Nitrosoglutathione modulation of platelet activation and nitric oxide synthase expression in promotion of flap survival after ischemia/reperfusion injury

BACKGROUND: Recent studies have shown that platelets play an important role in the pathogenesis of reperfusion injury. Using an inferior epigastric artery skin flap as a flap ischemia/reperfusion (I/R) injury model, we investigated whether the administration of a nitric oxide (NO) donor, nitrosoglutathione (GSNO), could decrease platelet activation and modulate the NO synthase (NOS) activity of platelets and promote flap survival. METHODS: Thirty minutes before flap reperfusion, normal saline (1 mL), nitrosoglutathione (GSNO 0.2, 0.6, 3 mg/kg), or N(G)-nitro-L-arginine-methyl ester (450 mg/kg) was injected intravenously in 10 rats, respectively. The p-selectin (CD62P) expression of platelet activation was detected by a flow cytometry. Immunohistochemical staining was performed to investigate the CD62P deposition on the microvasculature of the flap vessels. NOS isoform expression in the platelets was evaluated by Western blot. Tissue perfusion was monitored by using laser-Doppler flowmetry. Survival areas were assessed at 7 days postoperatively RESULTS: An optimal dose of GSNO (0.6 mg/kg), significantly decreased in CD62P expression on platelets (P < 0.001) and its deposition on the flap vessels, selectively suppressed iNOS induction of platelet, and significantly improved blood perfusion and the flap survival rate (59.8 +/- 4.9% versus 22.1 +/- 6.1%, P < 0.001). In contrast, the NO synthase inhibitor, N(G)-nitro-l-arginine methyl ester, although inhibiting iNOS expression of platelets, compromised platelet activation, tissue perfusion, and flap survival. CONCLUSION: This study suggests that GSNO can appropriately donate NO to suppress platelet activation and platelet iNOS induction, resulting in less platelet activation, better blood perfusion, and flap survival after I/R injury.     

缺血-再灌注损伤对扩张皮瓣转移术后的影响

目的：探讨缺血-再灌注损伤对扩张皮瓣转移术后的影响。方法：以实验兔每侧腹壁浅动脉为中线,于两侧腹部植入50ml软组织扩张器各一只,术后定期注水扩张至80ml为止。分别于扩张皮瓣转移前、转移后1h、24h、72h检测腹壁浅动脉血流速度,切取皮瓣远端组织在200倍光镜下进行白细胞计数,检测皮瓣组织中丙二醛（MDA）、髓过氧化物酶（MPO）含量。结果：扩张皮瓣转移前腹壁浅动脉的血流速度为（13.2±0.78）cm/s,光镜下白细胞计数为（8.33±2.61）个,皮瓣组织内MDA含量为（1.72±0.57）nmol/mgprot,MPO含量为（126.50±20.70）U/g。皮瓣转移术后1h血流速度为（6.22±0.93）cm/s,白细胞计数为（19.08±4.94）个,MDA含量为（4.05±0.67）nmol/mgprot,MPO含量为（349.42±27.27）U/g。皮瓣转移术后24h血流速度为（8.37±0.56）cm/s,白细胞计数为（60.17±6.24）个,MDA含量为（6.68±0.73）nmol/mgprot,MPO含量为（558.08±26.99）U/g。皮瓣转移术后72h血流速度为（17.36±1.06）cm/s,白细胞计数为（34.00±3.79）个,MDA含量为（2.51±0.41）nmol/mgprot,MPO含量为（215.92±25.97）U/g。结论：在扩张皮瓣转移术后发生缺血-再灌注的过程中,皮瓣组织发生再灌注损伤。     

心磷脂与缺血/再灌注损伤

心磷脂（CL）是维持线粒体能量代谢所必需的一种磷脂，参与了众多重要生理过程。此文对CL的结构、合成和转化；在维持线粒体正常功能中的作用；缺血／再灌注（I／R）损伤中的改变以及和线粒体功能的关系等作了逐一阐述，说明CL与I／R损伤导致的细胞死亡关系密切，CL量或性质的改变在细胞凋亡中处于中心地位。     

血小板活化因子与脑缺血/再灌注损伤

血小板活化因子(plateht-activating factor,PAF)是由体内多种细胞在特定条件下所释放的一种活性强大的内源性介质.PAF在脑缺血,再灌注损伤中含量明显增高,对脑缺血,再灌注损伤的发生和发展可能起着主导作用.PAF的作用是由其特异性受体(一种G蛋白耦联受体)所介导的.PAF受体拮抗剂能通过降低PAF的浓度以及抑制PAF受体活性来减轻其脑损伤效应,从而起到脑保护作用.     

Mannan-binding lectin mediates renal ischemia/reperfusion injury independent of complement activation

Ischemia/reperfusion injury (IRI) remains a major problem in renal transplantation. Clinical studies have identified that high serum levels of Mannan-binding lectin (MBL), the initiator of the lectin pathway of complement activation, are associated with inferior renal allograft survival. Using a rat model, we identified an entirely novel role for MBL in mediating renal IRI. Therapeutic inhibition of MBL was protective against kidney dysfunction, tubular damage, neutrophil and macrophage accumulation, and expression of proinflammatory cytokines and chemokines. Following reperfusion, exposure of tubular epithelial cells to circulation-derived MBL resulted in internalization of MBL followed by the rapid induction of tubular epithelial cell death. Interestingly, this MBL-mediated tubular injury was completely independent of complement activation since attenuation of complement activation was not protective against renal IRI. Our identification that MBL-mediated cell death precedes complement activation strongly suggests that exposure of epithelial cells to MBL immediately following reperfusion is the primary culprit of tubular injury. In addition, also human tubular epithelial cells in vitro were shown to be susceptible to the cytotoxic effect of human MBL. Taken together, these data reveal a crucial role for MBL in the early pathophysiology of renal IRI and identify MBL as a novel therapeutic target in kidney transplantation.     

缺血再灌注对大鼠岛状浅筋膜瓣超微结构的损伤及Verpamil的作用观察

探讨Ｖｅｒｐａｍｉｌ对大鼠皮瓣超微结构缺血再灌注损伤的保护作用。建立ＳＤ大鼠腹壁浅筋膜岛状皮瓣模型，缺血５小时再灌注２０分钟，在电子显微镜下观察其超微结构的变化，并用Ｖｅｒｐａｍｉｌ作保护性对比。损伤以细胞膜和线粒体为主，Ｖｅｒｐａｍｉｌ组的损伤明显减轻。实验结果提示，Ｖｅｒｐａｍｉｌ对皮瓣的超微结构具有保护作用。     

Role of leukotrienes on hepatic ischemia/reperfusion injury in rats

BACKGROUND: Leukotrienes (LT), composed of cysteinyl LT (cLT; LTC(4), LTD(4), and LTE(4)) and LTB(4), are potent lipid mediators enhancing the vascular permeability and recruitment of neutrophils, which are common features of hepatic ischemia/reperfusion (I/R) injury. The aim of this study was to investigate whether LT can mediate the liver and lung injuries following hepatic I/R. MATERIALS AND METHODS: Sprague-Dawley rats were subjected to 90 min of partial hepatic ischemia followed by 3, 12, and 24 h of reperfusion. In the hepatic and pulmonary tissues, LT content and the mRNA expression of LT-synthesis enzymes, 5-lypoxygenase (5-LO), LTC(4) synthase (LTC(4)-S), and LTA(4) hydrolase (LTA(4)-H) were measured. Tissue injuries were assessed by plasma ALT, histological examination, and wet-to-dry tissue weight ratios. RESULTS: The cLT content in the hepatic tissue after 12 and 24 h reperfusion was increased 4- to 5-fold compared to controls and this was accompanied by the enhancement of hepatic edema and plasma ALT elevation. There were no significant changes in the mRNA expression of LT-synthesis enzymes in both tissues. LTB(4) levels were not increased despite a significant neutrophil infiltration in both tissues. CONCLUSIONS: These data suggest that cLT are generated in the liver during the reperfusion period and may contribute to the development of hepatic edema and exert cytotoxicity. Factors other than LTB(4) may contribute to neutrophil infiltration.     

肢体缺血预处理减轻肝缺血/再灌注损伤的研究进展

背景 肝缺血/再灌注损伤(hepatic ischemia/reperfusion injury,HI/RI)是肝外科手术及肝移植中常见的病理生理现象,是术后肝功能衰竭和移植物无功能的主要原因.研究表明肢体缺血预处理(limb ischemia preconditioning,LIPC)可减轻HI/RI,具体机制仍不清楚.目的 通过综述LIPC减轻HI/R1的可能机制,为临床减轻HI/RI提供新的思路.内容 介绍HI/RI机制及LIPC减轻HI/RI的可能作用机制.趋向 LIPC作为减轻HI/RI的措施具有重大的临床应用价值.     

针刺预处理对脑缺血/再灌注损伤的保护作用

针刺预处理的脑保护可能机制如下:减轻脑水肿和微血管损伤,增加脑血流量,影响缺血脑组织在病理形态学及超微结构改变,有利于维持细胞内外离子的稳态,对抗自由基损伤及脂质过氧化反应.并影响细胞因子、神经递质及脑细胞信号转导、凋亡调节基因等;针刺预处理对脑缺血/再灌注的保护效果表现为其穴位、刺激频率和刺激持续时间上的特异性.     

心肌缺血再灌注损伤的线粒体通透性转换机制

线粒体功能障碍存心肌缺血再灌注（ischema／reperfusion I／R）损伤中占有重要地位．近年研究发现线粒体的功能障碍和线粒体通透性转换孔道（mitochondfial permeability transition pore，mPTP）密切相关，     

酮替酚和复合物48/80对肠缺血/再灌注大鼠生存率的影响

目的 观察肠缺血及再灌注后应用酮替酚和复合物48/80对大鼠生存率的影响.方法 96只健康清洁级SD大鼠(200 g～250 g)随机分为4组:S组(假手术组)、M组(缺血/再灌注组)、K组(模型+酮替酚组)及CP组(模型+复合物48/80组),每组24只.建立肠缺血75 min再灌注损伤模型.K组及CP组在再灌注前5 min及再灌注后3 d内每天分别静脉注射酮替酚1 mg/kg及复合物48/80 0.75 mg/kg,S组、M组分别给予等量生理盐水.观察各组动物第3天存活率,第3天存活大鼠肠黏膜病理及超微结构的变化,并测定血清天冬氨酸转氨酶(AST)、丙氨酸转氨酶(ALT)、AST/ALT比值(S/L)、总蛋白(TP)、白蛋白(ALB)、球蛋白(GLB)、白蛋白/球蛋白比值(A/G)、磷酸肌酸激酶(CK)、乳酸脱氢酶(LDH)、尿素氮(BUN)及肌酐(CRE).结果 与S组比较:M组存活率与TP、ALB及GLB明显降低,S/L明显升高(P<0.05),肠黏膜超微结构受损.与M组比较:K组存活率明显升高(P<0.05)和肠黏膜超微结构受损减轻;CP组存活率明显降低(P<0.05),肠黏膜超微结构受损加重.Chiu's评分各组间无统计学差异(P>0.05).CP组AST明显高于M组与K组;S/L及LDH明显高于K组(P<0.05).结论 缺血后应用酮替酚能够增加肠缺血/再灌注大鼠生存率.     

阿片类药物减轻急性缺血/再灌注损伤及相关机制

背景 缺血预处理对于器官缺血/再灌注损伤（ischemia/reperfusion injury,I/RI）具有强大的保护作用,但其临床应用受到时机以及伦理学的限制.近年来有研究发现阿片类药物预处理以及后处理对组织器官I/RI同样具有保护作用,其既不损伤器官又能产生与缺血预处理相同的效果,是更为可行的治疗措施. 目的 在将阿片类药物处理推广至临床应用前,仍需进行更多大规模的临床研究.拟就阿片类处理减轻I/RI的发展过程及其作用机制进行探讨. 内容 阿片类药物处理I/RI的几种方式及其机制. 趋向 阿片类药物处理比较其他损伤性处理方式更易操作,且对I/RI同样具有保护作用,有望成为日后治疗的热点之一.     

电针对脑缺血/再灌注损伤的神经保护的研究进展

背景 中国针灸用于中风等神经系统疾病的治疗有悠久的历史和丰富的临床经验.电针是传统针灸与现代电学技术相结合的治疗方式,它对脑缺血/再灌注损伤(ischemia/reperfusion injury,I/RI)的病理演变有重要影响.目的 探讨电针的神经保护及其机制.内容 依照脑I/RI的病理生理机制,分析与总结电针对脑I/RI的保护作用及其机制. 趋向 电针在运用补充与替代疗法预防、治疗或辅助治疗脑I/RI方面有良好的发展前景.     

心肌缺血/再灌注损伤分子信号保护机制的研究进展

缺血/再灌注损伤是一种常见的病理生理改变,近些年来,随着对其机制的大量研究,缺血/再灌注损伤的分子信号保护机制有了许多新的进展.腺苷激动腺苷2A受体(A2AAR),通过Gs蛋白-cAMP信号轴抑制与再灌注相关的炎症反应起保护作用.激活的阿片受体是通过抗细胞凋亡自身激酶信号路径的相互作用来减少再灌注损伤的.缺血后处理的机制也可能涉及到内源性腺苷释放增加.     

Protective effects of propofol against ischemia/reperfusion injury in rat kidneys

Aim: The purpose of this study was to investigate and compare the efficiency of propofol in the reduction of injury induced by free radicals in a rat model of renal ischemia/reperfusion (I/R). Method: Twenty-four Wistar rats were divided into four groups in our study. Rats in the sham group underwent laparotomy and were made to wait for 120 min without ischemia. Rats in the control group were given nothing with ischemia–reperfusion. Rats in the I/R groups were given propofol (25 mg/kg) and 10% intralipid (250 mg/kg) ip, respectively, 15 min before the ischemia for 60 min followed by reperfusion for 60 min. The kidney tissues of the rats were taken under anesthesia at the end of the reperfusion period. Evaluation of biochemical malondialdehyde (MDA), superoxide dismutase, and catalase activities and histopathological analysis were performed with these samples. Results: I/R significantly increased MDA levels (p < 0.05). Histopathological findings of the control group confirmed that there was renal impairment by tubular cell swelling, interstitial edema, medullary congestion, and tubular dilatation. MDA levels were lower in the propofol group compared to control group (p < 0.05). In the propofol group, the level of histopathological scores is significantly decreased than control and intralipid groups in ischemia–reperfusion. Conclusion: Our results demonstrate that I/R injury was significantly reduced in the presence of propofol. The protective effects of propofol may be due to their antioxidant properties. These results may indicate that propofol anesthesia protects against functional, biochemical, and morphological damage better than control in renal I/R injury.     

中性粒细胞与心肌缺血/再灌注损伤

背景 现已明确,炎症过程是心肌缺血/再灌注损伤(ischemia/reperfusion injury,I/RI)最重要的致病因素之一,而中性粒细胞是炎症反应的核心介导者.针对中性粒细胞的这种致病作用,部分研究者提出了抗中性粒细胞治疗,但是治疗效果却不尽相同,甚至大相径庭.更有研究者指出,中性粒细胞在心肌I/RI中尚发挥着一定的有益作用.针对这种现状,我们在此将中性粒细胞与心肌I/RI作一综述. 目的 评价中性粒细胞在心肌I/RI致病机制中的作用,探索抗中性粒细胞治疗的方向.内容 包括中性粒细胞对心肌I/RI的致病作用,抗中性粒细胞治疗的现状及其当前存在矛盾之处. 趋向 通过全面理解中性粒细胞在心肌I/RI中的作用,为今后进行适度的抗中性粒细胞治疗提供参考,并为今后发展多靶向联合措施治疗心肌I/RI提供思路.     

甘露醇对脑缺血/再灌注损伤后干预效果评价的实验研究

目的 探索脑缺血/再灌注损伤(ischemia/reperfusion injury,I/RI)后甘露醇干预的最佳时机.方法 健康昆明小鼠36只,制备I/RI模型后,按随机数字表法分为6组(每组6只):假手术组(A组)、对照组即I/RI组(B组)和再灌注即刻、30 min、1、1.5 h甘露醇干预组(分别为C、D、E和...     

Hypoxia-inducible factor prolyl hydroxylase inhibitor roxadustat (FG-4592) protects against renal ischemia/reperfusion injury by inhibiting inflammation

Hypoxia-induced inflammation is the critical pathological feature of acute kidney injury (AKI). Activation of hypoxia-inducible factor (HIF) signaling is considered as a central mechanism of body adapting to hypoxia. Hypoxia-inducible factor prolyl hydroxylase inhibitor FG-4592 (Roxadustat) is a first-in-class HIF stabilizer for the treatment of patients with renal anemia. The current study aimed to investigate whether FG-4592 could protect against ischemia/reperfusion (I/R)-induced kidney injury via inhibiting inflammation. Here, efficacy of FG-4592 was evaluated in a mice model of I/R-induced AKI. Interestingly, improved renal function and renal tubular injuries, combined with reduced kidney injury molecule-1 were observed in the mice with FG-4592 administration. Meanwhile, inflammation responses in FG-4592-treated mice were also strikingly attenuated, as evidenced by the decreased infiltration of macrophages and neutrophils and down-regulated expression of inflammatory cytokines. In vitro, FG-4592 treatment significantly protected the tubular epithelial cells against hypoxia-induced injury, with suppressed inflammation and cell injuries. In summary, FG-4592 treatment could protect against the I/R-induced kidney injury possibly through diminishing tubular cells injuries and suppression of sequence inflammatory responses. Thus, our findings definitely offered a clinical potential approach in treating AKI.