Pharmacological action of melatonin in shock, inflammation and ischemia/reperfusion injury

Phosphodiesterase 5 terminates the cellular actions of the second messenger molecule cyclic GMP; inhibitors of phosphodiesterase 5 will therefore increase and prolong the actions of endogenous substances that signal via the cyclic GMP pathway, including nitric oxide released as a neurotransmitter from nitrergic nerves. To date, the most widely used phosphodiesterase 5 inhibitors, zaprinast and sildenafil, have proved vital in the elucidation of the widespread role of cyclic GMP in nitrergic transmission and, specifically in the case of sildenafil, have provided a major breakthrough in the treatment of erectile dysfunction in men. Although still a matter of debate, early evidence indicates that sildenafil may also be of benefit in some forms of sexual dysfunction in women. The remarkable clinical success of sildenafil has prompted the search for further novel phosphodiesterase 5 inhibitors which might be used to enhance nitrergic function in other disease states.     

Gene therapy in liver ischemia and reperfusion injury

Ischemia and reperfusion injury (IRI) is a prime antigen-independent inflammatory factor in the dysfunction of liver transplants. Despite improved allograft preservation and surgical techniques, IRI can still cause up to 10% of early orthotopic liver transplant failure, and can lead to a higher incidence of both acute and chronic graft rejection. Recent advances in gene transfer have resulted in a reduction or inhibition of liver IRI in several experimental models. This review summarizes the development of existing and potential approaches to human gene therapy. These studies aimed at ameliorating I/R injury are focused on the cytoprotective effects in transplant recipients by induction of anti-apoptotic or protective genes, immunoregulation of cytokines or blockade of signaling transduction pathway in graft cells. Although this review focuses on the application of viral mediated gene therapy, new non-viral gene transfer techniques, such as RNA interference (RNAi) application, are discussed. Future advances in gene therapy technology should result in fewer side effects, and thus more acceptable for clinical application, and more successful for organ transplantation.     

The role of cytokines in pharmacological modulation of hepatic ischemia/reperfusion injury

Hepatic ischemia/reperfusion injury is a complication of liver resection surgery, transplantation and hypovolemic shock, leading to local and remote cellular damage and organ dysfunction. This injury is largely a result of an acute inflammatory response characterized by the induction of a cascade of proinflammatory mediators that culminates in the recruitment of leukocytes to the post-ischemic tissue leading to parenchymal cell injury. Endogenous regulatory mechanisms exist to attempt to control this inflammatory response. These include anti-inflammatory cytokines that function to suppress proinflammatory mediator expression. In this review, we address the current knowledge of the pro- and anti-inflammatory cytokine components of the acute liver inflammatory response to ischemia/reperfusion as well as how these cytokines can be manipulated to reduce post-ischemic liver injury.     

TNHH对大鼠全脑缺血再灌注损伤的抗氧化性保护作用

目的观察TNHH对大鼠全脑缺血再灌注损伤的抗氧化性保护作用。方法以改良的四血管阻塞法(Pulsinelli four-vessel occlusion model)建立大鼠全脑缺血模型,于缺血30 min,再灌注48 h后进行脑组织超氧化物歧化酶(SOD)、丙二醛(MDA)、髓过氧化物酶(MPO)测定。结果TNHH能显著降低大鼠缺血损伤脑组织中MDA含量,降低MPO活性,提高SOD活性。结论TNHH对大鼠全脑缺血再灌注损伤的具有明显的抗氧化作用。     

Glutamine contributes to ameliorate inflammation after renal ischemia/reperfusion injury in rats

The aim of this study was to investigate the effects of glutamine in an in vivo rat model of renal ischemia/reperfusion (I/R) injury. Male Wistar rats underwent bilateral renal pedicle clamping for 45 min followed by reperfusion for 6 h. Glutamine (1.5 mg/kg) was administered intraperitoneally (i.p.) 15 min prior to reperfusion. Plasma concentrations of urea, creatinine, γ-glutamyl transferase (γ-GT), and aspartate aminotransferase (AST) were measured for the assessment of renal function and reperfusion injury. Markers of oxidative stress, expression of the pro-inflammatory mediators inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), AT-1 expression, and changes in the oxidative stress-sensitive nuclear factor kappa B (NF-κB) signaling pathway were measured to investigate whether glutamine can reduce the renal dysfunction. Kidney myeloperoxidase (MPO) activity and malondialdehyde (MDA) levels were measured for assessment of polymorphonuclear (PMN) cell infiltration and lipid peroxidation, respectively. Renal sections were used for histologic grading of renal injury and for immunohistochemical localization of nitrotyrosine and poly(ADP-ribose) synthetase (PARS). In vivo, glutamine significantly reduced the increase in urea, creatinine, γ-GT, AST, produced by renal ischemia/reperfusion (I/R), suggesting an improvement in both renal function and injury. Glutamine significantly reduced iNOS and NF-κB, kidney MPO activity and MDA levels, indicating a reduction in PMN infiltration and lipid peroxidation, respectively. Glutamine reduced the histological evidence of renal damage associated with I/R and caused a substantial reduction in the staining for nitrotyrosine and PARS, suggesting reduced nitrosative and oxidative stress. Moreover, glutamine attenuated the reduction of COX-2 expression and prevented the increased AT-1 expression after I/R. Our results suggest that glutamine reduces the renal dysfunction and injury associated with I/R of the kidney.     

Ozone oxidative preconditioning inhibits inflammation and apoptosis in a rat model of renal ischemia/reperfusion injury

Ischemia/reperfusion injury, which is commonly seen in the field of renal surgery or transplantation, is a major cause of acute renal failure. Previous studies showed that ozone oxidative preconditioning (OzoneOP) attenuated renal ischemia/reperfusion injury. The objective of this study was to examine the role of the OzoneOP in modulating inflammation and apoptosis after renal ischemia/reperfusion injury. Rats were subjected to 45 min of renal ischemia, with or without treatment with OzoneOP (1 mg/kg). Renal function, inflammation and apoptosis were compared at 24 h after renal injury. OzoneOP improved the renal dysfunction and reduced inflammation and apoptosis after ischemia/reperfusion injury. In conclusion, OzoneOP has potent anti-apoptotic and anti-inflammatory properties. These findings may have major implications in the treatment of human ischemic acute renal failure.     

Antioxidant therapy for prevention of inflammation, ischemic reperfusion injuries and allograft rejection

Oxidative stress results from an imbalance, an excess of oxidants, depletion of antioxidants or failure to repair oxidative damage induced by reactive oxygen species. A vast amount of evidence implicates oxygen-derived free radicals and high-energy oxidants as mediators in many pathological conditions of inflammation, shock, and organ responses to ischemia/reperfusion, which arise during a number of clinical surgical interventions, including transplant graft rejection and coronary bypass surgery, and in such diseases as, diabetes, atherosclerosis, hypertension, organ ischemia/reperfusion, cardiovascular inflammation, cardiac/brain infarction, cancer, pulmonary emphysema and autoimmune diseases. To eliminate or attenuate oxidative stress, antioxidant therapies have been developed and may be of great help to these patients. This review describes recent developments in the field of oxidative stress research and antioxidant function, summarizes new pharmacological strategies that are ongoing in antioxidant therapy with small molecules, free radical-scavenging enzymes, superoxide dismutases, catalase mimetics, flavonoids, vitamins and poly polymerase inhibitors, and presents experimental and clinical evidence of the role of antioxidants in diseases.     

杜鹃花总黄酮药理性预处理对大鼠心肌缺血/再灌注损伤中炎症反应的影响

目的观察杜鹃花总黄酮(total flavones of rhododendra,TFR)药理性预处理对大鼠心肌缺血/再灌注损伤的保护作用及其对心肌细胞炎症反应的影响。方法在Langen-dorff离体灌流大鼠心脏,采用停灌K-H液30min后再灌注40min的方法制备大鼠心肌缺血/再灌注损伤模型。TFR药理性预处理(TFR pharmacological preconditioning,TFR-PP)大鼠心脏,在缺血前灌注含TFR的K-H液5min,然后用不含TFR的K-H液灌注5min,如此反复,共3次。观察心肌组织病理学损伤,心肌组织中肌酸激酶(CK)、乳酸脱氢酶(LDH)及髓过氧化物酶(MPO)活力的变化,心肌组织中核因子-κB(NF-κB)、肿瘤坏死因子-α(TNF-α)、细胞间粘附分子-1(ICAM-1)的表达。结果在Langendorff离体灌流模型中,TFR-PP(50、100mg.L-1)可明显抑制缺血/再灌注大鼠心肌组织中CK和LDH活性的降低,同时能明显改善心肌组织病理学损伤;TFR-PP(25、50、100mg·L-1)能不同程度的抑制心肌组织中MPO的增加及NF-κB、TNF-α、ICAM-1的表达。结论TFR药理性预处理对大鼠离体心脏缺血/再灌注损伤有明显保护作用,其作用可能与抑制心肌细胞炎症反应有关。     

心肌缺血/再灌注损伤与炎症反应

动物实验及临床研究均支持炎症反应参与了心肌缺血/再灌注损伤的过程,但炎症本身及其对心肌缺血/再灌注损伤的影响相当复杂。心肌缺血/再灌注后,在缺血损伤区有多种细胞因子表达及炎细胞浸润,构成了缺血再灌注损伤向炎症性损伤转变的基础。本文对几种炎症反应中的细胞因子、炎症细胞、花生四烯酸代谢产物及环氧合酶等在心肌缺血再灌注中的作用作一综述。     

Magnesium lithospermate B reduces myocardial ischemia/reperfusion injury in rats via regulating the inflammation response

Abstract

Context: Magnesium lithospermate B (MLB), an active polyphenol acid of Danshen [Radix Salviae miltiorrhizae (Labiatae)], showed renoprotective, neuroprotective and myocardial salvage effects. Previous studies demonstrated that MLB could effectively suppress the production of cytokines and their associated signaling pathways in activated human T cells.

Objective: The purpose of this study was to examine the beneficial effects of MLB on myocardial ischemia/reperfusion (MI/R) injury and to explore its potential mechanisms related to anti-inflammation.

Materials and methods: Sprague–Dawley rats were grouped as sham group, model group and MLB-treated (15, 30 and 60?mg/kg) groups. Animals were subjected to MI/R injury by the occlusion of left anterior descending artery for 30?min followed by reperfusion for 3?h. At the end of reperfusion, blood samples were collected to determine the serum levels of cardiac troponin (cTnI), creatine kinase-MB (CK-MB), tumor necrosis factor-α (TNF-α), interleukin 1β (IL-1β) and interleukin 6 (IL-6). Hearts were harvested to assess infarct size, histopathological changes and the activity of myeloperoxidase (MPO). The expression of phosphor-IkB-α and phosphor-nuclear factor kappa B (NF-κB) were assayed by western blot.

Results: MLB administration significantly (p?<?0.05) reduced: (1) ST-segment elevation (0.23?mv), (2) the infarct size (22.5%), (3) histological scores of myocardial injury (1.67 score), (4) myocardial injury marker enzymes: cTnI (5.64?ng/ml) and CK-MB (49.57?ng/ml) levels, (5) pro-inflammatory cytokines: TNF-α (97.36?pg/ml), IL-1β (93.35?pg/ml) and IL-6 (96.84?pg/ml) levels, (6) MPO activity (1.82?U/mg), (7) phosphor-NF-κB (0.87) and phosphor-IkB-α (0.96) expression.

Discussion and conclusion: Our study provided evidence that MLB ameliorated the inflammatory process associated with MI/R injury via NF-κB inactivation.     

地尔硫卓对心脏缺血/再灌注后心肌炎症的影响

目的探讨地尔硫卓对心脏缺血/再灌注后炎症细胞和细胞因子表达的影响。方法建立大鼠缺血/再灌注模型,存活鼠随机分为地尔硫卓组(D组)和缺血/再灌注组(I/R组),另设假手术组(S组)。分别在术后1、2和4wk检测各组大鼠超声心动图、心肌炎症细胞浸润及致炎因子IL-1β、TNF-α、IL-6及抗炎因子IL-10、TGF-β的表达。结果与IR组比较,超声心动图显示D组射血分数和左室重量明显改善,心肌组织炎症细胞浸润减少,致炎因子TNF-α、IL-1β、IL-6表达减少,抗炎因子IL-10、TGF-β呈现低水平表达。结论地尔硫卓减少心肌缺血;再灌注损伤后炎症细胞浸润和致炎因子表达,保护心脏功能。     

亚甲蓝对创伤性休克兔肺损伤的保护作用

目的通过测定创伤性休克兔血浆超氧化物歧化酶（SOD）、丙二醛（MDA）变化以及肺组织病理学改变,评价亚甲蓝（MB）对创伤性休克的疗效及对肺缺血再灌注损伤的保护作用。方法将日本长耳大白兔18只随机分为3,组：对照组、创伤性休克生理盐水复苏组（NS组）和创伤性休克MB复苏组（MB组）,每组6只,记录休克前（T4）、休克末（T2）、复苏末（T3）,复苏后0．5h（T4）、2h（T5）、4h（T6）时间点平均动脉压（MAP）的变化,并测定血浆SOD、MDA,复苏后4h放血处死动物,取肺测定肺叶湿重／干重比,并观察肺形态病理学变化。结果对照组SOD、MDA在各时间点变化不明显。另外2组在MDA水平变化明显升高,且生理盐水复苏组高于MB复苏组（P〈0．05）,SOD明显降低,生理盐水复苏组明显低于MB复苏组（P〈0．05）。肺组织病理学观察显示亚甲蓝对缺血再灌注损伤肺具有保护作用。结论亚甲蓝可能通过抑制氧自由基（ROS）的过度生成,对创伤性休克及其引起的缺血再灌注肺损伤（L／R）产生保护作用。     

Inhibition of post-ischaemic inflammation as a therapeutic approach to myocardial ischaemia reperfusion injury

Reperfusion injury of the heart remains an untreated condition even though reperfusion strategies have been successfully implemented in the clinical standard. Accordingly, low or no reflow phenomena with subsequent myocardial infarction, myocardial and endothelial stunning as well as arrhythmias remain aspects of reperfusion injury of the heart. Since leukocyte recruitment has been linked to these phenomena, inhibition of leukocyte adhesion and of the subsequent post-ischaemic inflammation of the heart has emerged as a therapeutic goal. Around 40 patents from 1997 to the first quarter of 2000 are implicitly or explicitly aimed at myocardial reperfusion injury.     

Antioxidant nutrients and hypoxia/ischemia brain injury in rodents

Cerebral ischemia and recirculation cause delayed neuronal death in rodents, such as Mongolian gerbils and stroke-prone spontaneously hypertensive rats (SHRSP), which were used as an experimental stroke model. It was documented that an enhanced nitric oxide production, the occurrence of apoptosis, and an attenuated redox regulatory system contribute to the development of delayed neuronal death. Many studies have suggested the beneficial antioxidant effects of antioxidant nutrients such as vitamin E, green tea extract, ginkgo biloba extract, resveratrol and niacin in cerebral ischemia and recirculation brain injury. These results are important in light of an attenuation of the deleterious consequences of oxidative stress in ischemia and recirculation injury.     

Aprotinin ameliorates ischemia/reperfusion injury in a rat hind limb model

The aim of the study was to investigate the protective effect of aprotinin in a rat hind limb ischemia/reperfusion (I/R) model. A well-known antioxidant, alpha-tocopherol, was also tested for comparison. Ischemia was induced for 4 h by vascular clamping of the iliac arteries of 24 Sprague-Dawley rats, followed by 1 h of reperfusion. Muscle injury was evaluated in three groups: a saline group, an alpha-tocopherol group and an aprotinin group. Blood pH, pO2, pCO2, HCO3, creatine kinase (CPK), lactate dehyrogenase (LDH) and thiobarbituric acid reactive substances (TBARS) as well as muscle TBARS were measured at the end of the reperfusion. Muscle tissue samples were taken for histological examination. alpha-Tocopherol and aprotinin groups showed a significant amelioration of plasma CPK (p=0.002, p=0.002), LDH (p=0.004, p=0.004) and muscle tissue TBARS (p=0.001, p=0.001) compared with the control. Plasma TBARS were significantly lower in the aprotinin group compared with the control (p=0.017). Also, tissue TBARS was significantly lower in the aprotinin group than the alpha-tocopherol group (p<0.001). Neutrophil infiltration was less prominent in the alpha-tocopherol and aprotinin groups compared to the control (p=0.006, p=0.001). These results suggest that aprotinin, a potent anti-inflammatory drug, is more useful than alpha-tocopherol, a powerful antioxidant, for attenuating muscle injury after I/R.     

甜菜碱对大鼠心肌缺血再灌注损伤炎症及心肌细胞凋亡的影响

目的 探讨甜菜碱对大鼠心肌缺血再灌注（IR）损伤的影响及发生机制。方法 选用成年雄性SD大鼠18只,采用随机数字表分为假手术组（SO组）、缺血再灌注组（IR组）及甜菜碱组（450 mg/kg灌胃）,每组6只大鼠。SO组：开胸,前降支动脉下穿线不结扎,IR组和甜菜碱组：开胸,缺血30 min,再灌注4 h。ELISA法检测并比较3组大鼠心肌损伤标记物乳酸脱氢酶（LDH）、肌酸激酶b（CK-Mb）和肌钙蛋白I（cTnI）和检测炎症因子（HMGB1、IL-17A、IL-6以及TNF-α）的表达。Western Blot法检测并比较3组大鼠心肌组织凋亡蛋白（caspase-3,Bcl-2和Bax）的相对表达量。结果 与SO组比较,IR组中心肌损伤标记物（CK、LDH和cTnI）、炎症因子和凋亡蛋白的表达均增高,差异均有统计学意义（P<0.05）。与IR比较,甜菜碱组心肌损伤标记物、炎症因子和凋亡蛋白的表达下降,抗凋亡蛋白Bcl-2的表达增加,差异有统计学意义（P<0.05）。结论 甜菜碱可以通过抑制炎症反应和心肌细胞凋亡减轻大鼠心肌IR损伤。     

内洋地黄素通过影响细胞凋亡和炎症相关基因表达介导心肌缺血再灌注损伤

目的：利用信号转导基因芯片观察心肌缺血再灌注（myocardial ischemia reperfusion,MIR）时心肌凋亡和炎症相关基因表达变化,以及内洋地黄素特异性拮抗剂地高辛抗体对它们的影响,证明内洋地黄素通过影响细胞凋亡和炎症相关基因表达介导MIR损伤,完善内洋地黄素介导MIR损伤的作用机制。方法：采用结扎大鼠左冠状动脉前降支30min,复灌60min制作在体大鼠MIR模型。SD大鼠随机分成3组,每组3只,分别为假手术组、MIR组、地高辛抗血清组,各组于再灌注60min后立即取左室心尖部缺血区心肌,应用基因芯片技术检测心肌凋亡和炎症相关基因表达。结果：与假手术组比较,MIR组Bax、Bcl-2、Bcl-2L1和Birc1b等凋亡相关基因表达下调,但Bcl-2/Bax比率下降;IL、TNF、ICAM-1等介导炎症相关基因表达有上调或是上调趋势。与MIR组比较,地高辛抗血清组Bax、Bcl-2和Birc3等相关凋亡基因表达均上调,但Bcl-2/Bax比率上升;IL、TNF、ICAM-1等介导炎症相关基因表达下调或是下调趋势。结论：内洋地黄素具有下调抑制凋亡基因表达和上调炎症基因表达作用,内洋地黄素拮抗剂地高辛抗血清通过拮抗内源性洋地黄素,阻断后者的下调抑制心肌凋亡相关基因和上调炎症相关基因表达的作用而发挥心肌保护作用。     

Matrix metalloproteinases as drug targets in ischemia/reperfusion injury

Deficient blood supply (ischemia) is a common consequence of some surgical procedures and certain pathologies. Once blood circulation is re-established (reperfusion), a complex series of events results in recruitment of inflammatory cells, rearrangement of the extracellular matrix and induction of cell death, which lead to organ dysfunction. Although ischemia/reperfusion (I/R) injury is an important cause of death, there is no effective therapy targeting the molecular mechanism of disease progression. Matrix metalloproteinases (MMPs), which are important regulators of many cellular activities, have a central role in disease progression after I/R injury, as suggested by numerous studies using MMP inhibitors or MMP-deficient mice. Here, we review the involvement of MMP activity in the various processes following I/R injury and the therapeutic potential of MMP inhibition.     

Antioxidants in the prevention of myocardial ischemia/reperfusion injury

In acute myocardial ischemia (AMI) the optimal treatment is rapid revascularization by angioplasty or pharmacological thrombolysis. While this is essential to resuscitate the ischemic myocardium, it results in further reperfusion injury and extension of the infarction. The main hypothesis for the mechanism of reperfusion injury is the generation of reactive oxygen species (ROS) to such a degree that endogenous antioxidant mechanisms are overcome and tissue injury results. There is growing evidence that ROS-induced injury may continue for weeks to months as a result of activation of apoptosis. In the longer term, this may result in ventricular remodeling and cardiac failure. Although a number of antioxidants have produced beneficial effects in animal models of AMI, none have proved efficacious in subsequent clinical trials. Drugs that are more specific for the source of ROS generation and that are better able to target the sources of oxidant stress may have greater potential for the prevention of reperfusion injury.     

Cyclosporine protects against ischemia/reperfusion injury in rat kidneys

Renal ischemia followed by reperfusion leads to acute renal failure in both native kidneys and renal allografts. Cyclosporine A (CsA) has been used as an immunosuppressive agent in organ transplantation. In the present study, the effect of CsA on ischemia/reperfusion (I/R)-induced injury in the kidney was investigated. Ischemia/reperfusion injury caused a significant deterioration in the renal function, morphology and gave rise to a severe oxidative stress in the kidney. At 3 mg/kg i.v., CsA significantly improved the functional and histological parameters and attenuated the oxidative stress induced by renal ischemia/reperfusion. From the results of our study, it can be concluded that low-dose CsA pretreatment preconditions the rat kidneys against subsequent ischemia/reperfusion injury.