丙泊酚对全肝缺血再灌注大鼠脑损伤的保护作用及机制研究

目的:探究丙泊酚对全肝缺血再灌注(THIR)大鼠脑损伤的保护作用及机制。方法:选取72只健康成年雄性SD大鼠,将其按照抽签法分成假手术组、对照组以及丙泊酚组。所有大鼠予以12h禁食处理,采用3%戊巴比妥钠行腹腔注射麻醉处理,常规消毒后取上腹部正中切口进入腹腔。假手术组仅暴露肝门,不予以阻断处理。对照组与丙泊酚组则以无创动脉夹阻断肝固有动脉、门静脉和胆总管,在右肾动脉水平处阻断肝下下腔静脉,膈肌水平阻断肝上下腔静脉,进入全肝缺血阶段,阻断30 min后去除动脉夹恢复肝血流。其中丙泊酚组在全肝缺血前10 min予以丙泊酚50 mg/kg腹腔注射干预,假手术组与对照组则予以等量的生理盐水腹腔注射干预。比较三组大鼠再灌注24h后的脑组织细胞凋亡率、特异性半胱氨酸蛋白酶-3(Caspase-3)蛋白表达水平,脑组织超氧化物歧化酶(SOD)、丙二醛(MDA)、一氧化氮(NO)水平,血清白介素-6(IL-6)以及肿瘤坏死因子-α(TNF-α)水平。结果:对照组与丙泊酚组大鼠的细胞凋亡率及Caspase-3相对表达量均高于假手术组,而丙泊酚组细胞凋亡率及Caspase-3相对表达量均低于对照组(均P<0.05)。对照组与丙泊酚组大鼠脑组织SOD水平均低于假手术组,而丙泊酚组脑组织SOD水平高于对照组;对照组与丙泊酚组大鼠脑组织MDA、NO水平均高于假手术组,而丙泊酚组脑组织MDA、NO水平低于对照组(均P<0.05)。对照组与丙泊酚组大鼠血清IL-6、TNF-α水平均高于假手术组,而丙泊酚组血清IL-6、TNF-α水平均低于对照组(均P<0.05)。结论:丙泊酚可有效抑制THIR大鼠脑损伤引起的细胞凋亡,其主要机制可能与抑制Caspase-3表达、炎症反应以及抗自由基损伤有关。     

连翘酯苷A通过Akt/Nrf2信号通路发挥抗脑缺血氧化损伤作用研究

目的:研究连翘酯苷A(Forsythiaside A,FA)对缺血再灌注引起的脑细胞损伤的保护作用及机制。方法:采用PC12细胞缺氧再复氧模型(OGD/R),细胞分组为正常组,模型组,FA处理组(1.25, 2.5和5μmol/L),测定细胞存活率、凋亡率、ROS、MDA以及抗氧化酶水平。采用Western blotting测定对Akt和Nrf2蛋白的影响,采用Akt抑制LY294002验证FA的调节作用。结果:FA能够有效抑制OGD/R引起的存活率下降和凋亡率增加,同时可以抑制细胞内ROS和MDA水平,升高细胞内抗氧化酶(SOD、GSH、GSH-Px和CAT)水平。FA处理能够增加Akt磷酸化水平以及Nrf2和其下游蛋白HO-1蛋白表达。进一步采用LY294002验证发现FA通过Akt调控Nrf2发挥抗氧化作用从而抑制脑细胞损伤。结论:FA能够抑制缺血再灌注引起的脑细胞损伤,其作用机制可能是通过促进Akt磷酸化,调控Nrf2下游抗氧蛋白酶表达,抑制氧化应激,从而保护脑细胞。     

阿托伐他汀预处理对心肌缺血再灌注损伤大鼠心室重构、炎症反应和氧化应激的影响

目的:研究阿托伐他汀预处理对心肌缺血再灌注损伤大鼠心室重构、炎症反应和氧化应激的影响。方法:选取90只SD级大鼠进行研究,将其随机分成假手术组、缺血再灌注组、阿托伐他汀组,每组30只。假手术组与缺血再灌注组大鼠予以生理盐水(5 m L/d)连续灌胃7d处理,阿托伐他汀组予以阿托伐他汀20 mg/(kg·d)连续灌胃7 d,上述干预结束后,缺血再灌注组与阿托伐他汀组大鼠通过阻断大鼠冠状动脉左前降支的方式建立心肌缺血再灌注损伤模型。比较三组大鼠心室重构指标水平、炎症反应以及氧化应激相关指标水平。结果:缺血再灌注组、阿托伐他汀组大鼠的左室相对重量、右室相对重量、室间隔厚度、肿瘤坏死因子-α(TNF-α)、白细胞介素-1β(IL-1β)、丙二醛(MDA)、乳酸脱氧酶(LDH)水平均高于假手术组,且阿托伐他汀组大鼠上述指标均低于缺血再灌注组(均P<0.05);缺血再灌注组、阿托伐他汀组大鼠白介素-10(IL-10)、超氧化物气化酶(SOD)水平低于假手术组,且阿托伐他汀组大鼠IL-10、SOD水平高于缺血再灌注组(均P<0.05)。结论:阿托伐他汀预处理可有效预防心肌缺血再灌注损伤大鼠心室重构,同时可在一定程度上改善大鼠的炎症反应和氧化应激反应。     

α-Synuclein在脑缺血中的作用

α-Syn(α-Synuclein,SNAC)最初是从阿尔茨海默病患者大脑的淀粉样斑块中分离出来的一种蛋白质,在突触活动中扮演着重要的角色。α-Syn主要在脑中表达,研究发现其参与脑缺血损伤发生发展。在现有证据的基础上,该文简要介绍α-Syn的基本概念,并介绍α-Syn在脑缺血后的表达变化,重点探讨α-Syn在脑缺血中的作用。该文提供的信息可能有助于对α-Syn进行深入探索,α-Syn可能是未来脑缺血诊治的有效靶点。     

Oxidants and antioxidants in myocardial infarction (MI): Investigation of ischemia modified albumin,malondialdehyde, superoxide dismutase and catalase in individuals diagnosed with ST elevated myocardial infarction (STEMI) and non-STEMI (NSTEMI)

BackgroundCoronary ischemia can lead to myocardial damage and necrosis. The pathogenesis of cardiovascular diseases often includes increased oxidative stress and decreased antioxidant defense. The study aimed to assess levels of ischemia modified albumin (IMA), malondialdehyde acid (MDA), superoxide dismutase (SOD), and catalase in individuals diagnosed with ST elevated myocardial infarction (STEMI) and non-STEMI.MethodsThe present study prospectively included 50 STEMI patients, 55 NSTEMI patients, and 55 healthy subjects. Only patients who were recently diagnosed with STEMI or NSTEMI were included in this study. IMA, MDA, SOD, and catalase activities were measured spectrophotometrically. Significant coronary artery lesions were determined by angiography.ResultsPatients with ACS had significantly greater IMA and MDA values than the healthy controls (p<0.001). Besides, patients with STEMI had IMA levels that were significantly greater than those of the patients with NSTEMI (p<0.001), while the reverse was true for MDA levels (p<0.001). The healthy controls had the highest levels of SOD and catalase levels, followed by patients with STEMI and patients with NSTEMI, respectively (p<0.001). There was a significant negative correlation among MDA and SOD with catalase levels (r = -0.771 p<0.001 MDA vs catalase; r = -0.821 p<0.001 SOD vs catalase).ConclusionsData obtained in this study reveals that compared to healthy controls, STEMI and NSTEMI patients had increased levels of MDA and IMA and decreased levels of SOD and catalase.     

木犀草素通过调节凝血活性物质及凝血因子含量维持机体血液循环功能的稳定

目的探讨木犀草素通过调节凝血活性物质及凝血因子含量维持机体血液循环功能的作用机制。方法采用试剂盒和试管法测定木犀草素作用后的凝血酶原时间和血浆复钙时间;采用酶联免疫吸附法检测木犀草素对血液凝血活性物质血栓素(TXB2)、纤维酶原激活物抑制剂(PAI-1)、促红细胞生成素(EPO)和凝血因子Ⅶ(FⅦ)、凝血因子Ⅸ(FⅨ)含量的影响;采用PCR法测定木犀草素对凝血因子Ⅶ、Ⅸ的基因表达情况。结果木犀草素能缩短凝血酶原时间和血浆复钙时间,与对照组相比,40 mg/kg的木犀草素使凝血酶原时间和血浆复钙时间分别降低62.89%和64.05%(t=8.713 6、6.218 1,均P0.000 1),表明木犀草素能够促进机体的凝血功能,从而调节血液循环。酶联免疫结果显示,木犀草素能提高小鼠凝血活性物质TXB2、PAI-1和EPO的含量,与对照组相比,40 mg/kg木犀草素能使其含量分别提高11.94%(t=-7.638 0,P=0.000 3)、80.75%(t=-21.698 4,P0.000 1)和26.15%(t=-9.610 4,P=0.000 2),表明木犀草素可通过促进血小板的凝集、纤维酶原的活化以及增加血液的黏度来维持机体血液循环功能的稳定。木犀草素也能提高凝血因子Ⅶ和Ⅸ的含量及其基因表达量,与对照组相比,40 mg/kg的木犀草素能使凝血因子Ⅶ和Ⅸ的含量分别提高290.86%(t=-16.369 1,P=0.000 1)和374.52%(t=-8.104 2,P=0.001 2),基因表达量分别提高172.73%和224.63%(t=-22.007 5、-31.198 6,均P0.000 1),表明木犀草素可通过调节凝血因子Ⅶ和Ⅸ的表达量促进机体凝血,维持机体血液循环功能的稳定。结论木犀草素具有维持机体血液循环功能稳定的作用,其作用机制是通过提高凝血活性物质的含量,调节凝血因子的基因表达量,提高凝血因子的含量,以及抑制纤维酶原的激活和增加血液的黏度等多方面综合作用来实现的。     

The relation of oxidative stress and apoptosis to histopathologic alterations in the lungs as a result of global cerebral ischemia

ABSTRACT

Heart attack and oxygen deficiency may cause necrosis in the brain and other tissues. We investigated the histopathological effects of nitric oxide (NO) on ischemia/reperfusion in lung and hippocampus using a rat brain bilateral occlusion ischemia model. Male rats were assigned to sham (SH), ischemic preconditioning (PC), global ischemia (GI) and ischemic reperfusion (IR) groups. Before ischemia was induced, blood was drawn to induce hypovolemic hypotension and for blood gas testing. After sacrifice, samples of hippocampus were harvested. Sections were examined using hematoxylin and eosin (H & E) staining and immunostaining using primary antibodies for GFAP, S100β, iNOS, eNOS and the TUNEL method. Following ischemia, we found evidence of gliosis induced oxidative stress and apoptosis in the hippocampus. No significant differences were detected between the SH and PC groups. In the GI and IR groups, apoptosis and necrosis were observed in the hippocampus. Lung sections were stained with H & E and Masson’s trichrome (MT) and immunostained for iNOS and eNOS. The TUNEL method was used to detect apoptosis. Interstitial edema, vascular congestion, intra-alveolar hemorrhage, perivascular edema, neutrophil infiltration and disruption of alveoli were observed after global ischemia and ischemic reperfusion. Inflammatory cells were detected in the connective tissue. The IR and GI groups exhibited significantly more apoptotic cells than the SH or PC groups. Free radicals, such as nitric oxide (NO), that appear following ischemia and reperfusion in the brain may also injure the lungs. Increased NO in both lung and brain tissue suggests that apoptosis in these organs can be induced by reactive nitrogen species.     

Role of nitric oxide in the reperfusion induced injury in hyperthyroid rat hearts

We recently reported that hyperthyroidism affects the heart response to ischemia/reperfusion. A significant tachycardia during reperfusion was associated with an increase in the oxidative stress of hearts from T₃-treated animals. In the present study we checked the possible role of nitric oxide (NO) in this major stress induced by the hyperthyroid state. We compared the functional recovery from ischemia/reperfusion of Langendorff preparations from euthyroid (E) and hyperthyroid (H, ten daily intraperitoneal injections of T₃, 10 μg/100 g body weight) rats, in the presence and in the absence of 0.2 mM N^ω-nitro-L-arginine (L-NNA). At the end of the ischemia/reperfusion protocol (10 min preischemic perfusion, 20 min global ischemia, 30 min reperfusion) lipid peroxidation, antioxidant capacity (C_A) and susceptibility to in vitro oxidative stress were determined on heart homogenates. The main effect of hyperthyroidism on the reperfusion functional response was confirmed to be a strong tachycardic response (154% recovery at 25 min reperfusion) accompanied by a low recovery in both left ventricular diastolic pressure (LVDP) and left ventricular dP/dt_max. This functional response was associated with a reduction in C_A and an increase in both lipid peroxidation and susceptibility to oxidative stress. Perfusion of hearts with L-NNA per se had small but significant negative chronotropic and positive inotropic effects on preischemic performance of euthyroid rat hearts only. More importantly, L-NNA perfusion completely blocked the reperfusion tachycardic response in the hyperthyroid rats. Concomitantly, myocardium oxidative state (lipid peroxidation, C_A and in vitro susceptibility to oxidative stress) of L-NNA perfused hearts was similar to that of E animals. These results suggest that the higher reperfusion-induced injury occurring in hyperthyroid animals is associated with overproduction of nitric oxide.     

Hydrogen-rich saline protects against intestinal ischemia/reperfusion injury in rats

Hydrogen gas was reported to reduce reactive oxygen species and alleviate cerebral, myocardial and hepatic ischemia/reperfusion (I/R) injuries. This paper studied the effect of hydrogen-rich saline, which was easier for clinical application, on the intestinal I/R injury. Model of intestinal I/R injury was induced in male Sprague-Dawley rats. Physiological saline, hydrogen-rich saline or nitrogen-rich saline (5 ml/kg) was administered via intravenous infusion at 10 min before reperfusion, respectively. The intestine damage was detected microscopically and was assessed by Chiu score system after I/R injury. In addition, serum DAO activity, TNF-α, IL-1β and IL-6 levels, tissue MDA, protein carbonyl and MPO activity were all increased significantly by I/R injury. Hydrogen-rich saline reduced these markers and relieved morphological intestinal injury, while no significant reduction was observed in the nitrogen-rich saline-treated animals. In conclusion, hydrogen-rich saline protected the small intestine against I/R injury, possibly by reduction of inflammation and oxidative stress.     

Mitochondrial Src tyrosine kinase plays a role in the cardioprotective effect of ischemic preconditioning by modulating complex I activity and mitochondrial ROS generation

Abstract

While ischemic preconditioning (IPC) and other cardioprotective interventions have been proposed to protect the heart from ischemia/reperfusion (I/R) injury by inhibiting mitochondrial complex I activity upon reperfusion, the exact mechanism underlying the modulation of complex I activity remains elusive. This study was aimed to test the hypothesis that IPC modulates complex I activity at reperfusion by activating mitochondrial Src tyrosine kinase, and induces cardioprotection against I/R injury. Isolated rat hearts were preconditioned by three cycles of 5-min ischemia and 5-min reperfusion prior to 30-min index ischemia followed by 2 h of reperfusion. Mitochondrial Src phosphorylation (Tyr⁴¹⁶) was dramatically decreased during I/R, implying inactivation of Src tyrosine kinase by I/R. IPC increased mitochondrial Src phosphorylation upon reperfusion and this was inhibited by the selective Src tyrosine kinase inhibitor PP2. IPC's anti-infarct effect was inhibited by the selective Src tyrosine kinase inhibitor PP2. Complex I activity was significantly increased upon reperfusion, an effect that was prevented by IPC in a Src tyrosine kinase-dependent manner. In support, Src and phospho-Src were found in complex I. Furthermore, IPC prevented hypoxia/reoxygenation-induced mitochondrial reactive oxygen species (ROS) generation and cellular injury in rat cardiomyocytes, which was revoked by PP2. Finally, IPC reduced LDH release induced by both hypoxia/reoxygenation and simulated ischemia/reperfusion, an effect that was reversed by PP2 and Src siRNA. These data suggest that mitochondrial Src tyrosine kinase accounts for the inhibitory action of IPC on complex I and mitochondrial ROS generation, and thereby plays a role in the cardioprotective effect of IPC.