Influence of different hemodialysis membranes on red blood cell susceptibility to oxidative stress

Oxidative stress is crucial in red blood cell (RBC) damage induced by activated neutrophils in in vitro experiments. The aim of the study was to evaluate whether the bioincompatibility phenomena occurring during hemodialysis (HD) (where neutrophil activation with increased free radical production is well documented) may have detrimental effects on RBC. We evaluated RBC susceptibility to oxidative stress before and after HD in 15 patients using Cuprophan, cellulose triacetate, and polysulfone membrane. RBC were incubated with t-butyl hydroperoxide as an oxidizing agent both in the presence and in the absence of the catalase inhibitor sodium azide. The level of malonaldehyde (MDA), a product of lipid peroxidation, was measured at 0, 5, 10, 15, and 30 min of incubation. When Cuprophan membrane was used, the MDA production was significantly higher after HD, indicating an increased susceptibility to oxidative stress in comparison to pre-HD. The addition of sodium azide enhanced this phenomenon. Both cellulose triacetate and polysulfone membranes did not significantly influence RBC susceptibility to oxidative stress. Neither the level of RBC reduced glutathione nor the RBC glutathione redox ratio changed significantly during HD with any of the membranes used. The RBC susceptibility to oxidative stress was influenced in different ways according to the dialysis membrane used, being increased only when using the more bioincompatible membrane Cuprophan, where neutrophil activation with increased free radical production is well documented. The alterations found in this study might contribute to the reduced RBC longevity of HD patients where a bioincompatible membrane is used.     

Infrequent Mutations of the hOGG1 Gene, That Is Involved in the Excision of 8-Hydroxyguanine in Damaged DNA, in Human Gastric Cancer

DNA glycosylase, encoded by the hOGG1 gene, repairs 8-hydroxyguanine (oh⁸Gua), which is an oxidatively damaged mutagenic base. To clarify whether the DNA repair activity of hOGG1 protein is involved in gastric carcinogenesis, we examined 9 gastric cancer cell lines and 35 primary gastric cancers for mutations and genetic polymorphisms of the hOGG1 gene by polymerase chain reaction-single strand conformation polymorphism analysis. A G-to-A transition was detected in a gastric cancer cell line, MKN1. This nucleotide change caused the conversion of the amino acid from Arg to His at codon 154, which is located in a domain highly conserved among human, mouse, and yeast OGG1 proteins. No mutation was detected in primary gastric cancers. We compared the distribution of the polymorphic alleles associated with enzymatic activity (hOGG1-Ser³²⁶ vs. hOGG1-Cys³²⁶) between 35 gastric cancer patients and 42 healthy individuals. Although the frequency of the Cys³²⁶ allele, associated with low enzymatic activity, in gastric cancer patients was a little higher than that in healthy individuals, the difference did not reach statistical significance. These results suggest that low hOGG1 activity due to mutations and genetic polymorphisms is involved in the development of only a small subset of gastric cancers.     

用荧光探针JC-1检测氧化应激对精子线粒体膜电位的影响

目的：利用荧光探针JC-1观察氧化应激对精子线粒体膜电位的变化。方法：用FeSO4/H2O2体系诱导精子氧化损伤模型，利用新型荧光探针JC 1标记精子线粒体,在FACS Calibur流式细胞仪上检测JC 1荧光强度的变化。结果：正常精子线粒体维持较高的膜电位,JC 1在线粒体内形成聚合物, 红色荧光占主导地位。FeSO4/H2O2体系导致线粒体膜电位下降, JC 1聚合物分解成单体,红色荧光强度减弱。结论：氧化应激导致精子线粒体膜电位下降; JC 1结合流式细胞仪是一种理想的检测线粒体膜电位的手段。     

心脏术后发生MODS伴ARF时机体氧化应激状态的初步研究

目的初步观察经体外循环心脏术后多脏器功能障碍综合征(MODS)伴急性肾功能衰竭(ARF)患者的氧化应激水平,为临床治疗提供理论基础。方法测定16例经体外循环心脏术后MODS伴ARF患者及16例健康人的血清丙二醛(MDA)、超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)、总抗氧化能力(TAC),同时对患者进行MODS评分,并将评分与氧化应激参数进行相关性分析。结果116例患者,8例存活,8例死亡(病死率50%);2与健康对照组相比,MODS伴ARF组在性别、年龄方面无显著性差异,TAC,SOD代偿性升高,但GSH-Px明显下降,MDA显著升高。3MDA同MODS评分呈正相关;GSH-Px同MODS评分呈负相关。SOD、TAC同评分无明显相关性。结论1经体外循环心脏手术后MODS伴ARF的患者发生了氧化应激。2监测MDA和GSH-Px有助于判断病情。3在MODS伴ARF的治疗中,有必要采用各种治疗措施恢复机体的氧化抗氧化。     

自然流产妇女血清MDA、SOD、VitE的测定及意义

目的:通过对自然流产妇女血清氧化应激指标———超氧化物歧化酶(SOD)、丙二醛(MDA)及维生素E(V itE)的测定,分析三个指标在自然流产发病机制中的意义。方法:用化学比色法对30例自然流产妇女及20例正常早孕组妇女血清中SOD、MDA及V it E进行测定。结果:与正常早孕妇女相比,自然流产妇女血清中MDA水平升高(P<0.05),SOD、V it E水平却下降(均P<0.05)。结论:上述三个指标对于预防及治疗自然流产有重要意义。     

氧化应激和炎症反应在子盖(癎)前期中的作用及其相互关系

目的通过测定子前期患者氧化应激产物和炎症标志物的水平,进一步研究子前期的发病机制。方法以53例子前期孕妇为研究组(其中轻度子前期32例、重度子前期21例),20例同期分娩的正常孕妇为对照组。检测血浆8-异前列腺素(8-isoprostane)、丙二醛(MDA)、氧化低密度脂蛋白(ox-LDL)和高敏C-反应蛋白(hs-CRP)、白细胞介素-6(IL-6)、肿瘤坏死因子-α(TNF-α)的浓度。结果(1)子前期患者血浆8-异前列腺素、MDA、ox-LDL的浓度分别为(153.07±44.84)pg/ml、(5.25±0.11)μmol/L、(772.04±151.00)μg/L,均高于对照组[(82.86±20.91)pg/ml、(4.67±0.38)μmol/L、(431.45±200.69)μg/L,P<0.01、>0.05和<0.05];(2)子前期患者血浆hs-CRP、IL-6、TNF-α水平分别为(2.17±1.29)mg/L、(26.49±12.73)pg/ml、(18.47±4.17)pg/ml均明显高于对照组[(1.46±1.00)mg/L、(13.35±5.01)pg/ml、(8.86±1.39)pg/ml,P均<0.01];(3)子前期患者8-异前列腺素与hs-CRP、IL-6、TNF-α呈显著正相关(P<0.01),而MDA及ox-LDL均与hs-CRP、IL-6、TNF-α无相关性(P>0.05)。结论氧化应激及炎症反应可能在子前期中发挥重要作用,干预氧化应激及炎症反应可能有利于控制子前期的发生和发展。     

硫辛酸在防治肝脏疾病中的作用及其机制研究

硫辛酸是一类功能强大的线粒体辅酶,具有抗氧化应激、抗炎、解毒、降脂等作用。肝脏是参与人体新陈代谢的重要器官,肝脏疾病严重影响着人类的生命健康,本文综述了硫辛酸在各种肝脏疾病中的作用,并系统阐明了硫辛酸的治疗机制,为硫辛酸在各种肝脏疾病中的应用提供思路。     

槟榔多酚对大鼠肺微血管内皮细胞低氧损伤的保护作用

目的：探究槟榔多酚对大鼠肺微血管内皮细胞（PMVEC）低氧损伤的保护作用。方法：采用氧化应激指标丙二醛和超氧化物歧化酶筛选肺部缺氧损伤细胞模型最适条件;采用细胞计数试剂盒法筛选槟榔多酚最适给药剂量。将PMVEC分为常氧对照组、模型对照组和槟榔多酚组,采用BCA法检测蛋白浓度并测定PMVEC中的氧化应激水平,蛋白质印迹法检测炎症和凋亡相关蛋白的表达,免疫荧光染色法检测闭合蛋白和闭锁小带1等紧密连接蛋白的表达,Transwell小室实验检测跨内皮细胞膜电阻,罗丹明荧光染料检测PMVEC屏障的通透性。结果：1%氧浓度培养PMVEC细胞48 h后成功构建肺部缺氧损伤细胞模型;20μg/mL的槟榔多酚可以显著逆转缺氧损伤细胞模型中PMVEC的存活率下降以及氧化应激水平的升高（均P<0.05）;槟榔多酚对于低氧诱导下PMVEC中炎症相关蛋白核因子κB(NF-κB)和核因子E2相关因子（Nrf）2的上调有显著抑制作用（均P<0.05）;槟榔多酚可以下调低氧诱导下PMVEC中凋亡相关蛋白胱天蛋白酶（caspase）3、Bcl-2相关X蛋白（Bax）的表达（均P<0.05）,从而减轻低...     

马尾松松针提取物调节JNK3/caspase-3信号转导减轻大鼠脑缺血再灌注后氧化应激损伤

目的：探讨马尾松松针提取物（PNE）对大鼠脑缺血再灌注后氧化应激损伤的保护作用。方法：将SD雄性大鼠随机分为手术对照组、模型对照组、依达拉奉组、PNE小剂量组（200 mg/kg）、PNE中剂量组（400 mg/kg）、PNE大剂量组（800 mg/kg）,于造模前连续7 d及造模后6 h分别灌胃给药。其中,手术对照组和模型对照组灌胃给予等渗氯化钠溶液,依达拉奉组灌胃给予等渗氯化钠溶液的同时腹腔注射依达拉奉3 mg/kg,PNE各组灌胃给予各剂量PNE。通过大脑中动脉阻塞法建立脑缺血再灌注损伤大鼠模型,于再灌注24 h后测定各组大鼠神经功能缺损评分、脑组织含水量、脑梗死体积。采用苏木素-伊红染色观察大脑皮层及海马组织结构病理变化并统计正常神经细胞数;TUNEL法检测大脑皮层神经细胞凋亡率;试剂盒检测缺血侧脑组织一氧化氮、丙二醛含量与超氧化物歧化酶（SOD）活性;蛋白质印迹法检测大脑皮层c-Jun氨基末端激酶（JNK）3、磷酸化JNK3、B淋巴细胞瘤蛋白（Bcl）-2、Bcl-2相关X蛋白（Bax）、细胞色素C、胱天蛋白酶（caspase）-3的蛋白表达水平。结果：与模型对照组比较,PN...     

Regulation of PPAR-γ activity in lipid-laden hepatocytes affects macrophage polarization and inflammation in nonalcoholic fatty liver disease

BACKGROUNDLipid metabolism disorder and inflammatory-immune activation are vital triggers in the pathogenesis of nonalcoholic fatty liver disease (NAFLD). Various studies have shown that PPAR-γ exerts potent anti-inflammatory and immunomodulatory properties. However, little is known about the regulation of PPAR-γ activity in modulating cell crosstalk in NAFLD.AIMTo investigate whether the regulation of PPAR-γ activity in lipid-laden hepatocytes affects macrophage polarization and inflammation.METHODSPrimary hepatocytes were isolated from wild-type C57BL6/J mice or hepatocyte-specific PPAR-γ knockout mice and incubated with free fatty acids (FFAs). Macrophages were incubated with conditioned medium (CM) from lipid-laden hepatocytes with or without a PPAR-γ agonist. Wild-type C57BL/6J mice were fed a high-fat (HF) diet and administered rosiglitazone.RESULTSPrimary hepatocytes exhibited significant lipid deposition and increased ROS production after incubation with FFAs. CM from lipid-laden hepatocytes promoted macrophage polarization to the M1 type and activation of the TLR4/NF-κB pathway. A PPAR-γ agonist ameliorated oxidative stress and NLRP3 inflammasome activation in lipid-laden hepatocytes and subsequently prevented M1 macrophage polarization. Hepatocyte-specific PPAR-γ deficiency aggravated oxidative stress and NLRP3 inflammasome activation in lipid-laden hepatocytes, which further promoted M1 macrophage polarization. Rosiglitazone administration improved oxidative stress and NLRP3 inflammasome activation in HF diet-induced NAFLD mice in vivo.CONCLUSIONUpregulation of PPAR-γ activity in hepatocytes alleviated NAFLD by modulating the crosstalk between hepatocytes and macrophages via the reactive oxygen species-NLRP3-IL-1β pathway.