表没食子儿茶素促进Nrf2的核转位减轻Aβ_(25-35)对SH-SY5Y细胞的损伤

目的研究表没食子儿茶素(epigallocatechin,EGC)对Aβ_(25-35)损伤SH-SY5Y细胞的保护作用及机制。方法采用Aβ_(25-35)损伤SH-SY5Y细胞,MTT和LDH法,考察EGC对SH-SY5Y细胞活力的影响。应用DCFH-DA荧光探针检测细胞内ROS水平,通过测定细胞内SOD、GSH-Px和MDA活性,考察细胞氧化应激水平。Western blot测定细胞中Nrf2、NQO1、HO-1、Prdx6和Trx1蛋白含量。结果 Aβ_(25-35)损伤SH-SY5Y细胞,导致细胞存活率明显降低。5、10、20μmol·L~(-1) EGC能够减轻Aβ_(25-35)诱导的SH-SY5Y细胞损伤及LDH释放。而且EGC能够减少Aβ_(25-35)诱导的细胞内ROS水平的增加,减轻氧化应激损伤。同时,EGC能够明显增强Aβ_(25-35)损伤后Nrf2、NQO1、HO-1、Prdx6和Trx1的表达。结论EGC能够抑制Aβ_(25-35)诱导的SH-SY5Y细胞损伤,通过促进Nrf2核转位,提高抗氧化水平,降低Aβ_(25-35)神经毒性。     

根皮苷对过氧化氢诱导损伤PC12细胞的保护作用

目的探讨根皮苷对过氧化氢(H2O2)诱导的PC12细胞氧化损伤的保护作用。方法以H_2O_2损伤PC12细胞建立氧化损伤模型,随机分为空白对照组、模型组(400μmol·L~(-1) H_2O_2)、阳性对照(20μmol·L~(-1)N-乙酰半胱氨酸)组和不同浓度根皮苷(16、32、64μmol·L~(-1))预处理组。采用MTT法检测细胞活力,显微镜观察细胞形态,ELISA检测细胞活性氧(ROS)和丙二醛(MDA)的含量及超氧化物歧化酶(SOD)活力,Western blot检测NF-E2相关因子2(Nrf2)和血红素加氧酶-1(HO-1)蛋白表达。结果模型组细胞活力较空白对照组显著降低,ROS和MDA含量增加,SOD活力下降,Nrf2和HO-1蛋白表达下降(均P<0.05)。根皮苷低、中、高浓度(16、32、64μmol·L~(-1))组较模型组细胞存活率均显著提高,ROS和MDA含量降低,SOD活力升高,Nrf2和HO-1蛋白表达上调(均P<0.05)。结论根皮苷能够抑制H_2O_2对PC12细胞的氧化损伤,其保护作用可能与抑制氧化应激引起的细胞死亡并调控Nrf2信号通路有关。     

丁氟螨酯对SH-SY5Y细胞的毒性作用及其机制

目的研究丁氟螨酯对人经神经母细胞瘤细胞SH-SY5Y细胞的毒性作用及其机制。方法加入丁氟螨酯0.03,0.06,0.125,0.25,0.5,1,2,2.6,4,6,8和16 mmol·L~(-1)处理SH-SY5Y细胞48 h,MTT法测定细胞存活;DCFH-DA荧光探针标记法检测细胞内活性氧(ROS)水平;JC-1标记法检测细胞线粒体膜电位;Hoechst 33258染色观察细胞核形态;碘化丙啶(PI)染色和流式细胞仪检测细胞周期和细胞凋亡;Western蛋白印迹法检测磷酸化P38蛋白(p-P38)和磷酸化Jun激酶(p-JNK)表达水平。结果与溶剂(DMSO)对照组相比,共孵育48 h后,丁氟螨酯≥0.06 mmol·L~(-1)时可降低细胞存活率(P<0.05),且随浓度增高细胞存活率有降低趋势,IC_(50)为2.6 mmol·L~(-1);丁氟螨酯1,2,4和6 mmol·L~(-1)组细胞ROS水平升高(P<0.01),线粒体膜电位下降(P<0.01)。Hoechst 33258染色结果显示,丁氟螨酯2,4和6 mmol·L~(-1)组SH-SY5Y细胞出现颗粒状荧光,细胞核固缩和崩解;流式细胞仪检测结果显示,丁氟螨酯2,4和6 mmol·L~(-1)组细胞凋亡率由DMSO对照组的(0.7±0.1)%分别上升至(6.7±0.1)%,(72.4±8.6)%和(90.7±3.2)%(P<0.01);丁氟螨酯4和6 mmol·L~(-1)组G_1期细胞较DMSO对照组明显增加(P<0.01);Western蛋白印迹结果表明,丁氟螨酯4和6 mmol·L~(-1)组p-JNK表达均升高(P<0.01),丁氟螨酯6 mmol·L~(-1)组p-P38表达水平增加(P<0.01)。结论丁氟螨酯可能通过氧化损伤、激活P38蛋白和JNK蛋白诱导SH-SY5Y细胞G_1期阻滞和凋亡。     

褐藻多糖硫酸酯在小鼠N2a细胞缺血再灌注损伤中的作用

目的 观察褐藻多糖硫酸酯(FPS)对氧糖剥夺/复糖复氧(OGD/R)诱导小鼠N2a细胞缺血再灌注损伤中的作用并探讨其可能的分子机制。方法 在细胞水平上,建立小鼠N2a细胞的OGD 2 h后复灌24 h的缺血再灌注损伤模型。实验分为对照组、OGD/R模型组和FPS处理组(1、2、5、10μg/ml)。3-(4,5-二甲基噻唑-2)-2,5-二苯基四氮唑溴盐(MTT)比色法和乳酸脱氢酶(LDH)释放率试剂盒分别检测各组细胞存活率和死亡率;Western blot检测Nrf2的核转位及其下游靶蛋白血红素加氧酶1(HO-1)的表达情况。结果 与OGD/R模型组比较,不同浓度的FPS均能提高N2a细胞存活率,降低死亡率,且增加Nrf2的核转位及其下游靶蛋白HO-1的表达(P<0.05)。结论 FPS对OGD/R诱导N2a细胞缺血再灌注损伤具有保护作用,其机制可能与激活Nrf2通路有关。     

银杏二萜内酯葡胺注射液对缺糖缺氧损伤的SH-SY5Y细胞保护作用

目的探讨银杏二萜内酯葡胺注射液(YXETNZ)对缺糖缺氧(oxygen-glucose deprivation,OGD)损伤的人神经母细胞瘤细胞(SH-SY5Y)的保护作用及可能的机制。方法 SHSY5Y细胞OGD损伤4 h后,与药物一起复氧1 h,然后测定细胞存活率(CCK-8法)、caspase-3/7酶活力、细胞质中核小体含量;蛋白质免疫印迹检测细胞中p-Akt、p-PKA、p-Bad蛋白量的变化。结果 OGD明显提高SH-SY5Y细胞caspase-3/7酶活力和细胞质中核小体含量,明显降低细胞的存活率。YXETNZ能明显提高OGD损伤的SH-SY5Y细胞的存活率,抑制caspase-3/7酶活性,减少细胞核核小体的释放量,上调p-Akt、p-PKA和p-Bad激酶蛋白量,提高Akt和PKA活性,保护神经细胞。结论 YXETNZ对OGD损伤的SHSY5Y细胞具有明显的保护作用,其保护机制可能与细胞内PI3K/Akt/Bad/caspase-3/7、c AMP/PKA/Bad/caspase-3/7细胞通路的激活有关。     

mTOR信号通路介导姜黄素抗抑郁作用机制

目的探讨mTOR信号通路介导姜黄素抗抑郁作用机制。方法建立皮质酮损伤SH-SY5Y细胞模型。通过CCK-8法检测姜黄素对皮质酮诱导SH-SY5Y细胞保护作用。建立小鼠强迫游泳和悬尾急性抑郁模型,将40只雄性ICR小鼠随机分成4组,分别为生理盐水(侧脑室注射生理盐水,ICV)+溶剂(灌胃,ig)组、生理盐水(ICV)+姜黄素(50 mg·kg-1,ig)组、雷帕霉素(150 nmol·L~(-1),ICV)+溶剂(ig)组、雷帕霉素(150 nmol·L~(-1),ICV)+姜黄素(50 mg·kg~(-1),ig)组。姜黄素给药前30 min预先侧脑室注射雷帕霉素,给药30 min后进行行为学测试。结果给予姜黄素共培养能够明显提高皮质酮损伤SH-SY5Y细胞存活率(1 nmol·L~(-1),P<0.01;0.5 nmol·L~(-1),P<0.01;0.25 nmol·L~(-1),P<0.05),而雷帕霉素能够阻断姜黄素的保护作用(P<0.05)。姜黄素能够明显降低小鼠强迫游泳不动时间(P<0.01)和悬尾不动时间(P<0.05),而预先侧脑室注射雷帕霉素后,姜黄素降低小鼠强迫游泳不动时间(P<0.01)和悬尾不动时间(P<0.05)的作用被降低。结论姜黄素具有明显的抗抑郁作用,且其抗抑郁作用可能与激动mTOR信号通路有关。     

Aβ_(25-35)对SH-SY5Y细胞Bcl-2、Bax基因启动子区DNA甲基化的影响

目的探讨Aβ_(25-35)介导SH-SY5Y细胞Bcl-2、Bax基因表达改变是否通过基因启动子区甲基化的机制。方法不同浓度Aβ_(25-35)(0、25、50μmol·L~(-1))分别作用于体外培养的SH-SY5Y细胞48、72 h,MTT法确定Aβ_(25-35)诱导SH-SY5Y细胞凋亡的最佳浓度和时间。Western blot检测不同药物处理组细胞凋亡相关蛋白Bcl-2、Bax表达变化,Real time PCR检测DNA甲基化酶DNMT1、DNMT3a、DNMT3b、Me CP2的mRNA水平。Methylation specific PCR(MSP)法分析Aβ_(25-35)介导的Bcl-2、Bax基因启动子区甲基化水平的变化。结果 25μmol·L~(-1)Aβ_(25-35)暴露SH-SY5Y细胞72 h后,MTT检测细胞存活率达(68.49±9.83)%,与对照组比较明显降低(P<0.05),表明成功建立了AD细胞凋亡模型。Western blot结果显示,Aβ_(25-35)药物处理组与空白组比较,Bcl-2表达明显减少,Bax表达明显增加。Real-time PCR结果显示,不同浓度的Aβ_(25-35)药物组与空白组比较,DNA甲基化酶DNMT1、DNMT3a、DNMT3b、MeC P2表达无变化(P<0.05);MSP结果显示空白对照组Bcl-2和Bax甲基化扩增阴性,非甲基化扩增阳性;Aβ_(25-35)处理组Bcl-2和Bax甲基化引物扩增阴性,非甲基化引物扩增阳性。结论 MSP结果显示Aβ_(25-35)介导SHSY5Y细胞凋亡未引起Bcl-2、Bax启动子区甲基化的改变。     

天麻素在甲基苯丙胺诱导SH-SY5Y细胞自噬中的作用及机制研究

目的研究天麻素(gastrodin)在甲基苯丙胺(methamphetamine,METH)诱导SH-SY5Y细胞自噬中的作用,并探讨其作用机制。方法体外培养人神经母细胞瘤SH-SY5Y细胞,不同浓度的METH(0.5、1.0、1.5、2.0、2.5、3.0 mmol·L~(-1))处理SY5Y细胞,并在6、12、24、48 h观察SY5Y细胞自噬的情况,确定自噬的最佳浓度和时间点。提前1 h给予1mmol·L~(-1)天麻素进行干预,用显微镜观察细胞形态变化,采用激光共聚焦显微镜观察LC3-Ⅱ的改变,Western blot检测天麻素干预前后LC3-Ⅱ、Beclin-1以及Akt、p-Akt、mTOR、p-mTOR的表达情况。结果随着METH浓度(0~3.0 mmol·L~(-1))的增加,SY5Y细胞逐渐变圆、突起逐渐变短、消失,同时部分细胞质内可见大小不等的空泡结构形成,细胞间隙逐渐增宽,最终细胞呈漂浮状态。随着METH浓度的增加,SY5Y细胞LC3-Ⅱ表达水平逐渐增强。激光共聚焦显微镜结果显示,天麻素+METH组LC3-Ⅱ的表达水平比METH组降低。与对照组相比,METH组LC3-Ⅱ和Beclin-1表达水平明显增强(P<0.01),mTOR和Akt差异无显著性,p-mTOR、p-Akt表达水平明显降低(P<0.01);给予天麻素干预后,与METH组相比,LC3-Ⅱ和Beclin-1表达水平降低,而mTOR、p-mTOR、Akt、p-Akt表达水平升高。结论 METH可诱导SY5Y细胞自噬,天麻素可减弱METH诱导的SY5Y细胞自噬,这一作用与天麻素调控Akt和mTOR信号通路密切相关。     

黄腐醇对SH-SY5Y细胞氧化应激损伤的保护机制研究

摘要：目的:研究黄腐醇体外缓解过氧化氢（H2O2）诱导SH-SY5Y细胞死亡的抗氧化损伤机制。方法:体外培养SH-SY5Y细胞,采用MTT法分别研究不同浓度的黄腐醇对SH-SY5Y细胞的毒性作用和对H2O2诱导细胞损伤的保护作用;采用流式细胞仪和显微成像实验检测黄腐醇对细胞内活性氧（ROS）水平的影响;采用免疫荧光实验检测黄腐醇对核因子E2相关因子2（Nrf2）核转位的影响及用Western Blot分析黄腐醇对抗氧化蛋白血红素加氧酶-1（HO-1）和谷氨酸半胱氨酸连接酶催化亚基（GCLC）的影响。结果:黄腐醇浓度≤0.5μmol·L-1时对SH-SY5Y细胞无毒性作用,黄腐醇对H2O2诱导的细胞损伤具有浓度依赖性保护作用（P<0.05或P<0.01）;同时黄腐醇能降低H2O2诱导的细胞内ROS水平和促进Nrf2核转位（P<0.05）及浓度依赖性地提高HO-1和GCLC蛋白的表达（P<0.05或P<0.01）。结论:黄腐醇具有一定的细胞保护作用,其通过激活Nrf2通路缓解H2O2诱导SH-SY5Y细胞的氧化损伤。     

淫羊藿苷对H_2O_2诱导的人脐静脉内皮细胞氧化损伤的保护作用及机制

目的研究淫羊藿苷(Ica)对H_2O_2诱导的人脐静脉内皮细胞(HUVEC)氧化损伤的保护作用及其机制。方法 H_2O_2诱导氧化损伤模型。药效学研究分为六组:空白组,模型组(750μmol·L-1 H2O2),Ica-L、M、H组(750μmol·L~(-1) H_2O_2+1×10-8、1×10-7、1×10-6mol·L~(-1)Ica)和溶媒组(0.1%DMSO)。Ica给药12 h后加入H_2O_2,Ica作用时间为24、36和48 h。Ica作用机制研究分为五组:空白组、模型组、Ica-H组、LY组(750μmol·L~(-1) H_2O_2+25μmol·L~(-1)LY294002)、Ica-H+LY组。LY294002为PI3K抑制剂,给予LY294002后2 h加入Ica,12 h后加入H_2O_2,Ica作用时间为48 h。MTT法检测细胞活力,ELISA检测细胞培养液中活性氧(ROS)的含量,显微镜观察细胞形态及存活细胞密度,Annexin V-FITC/PI染色荧光显微镜观察细胞凋亡率,Real time RT-PCR检测Bcl-2、Bax mRNA的表达,Western Blot检测p-Akt和Akt蛋白的表达。结果与空白组相比,模型组细胞活力降低(P<0.01),ROS分泌量和凋亡细胞增加(P<0.01);与模型组相比,Ica-L、M、H组均能提高细胞活力(P<0.01),降低细胞培养液中ROS的含量(P<0.05),其抑制率呈现时间和剂量依赖性。同时,Ica能明显降低细胞凋亡率(P<0.01),上调p-Akt蛋白和Bcl-2 m RNA的表达(P<0.05),下调Bax mRNA的表达(P<0.05);Ica的以上作用被LY294002拮抗。结论 Ica(1×10~(-8)-1×10-6 mol·L~(-1))对H_2O_2诱导的HUVEC氧化损伤有保护作用,能缓解氧化应激诱导的HUVEC凋亡,其机制与PI3K/Akt信号通路有关。     

Analgesia induced by brief footshock is inhibited by 5-hydroxytryptamine but unaffected by antagonists of 5-hydroxytryptamine or by naloxone

Exposure to footshock (1 mA) for 30 sec induced a marked analgesia that was enhanced by pretreatment with the 5HT synthesis inhibitor, p-chlorophenylalanine, and attenuated by the 5HT releasing drugs p-chloroamphetamine and fenfluramine, by the 5HT re-uptake inhibitor, fluoxetine and by the 5HT agonists, 5-methoxy-N,N-dimethyltryptamine and MK212. However, agonists, quipazine and trifluoromethylphenylpiperazine, with greated reported affinities for 5HT binding sites on rat brain membranes than MK212 were without effect as were the antagonists metergoline, methysergide, cyproheptadine, mianserine and methiothepin. The specific opioid antagonist naloxone was also without effect. The results in general indicate that analgesia induced by brief footshock (1 mA, 30 sec) is inversely related to 5HT availability but thereis little evidence of involvement of known 5HT receptors.     

Synergism by caffeine and by cocaine of the motor control deficit produced by midazolam

To evaluate the effects of caffeine and cocaine on the impairment of discriminative motor control produced by midazolam, rats were trained to hold a force transducer operated with a paw so that it remained between upper and lower limits of a force band for a continuous 1.5-s period to deliver each food pellet. Acute doses of 3 mg/kg midazolam SC impaired motor performance. Except for one animal, caffeine (10-40 mg/kg IP) had little or no effect on performance, while cocaine (3.75-22.5 mg/kg IP) produced dose-related impairment. When each dose of caffeine was combined with 3 mg/kg midazolam, a marked synergism in motor performance impairment occurred. Cocaine plus midazolam produced mainly an additive synergism. The conspicuous synergistic action of caffeine on the motor control deficit produced by midazolam contrasts with the typical antagonism found between the benzodiazepines and methylxanthines when performance is evaluated by psychomotor tests not requiring fine motor control.     

Deamination of beta-phenylethylamine by monoamine oxidase--inhibition by imipramine

The oxidative deamination of tyramine (Tyr), 5-hydroxytryptamine (5-HT), and β-phenylethylamine (PEA) by mitochondrial preparations of rabbit lung and brain was inhibited by imipramine. This tricyclic iminodibenzyl antidepressant drug was most effective in decreasing the deamination of PEA: at 1 × 10^?4M imipramine, deamination of PEA, Tyr and 5-HT was inhibited by approximately 70, 45 and 45 per cent, respectively, when either lung or brain mitochondrial monoamine oxidase (MAO) preparations were used. Imipramine-induced inhibition of MAO was shown to be of a mixed type based on Lineweaver-Burk plots, but was found to be completely reversible. The desmcthyl and didesmethyl derivatives of imipramine were equally as effective as the parent drug in inhibiting the deamination of PEA, whereas the N-oxide analog of imipramine was less effective as an inhibitor of this reaction. These results support the premise that the action of imipramine as a clinically effective antidepressive agent may be related to its inhibitory effect on the specific form of MAO which deaminates PEA.     

Augmentation by serrapeptase of tissue permeation by cefotiam

Cefotiam (CTM) is a new cephalosporin with a broad spectrum of activity against both Gram-positive and Gram-negative microorganisms. Cephalosporins are widely used for prophylaxis of infections in patients undergoing thoracotomy. Augmentation by serrapeptase on tissue permeation of CTM was examined in 35 thoracotomy patients with lung cancer. The subjects were divided into two groups according to the method of the administration of CTM. Group I consisted of 17 subjects, each of whom received a single dose of 2 g of CTM alone by an instillation for 30 minutes. Group II consisted of 18 subjects, each of whom received a combination of CTM and serrapeptase; serrapeptase was given 2 tablets (10 mg) each time for three times/day until the day before surgery, and then CTM was administered by the same procedure. The following results were obtained: Individual difference was observed for the permeation of CTM into tissues. Pathologic differences also affected the permeation. Nevertheless, the CTM levels in pulmonary tissues reached about a half of those in the blood in both the single dose group and the combination group, hence sufficient concentrations exceeding MIC80 for main microorganisms that caused infections in the lung were obtained. The concentrations of CTM in inflammatory tissues have showed lower levels than those of normal tissues in both CTM single dose and the combination groups. Decrease of blood flow volume may have contributed to the reduction in levels of CTM in the inflammatory tissues. The ratio of the concentration of the drug in pulmonary tissues to that in the blood was 29.1 +/- 2.5% in the single dose group, and 44.2 +/- 6.0% in the combination group, the latter showing quite a significant increase (P less than 0.05). Combined administrations of CTM and serrapeptase deserves more trials in the case when surgical treatments of the lung are performed. An antiinflammatory effect of serrapeptase in the respiratory system is expected, and in addition, the combined use of CTM and serrapeptase should stimulate permeation of the antibiotic into tissues.     

Immunomodulation by non-absorbable antibiotics given by the intragastric route

To test the role of bacterial fractions released from intestinal flora during immunomodulation by antimicrobial agents, BALB/c mice were treated with the non-absorbable antibiotics polymyxin B or teicoplanin by the intragastric route. The composition of faecal microbiota and the capacity of spleen cells to proliferate in response to B-cell and T-cell mitogens were assessed at several times during the treatment. Both antibiotics lowered the count of some bacteria of the intestinal flora and induced significant modifications in spleen cell ability to proliferate in response to mitogens. Thus, the active fractions released from intestinal bacteria during antibiotic treatments may be able to induce immunomodulating effects.