Ex Vivo Application of Carbon Monoxide in University of Wisconsin Solution to Prevent Intestinal Cold Ischemia/Reperfusion Injury

Carbon monoxide (CO), a byproduct of heme catalysis, was shown to have potent cytoprotective and anti-inflammatory effects. In vivo recipient CO inhalation at low concentrations prevented ischemia/reperfusion (I/R) injury associated with small intestinal transplantation (SITx). This study examined whether ex vivo delivery of CO in University of Wisconsin (UW) solution could ameliorate intestinal I/R injury. Orthotopic syngenic SITx was performed in Lewis rats after 6 h cold preservation in control UW or UW that was bubbled with CO gas (0.1-5%) (CO-UW). Recipient survival with intestinal grafts preserved in 5%, but not 0.1%, CO-UW improved to 86.7% (13/15) from 53% (9/17) with control UW. At 3 h after SITx, grafts stored in 5% CO-UW showed improved intestinal barrier function, less mucosal denudation and reduced inflammatory mediator upregulation compared to those in control UW. Preservation in CO-UW associated with reduced vascular resistance (end preservation), increased graft cyclic guanosine monophosphate levels (1 h), and improved graft blood flow (1 h). Protective effects of CO-UW were reversed by ODQ, an inhibitor of soluble guanylyl cyclase. In vitro culture experiment also showed better preservation of vascular endothelial cells with CO-UW. The study suggests that ex vivo CO delivery into UW solution would be a simple and innovative therapeutic strategy to prevent transplant-induced I/R injury.     

腺苷与异丙酚预处理对犬心肌缺血再灌注损伤的保护作用

目的探讨腺苷与异丙酚预处理对犬心肌缺血再灌注损伤的保护作用。方法 21只杂种犬,雌雄不拘,随机分为3组(n=7):缺血再灌注组(A组)、异丙酚预处理组(B组)、异丙酚与腺苷联合预处理组(C组)。A组冠状动脉的左前降支结扎60min后松开结扎,再灌注:120min;B组缺血前30min经静脉以5．6mg·kg-1·h-1速率持续泵注异丙酚30min;C组缺血前10min经主动脉根部一次性注入腺苷(10mmol·L-1,10ml),其余处理同B组。记录心脏血液动力学指标,并行节段性室壁运动评分(RWMS)。结果缺血即刻出现了缺血性心电图的变化。与基础值比较,A组缺血期及再灌注期 LVEDP升高,CO、SV、LVEF、CPP、RPP降低,再灌注期MAP降低,HR减慢,B、C组上述缺血再灌注诱导的血液动力学变化减弱,A组缺血期及再灌注期RWMS增加,但B、C组缺血期RWMS低于A组(P< 0．05或0．01)。结论异丙酚预处理对犬心肌缺血再灌注损伤有一定的保护作用,腺苷预处理并未增强其保护作用。     

Intracoronary thrombolysis: Organizational prerequisites,technique, and results

Reestablishing myocardial perfusion during evolving myocardial infarction may limit the ultimate extent of infarction if viable myocardial tissue is present when recanalization of the occluded vessel is achieved. This will result in improved left ventricular function and decreased mortality. In addition to their therapeutic benefits, recanalization procedures have contributed greatly to our knowledge of acute myocardial infarction. It has been demonstrated that myocardial infarction most often occurs after thrombotic occlusion of a coronary artery. This has settled a controversy that has preoccupied cardiologists for decades. Selective intracoronary administration of fibrinolytic agents is followed by recanalization in approximately 80% of cases. Therapeutic failures are attributable to occlusion caused by other factors, to inactivation of streptokinase by high antibody concentrations, and to insufficient concentrations of streptokinase at the thrombus as a results of unfavorable flow conditions. This study is dedicated to Prof. Dr. Med. Horst Schmutzler on the occasion of his 60th birthday.     

REPERFUSION FOLLOWING MYOCARDIAL ISCHAEMIA ENHANCES INOSITOL PHOSPHATE RELEASE IN THE ISOLATED PERFUSED RAT HEART

1. Global myocariial ischaemia (MI) for periods greater tan 5 min caused an inhibition of phosphatidylinositol specific phospholipase C (PtdIns-PLC) activity. 2. Two min reperfusion following a 20 min MI period, a time point associated with reperfusion-induced arrhythmias, resulted in an activation of PtdIns-PLC activity, dependent on endogenous noradrenaline and mediated via al-adrenoceptors. 3. This 2 min reperfusion response, in contrast to healthy myocardium, resulted in: (i) enhanced PtdIns-PLC activity; (ii) increased sensitivity to endogenous noradrenaline; (iii) rapid increases in inositol(1,4,5)trisphosphate (Ins(1,4,5)P3); and (iv) PLC hydrolysis primarily of PtdIns(4,5)P₂, such that the majority of InsP isomers derive from Ins(1,4,5)P₃. 4. Together, these data suggest a functional role for Ins(1,4,5)P3 under postischaemic reperfusion conditions, and provide a possible link between al-adrenoceptor stimulation of the PtdIns turnover pathway and reperfusion injury.     

猪心脏移植缺血再灌注损伤中NO和NOS的表达

①目的　了解猪同种原位心脏移植术后早期一氧化氮 (NO)、一氧化氮合酶 (NOS)含量的变化 ,及其与早期缺血再灌注损伤的关系。②方法　建立猪同种原位心脏移植模型。供心在移植前低温保存 (Thomas液 ,4℃ ) 4h ,移植成功心脏复搏后 2h取材。应用组织化学方法测定心肌组织中NO、NOS的含量 ,应用核酸原位末端标记法 (TUNEL)测定心肌细胞凋亡指数 ,作为评价心肌缺血再灌注损伤的指标。以正常心肌及单纯缺血心肌组织作为对照。③结果　移植后心肌组织NO、NOS的含量较缺血组与正常组低 ,差异有显著意义 (F =2 7.2 2 9、16 .2 0 3,q =5 .716～ 6 .4 12 ,P <0 .0 1)。移植组心肌细胞凋亡指数与正常组及缺血组比较明显升高 ,差异有显著性(F =16 3.884 ,q =7.4 82、6 .975 ,P <0 .0 1)。心肌组织NO、NOS含量与心肌细胞凋亡指数呈负相关关系 (r =- 0 .886、- 0 .795 ,P <0 .0 1)。④结论　猪心脏移植后早期心肌缺血再灌注损伤所致的细胞死亡主要表现为心肌细胞凋亡 ;再灌注期间内源性NO、NOS的减少参与了心脏移植后早期缺血再灌注损伤的发生     

Pretreatment with Tongxinluo protects porcine myocardium from ischaemia/reperfusion injury through a nitric oxide related mechanism

Background The traditional Chinese medicine Tongxinluo can protect myocardium against ischaemia/reperfusion injury, but the mechanism of its action is not well documented. We examined the involvement of nitric oxide in the protective role of Tongxinluo. Methods Miniswine were randomized to four groups of seven: sham, control, Tongxinluo and Tongxinluo coadministration with a nitric oxide synthase inhibitor Nω-nitro-L-arginine (L-NNA, 10 mg/kg i.v.). Three hours after administration of Tongxinluo, the animals were anaesthetised and the left anterior descending coronary artery ligated and maintained in situ for 90 minutes followed by 3 hours of reperfusion before death. Area of no reflow and necrosis and risk region were determined pathologically by planimetry. The degree of neutrophil accumulation in myocardium was obtained by measuring myeloperoxidase activity and histological analysis. Myocardial endothelial nitric oxide synthase activity and vascular endothelial cadherin content were measured by colorimetric method and immunoblotting analysis respectively.Results Tongxinluo significantly increased the local blood flow and limited the infarct and size of no reflow. Tongxinluo also attenuated myeloperoxidase activity and neutrophil accumulation in histological sections and maintained the level of vascular endothelial cadherin and endothelial nitric oxide synthase activity in the reflow region when compared with control group. The protection of Tongxinluo was counteracted by coadministration with L-NNA. Conclusions Tongxinluo may limit myocardial ischaemia and protect the heart against reperfusion injury. Tongxinluo regulates synthesis of nitric oxide by altering activity of endothelial nitric oxide synthase.     

低血流期间缺钠对心肌缺血再灌注损伤的影响

目的探讨低血流期间无销对再灌注心脏功能恢复的影响。方法采用等客收缩大鼠灌流心脏模型，低血流期以无钠的Krebs-Henseleit（K-H）液灌注．San-ei362型多道重理记录仪，测定再灌注不同时刻左心宝功能及乳酸脱氨酶活性．结果再灌注30min.在各相应时刻，缺钠组左心室收缩压（LVSP）、心率（HR）、左心室内压最大上升速率（dp／dtmax）的恢复均显著高于对照组（P＜0．001），左心室舒张期末压（LVEDP）显著低于对照组（P＜0.001），乳酸脱氢酶数据低于对照组。结论低血流缺血间无销减轻了心脏血液动力学的损害，心肌乳酸脱氢酶的漏出减少，这可能与因低血流期间无销细胞内钠超负荷减轻有关。     

ISCHAEMIA-REPERFUSION INJURY TO THE INTESTINE

Ischaemia-reperfusion injury (IRI) is of obvious relevance in situations where there is an interruption of blood supply to the gut, as in vascular surgery, or in the construction of free intestinal grafts. It is now appreciated that IRI also underlies the gut dysfunction that occurs in early shock, sepsis, and trauma. The events that occur during IRI are complex. However, recent advances in cellular biology have started to unravel these underlying processes. The aim of this review is to provide an outline of current knowledge on the mechanisms and consequences of IRI. Initially, IRI appears to be mediated by reactive oxygen metabolites and, at a later stage, by the priming and activation of polymorphonuclear neutrophils (PMN). Ischaemia-reperfusion injury can diminish the barrier function of the gut, and can promote an increase in the leakage of molecules (intestinal permeability) or the passage of microbes across the wall of the bowel (bacterial trans-location). Ischaemia-reperfusion injury to the gut can result in the generation of molecules that may also harm distant tissues.     

大鼠脊髓缺血再灌流时脊髓神经元对躯体和内脏传入刺激的反应

５０只大鼠用乌拉坦麻醉，箭毒制动。通过阻断腹主动脉血流以模拟腰段脊髓的局部缺血和再灌流损伤，玻璃微电极记录Ｌ２节段脊髓单位放电（ＳＣＵＤｓ），观察缺血再灌流时脊髓神经元对腓神经刺激（ＰＮＶ），内脏大神经刺激（ＶＬＮＶ）及两者同时刺激（ＳＶ）的反应。结果在缺血前所记录的１３３个自发放电单位中，对３种刺激均产生兴奋（Ｅ）、抑制（Ｉ）及无反应（ＮＲ）３种形式的反应，表明大鼠Ｌ２节段脊髓存在躯体、内脏和躯体内脏反应性神经元，并有会聚和阻塞现象。在脊髓缺血再灌流时，神经元对ＰＮＶ、ＶＬＮＶ、ＳＶ也产生Ｅ、Ｉ、ＮＲ３种形式的反应，提示脊髓缺血再灌流时神经元对躯体和内脏传入刺激的反应形式不受影响；但缺血时ＳＣＵＤｓ对ＰＮＶ、ＶＬＮＶ产生反应的单位数减少，这表明脊髓缺血损伤时神经元对躯体和内脏传入刺激的反应性减弱，随着缺血损伤加重，脊髓神经元对躯体内脏信号的整合功能下降