甘氨酰谷氨酰胺在大鼠离体心脏缺血/再灌注损伤中的保护作用研究

目的： 研究甘氨酰谷氨酰胺对缺血再灌注大鼠离体心脏的保护作用。方法：应用Langendorff离体心脏灌注系统建立心肌缺血再灌注模型。30只SD雄性大鼠随机分为正常对照组(control)、甘氨酰谷氨酰胺对照组(Gly-Gln)、缺血再灌注组(I/R)、缺血/再灌注+甘氨酰谷氨酰胺组(I/R+ Gly-Gln)。I/R组及I/R+ Gly-Gln组分别灌注30 min后,全心停灌20 min,再灌注40 min,I/R+ Gly-Gln组于再灌注时在灌流液中加入Gly-Gln;正常对照组连续灌流90 min,Gly-Gln对照组灌流液中加入Gly-Gln。记录各组灌注时,左室舒张末压(LVEDP)、左室发展压(LVDP)、左室压力最大变化速率(±dp/dtmax)、心率(HR)及心肌细胞单相动作电位(MAP);同时在相应的时点分别测定冠脉流出液中的乳酸脱氢酶（LDH)、肌酸激酶(CK)活性。结果：离体大鼠心脏缺血20min,再灌注40 min,导致严重的心功能抑制,表现为LVEDP升高,LVDP、±dp/dtmax降低;再灌注液中加入Gly-Gln后,LVEDP降低,LVDP、±dp/dtmax明显升高（P<0.01)。I/R+ Gly-Gln组冠脉流出液中LDH、CK活性明显低于I/R组(均P<0.01)。结论： Gly-Gln能有效减轻缺血再灌注引起的左室功能下降,减少心肌细胞LDH、CK的释出,表明Gly-Gln对缺血再灌注损伤的大鼠离体心脏具有保护作用。     

银杏达莫注射液抑制大鼠离体心脏缺血/再灌注损伤的机制研究

 目的：观察银杏达莫注射液预处理对大鼠离体心脏缺血/再灌注损伤的影响,并探讨其可能的作用机制。方法：SD雄性大鼠40只随机分成5组（n=8）：正常对照（NC）组、缺血/再灌注（I/R）组、缺血预处理（IPC+I/R）组、银杏达莫注射液预处理（GD+I/R）组和银杏达莫+氯化镧预处理（GD+LaCl3+I/R）组。观察各组相同时点（预灌30 min稳定点,缺血30 min,再灌5 min、30 min、60 min）的心功能指标,包括心率(HR)、左室收缩压(LVSP)和室内压变化速率（±dp/dtmax）,同时收集各时点冠脉流出液,检测其中乳酸脱氢酶（LDH）和肌酸激酶（CK）活性。实验结束后检测心肌线粒体Ca2+浓度和α-酮戊二酸脱氢酶（α-OGDH）含量。结果：与I/R组比较,IPC+I/R组和GD+I/R组在心脏再灌注期各项心功能指标均得到改善（P<0.05）;心肌LDH和CK的释放量降低（P<0.01）;线粒体内Ca2+超载降低（P<0.01）,且线粒体内α-OGDH含量升高（P<0.05）;而GD+I/R组中银杏达莫对心肌的保护作用被LaCl3抑制（P<0.05）。结论：银杏达莫可能通过抑制钙超载、增强线粒体酶活性以稳定线粒体能量代谢,从而缓解缺血/再灌注诱导的心肌细胞损伤。     

缺氧预处理对自发性高血压大鼠心肌细胞内钙的影响

目的:探讨缺氧预处理对后继缺氧再给氧所致心肌细胞内钙超载的影响及蛋白激酶C(PKC)和百日咳毒素(PTX)敏感的G-蛋白在缺氧预处理的作用.方法:循环灌流法分离自发性高血压大鼠(SHR)肥大心肌细胞,用Fu ra-2AM测定钙浓度.结果:[Ca2+].为1.0 mmol/L时,预处理组缺氧再给氧后其心肌细胞内游离钙浓度[Ca2+]i为(194.0±24.8) nmol/L,未预处理组为(297.5 ±24.5) nmol/L;无外钙预处理组缺氧再给氧后其心肌细胞[Ca2+]i为(162.0 ±30.7) nmol/L,未预处理组为(236.5±28.3) nmol/L,提示缺氧预处理可减少缺氧再给氧所致心肌细胞内钙释放及外钙内流.在[Ca2+].为1.0 mmol/L组,于预处理前分别预先给予PKC拮抗剂Staurosporine(10 nmol/L)及Gi-蛋白失活剂百日咳毒素(PTX,200 ng /L),可见经后继缺氧再给氧后其心肌细胞[Ca2+]i分别为(264.8±19.3)及(25 8.0±27.7) nmol/L,高于缺氧预处理组但低于未预处理组.结论:SH R肥大心肌细胞,缺氧预处理可减轻后继缺氧再给氧所致心肌细胞内钙超载;PKC及PTX敏感的G- 蛋白可能部分参与缺氧预处理的保护作用.     

厚朴酚减轻缺血大鼠心肌损伤

目的研究厚朴酚(Mag)对大鼠缺血心肌的保护作用及可能的机制。方法 SD大鼠分为对照组、模型组和厚朴酚组。模型组采用结扎大鼠左冠状动脉前降支建立急性心肌梗死模型。Mag组建模型前预先30 min给予高、中和低3种浓度的厚朴酚(40、20和10 mg/kg)。酶联免疫法检测血清超氧化物歧化酶(SOD)活力和丙二醛(MDA)含量,DNA断裂的原位末端标记法(TUNEL)检测心肌细胞凋亡,Western blot法检测Bcl-2、caspase-3和Bax蛋白表达,激光共聚焦技术检测[Ca2+]i。结果1)模型组LVEDP较对照组显著增加(P0.05),LVSP及±dp/dtmax较对照组显著降低(P0.05)。Mag组(40 mg/kg)LVEDP较模型组显著降低(P0.05),LVSP及±dp/dtmax较模型组显著增加(P0.05)。2)模型组Bcl-2表达较对照组显著降低(P0.05),30 mmol/L KCl诱导的[Ca2+]i、Bax及caspase-3表达较对照组显著升高(P0.05)。Mag组(40 mg/kg)Bcl-2表达水平较模型组显著增加(P0.05),30 mmol/L KCl诱导的[Ca2+]i、Bax及caspase-3表达较模型组显著降低(P0.05)。结论厚朴酚减轻大鼠缺血心肌损伤可能与下调[Ca2+]i和抑制心肌细胞凋亡有关。     

大电导钾通道对小鼠皮层神经元胞内游离钙和动作电位的影响

目的 探讨大电导钾通道（BK）对小鼠大脑皮层神经元胞内游离钙 ( [Ca2+]i） 和兴奋性的调节作用。方法 体外培养小鼠皮层神经元,用膜片钳技术观察BK特异性阻断剂IBERIOTOXIN对神经元 [Ca2+]i和动作电位频率的影响,用显微荧光测钙法观察IBERIOTOXIN对高钾条件下[Ca2+]i的影响。结果 生理状态下,IBERIOTOXIN灌流(100nmmol/L)对神经元细胞自发动作电位的频率、[Ca2+]i无显著影响;持续电刺激去极化后,IBERIOTOXIN灌流使动作电位频率增加,[Ca2+]i显著升高。高钾溶液(20mmol/L)引起神经元[Ca2+]i升高, 而IBERIOTOXIN灌流则使[Ca2+]i进一步显著升高。结论 BK对小鼠受持续去极化刺激或高钾条件时的神经元[Ca2+]i和兴奋性具有明显调节作用。     

非创伤缺血预处理对大鼠缺血再灌注心肌的作用

目的:确定非创伤性缺血预处理对大鼠缺血/再灌注(I/R)心肌损伤是否具有对抗作用,以扩展缺血预处理的实际应用.方法:采用非创伤性下肢缺血预处理及经典缺血预处理的动物模型,比较两种处理方法对I/R心肌损伤的效应.实验动物分4组:正常对照组(NC,n=8),开胸旷置50 min;缺血/再灌注组(I/R,n=12),结扎冠脉30 min,再灌注20、180 min;经典缺血预处理组(C-IPC,n=12),按经典Murry法复制;非创伤性下肢缺血预处理组(N-WIPC,n=12),捆绑双下肢5 min,松开5 min,反复4次后,阻断冠脉30 min,再灌20、180 min.以左室功能,心肌梗塞范围,血清肌酸激酶(CK)及心肌组织丙二醛(MDA)含量、超氧化物歧化酶(SOD)活性为观察指标.结果:与I/R组相比,N-WIPC组与C-IPC组均显著缩小I/R后的心肌梗塞范围(P＜0.01);明显恢复I/R后的左室功能(P＜0.05,0.01);减轻自由基对心肌的损害:血清CK,心肌MDA含量显著降低(P＜0.01).N-WIPC组还使心肌SOD活性增高(P＜0.05).结论:非创伤性下肢缺血预处理与经典缺血预处理可诱发同等强度的心肌预处理效应.     

钙预处理对离体大鼠缺血再灌注心肌细胞的保护作用

目的 :研究钙预处理是否对缺血再灌注心肌有保护作用 ,其作用是否通过蛋白激酶C(ProteinKinaseC ,PKC)及线粒体ATP依赖性钾通道 (KATP)起作用。方法 :3 2只SD大鼠 ,随机分为 4组 :缺血再灌注组 (I/R组 )、钙预处理组 (CPC组 )、钙预处理加PKC阻滞剂Chelerythine组 (CLT组 )、钙预处理加线粒体KATP通道阻滞剂 5 hy droxydecanoate组 (5 HD组 ) ,分别检测LDH及CK的漏出量、心肌ATP含量、心功能指标 (LVSP及±dp/dtmax)。 结果 :与I/R组比较 ,CPC组CK、LDH漏出量明显减少 (P <0 .0 1) ,心肌ATP含量增加 (P <0 .0 1) ,心功能改善 ;CLT组及 5 HD组上述各指标 (LDH、CK、ATP、LVSP及±dp/dtmax)分别与I/R组相同指标之间无显著性差异 (P >0 .0 5 )。结论 :钙预处理对I/R心肌有保护作用 ,其保护作用可被PKC阻滞剂及KATP阻滞剂所取消 ,提示其保护作用可能通过PKC途径及线粒体KATP通道起作用     

亚甲蓝减轻大鼠离体心脏缺血/再灌注引起的线粒体损伤

目的:探讨亚甲蓝(methylene blue,MB)对大鼠离体心脏缺血/再灌注(ischemia/reperfusion,I/R)线粒体损伤的作用。方法:将Spragure-Dawley大鼠随机分为对照组(control组)、I/R模型组和MB治疗组(I/R+MB组),建立Langendorff离体心脏灌注模型(n=6)。手术前2 h,MB组大鼠按2 mg/kg腹腔注射MB。对照组持续灌注K-H液110 min,I/R组与I/R+MB组平衡灌注20 min后停灌30 min,再灌注60 min。实时记录心率(HR)、左室发展压(LVDP)、左室最大压力变化速率(±dp/dt_(max))和左室舒张末压(LVEDP)。测定冠脉流出液中肌酸激酶MB同工酶(CK-MB)和乳酸脱氢酶(LDH)活性。测定心肌组织中活性氧簇(ROS)、丙二醛(MDA)和三磷酸腺苷(ATP)含量以及超氧化物歧化酶(SOD)活性。苏木精-伊红染色观察组织病理学变化。分离心肌组织线粒体,测定线粒体肿胀程度和线粒体膜电位(MMP)。结果:与对照组相比,I/R组的心功能恶化,冠脉流出液中的CK-MB和LDH活性升高,心肌组织中的ROS和MDA增加,SOD活性降低,ATP减少,线粒体肿胀程度升高,MMP下降(P0.05);与I/R组相比,I/R+MB组的心功能改善,CK-MB和LDH的释放减少,组织中的ROS和MDA减少,SOD活性和ATP含量升高,线粒体肿胀程度降低,MMP升高(P0.05)。结论:MB通过减轻线粒体损伤对大鼠离体I/R心脏发挥保护作用。     

甘氨酸对缺氧/复氧离体大鼠心脏功能的作用

目的：观察甘氨酸(glycine, GLY)对缺氧/复氧离体心脏功能的影响，探讨甘氨酸对心肌缺血-再灌注 (ischemia/reperfusion, I/R)损伤的防治作用及其机制。方法：利用Langendorff灌流装置复制心肌缺氧/复氧(hypoxia/reoxygenation, H/R)模型，观察不同浓度GLY处理后心脏左室收缩压（left ventricular systolic pressure, LVSP）、左室舒张末压（left ventricular end diastolic pressure, LVEDP）、左室发展压 (left ventricular developed pressure, LVDP=LVSP-LVEDP)、左室收缩压最大上升/下降速率(the maximum rising and dropping rates of left ventricular pressure, dp/dtmax and dp/dtmin)，并在相应的时点分别测定冠脉流出液中的超氧化物歧化酶(superoxide dismutase, SOD)活性和丙二醛(malondialdehyde, MDA)的水平。结果：H/R后各时点大鼠心功能各指标均低于缺氧前；GLY处理组复氧后心功能各指标均高于H/R组，并拮抗损伤导致的SOD减少和MDA升高。结论：一定浓度的GLY能显著改善缺氧/复氧心肌的舒缩功能，其机制可能与其提高SOD活性抑制脂质过氧化反应有关。     

皮质酮快速升高大鼠脊髓背角神经元钙浓度

目的:观察皮质酮(CORT)对培养的脊髓背角神经元Ca2+浓度([Ca2+]i)的调节作用及机制。方法:培养新生SD大鼠脊髓背角神经元,激光共聚焦显微镜检测神经元[Ca2+]i的变化。结果:CORT可快速升高培养的脊髓背角神经元[Ca2+]i,且呈现剂量依赖性(P0.05);CORT诱导的神经元[Ca2+]i升高是以外钙内流为主(P0.01);百日咳毒素(G蛋白活化阻断剂)可阻断CORT所致的脊髓背角神经元[Ca2+]i升高(P0.01),而糖皮质激素受体拮抗剂RU38486对CORT的效应无抑制作用。结论:CORT通过非基因组途径快速增高培养的脊髓背角神经元[Ca2+]i。     

雷公藤甲素抗肿瘤血管新生的研究进展（英文）

雷公藤甲素(triptolide,TPL)是从中草药雷公藤中提取的一种有效活性物质,已被用来治疗多种疾病,包括系统性红斑狼疮,类风湿性关节炎,肾病综合征等,TPL甚至有很强的抑制肿瘤的活性。近些年的研究显示,TPL具有抗血管新生的能力,TPL不仅可以抑制肿瘤的增殖,诱导细胞的凋亡,还可以抑制肿瘤的转移,可以增加其它化疗药物的抗肿瘤活性。本综述将讨论TPL在抗肿瘤血管新生方面的研究进展,以及初步探讨其潜在的作用机制。     

Changes in activity of neutral proteases in tissues of ground squirrels in the dynamics of hibernation

Total activities of neutral proteases in the cerebral, hepatic, and myocardial tissues of ground squirrel vary during hibernation: in autumn (before hibernation) activities of the enzymes in the brain and myocardium start increasing, while in the liver they do not change. A common feature for all tissues is minimum activity of active neutral proteases in the middle of hibernation month 1 bout, while the maximum activity is recorded before awakening. Translated from Byulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 146, No. 9, pp. 278–280, September, 2008     

Kinetics of decline of maternal measles virus-neutralizing antibodies in sera of infants in France in 2006

The optimal age for measles vaccination is an important health issue, since maternal antibodies may neutralize the vaccine antigen before a specific immune response develops, while delaying vaccination may increase the risk of complicated diseases in infants. However, measles vaccination impacts the duration of protection afforded by transplacental transfer of maternal antibodies: vaccination-induced maternal antibodies disappear faster than disease-induced antibodies. In order to maintain protection against measles in infants, it is important to monitor the dynamics of this phenomenon in vaccinated populations. To assess the current situation in France, a multicenter, prospective seroepidemiological study was conducted in seven French hospitals between October 2005 and January 2007. Maternal measles antibody concentrations from 348 infants 0 to 15 months old were measured using the plaque reduction neutralization assay. Geometric mean concentrations and the percentage of infants with maternal measles antibody concentrations above the protection threshold (≥120 mIU/ml) were assessed according to age. Results show that after more than 20 years of routine measles vaccination in France, maternal measles-neutralizing antibodies decrease dramatically in French infants by 6 months of age, from 1,740 mIU/ml for infants 0 to 1 month old to 223 mIU/ml for infants 5 to 6 months old, and that 90% of infants are not protected against measles after 6 months of age. Infant protection against measles could be optimized both by increasing herd immunity through an increased vaccine coverage and by lowering the age of routine vaccination from 12 to 9 months.     

Effect of vitamin C in reducing the toxicity of endosulfan in liver in rabbits

In this study, the effect of endosulfan, an organochlorine pesticide, and the ameliorating effect of vitamin C on the livers of New Zealand white rabbits were studied. Livers of the rabbits were examined grossly and histopathologically, and caspase-3 activity was detected by immunohistochemical methods. A total of twenty-four rabbits were divided into four groups (n=6). Rabbits in Group I (END) were daily given a sublethal dose of endosulfan (1 mg/kg bw) in corn oil by oral gavage for 6 weeks. Group II (END+C) received the same dose of endosulfan and additionally Vit C (20 mg/kg bw) every other day during this period. Group III (OIL+C) received corn oil daily by oral gavage and vitamin C every other day for 6 weeks. Group IV (OIL), the control group, received only corn oil daily, by oral gavage throughout the experiment. The concentration of α-endosulfan in the END group was higher in livers (0.102±0.012 ppb) than the β-endosulfan (0.072±0.001 ppb). Decreased accumulation of α and β endosulfan was observed in the END+C group (0.025±0.003 and 0.016±0.002 ppb, respectively) (p<0.0001). The most prominent gross findings at the necropsy were seen in the END group, in which swollen and pale livers were commonly observed. Hemorrhages, degenerations, necrosis, and in some rabbits bile duct hyperplasia were the marked histopathological findings of the END group. Caspase-3 positive reaction was more severe in this group than in the others. An ameliorating effect of Vit C on gross, histopathological and immunohistochemical findings was observed in the END+C group. The results revealed that endosulfan is highly toxic for rabbit livers. However, toxicity was decreased by Vit C treatment, which reduced the accumulation of endosulfan in livers four-fold.