Reactive Oxygen Species Play a Biphasic Role in Brain Ischemia

Objective: Reactive oxygen species (ROS) are the essential mechanism involving in the ischemic process. Due to their complex characteristics, the precise effects of ROS on post-ischemic neurons remain uncertain. This study aimed to investigate the potential role of ROS in brain ischemia. Methods: Dynamic ROS levels in the perifocal cortex were evaluated after right middle cerebral artery occlusion (MCAO) of SD rats. Furthermore the role of ROS was assessed following delayed treatment with the ROS scavenger dimethylthiourea (DMTU) after brain ischemia. Results: ROS levels markedly increased at 1 hr after reperfusion and then gradually decreased as the post-reperfusion time interval increased. ROS levels reached their lowest point at 3 days after reperfusion before increasing and showing a second peak at 7 days after reperfusion. ROS levels negatively correlated with neurological function scores. Delayed DMTU treatment after stroke worsened neurological outcomes, decreased microvessel density and inhibited stress-activated protein kinase activation. Conclusion: ROS may play a biphasic role in cerebral ischemia. Namely, ROS may induce damage during the injury phase of brain ischemia and participate in improving neurological function during the recovery phase.     

反应氧族促进血管生成的作用及其脑内意义

反应氧族（reactive oxygen specise,ROS）是细胞有氧代谢产生的物质,在脑缺血发生与进展的过程中扮演着重要角色。以往研究多以消除ROS 作为神经保护的重要途径。近年研究表明ROS 不只介导缺血后脑组织的损伤,更是重要的信号通路分子﹑参与调控缺血后的组织修复。一定含量的ROS 可激活细胞增殖、细胞迁移,激活血管生成的相关通路,促进血管生成。因此,全面了解ROS 在脑缺血后动态过程中的作用,合理调控脑缺血后组织中ROS 的含量,可促进受损区域的血管生成,对及时恢复血供、保护神经功能具有重要意义。     

马勃的化学成分及其药理作用的研究进展

马勃（Lasiosphaera seu Calvatia）是大型食药用真菌,为灰包科真菌脱皮马勃、大马勃或紫色马勃的干燥子实体,其营养成分十分丰富,在2015 年《中国药典》中记载功能与主治清肺利咽,止血,用于风热郁肺咽痛,音哑,咳嗽,外治鼻衄,创伤出血。该文通过对马勃的种类、化学成分及其药用的功效进行综述,为此类真菌研究开发做进一步参考。     

人参皂苷对过氧化氢诱导的HepG2细胞损伤的保护作用

目的：探讨人参皂苷对过氧化氢（H₂O₂）诱导的HepG2细胞氧化应激损伤的保护作用,并阐明其作用机制。方法：体外培养HepG2细胞,采用不同浓度（0.1、0.2、0.3、0.4、0.5、0.6、0.7、0.8和1.0 mmol·L^-1）H₂O₂诱导HepG2细胞损伤。将HepG2细胞分为空白组、对照组、损伤组、人参皂苷对照组和人参皂苷保护组。10、20和40μmol·L^-1人参皂苷RH1、F1、RD、RO和RE分别孵育细胞3 h,H₂O₂损伤2 h,采用细胞增殖与毒性检测试剂盒（CCK-8）检测细胞存活率,CAA法检测细胞抗氧化活性,2',7'-二氯荧光黄双乙酸盐（DCFH-DA）荧光探针法检测细胞中活性氧（ROS）水平,WST-1法检测细胞中超氧化物歧化酶（SOD）活性。结果：H₂O₂半数抑制浓度（IC₅₀）为0.4 mmol·L^-1。与损伤组比较,10、20和40μmol·L^-1人参皂苷RH1、F1、RD、RO和RE预处理后,H₂O₂诱导氧化损伤的HepG2细胞存活率均有不同程度的升高,其中人参皂苷F1保护组细胞存活率升高最明显（P<0.05）。与对照组比较,10、20和40μmol·L^-1人参皂苷RH1、F1、RD、RO和RE保护组HepG2细胞存活率差异无统计学意义（P>0.05）。人参皂苷F1的半数效应浓度（EC₅₀）为（15.82±0.82）μmol·L^-1,CAA当量为（1 275.20±33.90）μmol TE/100 μmol·L^-1人参皂苷F1。与对照组比较,损伤组细胞中ROS水平明显升高（P<0.05）,SOD活性明显降低（P<0.05）;与损伤组比较,人参皂苷F1保护组细胞中ROS水平明显降低（P<0.05）,SOD活性明显升高（P<0.05）。结论：人参皂苷F1通过提高细胞抗氧化能力,降低细胞中ROS水平,提高细胞SOD活性对H₂O₂诱导的HepG2细胞氧化应激损伤起到保护作用。     

活性氧调节因子1联合癌胚抗原诊断恶性胸腔积液的临床研究

目的 通过检测胸腔积液中活性氧调节因子1(Romo1)、癌胚抗原(CEA)的表达水平和含量,探究其在恶性胸腔积液(MPE)中的临床诊断价值。方法 收集57例MPE和60例良性胸腔积液(BPE)胸腔积液样本,其中男性68例,女性49例,平均年龄为62岁,BPE组包括结核性胸腔积液(TPE)27例,类肺炎性胸腔积液(PPE)22例,漏出液11例,并采用酶联免疫吸附法(ELISA)测定胸腔积液样本中Romo1、CEA的含量,利用SPSS软件绘制受试者工作特征曲线(ROC)、计算Romo1、CEA的敏感性、特异性,探究两者单独或联合应用对MPE的诊断价值。结果 MPE中的Romo1和CEA的浓度较BPE均显著升高(P<0.05),TPE组、PPE组、漏出液组3组间胸水中Romo1、CEA浓度无明显差异(P>0.05)。当Romo1的截断值为113.69 pg/mL时,Romo1诊断MPE的AUC为0.736,相应的敏感度为87.70%,特异度为50%;CEA的截断值为2858 pg/mL,诊断MPE的AUC为0.731,敏感度为59.60%,特异度为80%,CEA+Romo1联合可...     

MK2 plays an important role for the increased vascular permeability that follows thermal injury

We previously reported Rho kinase is involved in vessel hyper-permeability caused by burns. Here we further explore the Rho kinase downstream signaling, it is found that its specific inhibitor Y27632 significantly diminishes the activation of JNK and p38 MAPKs but not ERK that induced by serum from burned rats (burn-serum). JNK activation was found involved in the expression of HUVEC adhesion molecules following thermal injury, although not in the process of stress fiber formation. Inhibition of various MAPKs by specific inhibitors showed that SB203580 (inhibitor of p38), but neither SP600125 (inhibitor of JNK) nor PD98059 (inhibitor of ERK), abolish activation of the p38 downstream kinase MK2. Demonstration of stress fibers by fluorescent-labeled phalloidin showed that inhibition of MK2, either by its specific inhibitor or by dominant negative adeno-viral-carried constructs, significantly reduced burn-serum-induced HUVEC stress-fiber formation, while inhibition of another downstream p38 MAPK kinase, PRAK, had no such effects. Transfection of dominant negative adeno-viral MK2 (Ad-MK2(A)) significantly inhibited thermal injury-induced blood vessel hyper-permeability in rats and, moreover, prolonged the survival of burned rats beyond 72 h following thermal injury. One of the mechanisms behind these phenomena is that Ad-MK2(A) causes a significant depression of burn-serum-induced HSP27-phosphorylation, while the adeno-viral transported dominant negative PRAK (Ad-PRAK(A)) does not block. Although the effect of blockade of MK2 through its adeno-viral approach requires further study and investigation of alternatives to know for sure, we may have found a new pathway behind thermal-injury-induced blood vessel hyper-permeability, namely: Rho kinase > p38 > MK2 > HSP27.     

活性氧在芬太尼后处理和肢体远隔缺血后处理减轻大鼠心肌缺血再灌注损伤中的作用

目的 探讨活性氧在芬太尼后处理和肢体远隔缺血后处理减轻大鼠心肌缺血再灌注损伤中的作用.方法 成年雄性SD大鼠63只,8周龄,体重250 ～ 350 g,采用随机数字表法,将其随机分为7组(n=9):假手术组(S组)、心肌缺血再灌注组(I/R组)、芬太尼后处理组(F组)、肢体远隔缺血后处理组(R组)、活性氧清除剂N-(2-巯基丙酰基)-甘氨酸(MPG)组(M组)、MPG+芬太尼后处理组(MF组)和MPG+肢体远隔缺血后处理组(MR组).除S组外,其余6组采用结扎左冠状动脉前降支30 min再灌注180 min的方法制备心肌缺血再灌注损伤模型.在缺血前5 min至再灌注15 min M组、MF组和MR组静脉输注MPG 5 mg/kg,其他4组给予等容量生理盐水,心肌缺血15 min时,F组和MF组静脉注射芬太尼30 μg/kg;R组和MR组结扎大鼠双后肢造成缺血10 min.心肌再灌注180 min时,采集动脉血样,测定血清心肌肌钙蛋白Ⅰ(cTnI)浓度,然后处死大鼠,取心肌组织,采用TTC染色法测定心肌梗死体积.结果 与S组比较,其余6组血清cTnI浓度和心肌梗死体积均升高(P＜0.05);与I/R组比较,M组血清cTnI浓度和心肌梗死体积差异无统计学意义(P＞0.05),F组和R组血清cTnI浓度和心肌梗死体积降低(P＜ 0.05);MF组和F组血清cTnI浓度和心肌梗死体积差异无统计学意义(P ＞0.05); MR组血清cTnI浓度和心肌梗死体积高于R组(P＞0.05).结论 活性氧参与了肢体远隔缺血后处理减轻大鼠心肌缺血再灌注损伤的效应,而未参与芬太尼后处理的心肌保护作用.     

氧化应激介导的Ras-ERK信号通路活化参与醛固酮诱导的肾小球系膜细胞增殖

目的 探讨氧化应激介导的Ras-胞外信号调节激酶(ERK1/2)信号通路活化在醛同酮( ALDO)诱导的系膜细胞增殖中的作用.方法 体外培养人肾小球系膜细胞,应用3H-胸腺嘧啶(3H-TdR)掺入法和细胞计数测定系膜细胞增殖;Western印迹检测Ki-RasA、c-Raf、MEK1/2和ERK1/2活化.结果 ALDO可显著促进系膜细胞增殖,抗氧化剂乙酰半胱氨酸(NAC)、过氧化氢酶(CAT)、超氧化物歧化酶(SOD)显著抑制ALDO诱导的系膜细胞增殖(均P＜ 0.01).ALDO刺激系膜细胞3h,活化的Ki-RasA、c-Raf、MEK1/2和ERK1/2表达显著增强,分别是对照组的4.05倍、3.62倍、4.52倍和3.40倍(均P＜0.01).抗氧化剂NAC几乎完全阻断ALDO诱导的Ki-RasA、c-Raf、MEK1/2和ERK 1/2活化(均P＜0.01).Ki-RasA siRNA可呈浓度依赖性降低系膜细胞Ki-RasA表达,并显著抑制ALDO诱导的Ki-RasA活化及系膜细胞增殖(P＜0.01).c-Raf抑制剂GW5074和MEK1/2抑制剂PD98059亦显著抑制ALDO诱导的系膜细胞增殖,其抑制率均达到65％(P＜0.01).Ki- RasA siRNA不能降低ALDO诱导的磷酸肌醇-3激酶( PI3K)磷酸化.联合应用PI3K抑制剂LY294002和MEKl/2抑制剂PD98059可完全阻断ALDO诱导的系膜细胞增殖(P＜0.01).结论 ALDO可通过氧化应激活化Ki-RasA-c-Raf-MEK-ERK信号通路.同时阻断ERK1/2和PI3K信号通路可完全抑制ALDO诱导的系膜细胞增殖.     

Mechanisms of shock wave induced endothelial cell injury

BACKGROUND AND OBJECTIVES: Medical procedures, for example, laser angioplasty and extracorporeal lithotripsy as well as high-energy trauma expose human tissues to shock waves (SWs) that may cause tissue injury. The mechanisms for this injury, often affecting blood vessel walls, are poorly understood. Here we sought to assess the role of two suggested factors, viz., cavitation or reactive oxygen species (ROS). STUDY DESIGN/MATERIALS AND METHODS: A laser driven flyer-plate model was used to expose human umbilical cord vein endothelial cell (HUVEC) monolayers to SWs or to SWs plus cavitation (SWC). Cell injury was quantified with morphometry, trypan blue staining, and release of (51)Cr from labeled HUVECs. RESULTS: HUVECs, exposed to SWs only, could not be distinguished from controls in morphological appearance or ability to exclude trypan blue. Yet, release of (51)Cr, indicated a significant cell injury (P < 0.05). HUVEC cultures exposed to SWC, exhibited cell detachment and cell membrane damage detectable with trypan blue. Release of (51)Cr was fourfold compared to SW samples (P < 0.01). Signs of cell injury were evident at 15 minutes and did not change over the next 4 hours. No protective effects of ROS scavengers were demonstrated. CONCLUSIONS: Independent of ROS, SWC generated an immediate cell injury, which can explain, for example, vessel wall perturbation described in relation to SW treatments and trauma.