Neuregulin-1 alleviate oxidative stress and mitigate inflammation by suppressing NOX4 and NLRP3/caspase-1 in myocardial ischaemia-reperfusion injury

Neuregulin-1 (NRG-1) is reported to be cardioprotective through the extracellular-regulated protein kinase (ERK) 1/2 pathway in myocardial ischaemia-reperfusion injury (MIRI). NOX4-induced ROS activated NLRP3 inflammasome and exacerbates MIRI. This study aims to investigate whether NRG-1 can suppress NOX4 by ERK1/2 and consequently inhibit the NLRP3/caspase-1 signal in MIRI. The myocardial infarct size (IS) was measured by TTC-Evans blue staining. Immunohistochemical staining, real-time quantitative PCR (RT-qPCR) and Western blotting were used for detection of the factors, such as NOX4, ERK1/2, NLRP3, caspase-1 and IL-1β .The IS in the NRG-1 (3 μg/kg, intravenous) group was lower than that in the IR group. Immunohistochemical analysis revealed NRG-1 decreased 4HNE and NOX4. The RT-qPCR and Western blot analyses revealed that NRG-1 mitigated the IR-induced up-regulation of NOX4 and ROS production. Compared with the IR group, the NRG-1 group exhibited a higher level of P-ERK1/2 and a lower level of NLRP3. In the Langendorff model, PD98059 inhibited ERK1/2 and up-regulated the expression of NOX4, NLRP3, caspase-1 and IL-1β, which exacerbated oxidative stress and inflammation. In conclusion, NRG-1 can reduce ROS production by inhibiting NOX4 through ERK1/2 and inhibit the NLRP3/caspase-1 pathway to attenuate myocardial oxidative damage and inflammation in MIRI.     

刺槐素对大鼠心肌缺血再灌注损伤的保护作用与机制研究

摘要 目的：探讨刺槐素对大鼠心肌缺血再灌注损伤(MIRI)的作用以及可能的作用机制。方法：对24只Sprague-Dawley (SD)大鼠进行随机分组,分为：假手术组、模型组、刺槐素给药组、刺槐素+AG490给药组,每组6只,通过结扎冠状动脉左前降支,缺血30 min,再灌注120 min复制心肌缺血再灌注损伤模型。利用氯化三苯基四氮唑测定心肌梗死面积,紫外分光光度计和酶联免疫法检测血清中肌酸激酶同工酶（CK-MB）、乳酸脱氢酶（LDH）的活性,蛋白印迹法分别检测心肌组织中Bcl-2、Bax、Stat3和p-Stat3蛋白相对表达水平。结果：与假手术组比较,模型组大鼠血清中CK-MB、LDH活性明显升高（P＜0.01）,心肌梗死面积百分比显著增加（P＜0.01）,p-Stat3/Stat3比率、Bcl-2/Bax比率显著下降（P＜0.01）;与模型组相比,刺槐素给药组中CK-MB、LDH的活性,以及心肌梗死面积百分比显著降低（P＜0.01）,Bcl-2/Bax比率和p-Stat3/Stat3比率显著提高（P＜0.05）。然而在刺槐素+AG490药物组中刺槐素对于受损心肌的保护作用被AG490消除。结论：刺槐素可减轻MIRI大鼠心肌损伤,发挥心肌保护作用,其机制可能与活化Jak2/Stat3信号通路进而抑制心肌细胞凋亡有关。     

Post-infarct treatment with [Pyr1]-apelin-13 reduces myocardial damage through reduction of oxidative injury and nitric oxide enhancement in the rat model of myocardial infarction

Apelin is a newly discovered peptide that has been recently shown to have cardioprotective effects in the animal model of myocardial infarction (MI) and ischemia/reperfusion (I/R) injuries. The aim of the present study was to investigate the long term cardioprotective effect of [Pyr1]-apelin-13 in the rat model of MI. Male Wistar rats (n = 22) were randomly divided into three groups: (1) sham operated group (2) control MI group and (3) MI treated with apelin (MI-AP group). MI animals were subjected to 30 min of left anterior descending coronary artery (LAD) ligation and 14 days of reperfusion. 24 h after LAD ligation, apelin (10 nmol/kg/day) was administered i.p. for 5 days. Blood sampling was performed at days 1, 3, 5 and 7 after MI for determination of serum changes of lactate dehydrogenase (LDH), creatine kinase-MB (CK-MB), malondialdehyde (MDA) and nitric oxide (NO). Myocardial infarct size (IS) and hemodynamic function were also measured at the end of the study at day 14. We found out that post infarct treatment with apelin decreases infarct size, serum levels of LDH, CK-MB and MDA and increases heart rate and serum level of NO in the consecutive days, but there were no significant differences in blood pressure in the MI-AP group in comparison with MI. In conclusion, apelin has long term cardioprotective effects against myocardial infarction through attenuation of cardiac tissue injury and lipid peroxidation and enhancement of NO production.     

Protective effects of <Emphasis Type="Italic">N</Emphasis>-acetylcysteine in isoproterenol-induced myocardium injury in rats

Isoproterenol (ISO) has been found to cause severe injury in the myocardium. The aim of this study was to investigate the protective effects of N-acetylcysteine (NAC) on ISO-induced myocardial injury in rats and its underlying mechanisms. Fouty male Wistar rats were randomly divided into four groups: control, ISO, NAC, and ISO + NAC group. Myocardial histopathological observation were performed; The activities of creatine kinase isoenzyme-MB (CK-MB) and lactate dehydrogenase (LDH) were examined; Myocardium TNF-αand IL-1β gene expressions were examined by RT-PCR analysis; Myocardial expressions of TNF-αand IL-1βproteins were observed by immunohistochemical assay and western blotting analysis. The myocardial injury induced by ISO was significantly reduced by the treatment of NAC as judged by the reduction of myocardial necrosis. Compared with ISO group, rats pre-injected with NAC showed a significant decrease in the activities of cardiac marker enzymes such as CK-MB and LDH in serum. NAC inhibits the pro-inflammatory factors expressions (TNF-αand IL-1β) stimulated by ISO. In conclusion, NAC exerts significant cardio-protective effects against ISO-induced myocardial injury in rats, likely regulating pro-inflammatory factors expressions.     

Protective effect of ginsenoside Rb1 against myocardial ischemia/reperfusion injury in streptozotocin-induced diabetic rats

The objective of the current study is to investigate whether ginsenoside Rb1, a major pharmacological extract of ginseng that could attenuate myocardial ischemia reperfusion (MI/R) injury in non-diabetic myocardium, can attenuate MI/R injury in diabetes that are more vulnerable to ischemic insult. Rats were divided into seven groups: (i) diabetic sham, (ii) diabetic, (iii) normal, (iv) diabetic + ginsenoside Rb1, (v) diabetic + wortmannin, (vi) diabetic + wortmannin + ginsenoside Rb1, (vii) diabetic sham + wortmannin. Ginsenoside Rb1 and/or wortmannin were administered prior to inducing MI/R (30 min of coronary artery occlusion followed by 120 min reperfusion). At the end of the experiment, postischemic myocardial infarct size was significantly higher in the diabetic untreated group as compared to normal (P < 0.05), accompanied with increased myocardial apoptosis, elevated plasma CK-MB and LDH release and reduced blood pressure. Ginsenoside Rb1 reduced infarct size, cardiomyocyte apoptosis and caspase-3 activity compared to the diabetic group. The cardioprotective effects of ginsenoside Rb1 were cancelled by wortmannin. Ginsenoside Rb1 significantly upregulated phosphorylated Akt expression, which was attenuated by wortmannin. Ginsenoside Rb1 exerts cardioprotective effects against MI/R injury in diabetic rats, which is partly through activation of phosphatidylinositol 3-kinase (PI3 K)/Akt pathway. Thus this study shows a novel pharmacological preconditioning with ginsenoside Rb1 in the diabetic myocardium.     

Piperine protects against pyroptosis in myocardial ischaemia/reperfusion injury by regulating the miR-383/RP105/AKT signalling pathway

miRNA-mediated pyroptosis play crucial effects in the development of myocardial ischaemia/reperfusion (I/R) injury (MIRI). Piperine (PIP) possesses multiple pharmacological effects especially in I/R condition. This study focuses on whether PIP protects MIRI from pyroptosis via miR-383-dependent pathway. Rat MIRI model was established by 30 minutes of LAD ligation and 4 hours of reperfusion. Myocardial enzymes, histomorphology, structure and function were detected to evaluate MIRI. Recombinant adenoviral vectors for miR-383 overexpression or miR-383 silencing or RP105 knockdown were constructed, respectively. Luciferase reporter analysis was used to confirm RP105 as a target of miR-383. Pyroptosis-related markers were measured by Western blotting assay. The results showed that I/R provoked myocardial injury, as shown by the increases of LDH/CK releases, infarcted areas and apoptosis as well as worsened function and structure. Pyroptosis-related mediators including NLRP3, cleaved caspase-1, cleaved IL-1β and IL-18 were also reinforced after MIRI. However, PIP treatment greatly ameliorated MIRI in parallel with pyroptotic repression. In mechanistic studies, MIRI-caused elevation of miR-383 and decrease of RP105/PI3K/AKT pathway were reverted by PIP treatment. Luciferase reporter assay confirmed RP105 as a miR-383 target. miR-383 knockdown ameliorated but miR-383 overexpression facilitated pyroptosis and MIRI. Moreover, the anti-pyroptotic effect from miR-383 silencing was verified to be relied on the RP105/PI3K/AKT signalling pathway. Additionally, our present study further indicated the miR-383/RP105/AKT-dependent approach resulting from PIP administration against pyroptosis in MIRI. Therefore, PIP treatment attenuates MIRI and pyroptosis by regulating miR-383/RP105/AKT pathway, and it may provide a therapeutic manner for the treatment of MIRI.     

Nitrate tolerance aggravates postischemic myocardial apoptosis and impairs cardiac functional recovery after ischemia

Objectives: This study examined the effects of nitrate tolerance (NT) on myocardial ischemia reperfusion (MI/R) injury and elucidated the potential mechanisms involved. Furthermore, the effects of GSH on postischemic myocardial apoptosis in NT rats were investigated. Methods and results: Male Sprague–Dawley rats were randomized to receive nitroglycerin (60 μg/kg/h) or saline for 12 h followed by 40 min of MI and 4 h of reperfusion. Myocardial apoptosis, infarct size, nitrotyrosine formation, plasma CK and LDH activity, and cardiac function were determined. MI/R resulted in significant apoptotic cell death, which was further increased in animals with NT. In addition, NT further increased plasma CK and LDH activity, enlarged infarct size, and impaired cardiac functional recovery after ischemia. Myocardial nitrotyrosine, a footprint for cytotoxic reactive nitrogen species formation, was further enhanced in the NT heart after MI/R. Treatment of NT animals with exogenous GSH inhibited nitrotyrosine formation, reduced apoptosis, decreased infarct size, and improved cardiac functional recovery. Conclusion: Our results demonstrate that nitrate tolerance markedly enhances MI/R injury and that increased peroxynitrite formation likely plays a role in this pathologic process. In addition, our results suggest that GSH could decrease peroxynitrite formation and reduce MI/R injury in nitrate tolerant hearts.     

DUSP12 ameliorates myocardial ischemia–reperfusion injury through HSPB8-induced mitophagy

This study aimed to explore the role of dual specificity phosphatase 12 (DUSP12) in regulating myocardial ischemia–reperfusion (I/R) injury and the underlying mechanism. The expression of DUSP12 in myocardial tissues and heat-shock protein beta-8 (HSPB8) and mitophagy-related proteins in myocardial tissues and H9c2 cells were detected by western blot analysis. The serum creatine kinase isoenzymes (CK-MB) and lactate dehydrogenase (LDH), levels of reactive oxygen species and malondialdehyde, superoxide dismutase activity in myocardial tissues and H9c2 cells, and caspase-3 activity in H9c2 cells were analyzed by corresponding assay kits. The infarct area in the rat's heart was observed by triphenyl tetrazolium chloride staining. The apoptosis of myocardial cells in myocardial tissues and H9c2 cells was detected by terminal-deoxynucleotidyl transferase dUTP-biotin nick-end labeling assay. The interaction between DUSP12 and HSPB8 was clarified by the coimmunoprecipitation assay. The transfection efficacy of si-HSPB8#1 and si-HSPB8#2 in H9c2 cells was confirmed by real-time quantitative-polymerase chain reaction and western blot analysis. As a result, DUSP12 expression was downregulated in I/R rats, which was promoted by lentivirus-expressing DUSP12. DUSP12 overexpression reduced the serum creatine kinase isoenzymes (CK-MB) and LDH, decreased the infarct area in the rat's heart, and suppressed the apoptosis and oxidative stress in myocardial tissues. DUSP12 overexpression also upregulated the expression of HSPB8 to promote mitophagy. The coimmunoprecipitation assay indicated that DUSP12 could be combined with HSPB8. In addition, DUSP12 overexpression could inhibit hypoxia/reoxygenation-elicited apoptosis as well as oxidative stress in H9c2 cells by upregulating HSPB8 expression to promote mitophagy, which was countervailed by HSPB8 deficiency. In conclusion, DUSP12 overexpression decreased the apoptosis and oxidative stress in myocardial I/R injury through HSPB8-induced mitophagy.     

Retracted: AT1R knockdown confers cardioprotection against sepsis-induced myocardial injury by inhibiting the MAPK signaling pathway in rats

Myocardial dysfunction is an important manifestation of sepsis. In addition, inactivation of the mitogen-activated protein kinase (MAPK) signaling pathway has been reported to be beneficial in sepsis. The current study used gene expression profiling to demonstrate the overexpression of angiotensin II type 1 receptor (AT1R) and activation of the MAPK signaling pathway in sepsis. In this study, we used a rat model of sepsis established by cecal ligation and puncture to explore the mechanism of AT1R silencing in relation to the MAPK signaling pathway on myocardial injury. Various parameters including blood pressure, heart rate, and cardiac function changes were observed. Enzyme-linked immunosorbent assay was used to measure the concentration of cardiac troponin T (TnT), cardiac troponin I (cTnI), and creatine kinase isoenzyme muscle/brain (CK-MB). Myocardial enzyme, tissue antioxidant capacity, mitochondria swelling, and membrane potential were also detected. Terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick end labeling staining was applied to measure cell apoptosis, and messenger RNA and protein levels of apoptosis-related proteins (Fas ligand [Fasl], B-cell CLL/lymphoma [Bcl-2], p53) were also detected. Initially, sepsis rats exhibited decreased survival rate, but increased ejection fraction (EF), heart rate, and concentrations of TnT, cTnI, and CK-MB. Furthermore, decreased AT1R expression inactivated the MAPK signaling pathway (shown as decreased extracellular signal–regulated kinase and cyclic adenosine 3′,5′-monophosphate response element binding protein expression), decreased EF, heart rate, and concentrations of TnT, cTnI, and CK-MB, but increased sepsis rat survival rate. Eventually, decreased AT1R expression inhibited myocardial cell apoptosis (shown as decreased apoptosis rate and p53 and Fasl expression as well as increased Bcl-2 expression). These findings indicated that AT1R silencing plays an inhibitory role in sepsis-induced myocardial injury by inhibiting the MAPK signaling pathway.     

Cardioprotective effects of resveratrol following myocardial ischemia and reperfusion

Resveratrol (RSV), a plant origin polyphenol, has shown beneficial cardiovascular effects. In this study, isolated hearts from male Wistar rats were studied using the Langendorff technique. Following 30 min stabilization, the hearts underwent 30 min global ischemia and 120 min reperfusion. The perfusion solution in the test group contained RSV (10 μM). Hemodynamics of the hearts, the markers of myocardial damage including creatine kinase-MB (CK-MB), lactate dehydrogenase (LDH), and troponin I were studied during the study. Furthermore, the infarct size and the markers of oxidative stress including catalase (CAT), superoxide dismutase (SOD), malondialdehyde (MDA), and glutathione peroxidase (GPX) were assayed in the homogenates of the hearts. The release of nitrite from the hearts and the occurrence of ventricular arrhythmias were also monitored throughout the experiment. Resveratrol caused a significant improvement in the restoration of the mechanical performance of the hearts following myocardial ischemia and reperfusion (MIR). Besides, the infarct size, CK-MB, LDH, and troponin I declined in the test group. Besides, the cardiac release of nitrite increased, and the redox status of the heart was improved as indicated by the levels of CAT, SOD, GPX, and MDA. Finally, the treatment caused significant decreases in the occurrences of single and salvo arrhythmias, ventricular tachycardia, and ventricular fibrillation. The current study suggests strong cardioprotective and antiarrhythmic effects for RSV following MIR.

     

心宁片对糖尿病合并心肌缺血再灌注损伤的保护作用和机制研究

目的:研究心宁片对糖尿病合并心肌缺血再灌注损伤的保护作用及其作用机制。方法:腹腔注射STZ加高脂高糖饲料喂养诱导二型糖尿病小鼠模型,随机分为假手术组、模型组及心宁片高、中、低剂量组(心宁片10、20和30 mg·kg~(-1)),每组10只。在此基础上,制作心肌缺血再灌注模型。测定小鼠体内血糖和血脂水平,测定缺血再灌注后心肌酶(LDH和CK-MB)、心梗面积以及AMPK磷酸化水平。结果:心宁片能够有效的控制糖尿病小鼠体内血糖和血脂水平,减轻胰岛素抵抗情况。心宁片能够减轻缺血再灌注引起的心肌梗死,降低LDH和CK-MB水平,减少MDA水平。同时,还发现心宁片能够促进AMPK蛋白磷酸化。采用AMPK特异性抑制剂Compound C抑制AMPK后,LDH水平显著升高,心宁片的心肌保护作用减弱。结论:心宁片能够保护糖尿病合并缺血再灌注损伤,其机制可能是通过AMPK信号通路。     

Carnosic acid promotes myocardial antioxidant response and prevents isoproterenol-induced myocardial oxidative stress and apoptosis in mice

Carnosic acid is a well-known antioxidant. Recently, it has been identified as modulator of nuclear factor erythroid 2-related factor 2 (Nrf2). The effect of carnosic acid in the context of cardiovascular disorders has not been studied. In the present study, we investigated the beneficial effect and the underlying cardioprotective mechanism of carnosic acid by using mouse model of isoproterenol (ISO)-induced myocardial stress. Elevated serum levels of Troponin I, CK-MB, LDH, SGOT and SGPT, and myofibrillar degeneration with necrotic damage, and the presence of epicardial inflammatory infiltrate (H & E staining) confirmed the ISO-induced myocardial stress. Myocardial content of vitamin C, reduced glutathione, glutathione peroxidase, glutathione reductase, glutathione S-transferase, NAD(P)H: quinine oxidoreductase 1, superoxide dismutase, catalase, nuclear translocation of Nrf2 and protein expression heme oxygenase-1 were evaluated. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and myocardial expression of cleaved caspase-3, caspase-9, p53, Bax, and Bcl-2 were investigated to assess the apoptotic cell death. Pretreatment with carnosic acid attenuated ISO-induced elevated serum levels of Troponin I, CK-MB, LDH, SGOT and SGPT, and histopathological alterations in heart. Moreover, carnosic acid enhanced the nuclear translocation of Nrf2 and up-regulated the phase II/antioxidant enzyme activities. Furthermore, TUNEL assay and apoptosis-related protein analysis indicated that carnosic acid prevented ISO-induced cardiomyocyte apoptosis. Isoproterenol-induced myocardial lipid peroxidation and protein oxidation were also significantly decreased by carnosic acid pretreatment. The overall results clearly indicate that therapeutic application of carnosic acid might be beneficial in treating cardiovascular disorders.     

KRT1 gene silencing ameliorates myocardial ischemia–reperfusion injury via the activation of the Notch signaling pathway in mouse models

Myocardial ischemia and reperfusion injury (MIRI) includes major drawbacks, such as excessive formation of free radicals and also overload of calcium, which lead to cell death, tissue scarring, and remodeling. The current study aims to explore whether KRT1 silencing may ameliorate MIRI via the Notch signaling pathway in mouse models. Myocardial tissues were used for the determination of the positive rate of KRT1 protein expression, apoptosis of myocardial cells, creatine kinase (CK) and lactate dehydrogenase (LDH) expression, expression of related biomarkers as well as myocardial infarction area. The transfected myocardial cells were treated with KRT1-siRNA, Jagged1, and DAPT (inhibitor of Notch-1 signaling pathway). The expression of KRT1, NICD, Hes1, Bcl-2, and Bax protein was detected. The MTT assay was applied for cell proliferation and flow cytometry was used for cell apoptosis. Mice with MIRI had a higher positive rate of KRT1 protein expression, apoptosis of myocardial cells, CK and LDH expression, myocardial infarction area, increased expression of MDA, NO, SDH, IL-1, IL-6, TNF-α, CRP, KRT1, Bax protein, CK, and LDH, and decreased expression of SOD, NICD, Hes1, and Bcl-2. The downregulation of KRT1 led to decreased expression of KRT1 and Bax protein, increased expression of NICD, Hes1, and Bcl-2, decreased cell apoptosis, and improved cell proliferation. The inhibition of the Notch signaling pathway leads to reduced expression of Bax, increased expression of NICD, Hes1, and Bcl 2, and also decreased cell apoptosis and increased cell proliferation. Our data conclude that KRT1 silencing is able to make MIRI better by activating the Notch signaling pathway in mice.     

基于PERK/Nrf2/HO-1信号通路研究瑞马唑仑对心肌缺血再灌注损伤大鼠铁死亡的影响

摘要 目的：基于蛋白激酶R样内质网激酶（PERK）/核因子E2相关因子2（Nrf2）/血红素氧合酶-1（HO-1）信号通路探究瑞马唑仑对心肌缺血再灌注损伤（MIRI）大鼠铁死亡的影响。方法：将90只SD大鼠随机分为假手术（Sham）组、MIRI组、低剂量-瑞马唑仑组（L-瑞马唑仑组，5 mg/kg）、高剂量-瑞马唑仑组（H-瑞马唑仑组，20 mg/kg）、H-瑞马唑仑+PERK抑制剂组（瑞马唑仑20 mg/kg+GSK2606414 1 mg/kg），每组18只。采用结扎冠状动脉左前降支（LAD）0.5 h、再灌注2 h制备MIRI大鼠模型，于再灌注2 h后即刻尾静脉注射给药，再灌注24 h后进行组织取材。酶联免疫吸附（ELISA）法检测血清心肌损伤标志物[肌酸激酶同工酶（CK-MB）、心肌肌钙蛋白I（cTnI）]水平；HE染色观察心肌组织病理改变；Tunel染色检测心肌细胞凋亡；透射电镜观察心肌细胞超微结构变化；检测心肌组织中铁死亡相关标志物[铁、活性氧（ROS）、谷胱甘肽（GSH）、丙二醛（MDA）]水平；蛋白质印迹法（Western Blot）检测心肌组织中PERK/Nrf2/HO-1信号通路相关蛋白表达。结果：与Sham组相比，MIRI组心肌结构受损，纤维排列紊乱，线粒体呈现显著的铁死亡特征（膜固缩，膜密度增加，嵴减少），血清中CK-MB、cTnI水平，心肌细胞凋亡率及心肌组织中铁、ROS、MDA水平升高（P<0.05），心肌组织中GSH水平及p-PERK/PERK、核Nrf2/Nrf2、HO-1蛋白表达降低（P<0.05）；与MIRI组相比，L-瑞马唑仑组和H-瑞马唑仑组心肌组织上述病理改变明显减轻，血清CK-MB、cTnI水平，心肌细胞凋亡率及心肌组织中铁、ROS、MDA水平降低（P<0.05），心肌组织中GSH水平及p-PERK/PERK、核Nrf2/Nrf2、HO-1蛋白表达升高（P<0.05）；与H-瑞马唑仑组相比，H-瑞马唑仑+PERK抑制剂组心肌组织上述病理改变加重，血清CK-MB、cTnI水平，心肌细胞凋亡率及心肌组织中铁、ROS、MDA水平升高（P<0.05），心肌组织中GSH水平及p-PERK/PERK、核Nrf2/Nrf2、HO-1蛋白表达降低（P<0.05）。结论：瑞马唑仑可通过抑制铁死亡减轻大鼠MIRI，可能通过激活PERK/Nrf2/HO-1信号通路而实现。     

蒙药绍沙-7味丸防治大鼠心肌缺血/再灌注损伤的作用

目的: 探讨蒙药绍沙-7味丸对心肌缺血/再灌注损伤大鼠的防治作用及机制。方法: 60只大鼠随机分成6组:假手术组、模型组、蒙药绍沙-7味丸低、中、高剂量组以及阳性药对照组,每组10只;蒙药绍沙-7味丸低、中、高剂量组分别灌胃0.4 g/kg、0.8 g/kg、1.6 g/kg蒙药绍沙-7味丸,阳性药对照组灌胃0.3 g/kg复方丹参片,假手术组和模型组灌胃2 ml/100 g蒸馏水,均连续灌胃15 d,1次/日;15 d后,模型组及治疗组大鼠开胸结扎冠状动脉30 min后,解开结扎线行再灌注120 min后关闭胸腔处理;6组大鼠术后行心电图检查后处死大鼠取心脏行HE染色、TTC染色,观察梗死面积及病理变化。ELISA法检测血清中cTnI、CK-MB、 LDH、MDA、SOD、GSH-PX及TNF-α、IL-18、IL-6、IL-1β的水平,免疫组化法检测心肌组织NF-кB水平。结果: 与假手术组相比,心肌缺血/再灌注损伤大鼠心肌梗死面积增大,同时血清中cTnI、CK-MB、 LDH、MDA、GSH-PX及TNF-α、IL-18、IL-6、IL-1β的含量明显增加(P＜0.01),SOD的含量则明显降低(P＜0.01),心脏组织中的NF-кB水平增加;与心肌缺血/再灌注损伤大鼠相较,蒙药绍沙-7味丸改善大鼠心律失常现象及病理变化,减少梗死面积;血清中cTnI、CK-MB、 LDH、MDA、GSH-PX及TNF-α、IL-18、IL-6、IL-1β的含量明显降低(P＜0.01),SOD的含量明显增加(P＜0.01),心脏组织中的NF-кB水平降低。结论: 蒙药绍沙-7味丸可有效缓解大鼠心肌缺血/再灌注损伤,其作用与氧化应激和凋亡相关。     

Neuroprotection conferred by post‐ischemia ethanol therapy in experimental stroke: an inhibitory effect on hyperglycolysis and NADPH oxidase activation

Ethanol provides neuroprotection following ischemia/reperfusion. This study assessed ethanol's effect on hyperglycolysis and NADPH oxidase (NOX) activation. Adult, male Sprague–Dawley rats were subjected to middle cerebral artery occlusion (MCAO) for 2 h. Three sets of experiments were conducted to determine ethanol's effect on (i) conferring neuroprotection by measuring infarct volume and neurological deficits 24 h post reperfusion; (ii) cerebral glucose metabolism and lactic acidosis by measuring brain and blood glucose concentrations and protein expression of glucose transporter 1 and 3 (GLUT1, GLUT3), phosphofructokinase (PFK), as well as lactic acidosis by measuring lactate dehydrogenase (LDH), and lactate; and (iii) nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX) activation by detecting enzymatic activity and subunit expression at 3 h after reperfusion. When administered upon reperfusion, ethanol (1.5 g/kg) reduced infarct volume by 40% (p < 0.01) and neurological deficits by 48% at 24 h post reperfusion while reducing (p < 0.01) elevations in glycolytic protein expression and lactate levels during early reperfusion (3 h). Ethanol increased the reductions in cerebral glucose concentration at 3 h post reperfusion by 64% (p < 0.01) while enhancing (p < 0.01) post stroke blood glucose concentration, suggesting a reduced cellular glucose uptake and utilization. Ethanol decreased (p < 0.01) stroke‐induced NOX activation by reducing enzymatic activity and gp91^phox expression by 45% and 38%, respectively. Post‐ischemia ethanol treatment exerts neuroprotection through attenuation of hyperglycolysis and associated NOX activation. Because of the lack of associated hypoglycemia and selectivity toward decreasing cerebral metabolism, further investigation of ethanol's use as a post‐stroke therapy, especially in the context of hyperglycemia, seems warranted.     

Activation of the mammalian target of rapamycin signaling pathway underlies a novel inhibitory role of ring finger protein 182 in ventricular remodeling after myocardial ischemia-reperfusion injury

Myocardial ischemia-reperfusion injury (MIRI) is a major cause of cardiovascular disease, leading to mortality and disability associated with coronary occlusion worldwide. A correlation of mammalian target of rapamycin (mTOR)/nuclear factor-kappa B (NF-κB) signaling pathway has been observed with brain damage resulting from myocardial ischemia. Therefore, by establishing MIRI rat model, this study aimed to explore whether ring finger protein 182 (RNF182) regulates the mTOR signaling pathway affecting MIRI. Initially, MIRI rat model was successfully established, followed by either treatment of shRNF182 or phosphoesterase (PITE) (inhibitor of the mTOR signaling pathway). Then, the serum levels of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and malondialdehyde (MDA), left ventricular ejection fraction (LVEF), left ventricular fractional shortening (LVFS), left ventricular systolic pressure (LVSP), and left ventricular end-diastolic pressure (LVEDP) were determined, followed by detection of myocardial infarct sizes and myocardial cell apoptosis. Moreover, the levels of related genes/proteins were determined to further determine the mechanisms of RNF182 in MIRI. First, RNF182 was upregulated in MIRI. Another key observation of this study was that rats with shRNF182 presented with downregulated SOD, GSH-Px, and MDA in serum, accompanied by decreased levels of LVEF, LVFS, LVSP, and LVEDP. In addition, both reduced myocardial infarct sizes and apoptosis of myocardial cells were observed after silencing RNF182. Furthermore, silencing of the RNF182 was observed to downregulate Bcl 2–associated X and cysteine proteinase 3 but upregulate mTOR, ribosome protein subunit 6 kinase 1, eukaryotic elongation factor 2, and B-cell lymphoma-2. Importantly, the effects of RNF182 silencing were reversed after PITE treatment. In conclusion, our study demonstrates that RNF182 silencing can prevent ventricular remodeling in rats after MIRI by activating the mTOR signaling pathway.     

Urotensin-ⅡReceptor Antagonist SB-710411 Protects Rat Heart against Ischemia-Reperfusion Injury via RhoA/ROCK Pathway

Aim

SB-710411 is a rat selective urotensin-II (U-II) receptor antagonist, which can block U-II-induced contraction of the aorta and inhibit U-II-induced myocardial fibrosis in rats. However, the effect of SB-710411 on myocardial ischemia-reperfusion (I/R) injury is unclear. The present study was designed to investigate whether SB-710411 has a protective effect on myocardial I/R injury in rats and the possible mechanisms.

Methods and Results

Myocardial I/R injury was induced by occluding the left anterior descending coronary artery in adult male Sprague-Dawley rats. Hemodynamic parameters, electrocardiogram (ECG), infarct size, histological alteration, lactate dehydrogenase (LDH), creatine phosphokinase-MB (CK-MB), cardiac troponin I (cTnI), RhoA, and the protein expressions of U-II receptor (UTR), ROCK₁ and ROCK₂ were evaluated. Cardiac I/R injury significantly up-regulated the expressions of UTR, ROCK₁ and ROCK₂ proteins in rat myocardium. SB-710411 1.0 and 2.0 μg/kg significantly reduced cardiac I/R-induced the infarct size and histological damage in rat myocardium, markedly inhibited the changes of hemodynamic parameters and the increases of ST-segment in ECG, the serum LDH and CK-MB activities and cTnI level in rats subjected to myocardial I/R injury. Furthermore, SB-710411 obviously prevented myocardial I/R-increased RhoA activity and UTR, ROCK₁ and ROCK₂ protein expressions.

Conclusions

Our results indicate that cardiac I/R injury increases myocardial UTR expression, and SB-710411 has a potent protective effect on myocardial I/R injury in rats. The cardioprotection may be associated with the inhibition of UTR-RhoA/ROCK pathway.     

脂联素后处理对大鼠心肌缺血/再灌注损伤的影响及ADP/PI3K/Akt信号通路的作用

目的：探讨脂联素（ADP）后处理对大鼠心肌缺血/再灌注损伤（MIRI）的影响以及脂联素/磷脂酰肌醇-3激酶/蛋白激酶B （ADP/PI3K/Akt）通路的作用。方法：SD大鼠麻醉后气管插管连接呼吸机,开胸暴露心肌,在左心耳和肺动脉圆锥之间用带线圆针对冠脉左前降支（LAD）穿线,LAD结扎断流30 min后松线再灌注120 min,建立大鼠MIRI模型。大鼠随机分为以下5组（n=12）：①假手术组（Sham组）：LAD仅穿线不结扎;② MIRI组;③ADP后处理组（ADP组）：LAD断流10 min时静注ADP继续断流20 min,然后再灌注120 min;④ADP+LY294002组：LAD断流10 min时静注ADP和LY294002,其余同ADP组;⑤LY294002组：LAD断流10 min时静注LY294002,其余同ADP组。各组取血检测LDH和cTnI含量,取左心室心肌测定PI3k、Akt、p-Akt、ADPmRNA、ADPR1mRNA和PI3KmRNA表达。结果：与Sham组比较,MIRI组血浆LDH和cTnI均明显升高（P<0.05）;和MIRI组相比,ADP组心肌损伤指标明显下降（P<0.05）,而应用LY294002的两组心肌损伤比ADP组加重（P<0.05）。ADP组心肌PI3K、p-Akt、ADPmRNA、ADPR1mRNA和PI3kmRNA表达比MIRI组升高（P<0.05）,应用LY294002两组上述5个指标比MIRI组降低（P<0.05）。结论：ADP后处理对大鼠MIRI有保护作用,ADP/PI3K/Akt通路参与了以上作用。     

The relation between myocardial blush grade and myocardial contrast echocardiography: which one is a better predictor of myocardial damage?

Background. Myocardial blush grade (MBG) and myocardial contrast echocardiography (MCE) are both indices for myocardial perfusion in patients with ST-elevation acute myocardial infarction (STEMI). We aimed to compare MBG with MCE in the infarct-related artery segment for assessing infarct size in patients with STEMI treated with primary percutaneous coronary intervention (PCI).Methods. 43 patients underwent successful (postprocedural TIMI flow 3) primary PCI for STEMI. MBG was assessed at the end of the PCI procedure and MCE was assessed 1.7±1.8 days after PCI. Enzymatic infarct size was estimated by measurementof enzyme activities by using lactate dehydrogenase (LDH) as the referenceenzyme. Cumulative enzyme release (LDHQ₄₈) from at least five serial measurements up to 48 hours after symptom onset was calculated. Also peak creatine kinase, CK-MB and peak LDH were measured.Results. MBG 0/1, 2 and 3 were observed in 14, 12 and 17 patients, respectively, and was compared with tertiles of MCE. We found a parallel correlation between both MBG and MCE and LDHQ₄₈. However, there was no correlation between MCE and MBG. Patients with both normal MCE and a normal MBG had least myocardial damage and those with both impaired MCE and an impaired MBG had most myocardial damage.Conclusion. Both MBG and MCE are good predictors of infarct size in STEMI patients treated with PCI. However, these markers are not mutually related, possibly due to time-related changes in myocardial perfusion. Combining these two markers may yield a more accurate prediction of final myocardial damage. (Neth Heart J 2010;18:25-30.)