胰高血糖素样肽-1对AGEs诱导H9C2心肌细胞自噬的影响

目的观察胰高血糖素样肽-1(GLP-1)对晚期糖基化终产物(AGEs)诱导H9C2心肌细胞自噬(Autophagy)的影响,初步探讨GLP-1心肌细胞保护作用与自噬活性关系。方法将传代培养H9C2心肌细胞随机分4组:(1)Control组:加入0.9%生理盐水;(2)AGEs组:加入100 mg·L~(-1)AGEs;(3)AGEs+GLP-1组:同时加入100 mg·L~(-1)AGEs和10 nmol·L~(-1)GLP-1;(4)AGEs+GLP-1+Rapamycin组:同时加入100 mg·L~(-1)AGEs、10 nmol·L~(-1)GLP-1及5μmol·L~(-1)Rapamycin(自噬诱导剂)。各组在经上述预处理24 h后,分别用CCK-8法检测细胞存活率Hoechst 33258试剂盒检测细胞的凋亡率,DCFH-DA荧光探针检测细胞内活性氧(ROS)水平,流式细胞术检测细胞自噬溶酶体形成,Western blot法检测自噬相关蛋白(LC3Ⅱ,Beclin-1)表达。结果 (1)与Control组相比,AGEs组细胞生存率明显减少,细胞内ROS水平明显增高,细胞自噬溶酶体水平及自噬相关蛋白(LC3Ⅱ、Beclin-1)表达均明显增加;(2)与AGEs组相比,AGEs+GLP-1组细胞生存率明显增高,细胞内ROS水平、细胞自噬溶酶体水平及自噬相关蛋白(LC3Ⅱ、Beclin-1)表达均明显下降;(3)与AGEs组相比,AGEs+GLP-1+rapamycin组中细胞内ROS水平降低,而细胞生存率、细胞自噬溶酶体水平及自噬相关蛋白(LC3Ⅱ、Beclin-1)表达未见差异。结论 (1)AGEs可导致H9C2心肌细胞内ROS升高,诱导细胞损伤并激活细胞自噬;(2)GLP-1对AGEs诱导的H9C2心肌细胞损伤具有保护作用,其保护机制可能与抑制细胞自噬活性有关。     

金钗石斛生物碱激活自噬抑制谷氨酸诱导的大鼠海马神经元轴突变性

目的观察金钗石斛生物碱(ADNL)对谷氨酸诱导的大鼠海马神经元轴突变性的保护作用,并探讨该保护作用与影响细胞自噬的关系。方法体外培养的大鼠海马神经元被随机分为对照组、模型组、ADNL(3.5、35、350μg·L~(-1)组、ADNL(350μg·L~(-1)+3~(-1)甲基腺嘌呤(3MA,1 mmol·L~(-1)或羟氯喹(HCQ,50μmol·L~(-1)组。谷氨酸(50μmol·L~(-1)诱导神经元轴突变性,βⅢTubulin免疫荧光观察轴突变性形态学改变并作定量分析,MTT比色法检测细胞活力,神经元过表达GFP~(-1)LC3B观察自噬体数量的变化,DQ~(-1)RED~(-1)BSA检测自噬体的降解,Western blot检测突触后密度蛋白~(-1)95(PSD95)、突触素(SYN)、LC3BⅠ、LC3BⅡ和p62蛋白水平。结果谷氨酸可诱导大鼠海马神经元轴突变性,变性指数显著增高,细胞活力、PSD95和SYN蛋白水平显著降低(P<0.05或P<0.01),除ADNL(3.5μg·L~(-1)对变性指数(72 h)、细胞活力和SYN蛋白水平未见显著影响(P>0.05)外,谷氨酸诱导的上述各指标的改变均被ADNL显著抑制,而且ADNL(350μg·L~(-1)对轴突变性的保护作用可被自噬抑制剂3MA拮抗。在谷氨酸诱导的轴突变性神经元中GFP~(-1)LC3B荧光斑点数量减少(P<0.01)、LC3BⅡ/LC3BⅠ比值降低(P<0.01),p62降解受阻(P<0.01),表明自噬功能被抑制。不同浓度的ADNL均可增加GFP~(-1)LC3B荧光斑点数量,增高LC3BⅡ/LC3BⅠ比值,促进p62和DQ~(-1)RED~(-1)BSA降解,其中对GFP~(-1)LC3B荧光斑点的影响呈浓度依赖性。ADNL(350μg·L~(-1)对自噬功能的影响可被自噬抑制剂3MA或HCQ拮抗。结论 ADNL通过激活自噬改善谷氨酸诱导的大鼠海马神经元轴突变性。     

过氧化氢诱导血管平滑肌细胞内质网应激及其自噬作用

目的观察过氧化氢(H_2O_2)诱导血管平滑肌细胞(VSMC)内质网应激及其自噬的作用机制。方法体外培养VSMC细胞,加入H_2O_250,100,200,400,600,800,1200和1600μmol·L~(-1)分别作用12和24 h后,MTT法检测H_2O_2对VSMC的抑制率;倒置相差显微镜观察H_2O_2对VSMC细胞形态的影响;采用间接免疫荧光法检测自噬相关蛋白微管相关蛋白轻链3(LC3)和泛素结合蛋白p62的表达,采用Western蛋白印迹法检测自噬相关蛋白人卷曲螺旋肌球蛋白样BCL2相互作用蛋白/自噬基因(Beclin-1)和LC3、内质网应激相关蛋白葡萄糖调节蛋白78(GRP78)和CCAAT-增强子结合蛋白同源蛋白(CHOP)及自噬上游信号通路哺乳动物西罗莫司(雷帕霉素)靶蛋白(m TOR)的表达。结果 MTT结果显示,H_2O_250~1600μmol·L~(-1)作用VSMC细胞12和24 h,VSMC细胞存活率明显降低,12和24 h的IC50分别为(597.2±2.3)和(447.4±1.7)μmol·L~(-1)。倒置相差显微镜观察可见H_2O_2400μmol·L~(-1)组VSMC收缩变圆。H_2O_2400μmol·L~(-1)作用VSMC 12 h时,细胞存活率由(97.5±0.1)%下降至(74.4±1.0)%;作用VSMC 24 h,下降至(56.8±0.9)%(P<0.01)。激光共聚焦显微镜检测发现,H_2O_2400μmol·L~(-1)作用VSMC 8 h,细胞浆中LC3和p62蛋白随H_2O_2作用时间的延长表达增加。LC3与p62的共定位显示,H_2O_2400μmol·L~(-1)作用8 h最明显。Western蛋白印迹结果表明,H_2O_2诱导内质网应激相关蛋白GRP78,CHOP和自噬相关蛋白Beclin-1,LC3Ⅱ/LC3Ⅰ的表达显著增加(P<0.01),m TOR的表达显著降低(P<0.01)。结论 H_2O_2可能通过诱导VSMC内质网应激激活自噬。     

氯喹对三阴乳腺癌MDA-MB-231细胞增殖的影响及其机制

目的观察氯喹对三阴乳腺癌MDA-MB-231细胞增殖的影响,并探讨其机制。方法用氯喹20,40和80μmol·L~(-1)分别处理MDA-MB-231细胞24和48 h,采用CCK-8法和细胞克隆形成实验检测细胞增殖,流式细胞术检测细胞周期和凋亡,Western印迹法检测细胞周期相关蛋白即细胞周期蛋白D3、细胞周期蛋白依赖性激酶2(CDK2)和CDK4,细胞凋亡相关蛋白即活化胱天蛋白酶3和活化聚腺苷二磷酸-核糖聚合酶(PARP)及自噬标志蛋白即自噬微管相关蛋白轻链3B(LC3B)和自噬底物SQSTM1表达水平。结果氯喹20,40和80μmol·L~(-1)与MDA-MB-231细胞作用24和48 h后,均能有效抑制细胞增殖(P<0.01)。与细胞对照组相比,氯喹20和40μmol·L~(-1)处理24 h,G_0/G_1期细胞百分比显著增高(P<0.01);80μmol·L~(-1)组G_2/M期细胞百分比升高(P<0.01),且细胞凋亡率增加(P<0.01)。处理48 h,与细胞对照组相比,氯喹用药3组细胞凋亡率均显著升高(P<0.05)。氯喹3组处理24 h,与细胞对照组相比,细胞周期蛋白D3、CDK2和CDK4表达水平降低(P<0.01),活化胱天蛋白酶3和活化PARP表达增强(P<0.01),LC3B和SQSTM1表达水平显著升高(P<0.01)。结论氯喹可通过抑制MDA-MB-231细胞自噬、阻滞细胞周期进程并促进细胞凋亡而抑制其增殖。     

1,10-邻二氮杂菲双过氧钒酸钾对HT22细胞增殖和周期的影响

目的探讨1,10-邻二氮杂菲双过氧钒酸钾〔BPV(phen)〕是否通过调节DNA甲基转移酶(DNMT)的表达,调控细胞周期相关基因表达,进而影响细胞周期。方法 BPV(phen)0.3和3.0μmol·L~(-1)处理HT22细胞24 h,MTS法检测细胞存活;流式细胞术方法检测细胞周期;ELISA法检测DNMT活性;实时荧光定量PCR检测p21,DNMT1,DNMT3A和DNMT3B mRNA表达水平;Western印迹法分别检测相应蛋白表达水平。结果与DMSO对照组相比,BPV(phen)0.3μmol·L~(-1)对细胞存活率无显著影响,BPV(phen)3.0μmol·L~(-1)组细胞存活率显著降低(P<0.05)。细胞周期结果显示,与DMSO对照组相比,BPV(phen)0.3μmol·L~(-1)组各细胞周期百分比无显著差异,BPV(phen)3.0μmol·L~(-1)组S期细胞显著增加,为(76.1±1.6)%(P<0.05),G2期细胞显著降低(P<0.05),为(2.1±1.5)%。与DMSO对照组相比,BPV(phen)3.0μmol·L~(-1)组细胞DNMT活性显著增加(P<0.05)。实时荧光定量PCR结果显示,与DMSO对照组相比,BPV(phen)0.3μmol·L~(-1)组p21,DNMT1,DNMT3A和DNMT3B mRNA表达水平无显著差异,BPV(phen)3.0μmol·L~(-1)组各基因表达水平均显著增加(P<0.05,P<0.01)。Western印迹结果显示,与DMSO对照组相比,BPV(phen)0.3μmol·L~(-1)组各蛋白表达水平均无显著性差异,只有BPV(phen)3.0μmol·L~(-1)组DNMT3B和P21蛋白表达显著增加(P<0.05)。结论 BPV能够通过改变DNMT的表达,调节下游与细胞周期相关基因的表达,进而影响HT22细胞的生长和增殖。     

橘红素对人胃癌AGS细胞自噬的作用及其机制研究

目的探讨橘红素(Tangeretin, Tan)对人胃癌AGS细胞自噬的作用及其机制。方法 Western blot检测Tan对LC3II、p62及p-Akt蛋白表达的影响,以及自噬抑制剂CQ和促进剂Rapa干预后,LC3II和p62蛋白表达的变化。Annexin V/PI双染,流式细胞术检测CQ对Tan诱导细胞凋亡作用的影响。结果作用24 h,Tan可呈剂量依赖地增强LC3II蛋白(P<0.05,P<0.01)和p62蛋白(P<0.05)的表达;作用48 h,Tan可呈剂量依赖地增强p62蛋白的表达(P<0.05,P<0.01)。作用24 h和48 h,与Tan单独处理组比较,CQ与Tan联合处理可明显增强LC3Ⅱ和p62蛋白的表达(P<0.01),而Rapa和Tan联合处理则下调LC3Ⅱ和p62蛋白的表达(P<0.05)。10μmol·L~(-1) CQ与60μmol·L~(-1) Tan联合作用48 h,CQ+Tan组与Tan组比较,细胞凋亡率明显增加(P<0.01)。Tan作用24 h和48 h,p-Akt蛋白的表达均呈剂量依赖地下降(P<0.05,P<0.01)。结论橘红素可以抑制人胃癌AGS细胞的自噬流,造成自噬体的堆积,促进AGS细胞凋亡,Akt蛋白的磷酸化可能参与其中。     

西罗莫司抗缺血性脑卒中的自噬机制

目的观察神经元氧糖剥夺(OGD)后自噬的动态变化,并探讨西罗莫司对缺血性脑卒中的保护作用及自噬机制。方法利用OGD神经元,观察神经元氧糖剥夺后不同时间点自噬蛋白LC3-Ⅱ、Beclin-1和β-arrestin的变化,并观察10-6 mol·L-1西罗莫司对正常对照或OGD 6h后神经元LC3-Ⅱ的影响及抗凋亡作用。30只小鼠随机分为模型组、西罗莫司1μg·kg-1组和10μg·kg-1组(均n=10),观察西罗莫司对大脑中动脉阻塞(MCAO)模型小鼠半暗带脑组织LC3-Ⅱ和脑梗死面积的影响。结果神经元OGD 2 h后,自噬蛋白LC3-Ⅱ、Beclin-1和β-arrestin表达均减少,随OGD时间延长,LC3-Ⅱ和Beclin-1表达呈明显下降趋势(P<0.01);西罗莫司能促进神经元OGD 6h后LC3-Ⅱ的表达,并明显减少神经元的凋亡(P<0.01)。MCAO小鼠脑缺血6 h后,西罗莫司10μg·kg-1组梗死面积百分比(37.8±6.3)%显著小于模型组的(48.0±6.7)%(P<0.05)。结论西罗莫司对缺血性脑卒中有保护作用,其机制可能与促进自噬有关。     

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。     

内源性硫化氢对硫酸铍诱导人支气管上皮细胞自噬的影响

目的探讨内源性硫化氢(H_2S)对硫酸铍(BeSO_4)诱导人支气管上皮细胞(16HBE)自噬的影响。方法用0、100、150、200、250和300μmol/L BeSO_4处理16HBE细胞48 h,MTT法测定细胞活力,亚甲基蓝分光光度法测定细胞内H_2S含量,Western blot测定自噬标志蛋白LC3-B、Beclin-1及P62表达;用300μmol/L硫氢化钠(NaHS)或10 mmol/L DL-炔丙基甘氨酸(PPG)预处理16HBE细胞6 h后,用BeSO_4处理细胞,研究H_2S含量对上述指标的影响。结果 (1)BeSO_4作用16HBE细胞48 h的半数致死浓度为249μmol/L;与对照组相比,BeSO_4组自噬蛋白LC3-II/LC3-I和Beclin-1表达升高,细胞活力、H_2S含量和P62蛋白表达降低,当BeSO_4浓度100μmol/L时,差异均有统计学意义(P0.05);(2)与BeSO_4组比较,NaHS+BeSO_4组细胞活力、H_2S水平和P62蛋白表达均升高(P0.05),LC3-II/LC3-I和Beclin-1蛋白表达有降低趋势,但差异无统计学意义;(3)与BeSO_4组比较,PPG+BeSO_4组细胞活力、H_2S水平及P62蛋白表达降低,LC3-II/LC3-I和Beclin-1蛋白表达升高(P0.05)。结论在本试验条件下,BeSO_4染毒能致16HBE细胞活力和内源性H_2S含量下降,并引起细胞自噬;内源性H_2S能抑制BeSO_4诱导的16HBE细胞自噬、减轻细胞毒性,发挥保护功能。     

腺苷对肝癌细胞自噬和增殖的作用

目的研究腺苷对肝癌细胞增殖和自噬的作用。方法腺苷作用于HepG2细胞,CCK-8法观察细胞增殖的变化,Western blot研究LC3-Ⅱ和LC3-Ⅰ蛋白的表达,MDC染色观察自噬体数量。结果腺苷(1.0~4.0 mmol·L~(-1))作用于HepG2细胞,在12、24、48 h可明显抑制细胞增殖(P<0.01)。低浓度腺苷(0.2、0.5、1.0 mmol·L~(-1))处理细胞24h,LC3-Ⅱ/LC3-Ⅰ明显降低,腺苷(1.0 mmol·L~(-1))对HepG2细胞自噬抑制作用最强(P<0.01),高浓度腺苷(4 mmol·L~(-1))反而增强Hep G2细胞内自噬(P<0.05)。腺苷(1.0mmol·L~(-1))作用细胞24 h,LC3-Ⅱ/LC3-Ⅰ比值在6、12、24 h检测点明显降低,MDC染色显示自噬体减少,在12 h检测点发现LC3-Ⅱ/LC3-Ⅰ最低(P<0.01),自噬体基本消失。结论腺苷抑制肝癌细胞增殖,低浓度腺苷抑制细胞自噬,高浓度腺苷促进细胞自噬,对提高肝癌药物的治疗效果有重要意义。     

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.