Cardioprotective Effect of Licochalcone D against Myocardial Ischemia/Reperfusion Injury in Langendorff-Perfused Rat Hearts

Flavonoids are important components of ‘functional foods’, with beneficial effects on cardiovascular function. The present study was designed to investigate whether licochalcone D (LD) could be a cardioprotective agent in ischemia/reperfusion (I/R) injury and to shed light on its possible mechanism. Compared with the I/R group, LD treatment enhanced myocardial function (increased LVDP, dp/dt _max, dp/dt _min, HR and CR) and suppressed cardiac injury (decreased LDH, CK and myocardial infarct size). Moreover, LD treatment reversed the I/R-induced cleavage of caspase-3 and PARP, resulting in a significant decrease in proinflammatory factors and an increase in antioxidant capacity in I/R myocardial tissue. The mechanisms underlying the antiapoptosis, antiinflammation and antioxidant effects were related to the activation of the AKT pathway and to the blockage of the NF-κB/p65 and p38 MAPK pathways in the I/R-injured heart. Additionally, LD treatment markedly activated endothelial nitric oxide synthase (eNOS) and reduced nitric oxide (NO) production. The findings indicated that LD had real cardioprotective potential and provided support for the use of LD in myocardial I/R injury.     

Eritoran对大鼠肾脏缺血再灌注损伤的保护作用

目的:观察eritoran对大鼠肾脏缺血再灌注损伤模型的.方法:建立SD大鼠缺血再灌注模型,给予eritoran治疗而对照组给予生理盐水治疗,观察各组的肾功能情况、肾组织光镜病理,并采用核糖核酸酶保护测定检测肾组织炎症因子/趋化因子的表达.结果:与模型组相比,eritoran预处理可显著改善大鼠的肾功能,减轻缺血再灌注引起的肾小管损伤,减轻肾组织病变,减少肾组织单核细胞浸润并下调多种炎症因子的表达(TNF-α,IL-6,IL-1β和MCP-1).结论:本研究证实通过eritoran抑制Toll样受体4,可减轻大鼠肾脏缺血再灌注损伤中的炎症反应,减轻肾脏缺血再灌注损伤,eritoran可望成为肾脏I/R损伤的新治疗手段.     

Apelin-13 Inhibits Apoptosis of Cortical Neurons Following Brain Ischemic Reperfusion Injury in a Transient Model of Focal Cerebral Ischemia

Stroke is the third leading cause of death world-wide, affecting 15 million people annually. Diminished blood supply to the brain cells is the main cause of damage following stroke. When focal ischemia occurs, the core of brain tissue influenced by reduced blood supply undergoes necrotic cell death. The adipocytokine Apelin is a peptide that was isolated from a bovine stomach for the first time. This peptide and its receptor are abundantly expressed in the nervous and cardiovascular systems. According to previous studies, Apelin-13 protects cardiomyocytes from ischemic injury and apoptosis. In addition, this peptide has neuroprotective effect on hippocampal and cultured mouse cortical neurons against NMDA receptor-mediated excitotoxicity as well as cortical neurons from ischemic injury. The present study was conducted to determine whether Apelin-13 inhibits apoptosis in the ischemic penumbra in transient focal cerebral ischemia. Focal cerebral ischemia was induced in male Wistar rats by 60 min middle cerebral artery occlusion (MCAO) using a filament method, followed by 23-h reperfusion. Saline as a vehicle and Apelin-13 at doses of 50 and 100 μg were injected intracerebro-ventriculary (ICV) at the beginning of ischemia. Apoptosis and neurological dysfunction were assessed 24-h after MCAO. Our results indicated that administration of Apelin-13 at doses of 50 and 100 μg ICV markedly reduced apoptosis by decreasing positive TUNEL cells (P < 0.001). In addition, Apelin-13 at doses of 100 μg significantly change neurological dysfunction (P < 0.05). Our findings demonstrate that treatment by Apelin-13 exerts its protective effects in ischemic models via blocking programmed cell-death. We suggest that Apelin-13 might be a promising therapeutic target for stroke, although more researches are necessary to take into account the potential therapeutic effects of Apelin-13 in stroke patients.     

Prion Protein Protects against Renal Ischemia/Reperfusion Injury

The cellular prion protein (PrP^C), a protein most noted for its link to prion diseases, has been found to play a protective role in ischemic brain injury. To investigate the role of PrP^C in the kidney, an organ highly prone to ischemia/reperfusion (IR) injury, we examined wild-type (WT) and PrP^C knockout (KO) mice that were subjected to 30-min of renal ischemia followed by 1, 2, or 3 days of reperfusion. Renal dysfunction and structural damage was more severe in KO than in WT mice. While PrP was undetectable in KO kidneys, Western blotting revealed an increase in PrP in IR-injured WT kidneys compared to sham-treated kidneys. Compared to WT, KO kidneys exhibited increases in oxidative stress markers heme oxygenase-1, nitrotyrosine, and N^ε-(carboxymethyl)lysine, and decreases in mitochondrial complexes I and III. Notably, phosphorylated extracellular signal-regulated kinase (pERK) staining was predominantly observed in tubular cells from KO mice following 2 days of reperfusion, a time at which significant differences in renal dysfunction, histological changes, oxidative stress, and mitochondrial complexes between WT and KO mice were observed. Our study provides the first evidence that PrP^C may play a protective role in renal IR injury, likely through its effects on mitochondria and ERK signaling pathways.     

Renal Ischemia/Reperfusion Injury in Soluble Epoxide Hydrolase-Deficient Mice

Aim

20-hydroxyeicosatetraenoic acid (20-HETE) and epoxyeicosatrienoic acids (EETs) are cytochrome P450 (CYP)-dependent eicosanoids that play opposite roles in the regulation of vascular tone, inflammation, and apoptosis. 20-HETE aggravates, whereas EETs ameliorate ischemia/reperfusion (I/R)-induced organ damage. EETs are rapidly metabolized to dihydroxyeicosatrienoic acids (DHETs) by the soluble epoxide hydrolase (sEH). We hypothesized that sEH gene (EPHX2) deletion would increase endogenous EET levels and thereby protect against I/R-induced acute kidney injury (AKI).

Methods

Kidney damage was evaluated in male wildtype (WT) and sEH-knockout (KO)-mice that underwent 22-min renal ischemia followed by two days of reperfusion. CYP-eicosanoids were analyzed by liquid chromatography tandem mass spectrometry.

Results

Contrary to our initial hypothesis, renal function declined more severely in sEH-KO mice as indicated by higher serum creatinine and urea levels. The sEH-KO-mice also featured stronger tubular lesion scores, tubular apoptosis, and inflammatory cell infiltration. Plasma and renal EET/DHET-ratios were higher in sEH-KO than WT mice, thus confirming the expected metabolic consequences of sEH deficiency. However, CYP-eicosanoid profiling also revealed that renal, but not plasma and hepatic, 20-HETE levels were significantly increased in sEH-KO compared to WT mice. In line with this finding, renal expression of Cyp4a12a, the murine 20-HETE-generating CYP-enzyme, was up-regulated both at the mRNA and protein level, and Cyp4a12a immunostaining was more intense in the renal arterioles of sEH-KO compared with WT mice.

Conclusion

These results indicate that the potential beneficial effects of reducing EET degradation were obliterated by a thus far unknown mechanism leading to kidney-specific up-regulation of 20-HETE formation in sEH-KO-mice.     

氨磷汀对氧糖剥夺引起的PC12 细胞缺血再灌注损伤的保护作用研究

目的:研究氨磷汀对体外培养的神经元样细胞的缺血再灌注损伤的保护作用,为其最终用于临床脑缺血的治疗打下基础。方法:体外培养的PC12细胞氧糖剥夺4h后复氧复糖,给予不同浓度的氨磷汀处理,20h后镜下观察细胞形态学变化,用MTT和LDH检测细胞活力和损伤情况,免疫荧光染色观察凋亡细胞,流式细胞仪计数凋亡细胞的比例。结果:高浓度氨磷汀对正常PC12细胞活力有抑制作用(P<0.05),而低浓度则无。氨磷汀可以提高缺血再灌注损伤PC12细胞活力(P<0.05),减少LDH释放(P<0.05),保护细胞正常形态,抑制细胞凋亡(P<0.05)。结论:氨磷汀对氧糖剥夺引起的神经元样细胞的缺血再灌注损伤具有保护作用。     

Vascular Oxidant Stress and Hepatic Ischemia/Reperfusion Injury

The objective of this study was to test the hypothesis that the extracellular oxidation of glutathione (GSH) may represent an important mechanism to limit hepatic ischemia/reperfusion injury in male Fischer rats in vivo. Basal plasma levels of glutatione disulfide (GSSG: 1.5 ± 0.2μM GSH-equivalents), glutathione (GSH: 6.2 ± 0.4 μM) and alanine aminotransferase activities (ALT 12 ± 2U/I) were significantly increased during the l h reperfusion period following l h of partial hepatic no-flow ischemia (GSSG: 19.7 ± 2.2μM; GSH 36.9 ± 7.4μM; ALT: 2260 ± 355 U/l). Pretreatment with 1,3-bis-(2-chloroethyl)-I-nitrosourea (40mg BCNU/kg), which inhibited glutathione reductase activity in the liver by 60%. did not affect any of these parameters. Biliary GSSG and GSH efflux rates were reduced and the GSSG-to-GSH ratio was not altered in controls and BCNU-treated rats at any time during ischemia and reperfusion. A 90% depletion of the hepatic glutathione content by phorone treatment (300 mg/kg) reduced the increase of plasma GSSG levels by 54%, totally suppressed the rise of plasma GSH concentrations and increased plasma ALT to 4290 ± 755 U/I during reperfusion. The data suggest that hepatic glutathione serves to limit ischemialreperfusion injury as a source of extracellular glutathione, not as a cofactor for the intracellular enzymatic detoxification of reactive oxygen species.     

血红素加氧酶-1在缺血/再灌注损伤中的保护作用

血红素加氧酶-1(Heme Oxygenase-1,HO-1)是催化血红素分解的关键酶。近年来,人们对血红素降解产物的抗氧化、抗炎症等功能的认识推动了对HO酶系的研究。缺血／再灌注损伤(IRI)是一个重要的临床问题,而临床上对IRI的防治尚缺乏有效的方法。目前发现HO-1过表达具有抗IRI的作用,其保护作用的可能机制有：抗氧化作用、调节微循环、调节细胞周期和抗炎症作用。     

氨磷汀对氧糖剥夺引起的PC12细胞缺血再灌注损伤的保护作用研究

目的：研究氨磷汀对体外培养的神经元样细胞的缺血再灌注损伤的保护作用,为其最终用于临床脑缺血的治疗打下基础。方法：体外培养的PC12细胞氧糖剥夺4h后复氧复糖,给予不同浓度的氨磷汀处理,20h后镜下观察细胞形态学变化,用MTT和LDH检测细胞活力和损伤情况,免疫荧光染色观察凋亡细胞,流式细胞仪计数凋亡细胞的比例。结果：高浓度氨磷汀对正常PC12细胞活力有抑制作用（P〈0.05）,而低浓度则无。氨磷汀可以提高缺血再灌注损伤PC12细胞活力（P〈0.05）,减少LDH释放（P〈0.05）,保护细胞正常形态,抑制细胞凋亡（P〈0.05）。结论：氨磷汀对氧糖剥夺引起的神经元样细胞的缺血再灌注损伤具有保护作用。     

Dose-Dependent Effects of Astaxanthin on Ischemia/Reperfusion Induced Brain Injury in MCAO Model Rat

Excitotoxicity and oxidative stress are central to the pathology of the nervous system, and inhibition of excitotoxicity induced by glutamate is one of the therapeutic goals determined for stroke. The present study aimed to investigate the effects of Astaxanthin, a potent natural antioxidant, on complications caused by acute cerebral stroke. In this research, 60 male Wistar rats were used which were divided into 5 groups as follow: (1) the sham group (vehicle), (2) the ischemic control group (vehicle), and the ischemic groups treated by Astaxanthin with doses of 25, 45, and 65 mg/kg. In the ischemic groups, ischemic model was performed by middle cerebral artery occlusion (MCAO) method, and the Astaxanthin administration was carried out after the artery occlusion and before opening the artery. The obtained results indicated that Astaxanthin could significantly reduce stroke volume, neurological deficits, and lipid peroxidation. Moreover, it was able to restore total oxidant status (TOS) and caspase 3 level to the normal level. The activity of antioxidant enzyme glutathione peroxidase (GPX), and the expression of catalase, GPx and nuclear factor kappa B (NFκb) genes, which were reduced after ischemia, were increased. This phenomenon was particularly pronounced for glutamate transporter 1 (GLT-1). Furthermore, Astaxanthin decreased the augmented pro-apoptotic gene Bax and restored the reduced Bcl2 expression to the normal level. Significant effects on the P53 and PUMA expression were not observed. Overall, the medium dosage of Astaxanthin appears to be more effective in reducing the complications of ischemia, particularly on our major study endpoints (stroke volume and neurological defects). Longer studies with a more frequent administration of Astaxanthin are required to better understand the precise mechanism of Astaxanthin.

     

丹酚酸A对大鼠脑缺血/再灌注损伤及抗氧化酶活性的影响

目的：探讨丹酚酸A对大鼠脑缺血/再灌注（cerebral ischemia/reperfusion,CI/R）损伤及抗氧化酶活性的影响。方法：采用大鼠脑中动脉闭塞（middle cerebral arteryocclusion,MCAO）2 h再灌注24 h模型。实验终末,检测脑梗死面积,脑水肿以及评价神经功能损伤,并进一步分析脑组织中三种抗氧化酶的活性水平。结果：与模型组相比,丹酚酸A组大鼠脑梗死面积显著减少（P〈0.05）,水肿程度显著减轻（P〈0.05）,神经功能学评分显著下降（P〈0.05）。模型组再灌注24 h后,SOD,GSH-PX及CAT活性显著下降（P〈0.05）;丹酚酸A组SOD,GSH-PX及CAT活性则显著升高（P〈0.05）。结论：丹酚酸A对大鼠CI/R损伤具有保护作用,可能与CI/R损伤时的脑组织SOD,GSH-PX及CAT活性显著升高相关。     

丹酚酸A对大鼠脑缺血/再灌注损伤及抗氧化酶活性的影响

目的:探讨丹酚酸A对大鼠脑缺血/再灌注(cerebral ischemia/reperfusion,CI/R)损伤及抗氧化酶活性的影响。方法:采用大鼠脑中动脉闭塞(middle cerebral arteryocclusion,MCAO)2 h再灌注24 h模型。实验终末,检测脑梗死面积,脑水肿以及评价神经功能损伤,并进一步分析脑组织中三种抗氧化酶的活性水平。结果:与模型组相比,丹酚酸A组大鼠脑梗死面积显著减少(P0.05),水肿程度显著减轻(P0.05),神经功能学评分显著下降(P0.05)。模型组再灌注24 h后,SOD,GSH-PX及CAT活性显著下降(P0.05);丹酚酸A组SOD,GSH-PX及CAT活性则显著升高(P0.05)。结论:丹酚酸A对大鼠CI/R损伤具有保护作用,可能与CI/R损伤时的脑组织SOD,GSH-PX及CAT活性显著升高相关。     

楤木皂苷对大鼠心肌缺血/再灌注损伤的保护作用

目的:观察楤木皂苷(total saponins extracted from Aralia taibaiensis,s AT)对大鼠心肌缺血/再灌注(myocardia1 ischemia/reperfusion,MI/R)损伤的影响。方法:可逆性冠脉左前降支结扎缺血30 min再灌注3 h复制MI/R模型,将SD大鼠随机分为假手术组、模型组、s AT低、中、高剂量组,每组10只。采用伊文思蓝(EB)、2,3,5-氯化三苯基四氮唑蓝(TTC)双染法测定心肌梗死面积,苏木精-伊红(HE)染色法观察心肌病理学形态变化,并检测血清中乳酸脱氢酶(LDH)、肌酸激酶同工酶(CK-MB)、超氧化物歧化酶(SOD)、丙二醛(MDA)、过氧化氢酶(CAT)及谷胱甘肽过氧化物酶(GSH-Px)水平。结果:与模型组比较,s AT中、高剂量组可明显缩小心肌梗死面积(P0.05),并显著降低血清中LDH、CK-MB及MDA的含量,同时使得血清中SOD、CAT和GSH-Px的活性增加。且所有给药组心肌组织的病理损伤也小于模型组。结论:s AT对大鼠MI/R损伤具有保护作用,其机制可能与抗氧化作用相关。     

七氟烷对糖尿病心肌缺血/再灌注损伤的影响

糖尿病是一种常见病、多发病,严重威胁着人类的健康。现已明确,糖尿病是冠心病发病的一个重要因素。心肌缺血/再灌注(ischemia/reperfusion,I/R)损伤是临床常见的病理过程,同时是冠心病发病及心肌血运重建治疗过程中的核心环节,如何减轻I/R损伤一直是国际研究热点之一。糖尿病与I/R损伤对心肌都有损害作用,相关研究证明糖尿病能够进一步恶化I/R损伤对心肌的损伤作用。研究表明,缺血预处理(ischemia preconditioning,IPC)可以延缓或减轻心肌I/R损伤,同时,麻醉药预处理(anesthetic induced preconditioning,APC)也具有IPC样的心肌保护作用。其中,七氟烷作为现阶段临床较常用的吸入麻醉药,同样对心肌I/R损伤具有保护作用。本文就七氟烷对糖尿病心肌I/R损伤的影响及其机制做一综述。     

Ultrasound-Enhanced Protective Effect of Tetramethylpyrazine against Cerebral Ischemia/Reperfusion Injury

In traditional Chinese medicine, Ligusticum wallichii (Chuan Xiong) and its bioactive ingredient, tetramethylpyrazine (TMP), have been used to treat cardiovascular diseases and to relieve various neurological symptoms, such as those associated with ischemic injury. In the present study, we investigated whether ultrasound (US) exposure could enhance the protective effect of TMP against cerebral ischemia/reperfusion (I/R) injury. Glutamate-induced toxicity to pheochromocytoma (PC12) cells was used to model I/R injury. TMP was paired with US to examine whether this combination could alleviate glutamate-induced cytotoxicity. The administration of TMP effectively protected cells against glutamate-induced apoptosis, which could be further enhanced by US-mediated sonoporation. The anti-apoptotic effect of TMP was associated with the inhibition of oxidative stress and a change in the levels of apoptosis-related proteins, Bcl-2 and Bax. Furthermore, TMP reduced the expression of proinflammatory cytokines such as TNF-α and IL-8, which likely also contributes to its cytoprotective effects. Taken together, our findings suggest that ultrasound-enhanced TMP treatment might be a promising therapeutic strategy for ischemic stroke. Further study is required to optimize ultrasound treatment parameters.     

Oxymatrine Alleviates Hyperglycemic Cerebral Ischemia/Reperfusion Injury via Protecting Microvessel

Neurochemical Research - Hyperglycemia aggravates cerebral ischemia/reperfusion (I/R) injury via vascular injury. There is still a lack of effective pharmaceutical preparations for cerebral I/R...     

Secreted Frizzled-related Protein 5 Diminishes Cardiac Inflammation and Protects the Heart from Ischemia/Reperfusion Injury

Wnt signaling has diverse actions in cardiovascular development and disease processes. Secreted frizzled-related protein 5 (Sfrp5) has been shown to function as an extracellular inhibitor of non-canonical Wnt signaling that is expressed at relatively high levels in white adipose tissue. The aim of this study was to investigate the role of Sfrp5 in the heart under ischemic stress. Sfrp5 KO and WT mice were subjected to ischemia/reperfusion (I/R). Although Sfrp5-KO mice exhibited no detectable phenotype when compared with WT control at baseline, they displayed larger infarct sizes, enhanced cardiac myocyte apoptosis, and diminished cardiac function following I/R. The ischemic lesions of Sfrp5-KO mice had greater infiltration of Wnt5a-positive macrophages and greater inflammatory cytokine and chemokine gene expression when compared with WT mice. In bone marrow-derived macrophages, Wnt5a promoted JNK activation and increased inflammatory gene expression, whereas treatment with Sfrp5 blocked these effects. These results indicate that Sfrp5 functions to antagonize inflammatory responses after I/R in the heart, possibly through a mechanism involving non-canonical Wnt5a/JNK signaling.     

Homer1a基因敲除对小鼠局灶性脑缺血再灌注损伤的作用

目的:通过研究homer1a基因敲除小鼠脑缺血再灌注损伤及海马区星形胶质细胞活化、数目形态变化,探讨homer1a基因在脑缺血损伤中的作用及机制。方法:取雄性homer1a基因敲除(Knock Out,KO)小鼠及同窝野生型(Wild Type,WT)小鼠各15只,分为基因敲除假手术组(Sham Knock Out,SKO,n=3)、基因敲除型缺血2 h再灌注24 h组(Model Knock Out,MKO,n=12)、野生型假手术组(Sham Wild Type,SWT,n=3)及野生型缺血2 h再灌24h组(Model Wild Type,MWT,n=12)。线栓法闭塞小鼠大脑中动脉制作脑缺血再灌注损伤模型(middle cerebral artery occlusion and reperfusion,MCAO/R),在缺血再灌注损伤前(0 h)及缺血再灌注后3 h、6 h、12 h、24 h后进行改良版神经损伤严重性评分(modified Neurological severity scores,m NSS)、2,3,5—氯化三苯基四氮唑(2,3,5triphenyltetrazolium chloride,TTC)染色、苏木素—伊红染色(Hematoxylin-eosin staining,HE)、原位末端转移酶标记技术(terminal deoxynucleotidyl transferase(Td T)-mediated deoxyuridine triphosphate(d UTP)nick end labeling,TUNEL)检测及免疫荧光染色观察海马区星形胶质细胞神经纤维酸性蛋白(Glial Fibrillary Acidic Protein,GFAP)改变。结果:SKO组、SWT组行为学m NSS评分均为0分,TTC染色未见梗死灶。TUNLE及GFAP染色阳性细胞数很少且未见统计学差异(P0.05)。脑缺血再灌注24 h后,MKO组m NSS评分较MWT组高;TTC染色MKO组较MWT组梗死百分比高;MKO组较MWT组TUNEL凋亡率高;GFAP免疫荧光染色阳性数MKO组少于MWT组,且均有统计学差异(P0.05)。结论:homer1a基因敲除加重了小鼠脑缺血再灌注损伤,星形胶质细胞可能参与并发挥复杂作用。