Apocynin对缺氧复氧后肾小管上皮细胞MCP-1表达的干预作用

目的：研究缺氧复氧后肾小管上皮细胞单核细胞趋化蛋白-1（MCP-1）的表达及Apocynin对其影响。方法：选用人肾小管上皮细胞（HK-2）建立缺氧复氧损伤模型,设正常对照组、单纯缺氧复氧组、不同浓度（0.05、0.25、0．5mmol／L）Apocynin干预组。流式细胞术检测细胞内氧化应激水平,流式细胞术检测MCP-1蛋白表达、RT-PCR法测定细胞MCP-1 mRNA表达。结果：缺氧复氧后HK-2细胞内氧化应激水平提高,细胞MCP-1蛋白和mRNA表达上调,且随缺氧时间的延长,细胞内氧化应激水平逐渐升高,MCP-1蛋白和mRNA表达逐渐增强;Apocynin呈剂量关系抑制细胞内氧化应激水平,同时呈剂量关系抑制MCP-1蛋白和mRNA表达的上调。结论：缺氧复氧诱导细胞内氧化应激的产生,诱导MCP-1表达上调;Apocynin可以通过抑制细胞内氧化应激抑制MCP-1的上调。     

Reactive oxygen species generated by NADPH oxidase are involved in neurodegeneration in the pilocarpine model of temporal lobe epilepsy

Reactive oxygen species (ROS) appear to be involved in several neurodegenerative disorders. We tested the hypothesis that oxidative stress could have a role in the hippocampal neurodegeneration observed in temporal lobe epilepsy induced by pilocarpine. We first determined the spatio-temporal pattern of ROS generation, by means of detection with dihydroethidium oxidation, in the CA1 and CA3 areas and the dentate gyrus of the dorsal hippocampus during status epilepticus induced by pilocarpine. Fluoro-Jade B assays were also performed to detect degenerating neurons. ROS generation was increased in CA1, CA3 and the dentate gyrus after pilocarpine-induced seizures, which was accompanied by marked cell death. Treatment of rats with a NADPH oxidase inhibitor (apocynin) for 7 days prior to induction of status epilepticus was effective in decreasing both ROS production (by an average of 20%) and neurodegeneration (by an average of 61%). These results suggest an involvement of ROS generated by NADPH oxidase in neuronal death in the pilocarpine model of epilepsy.     

Arsenic-induced alteration in intracellular calcium homeostasis induces head kidney macrophage apoptosis involving the activation of calpain-2 and ERK in Clarias batrachus

We had earlier shown that exposure to arsenic (0.50 μM) caused caspase-3 mediated head kidney macrophage (HKM) apoptosis involving the p38-JNK pathway in Clarias batrachus. Here we examined the roles of calcium (Ca²⁺) and extra-cellular signal-regulated protein kinase (ERK), the other member of MAPK-pathway on arsenic-induced HKM apoptosis. Arsenic-induced HKM apoptosis involved increased expression of ERK and calpain-2. Nifedipine, verapamil and EGTA pre-treatment inhibited the activation of calpain-2, ERK and reduced arsenic-induced HKM apoptosis as evidenced from reduced caspase-3 activity, Annexin V-FITC-propidium iodide and Hoechst 33342 staining. Pre-incubation with ERK inhibitor U 0126 inhibited the activation of calpain-2 and interfered with arsenic-induced HKM apoptosis. Additionally, pre-incubation with calpain-2 inhibitor also interfered with the activation of ERK and inhibited arsenic-induced HKM apoptosis. The NADPH oxidase inhibitor apocynin and diphenyleneiodonium chloride also inhibited ERK activation indicating activation of ERK in arsenic-exposed HKM also depends on signals from NADPH oxidase pathway. Our study demonstrates the critical role of Ca²⁺ homeostasis on arsenic-induced HKM apoptosis. We suggest that arsenic-induced alteration in intracellular Ca²⁺ levels initiates pro-apoptotic ERK and calpain-2; the two pathways influence each other positively and induce caspase-3 mediated HKM apoptosis. Besides, our study also indicates the role of ROS in the activation of ERK pathway in arsenic-induced HKM apoptosis in C. batrachus.     

Apocynin administration does not improve behavioral and neuropathological deficits in a transgenic mouse model of Alzheimer's disease

In addition to mitochondria, NADPH oxidase (NOX) is a source of oxidative stress, which can induce oxidative damage in Alzheimer's disease (AD). For this reason, several groups have investigated the effect of its inhibition. In AD mice, NADPH oxidase 2 (NOX2) deficiency improved behavior and cerebrovascular function, and reduced oxidative stress. In our study, we administered the NOX inhibitor apocynin to Tg19959 mice, and found that it did not improve cognitive and synaptic deficits, and did not decrease amyloid deposition, microgliosis and hyperphosphorylated tau. However, apocynin reduced carbonyl levels in the cerebral cortex but not the hippocampus, which may have not been sufficient to ameliorate symptoms. Also, the reduction of NOX-mediated oxidative stress may not be sufficient to prevent AD, since other sources of reactive oxygen species such as mitochondria may be more important.     

Apocynin对缺氧复氧后肾小管上皮细胞凋亡的干预研究

 目的 研究缺氧复氧后肾小管上皮细胞凋亡的表达及Apocynin对其影响.方法 选用人肾小管上皮细胞(HK2)建立缺氧复氧损伤模型,设正常对照组、单纯缺氧复氧组、不同浓度(0.05、0.25、0.5 mM)Apocynin干预组.流式细胞术检测细胞内氧化应激水平,检测细胞凋亡.结果 缺氧复氧后HK2细胞内氧化应激水平提高,HK2细胞凋亡和死亡细胞数量增多,且随缺氧时间的延长,细胞内氧化应激水平逐渐升高,凋亡细胞和死亡细胞数量逐渐增多;Apocynin呈剂量关系抑制细胞内氧化应激水平,同时呈剂量关系减少凋亡细胞和坏死细胞的数量.结论 缺氧复氧诱导细胞内氧化应激的产生,诱导HK2细胞凋亡和死亡;Apocynin可以通过抑制细胞内氧化应激,减少细胞和坏死细胞的数量.     

香草乙酮对大鼠心肌再灌注损伤的保护作用

目的为明确烟酰胺腺嘌呤二核苷酸磷酸(NADPH)氧化酶在心肌再灌注损伤中的作用,并探索治疗再灌注损伤的新途径,使用香草乙酮(apocynin)这一特异的NADPH氧化酶抑制剂对心肌再灌注损伤进行干预,并对其效果和机制进行了观察分析。方法使用在体大鼠心脏缺血再灌注模型,给予30 min左前降支结扎造成缺血,随后松扎进行3 h再灌注。Apocynin干预组于再灌注前10 min给予不同剂量的apocynin,观察其剂量与心脏保护效应关系,并测定心功能、梗死面积、心肌细胞凋亡、NADPH氧化酶活性和自由基生成等指标。结果再灌注后心肌NADPH氧化酶活性明显升高,自由基生成也显著增加。给予apocynin可剂量依赖性地减轻心肌再灌注引起的细胞凋亡和自由基生成,apocynin 10 mg/kg剂量可以改善再灌注后的心脏功能,缩小梗死面积,减少心肌凋亡的发生,抑制NADPH氧化酶的活化,从而减少超氧阴离子和过氧化亚硝酸盐自由基的生成及其损伤,但对一氧化氮的生成无明显影响。结论NADPH氧化酶在心肌再灌注损伤中发挥重要作用,apocynin可以对再灌注大鼠心肌发挥保护作用,这种保护与其抑制NADPH氧化酶的活性,减少其介导的超氧阴离子和过氧化亚硝酸盐自由基生成有关。     

NADPH氧化酶抑制剂apocynin对大鼠糖尿病肾小球细胞外基质代谢的影响

目的探讨NADPH氧化酶亚基p22phoxmRNA在糖尿病大鼠肾脏表达时间模式及抑制NADPH氧化酶活性对肾小球细胞外基质(ECM)代谢的影响。方法链脲佐菌素诱导的大鼠糖尿病模型随机地分为糖尿病非治疗组(DM),观察12周;NADPH氧化酶抑制剂apocynin治疗组(DM+Apo,0.2g·kg-1·d-1),疗程8周。用RT-PCR检测肾脏NADPH氧化酶亚基p22phoxmRNA的表达。免疫组织化学检测肾脏纤连蛋白(FN)表达。白明胶酶谱法(zymography)检测肾脏基质金属蛋白酶-9(MMP-9)的活性。并测定Scr、尿蛋白量和肾重指数。结果DM组肾脏p22phoxmRNA的表达在4、6和8周时较正常对照组(C)明显升高(P<0.05);12周时降低至正常水平。DM+Apo组肾脏p22phoxmRNA的表达与DM组差异无统计学意义(P>0.05),但可显著逆转由糖尿病导致的肾小球体积、肾小球FN表达、肾小球ECM含量、Scr、尿蛋白量和肾重指数的升高(P<0.05),并显著提高肾脏MMP-9活性(P<0.05)。结论NADPH氧化酶的过度表达在糖尿病肾病(DN)发病的早期阶段起重要作用。抑制NADPH氧化酶活性的治疗措施可减少DN肾小球ECM积聚、延缓DN的发生和发展。