高钙预处理对未成熟心肌的保护作用机制

目的 探讨高钙预处理对未成熟心肌保护作用及其可能的机制。方法 采用Langendorff离体心脏灌注模型，24只新生日本长耳大白兔分为对照组（I／R），高钙预处理（HCP）组，多黏菌素B（PMB）组和5-hydroxydecanoate（5-HD）组4组，分别行不同的处理方法。以血流动力学指标、生化指标和心肌超微结构作为观察指标。结果 HCP组心功能恢复优于I／R、PMB和5-HD组（P〈0．05），心肌生化指标优于I／R、PMB和5-HD组（P〈0．01），心肌超微结构损伤较I／R、PMB和5-HD组明显减轻，各指标I／R、PMB和5-HD组间差异无统计学意义（P〉0．05）。结论 高Ca^2＋预处理对未成熟心肌具有明显的保护作用，其机制是可能是通过蛋白激酶C激活和线粒体ATP敏感性钾通道开放起作用。     

己酮可可碱预处理对大鼠供肝冷缺血损伤影响的实验研究

目的　探讨已酮可可碱预处理供者及肝脏对供肝冷缺血损伤的影响。方法　Wistar大鼠按处理方法的不同分为 4组 :对照组、供者预处理组 (实验 1组 )、供肝预处理组 (实验 2组 )、供者及供肝联合预处理组 (实验 3组 ) ,预处理使用己酮可可碱。各组动物均在供肝冷保存 6h后行原位肝移植 ,门静脉血流恢复后第 30min、3h及 2 4h取门静脉血测定肿瘤坏死因子 (TNF α)、丙氨酸转氨酶(ALT)、天冬氨酸转氨酶 (AST)及谷胱甘肽S转移酶 (GST)的水平。结果　门静脉复流后 30min、3h时血清TNF α水平 ,各实验组明显低于对照组 ,实验 3组显著低于实验 1组及实验 2组 (P <0 .0 5) ;30min及 3h时血清GST水平 ,各实验组明显低于对照组 (P <0 .0 5) ,实验 3组显著低于实验 1组及实验 2组 (P <0 .0 5) ;30min及 3h时血清ALT水平 ,各实验组明显低于对照组 ,实验 3组显著低于实验1组及实验 2组 (P <0 .0 5) ;2 4h时前述各指标各实验组明显低于对照组 ,实验 3组显著低于实验 2组 (P <0 .0 5) ;30min时血清AST水平 ,各实验组明显低于对照组 ,实验 3组显著低于实验 1组及实验 2组 (P <0 .0 5)。结论　己酮可可碱预处理对供肝的冷缺血再灌注损伤有一定的保护作用     

不同器官保存液对大鼠肝脏透明质酸吸收率的影响

目的　探讨不同器官保存液对大鼠肝脏透明质酸吸收率的影响 ,以评价它们对肝窦内皮细胞的保护作用。方法　大鼠肝脏原位灌洗后 ,分别在UW液、Celsior液或Histidine Tryptopan Ketoglutarate液 (HTK液 )中低温保存 16和 2 4h ,然后用含透明质酸的Kreb Henseleit液在 37℃下连续循环灌注 90min ,分别于灌注 0、15、30、6 0和 90min时检测肝脏对外源性透明质酸的吸收率。结果　低温保存 16h ,再灌注 0、15、30、6 0和 90min时 ,3种保存液保存的肝脏对外源性透明质酸的吸收率均为负值 ,表明肝窦内皮细胞受到一定程度的损伤 ,但UW液和Celsior液对肝窦内皮细胞的保护作用较HTK液为优 (P <0 .0 1) ;保存 2 4h者 ,UW液对肝窦内皮细胞的保护作用优于Celsior液和HTK液。结论　UW液对肝窦内皮细胞具有较强的保护作用     

R56865, a Na- and Ca-Overload Inhibitor, Reduces Myocardial Ischemia-Reperfusion Injury in Blood-Perfused Rabbit Hearts

The cardioprotective effects of R56865 were studied in isolated rabbit hearts, blood-perfused with a support rabbit system. The effect on ischemic injury was evaluated by comparing myocardial contracture and contents of ATP catabolites and of lactate during 60 min of normothermic ischemia in untreated hearts (group I) and in hearts treated with 0.63 mg/kg of R56865 starting 20 min before ischemia (group II; n = 5 in each group). R56865 delayed the onset, and decreased the extent of ischemic contracture, but had no effect on the myocardial content of ATP, of its catabolites or of lactate. The effect on reperfusion injury was studied by monitoring left ventricular function during 80-min reperfusion after the 60-min ischemia in three groups (n = 6 in each): an untreated group (group I) and two groups treated with R56865 given either before (group II) or after ischemia (group III). Ultrastructural changes and cellular calcium distribution after reperfusion were also studied. R56865 improved the recovery of function and prevented contracture during reperfusion. Left ventricular end-diastolic pressure was 13.2 ± 2.8 mmHg in group II and 31.3 ± 8.1 mmHg in group III vs 45.0 ± 2.6 mmHg in group I (P < 0.0001 for II vs I; P > 0.05 for III vs I). Left ventricular developed pressure, maximum dP/dt and minimum dP/dt recovered to 71.0 ± 5.4%, 98.9 ± 6.1%, 85.3 ± 4.8% of baseline values, respectively, in group II, to 64.5 ± 3.0% (P > 0.05), 76.8 ± 3.0%, 70.2 ± 4.0% in group III, vs 52.0 ± 6.5%, 58.9 ± 6.9% and 53.6 ± 5.8% in untreated hearts (P < 0.05 for II or III vs I). Coronary flow was 24.5 ± 2.2 ml/min and 19.8 ± 1.8 ml/min in groups II and III vs 14.8 ± 0.7 ml/min (P < 0.05) in the untreated group. On histology the myocardium in hearts treated either before after ischemia was well protected and calcium distribution was almost normal after reperfusion, while in untreated hearts, most of the myocardium displayed irreversible damage accompanied by massive intracellular calcium accumulation. We conclude that R56865 could attenuate Ca²⁺-overload, thereby reducing myocardial ischemia-reperfusion injury after an extended period of ischemia.     

Gaseous mediators in resolution of inflammation

There are numerous gaseous substances that can act as signaling molecules, but the best characterized of these are nitric oxide, hydrogen sulfide and carbon monoxide. Each has been shown to play important roles in many physiological and pathophysiological processes. This article is focused on the effects of these gasotransmitters in the context of inflammation. There is considerable overlap in the actions of nitric oxide, hydrogen sulfide and carbon monoxide with respect to inflammation, and these mediators appear to act primarily as anti-inflammatory substances, promoting resolution of inflammatory processes. They also have protective and pro-healing effects in some tissues, such as the gastrointestinal tract and lung. Over the past two decades, significant progress has been made in the development of novel anti-inflammatory and cytoprotective drugs that release of one or more of these gaseous mediators.     

Survivin在过氧化氢预处理诱导的适应性细胞保护中的作用

目的探讨H2O2预处理对存活素(survivin)表达的影响及存活素在H2O2预处理的适应性细胞保护中的作用。方法在PC12细胞建立H2O2预处理对抗H2O2诱导细胞凋亡的实验模型,应用甲氮甲唑蓝(MTT)法检测细胞存活率,碘化丙啶(PI)染色流式细胞术检测细胞凋亡率,Hoechst染色检测细胞凋亡的形态学改变,免疫印迹法(Westernblot)测定存活素的表达水平。结果用100μmol/LH2O2预处理PC12细胞90min可明显地抑制300μmol/LH2O2作用12h后引起的细胞毒性和细胞凋亡,并可以显著地上调PC12细胞存活素的表达;JAK2抑制剂AG-490不仅可以抑制存活素的表达,而且拮抗H2O2预处理的适应性细胞保护作用。结论存活素是JAK-STAT通路的靶基因,可能在H2O2预处理诱导的适应性细胞保护机制中起着重要的作用。     

亚砷酸钠诱导HSP 72在大鼠肝脏热缺血–再灌注损伤中的保护作用

目的:观察亚砷酸钠(SA)诱导大鼠肝脏产生热休克蛋白72(HSP72)的过程及其抗肝脏热缺血-再灌注损伤的作用。材料与方法:将24只SD大鼠随机分成SA组(预先给予SA6mg/kg)和对照组(预先给予生理盐水)。24h后,两组均阻断肝脏中、左叶血供60min,再灌注3、6h;分别用Westernblot检测肝脏中的HSP72表达;外周血测定ALT、AST、LDH;组织学作HE染色、免疫组化测定HSP72。结果:注射SA6mg/kg后12h肝脏开始产生HSP72,24h达到高峰,并持续至60h。肝脏热缺血60min再灌注3、6h后,SA组HSP72显著表达,血清ALT、AST、LDH显著下降(P<0.05),组织学检查显示肝脏损伤明显减轻。结论:SA可诱导大鼠肝脏产生HSP72;SA预先诱导肝脏产生对HSP72可使肝脏抵御热缺血鄄再灌注损伤。     

Biglycan protects cardiomyocytes against hypoxia/reoxygenation injury: Role of nitric oxide

Biglycan, a proteoglycan component of extracellular matrix, has been suspected to contribute to the development of atherosclerosis, but overexpression of biglycan in transgenic mice has been shown to induce cardioprotective genes including nitric oxide (NO) synthases in the heart. Therefore, here we hypothesized if exogenous administration of biglycan exerts cytoprotection. Primary cardiomyocytes from neonatal rats were subjected to 150 min hypoxia and 2 h reoxygenation. Mortality of cardiomyocytes was dose-dependently attenuated by pretreatment with 1-100 nM biglycan. Biglycan enhanced eNOS mRNA and protein, and significantly increased NO content of cardiomyocytes. The NO synthase inhibitor l-nitro-arginine-methyl-ester significantly attenuated the cytoprotective effect of biglycan. This is the first demonstration that biglycan leads to cytoprotection against hypoxia/reoxygenation injury, and that this phenomenon is partially mediated by an NO-dependent mechanism.     

人参皂苷Rg1对6-OHDA所致MES23.5神经细胞损伤的保护作用

目的 探讨人参皂苷Rg1对6-羟基多巴胺(6-OHDA) 所致MES23.5神经细胞损伤的保护作用.方法 MES23.5细胞常规培养,观察人参皂苷Rg1预处理对6-OHDA毒性作用的影响,MTT法观察细胞存活率,实时荧光半定量反转录聚合酶链反应(real time RT-PCR)观察酪氨酸羟化酶(TH)和Bcl-2基因的表达情况.结果 6-OHDA 可剂量依赖性地损伤MES23.5细胞(F=71.24,P<0.01),人参皂苷Rg1预处理可对抗6-OHDA的毒性作用(F=14.63,P<0.01);6-OHDA可明显降低TH和Bcl-2基因的表达,人参皂苷Rg1预处理可明显逆转上述改变(F=9.80、15.34,P<0.01).结论 人参皂苷Rg1可明显对抗6-OHDA对MES23.5神经细胞的损伤,其作用机制可能与抗凋亡有关.     

TGF-β1对MSCs体外模拟缺血性损伤的保护作用

目的 观察转化生长因子β1(TGF-β1)对骨髓间充质干细胞(MSCs)体外模拟缺血性损伤的保护作用.方法 采用密度梯度离心结合贴壁法分离、培养大鼠MSCs,对培养第3代的MSCs进行鉴定;用1、2、5 μg/L 的TGF-β1分别预处理细胞8 h,然后用血清剥夺和低氧(SOD)处理建立MSCs体外模拟缺血性损伤模型,通过流式细胞术评价MSCs的凋亡及存活情况;用Western blot方法 检测2 μg/L的TGF-β1对Akt和p-Akt表达的影响.结果 密度梯度离心结合贴壁法能有效分离、纯化大鼠MSCs,免疫荧光检测显示培养的细胞CD29表达阳性,而CD34表达阴性.用2 μg/L的TGF-β1预处理MSCs后,可抑制SOD诱导的细胞凋亡,其早期凋亡率和中晚期凋亡率均明显下降,与凋亡模型组相比差异具有显著性(F=199.77、232.82,P<0.05),而PI3K抑制剂Wortmannin能明显抑制TGF-β1的抗凋亡作用.2 μg/L的TGF-β1可升高p-Akt的表达,p-Akt在8 h达到高峰,p-Akt/Akt显著增高,和其他时间点相比差异具有显著性(F=6.306,P<0.05).结论 TGF-β1对SOD诱导MSCs的凋亡具有抑制作用,其抗凋亡作用是通过激活PI3K/Akt实现的.