephrotoxicity, they did not mitigate gentamicin's adverse impact on postischemic acute renal failure. Gentamicin did not influence ischemia/immediate reperfusion deacylation/reacylation (assessed by renal free fatty acid content) despite its known antiphospholipase activity. Although in the normal kidney gentamicin preferentially accumulated in cortex, in the postischemic kidney, both cortex and outer medullary stripe developed striking (approximately threefold to fivefold) and comparable gentamicin increments. In conclusion, gentamicin appears to exacerbate postischemic acute renal failure by adversely influencing the reperfusion, not the ischemic injury, process. This may occur because increased gentamicin accumulation negatively impacts on reperfusion cellular energetics.     

Melatonin protects against ischemia/reperfusion injury in skeletal muscle

Abstract:  Melatonin has been shown to diminish ischemia-reperfusion (I/R) injury in many tissues. The main aim of this study was to evaluate the protective antioxidant effect of melatonin in skeletal muscle during I/R injury. Wistar albino rats were randomly divided into three groups. Hindlimb ischemia was achieved by clamping the common femoral artery in two groups but not in control group. Limbs were rendered ischemic for 1.5 hr; at the end of the reperfusion period of 1.5 hr muscle tissue samples were taken for the histological evaluation and biochemical analysis. Melatonin (10 mg/kg) was injected i.p. in the I/R + Mel group at the onset of ischemia whereas the vehicle solution was injected in the I/R group. In I/R + Mel group histological damage was significantly less than in the I/R group ( P  < 0.001). In the I/R + Mel group, the mean malonedialdehyde level was lower than in the I/R group ( P  < 0.01) and was quite near to the levels in the control group ( P  > 0.05). Glutathione levels were found to be reduced in the I/R group compared with the control ( P  < 0.01) and I/R + Mel group ( P  < 0.01). Melatonin has a protective effect against I/R injury in skeletal muscle and may reduce the incidence of compartment syndrome, especially after acute or chronic peripheral arterial occlusions.     

Protective effects of hydrogen peroxide against ischemia/reperfusion injury in perfused rat hearts.

Among the several mechanisms proposed for ischemic preconditioning (IPC), generation of reactive oxygen species (ROS) is reported to be involved in the cardioprotective effects of IPC. The present study was designed to investigate whether repetitive exposure to hydrogen peroxide (H(2)O(2)) can protect the myocardium against subsequent ischemia/reperfusion injury, and whether the H(2)O(2)-induced cardioprotection is related to the preservation of energy metabolism. Langendorff-perfused rat hearts were exposed to two, 5 min episodes of IPC or to various concentrations of H(2)O(2) twice and then to 35 min global ischemia and 40 min reperfusion. Using (31)P nuclear magnetic resonance ((31)P-NMR) spectroscopy, cardiac phosphocreatine (PCr) and ATP and intracellular pH (pH(i)) were monitored. IPC and the treatment with 2 micromol/L H(2)O(2) significantly improved the post-ischemic recovery of left ventricular developed pressure (LVDP) and the PCr and ATP compared with those of the control ischemia/reperfusion (LVDP: 36.9 +/-7.4% of baseline in control hearts, 84.0+/-3.5% in IPC, 65.4+/-3.8% in H(2)O(2); PCr: 51.1+/-5.3% in control hearts, 81.4+/-5.5% in IPC, 81.7+/-5.2% in H(2)O(2); ATP: 12.3+/-1.6% in control hearts; 30.0+/-2.8% in IPC, 28.6+/-2.3% in H(2)O(2), mean +/- SE, p<0.05). However, lower (0.5 micromol/L) or higher (10 micromol/L) concentration of H(2)O (2) had no effect. There were significant linear correlations between mean LVDP and high-energy metabolites after 40 min reperfusion in H(2)O(2)-treated hearts. In IPC-treated hearts, the mean LVDP was greater than that in the 2 micromol/L H(2)O(2)-treated hearts under similar levels of high-energy metabolites. IPC also ameliorated intracellular acidification (6.38+/-0.03 in control hearts, 6.65+/-0.04 in IPC, p<0.05), but treatment with H(2)O(2) did not affect pH(i) during ischemia (6.40+/-0.05 in H(2)O(2)). In conclusion, H(2)O(2) had protective effects against ischemia/reperfusion injury and the effects were related to the preservation of energy metabolism. IPC could have additional protective mechanisms that are associated with the amelioration of intracellular acidosis during ischemia.     

红景天苷抑制缺血/再灌注诱导的心肌微血管内皮细胞凋亡

目的探讨红景天苷对大鼠心肌微血管内皮细胞(CMECs)缺血/再灌注损伤的影响及其可能的机制。方法分离培养大鼠CMECs,建立模拟缺血/再灌注模型,分为对照组、模拟缺血/再灌注(SI/R)组、SI/R+红景天苷组(1.0、2.5、5.0、10.0μmol/L)组。待红景天苷最适浓度确认为5μmol/L后,增加SI/R+红景天苷+LY[磷酯酰肌醇3激酶(PI3k)特异性抑制剂LY294002]组。MTT法检测细胞增殖能力,细胞划痕实验检测细胞迁移能力,TUNEL法检测细胞凋亡,采用Western blot检测Akt磷酸化水平,以及凋亡抑制蛋白生存素和Bcl-2的表达。结果与对照组相比较,SI/R组CMECs增殖能力明显降低(0.410±0.011比0.200±0.014,P=0.041),凋亡率显著上升(4.15%±0.12%比26.05%±0.97%,P=0.018),而与SI/R组相比,SI/R+红景天苷组(1.0、2.5、5.0、10.0μmol/L)细胞增殖能力明显升高并呈剂量依赖性,细胞迁移率,而凋亡率则明显下降(均为P<0.05),LY294002组凋亡指数与SI/R+红景天苷组相比显著提高(22.03%±0.98%比16.28%±1.40%,P=0.029)。与SI/R组相比较,红景天苷可显著上调Akt的磷酸化,以及上调抗凋亡蛋白生存素和Bcl-2的表达(均为P<0.05),而此作用可被LY294002显著抑制(均为P<0.05)。结论红景天苷可显著抑制缺血/再灌注损伤诱导的CMECs凋亡,促进细胞存活,改善细胞功能,其作用机制可能与激活PI3K/Akt,以及上调凋亡抑制蛋白生存素和Bcl-2表达相关。     

Cardioprotective effects of Guanxinshutong (GXST) against myocardial ischemia/ reperfusion injury in rats

Background The protective effects against reperfusion injury of cardioprotective drugs have recently been evaluated and found to be inadequate. Guanxinshutong (GXST), a combination of the traditional herb and Mongolian medicine, is effective and safe in treating angina pectoris in clinical trials. We assess the cardioprotective effects of GXST against myocardial ischemia and reperfusion (MI/R) injury in rats and explore its possible mechanism. Methods Forty-five male Sprague Dawley rats were randomized into three groups: non-MI/R group (Sham, n = 15), MI/R group treated with vehicle (Control, n = 15) and MI/R group treated with GXST (Drug, n = 15). MI/R was induced by ligation of the left anterior descending coronary artery (LAD) for 30 minutes, followed by 2/24 hour reperfusion in the Control and Drug groups. In the Sham group, the LAD was exposed without occlusion. GXST powder (in the Drug group) or saline (in the Control and Sham groups) were administered via direct gastric gavage from 7 day prior to surgery. Blood samples were collected from the carotid artery (10 rats each group) after 2 hours of reperfusion, to determine the levels of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6) and intercellular adhesion molecule-1 (ICAM-1) using enzyme-linked immunosorbent assays. The animals were then sacrificed and the hearts were harvested for histopathology and western blot analysis. Infarct size was measured in the remaining five rats in each group after 24 hours reperfusion. Results GXST significantly decreased levels of TNF-α, IL-1β, IL-6, ICAM-1, apoptosis index (AI) and infarct size. GXST also obviously inhibited nuclear factor kappa B (NF-κB) activity when compared with the Control group (all P < 0.05). Conclusions GXST is effective in protecting the myocardium against MI/R injury in rats. Its possible cardioprotective mechanism involves inhibition of the inflammatory response and apoptosis following MI/R injury.     

Inhibition of N-ethylmaleimide-sensitive factor protects against myocardial ischemia/reperfusion injury

Exocytosis of endothelial granules promotes thrombosis and inflammation and may contribute to the pathophysiology of early reperfusion injury following myocardial ischemia. TAT-NSF700 is a novel peptide that reduces endothelial exocytosis by inhibiting the ATPase activity and disassembly activity of N-ethylmaleimide-sensitive factor (NSF), a critical component of the exocytic machinery. We hypothesized that TAT-NSF700 would limit myocardial injury in an in vivo murine model of myocardial ischemia/reperfusion injury. Mice were subjected to 30 minutes of ischemia followed by 24 hours of reperfusion. TAT-NSF700 or the scrambled control peptide TAT-NSF700scr was administered intravenously 20 minutes before the onset of ischemia. Myocardial ischemia/reperfusion caused endothelial exocytosis, myocardial infarction, and left ventricular dysfunction. However, TAT-NSF700 decreased von Willebrand factor levels after myocardial ischemia/reperfusion, attenuated myocardial infarct size by 47%, and preserved left ventricular structure and function. These data suggest that drugs targeting endothelial exocytosis may be useful in the treatment of myocardial injury following ischemia/reperfusion.     

褪黑素减轻心肌缺血/再灌注损伤的作用及机制

目的:探讨褪黑素（melatonin,Mel）在大鼠心肌缺血/再灌注（MI/R）损伤中的拮抗作用及其机制。方法:80只体质量200~250 g雄性SD大鼠随机分为4组:假手术（Sham）组、溶剂对照（MI/R+V）组、Mel治疗（MI/R+Mel）组、Mel+EX527（MI/R+Mel+EX）组。常规结扎左冠状动脉前降支行心肌缺血/再灌注手术,缺血30 min,再灌72 h后超声心动图法检测各组大鼠心功能,再灌6 h后ELISA法检测血清酶学指标,TUNEL法检测心肌细胞凋亡率,Evans blue-TTC双染法测定梗死面积,Western blot法检测沉默信息转录调控因子1（SIRT1）、乙酰化叉头转录因子1（Ac-Foxo1）及凋亡相关蛋白表达水平。结果:Mel治疗可显著改善MI/R损伤后心功能,降低血清肌酸激酶（CK）及乳酸脱氢酶（LDH）水平,降低凋亡率及梗死面积,上调SIRT1表达,下调Ac-Foxo1水平,降低凋亡相关蛋白表达。而使用EX527阻断SIRT1信号后逆转Mel的上述作用（均P<0.01）。结论:Mel可发挥抗凋亡作用减轻MI/R损伤并改善心功能,其作用机制可能与其激活SIRT1信号通路并降低Ac-Foxo1水平有关。     

Inhibition of Rho-kinase protects the heart against ischemia/reperfusion injury

OBJECTIVE: To investigate the role of Rho A and Rho-kinase in acute myocardial ischemia/reperfusion injury and the protective effect of Rho-kinase inhibitor, Y-27632 [(R)-(+)-trans-N-(4-pyridyl)-4-(1-aminoethyl)cyclohexanecarboxamide]. METHODS AND RESULTS: Male CD1 mice were subjected to 30 min of coronary occlusion and 24 h reperfusion. Ischemia/reperfusion upregulated expression of Rho A in ischemic myocardium, and subsequently activated Rho-kinase. Y-27632 significantly inhibited the activation of Rho-kinase following ischemia/reperfusion. Treatment with Y-27632 at 10 and 30 mg/kg oral administration, reduced infarct size by 30.2% and 41.1%, respectively (P<0.01 vs. vehicle). Y-27632 also enhanced post-ischemia cardiac function. Left ventricular systolic pressure, +dP/dt and -dP/dt were significantly improved by 23.5%, 52.3%, and 59.4%, respectively (P<0.01 vs. vehicle). Moreover, Y-27632 reduced ischemia/reperfusion-induced myocardial apoptosis. The apoptotic myocytes in ischemic myocardium after 4 h reperfusion were reduced from 13.1% in vehicle group to 6.4% in Y-27632-treated group (P<0.01). Meanwhile, ischemia/reperfusion-induced downregulation of Bcl-2 in myocardium was remarkably attenuated in the treated animals. Ischemia/reperfusion resulted in remarkable elevation in serum levels of proinflammatory cytokines, interleukin-6 (IL-6), keratinocyte chemoattractant (KC) and granulocyte colony-stimulating factor (G-CSF), which was significantly suppressed by Y-27632. In addition, Y-27632 decreased ischemia/reperfusion-induced accumulation of neutrophils in the heart by 45% (P<0.01). CONCLUSIONS: These results suggest that Rho-kinase plays a pivotal role in myocardial ischemia/reperfusion injury. The cardiac protection provided by treatment with a selective Rho-kinase inhibitor is likely via anti-apoptotic effect and attenuation of ischemia/reperfusion-induced inflammatory responses. The finding of this study suggest a novel therapeutic approach to the treatment of acute myocardial ischemia/reperfusion injury.     

Investigation of dose-dependent effects of berberine against renal ischemia/reperfusion injury in experimental diabetic rats

BackgroundIschemia–reperfusion injury causes various severe morphological and functional changes in diabetic patients. To date, numerous antidiabetic and antioxidant agents have been used for treatment of the disease-related changes.ObjectivesWe aimed to examine effective therapeutic doses or doses of berberine against renal ischemia/reperfusion injury (IRI) in a streptozotocin (STZ)-induced diabetic rat model by histopathological and biochemical analysis.MethodsThirty male Sprague Dawley rats were treated with STZ injection for the development of diabetes, and divided into the following groups: STZ-induced diabetic group (STZ); IRI-induced diabetic group (STZ + IRI); 50 mg/kg berberine (BRB) treated diabetic group after inducing IRI (STZ + IRI + BRB₁); 100 mg/kg BRB treated diabetic group after IRI (STZ + IRI + BRB₂); 150 mg/kg BRB treated diabetic group after IRI (STZ + IRI + BRB₃). Bilateral renal ischemia model was applied for 45 min, then reperfusion was allowed for 14 days in STZ-induced diabetic rats. Renal injury was detected histopathologically. Blood urea nitrogen (BUN), creatinine and lactate dehydrogenase (LDH) levels were measured in serum using the ELISA method. Total antioxidant status (TAS) and total oxidant status (TOS) of renal tissue was studied by spectrophotometric assay. Oxidative stress index (OSI) was calculated as TOS-to-TAS ratio. Tumor necrosis factor alpha (TNF-α), C-reactive protein (CRP), Na⁺/K⁺-ATPase (sodium pump), and Ca²⁺-ATPase (calcium ATPase) enzyme levels were measured in tissues using the ELISA method. Anti-apoptotic Bax and pro-apoptotic Bcl-2 protein levels were detected by Western blot analysis. All data were evaluated statistically.ResultsThe highest histopathological score was detected in the STZ + IRI group compared to the other group. BRB administration at the doses of 100 mg/kg and 150 mg/kg markedly improved renal injury. BUN and creatinine levels significantly increased in the STZ + IRI group compared to the STZ group (p < 0.001). 100 mg/kg and 150 mg/kg BRB administration significantly decreased those levels (p < 0.01). The highest TOS and the lowest TAS levels were detected in the STZ + IRI group (p < 0.001). IRI markedly aggravated inflammation via increasing levels of TNF-α and CRP (<0.001), and caused apoptosis via inducing Bcl-2 protein, and suppressing Bax protein (p < 0.001). BRB administration at the doses of 100 mg/kg and 150 mg/kg showed anti-oxidant, anti-inflammatory and anti-apoptotic effects (p < 0.01). The LDH enzyme, was used as a necrosis marker, was higher in the STZ + IRI group than other groups. BRB administration at all of the doses, resulted in the decline of LDH enzyme level (p < 0.001). Ca²⁺-ATPase and Na⁺/K⁺-ATPase enzyme activities decreased in the STZ + IRI group compared to the STZ group (p < 0.001), while BRB administration at the doses of 100 mg/kg and 150 mg/kg significantly increased those of enzyme activities, respectively (p < 0.05).ConclusionIschemia with diabetes caused severe histopathological and biochemical damage in renal tissue. The high doses of berberine markedly improved histopathological findings, regulated kidney function via decreasing BUN and creatinine levels, and rearranged intercellular ion concentration via increasing Na⁺/K⁺-ATPase and Ca^2+? ATPase levels. Berberine showed anti-oxidant, anti-apoptotic, and anti-inflammatory effects. According to these data, we suggest that berberine at the doses of 100 and 150 mg may be used as a potential therapeutic agent to prevent renal ischemic injury.     

神经调节蛋白-1对大鼠心肌缺血/再灌注损伤保护作用的研究

目的:探讨神经调节蛋白-1(NRG-1)对大鼠心肌缺血/再灌注(I/R)损伤的保护作用及其潜在机制。方法:雄性,SD大鼠,分三组:假手术组(n=8)、心肌(I/R)组(n=8)和NRG-1+I/R组(n=9)。通过结扎冠状动脉左前降支45 min,再灌注3 h建立在体大鼠心肌I/R模型。用伊文氏蓝/2,3,5-三苯基氯化四氮唑(TTC)染色法测定心肌梗死范围。用脱氧核糖核苷酸末端转移酶介导的d UTP缺口末端标记法(TUNEL)染色法检测心肌细胞凋亡指数;免疫荧光法测定线粒体膜电位水平;用Western blot方法检测线粒体细胞色素c的转位、凋亡相关因子Bcl-2和Bax的表达;caspase 3试剂盒检测caspase 3活性;用透射电镜观察心肌组织线粒体超微结构。结果:与假手术组相比,I/R组心肌细胞凋亡显著增加[(23.2±3.8)vs.(3.0±1.3)%,P0.01],心肌线粒体膜电位降低[(209.1±13.6)vs.(336.8±10.3)m V,P0.05],细胞色素c向胞浆发生转位,caspase 3活性显著升高[(20.1±3.6)vs.(8,3±1.5),P0.01]。与单纯I/R组比较,NRG-1给药显著降低I/R大鼠心肌的梗死面积/危险区面积[(28.6±9.2)vs.(51.7±7.8)%,P0.01],减少心肌细胞凋亡指数[(11.9±3.5)vs.(23.2±3.8)%,P0.01],升高Bcl-2/Bax蛋白表达比值[(1.647±0.172)vs.(0.490±0.080),P0.01],升高线粒体膜电位[(327.2±15.4)vs.(209.1±13.6)m V,P0.05],抑制细胞色素c向胞浆的转位[(0.207±0.055)vs.(0.483±0.075),P0.01],降低心肌caspase 3活性[(9.3±2.6)vs.(20.1±3.6),P0.01],改善线粒体超微结构。结论:NRG-1具有抗心肌I/R损伤的保护作用,其机制部分通过抑制线粒体介导的心肌细胞凋亡途径实现。