实验性急性心肌梗死心肌细胞凋亡与p53和Bcl-2蛋白表达的相关性研究

目的　探讨p5 3和Bcl- 2蛋白在实验性急性心肌梗死 (AMI)心肌细胞凋亡中的作用。方法　用TUNEL法检测 48只兔AMI模型梗死区的心肌细胞凋亡 ,用免疫组化法检测p5 3和Bcl- 2蛋白在心肌细胞中的表达水平 ,并探讨它们之间的相互关系。结果　TUNEL法发现兔梗死区心肌细胞凋亡千分率在冠脉结扎前 (0h)和结扎后 1、2、3、4、6、8、12h的改变如下 :0h组 (31 0 0± 14 0 0‰ )和 12h组 (6 8 0 0± 31 72‰ ) <1h组 (142 33± 5 3 5 2‰ ) <2h组 (370 83± 6 6 0 1‰ )和 8h组 (32 1 17± 86 43‰ ) <3h组 (5 86 83± 5 5 0 2‰ ) <4h组 (836 17± 43 73‰ ) (P均 <0 0 5 ) ,即急性心梗心肌细胞凋亡数在冠脉结扎后 1h时开始逐渐增多 ,到 4h时达高峰 ,其后逐渐下降 ,到 12h时已逐渐降至正常 ;阳性表达的p5 3蛋白积聚于胞核内 ,阳性心肌细胞千分率在冠脉未结扎 (0h)组 (4 5± 4 14 )和结扎后 1h组 (37 33± 35 43‰ )、2h组 (71 33± 5 4 93‰ )、8h组 (76 6 0±45 31‰ )、12h组 (6 5 0± 4 32‰ ) (P均 <0 0 5 ) ,而其它各组之间相互比较则无统计学上的差异 (P均 >0 0 5 ) ;阳性的Bcl- 2蛋白积聚于胞浆中 ,阳性心肌细胞千分率在冠脉结扎后 3h组 (41 0 0± 2 1 6 0‰ )、4h组 (6 83± 5 34‰ )和 6     

依达拉奉对大鼠缺血/再灌注心肌细胞凋亡的影响

目的：观察依达拉奉对心肌缺血／再灌注后心肌细胞凋亡的影响。方法：选择30只健康SD大鼠，采用结扎冠状动脉左前降支后再通的方法复制心肌缺血再灌注的动物模型，随机分为假手术组（n=10）、缺血／再灌注（I／R）组（n=10）和药物（依达拉秦）组（n=10）。检测各组3h后心肌组织的超氧化物歧化酶（SOD）和丙二醛（MDA）的含量。并用免疫组化法测定局部凋亡相关因子Bcl-2、Fas的表达，比较各组间差异。结果：与假手术组比较，I／R组中反映氧化损伤程度的MDA明显升高（P〈0．01），抗氧化酶SOD则明显减少（P〈0．01），Fas含量升高（P〈0、01），Bcl-2含量明显减少（P〈0、01）；药物组较I／R组MDA含量明显减少（P〈0．01），SOD活性显著增加（P〈0．01），Fas含量明显降低（P〈0，05），Bcl-2含量明显增加（P〈0．01）。结论：依达拉奉具有抗心肌缺血再灌注损伤作用，其机制可能是通过调节Bcl-2和Fas介导的细胞凋亡而实现     

急性心肌梗死猝死者心肌细胞凋亡与p53蛋白和Bcl2蛋白表达

目的 :探讨 p5 3和 Bcl 2蛋白在急性心肌梗死 (AMI)猝死者心肌细胞凋亡中的作用。方法 :用凋亡原位末端标记检测 (TU NEL)法检测 2 0例 AMI猝死者和 10例心脏正常车祸死亡者心肌细胞凋亡 ,用免疫组化法检测 p5 3和 Bcl 2蛋白在心肌细胞中表达水平 ,并探讨其相互关系。结果 :AMI猝死者梗死区心肌细胞凋亡数为 (5 5 7.95± 144 .10 )个 / 10 0 0个 ,明显高于正常对照组 (34.30± 2 0 .6 8)个 / 10 0 0个 (P<0 .0 5 ) ;猝死者梗死区心肌细胞中 p5 3蛋白表达阳性细胞数为 (4 41.6 5± 131.6 8)个 / 10 0 0个 ,明显高于正常对照组 (2 0 .2 0±2 6 .2 7)个 / 10 0 0个 (P<0 .0 5 ) ,且与梗死区心肌细胞凋亡数成明显的正相关性 (r=0 .6 5 5 3,P<0 .0 0 2 ) ;Bcl 2蛋白表达阳性细胞数为 (36 .2 5± 43.17)个 / 10 0 0个 ,明显低于正常对照组 (10 0 .10± 71.34)个 / 10 0 0个 (P<0 .0 5 ) ,且与梗死区心肌细胞凋亡数成明显负相关性 (r=- 0 .810 3,P<0 .0 0 1) ;梗死区心肌细胞内 p5 3与Bcl 2蛋白表达数之间呈明显的负相关性 (r=- 0 .80 78,P<0 .0 0 1)。不同支数冠状动脉病变猝死者梗死区心肌细胞的凋亡数 1支者 (5 0 6 .38± 175 .88)个 / 10 0 0个 ,2支者 (5 5 4.38± 92 .15 )个 / 10 0 0个 ,3支者 (6 6 8.2     

Restoration of p53 function for selective Fas-mediated apoptosis in human and rat glioma cells in vitro and in vivo by a p53 COOH-terminal peptide

We have shown that a COOH-terminal peptide of p53 (amino acids 361-382, p53p), linked to the truncated homeobox domain of Antennapedia (Ant) as a carrier for transduction, induced rapid apoptosis in human premalignant and malignant cell lines. Here, we report that human and rat glioma lines containing endogenous mutant p53 or wild-type (WT) p53 were induced into apoptosis by exposure to this peptide called p53p-Ant. The peptide was comparatively nontoxic to proliferating nonmalignant human and rat glial cell lines containing WT p53 and proliferating normal human peripheral marrow blood stem cells. Degree of sensitivity to the peptide correlated directly with the level of endogenous p53 expression and mutant p53 conformation. Apoptosis induction by p53p-Ant was quantitated by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay and Annexin V staining in human glioma cells in vitro and in a syngeneic orthotopic 9L glioma rat model using convection-enhanced delivery in vivo. The mechanism of cell death by this peptide was solely through the Fas extrinsic apoptotic pathway. p53p-Ant induced a 3-fold increase in extracellular membrane Fas expression in glioma cells but no significant increase in nonmalignant glial cells. These data suggest that p53 function for inducing Fas-mediated apoptosis in gliomas, which express sufficient quantities of endogenous mutant or WT p53, may be restored or activated, respectively, by a cell-permeable peptide derived from the p53 COOH-terminal regulatory domain (p53p-Ant). p53p-Ant may serve as a prototypic model for the development of new anticancer agents with unique selectivity for glioma cancer cells and it can be successfully delivered in vivo into a brain tumor by a convection-enhanced delivery system, which circumvents the blood-brain barrier.     

异丙酚对离体大鼠心肌缺血/再灌注损伤后细胞凋亡及HSP70表达的影响

目的观察异丙酚对离体大鼠心肌缺血/再灌注损伤的影响并探讨其作用机制。方法应用langendorff离体心脏灌注系统建立心肌缺血/再灌注损伤模型。40只SD大鼠随机分为正常对照组、缺血/再灌注模型(I/R)组、异丙酚15、30、60μmol/L组。除正常对照外,各组分别平衡灌注20min后,常温全心停灌25min,再灌注30min。Powerlab/8s仪记录各组平衡末、缺血前及再灌30min时心率(HR)、左室发展压(LVDP)、左室舒张末压(LVDEP)、左室压力变化速率(±dp/dtmax)、冠脉流量(CF)等心功能指标;测定冠脉流出液中乳酸脱氢酶(LDH)、磷酸肌酸激酶(CK)活性;差速离心法提取心肌线粒体,测定线粒体活力、膜肿胀度、锰超氧化物歧化酶(Mn-SOD)活性和丙二醛(MDA)含量;原位末端转移酶标记法(TUNEL)检测心肌细胞凋亡,免疫组化法测定天冬氨酸特异的半胱氨酸蛋白酶(caspase)-3和热休克蛋白70(HSP70)的表达。结果异丙酚30、60μmol/L能明显改善缺血/再灌注后的心脏机械功能,降低冠脉流出液中LDH、CK的活性(P<0.05);异丙酚在30、60μmol/L浓度情况下心肌线粒体活力有所恢复,膜肿胀度减轻,Mn-SOD活性升高,MDA生成明显减少(P<0.05),心肌HSP70表达增多,心肌细胞凋亡率和caspase-3阳性细胞数明显减少(P<0.05)。结论异丙酚明显减轻缺血/再灌注所致的心肌线粒体的过氧化损伤,上调HSP70的表达,抑制caspase-3表达和心肌细胞凋亡的发生,可能是其心肌保护作用机制之一。     

p53 and the hypoxia-induced apoptosis of cultured neonatal rat cardiac myocytes.

Myocyte cell loss is a prominent and important pathogenic feature of cardiac ischemia. We have used cultured neonatal rat cardiac myocytes exposed to prolonged hypoxia as an experimental system to identify critical factors involved in cardiomyocyte death. Exposure of myocytes to hypoxia for 48 h resulted in intranucleosomal cleavage of genomic DNA characteristic of apoptosis and was accompanied by increased p53 transactivating activity and protein accumulation. Expression of p21/WAF-1/CIP-1, a well-characterized target of p53 transactivation, also increased in response to hypoxia. Hypoxia did not cause DNA laddering or cell loss in cardiac fibroblasts. To determine whether the increase in p53 expression in myocytes was sufficient to induce apoptosis, normoxic cultures were infected with a replication-defective adenovirus expressing wild-type human p53 (AdCMV.p53). Infected cells expressed high intracellular levels of p53 protein and exhibited the morphological changes and genomic DNA fragmentation characteristic of apoptosis. In contrast, no genomic DNA fragmentation was observed in myocytes infected with the control virus lacking an insert (AdCMV.null) or in cardiac fibroblasts infected with AdCMV.p53. These results suggest that the intracellular signaling pathways activated by p53 might play a critical role in the regulation of hypoxia-induced apoptosis of cardiomyocytes.     

ASPP家族及其与p53相互作用的研究进展

p53是一个肿瘤抑制蛋白,它通过影响编码细胞周期相关蛋白质的基因表达来调控细胞周期的G1停滞,同时还会因为DNA的损伤增多,诱导细胞发生细胞凋亡。p53诱导细胞凋亡的机制多年来一直不太清楚,而最近发现的 p53凋亡刺激蛋白 ASPP蛋白家族对 p53 诱导细胞凋亡的机制的研究有了新的进展。ASPP蛋白家族与 p53 的作用主要是特异性增强 p53 的细胞凋亡功能,而对 p53的细胞生长停滞功能则没有作用。ASPP蛋白家族增强 p53 的细胞凋亡功能是通过增强 p53的促凋亡基因启动子与DNA的结合而促进细胞凋亡,现就此作一综述。     

Gabexate mesilate, a synthetic protease inhibitor, reduces ischemia/reperfusion injury of rat liver by inhibiting leukocyte activation.

OBJECTIVE: To investigate whether gabexate mesilate, a synthetic protease inhibitor with anticoagulant properties, prevents hepatic damage by inhibiting leukocyte activation, we examined its effect on ischemia/reperfusion injury of rat liver in which activated leukocytes play a critical role. DESIGN: Prospective, randomized, controlled study. SETTING: Research laboratory at a university medical center. SUBJECTS: Male Wistar rats weighing 220 to 280 g. INTERVENTIONS: Hepatic damage was evaluated by changes in bile flow and serum transaminase concentrations after ischemia/ reperfusion. Rats received continuous intravenous infusions of gabexate mesilate (10 mg/kg/hr) or intravenous administration of an inactive derivative of activated factor X (Xa), a selective inhibitor of thrombin generation (3 mg/kg), immediately before the induction of ischemia in the median and left lobes of the liver. To determine whether gabexate mesilate inhibits leukocyte activation, we examined the effects of gabexate mesilate on hepatic concentrations of tumor necrosis factor-alpha and rat interleukin-8 and on hepatic myeloperoxidase activity after ischemia/reperfusion. MEASUREMENTS AND MAIN RESULTS: Hepatic dysfunction, observed after 60 mins of ischemia/reperfusion, showed a reduction in bile flow. The ischemia/reperfusion-induced decrease in bile flow was prevented by administration of gabexate mesilate. Serum transaminase concentrations increased after hepatic ischemia/reperfusion, peaking 12 hrs after reperfusion. Gabexate mesilate significantly inhibited the ischemia/reperfusion-induced increase in serum transaminase levels seen 12 hrs after reperfusion. Although an inactive derivative of factor Xa inhibited the increases in serum levels of fibrin and fibrinogen degradation products 6 hrs after reperfusion, it did not prevent ischemia/ reperfusion-induced liver injury. Hepatic levels of tumor necrosis factor-alpha, rat interleukin-8, and myeloperoxidase were significantly increased after ischemia/reperfusion. These increases were significantly inhibited by gabexate mesilate but unaffected by an inactive derivative of factor Xa. CONCLUSION: Gabexate mesilate reduced ischemia/reperfusion-induced hepatic injury not by inhibiting coagulation, but by inhibiting leukocyte activation.     

Cycloheximide protects HepG2 cells from serum withdrawal-induced apoptosis by decreasing p53 and phosphorylated p53 levels

Cycloheximide (CHX), an inhibitor of protein synthesis, has been reported to prevent cell death in a wide variety of cell types and produced by different apoptotic stimuli. However, the mechanisms by which CHX protects cells from apoptosis are still unclear. In this study, we investigated whether p53 plays a role in the protection by CHX against serum withdrawal-induced apoptosis. Deprivation of serum from the culture medium causes apoptosis in HepG2 cells, and CHX dramatically protects cells from death. p53, p21, and Bax protein levels were elevated, and cell cycle arrest was produced after serum withdrawal. CHX abolished this elevation of p53, p21, and Bax as well as the cell cycle arrest induced by serum deprivation. The p53 inhibitor pifithrin-alpha protects HepG2 cells against apoptosis induced by serum withdrawal. HepG2 cells expressing a dominant negative form of mutant p53 and Hep3B cells lacking p53 were resistant to serum withdrawal-induced apoptosis. Lowering of p53 by small interfering RNA protects HepG2 cells from serum withdrawal-induced apoptosis. p53 phosphorylation was induced by serum withdrawal and other chemotherapeutic reagents such as actinomycin D, doxorubicin, and etoposide. CHX decreases the levels of phosphorylated p53 (pp53) even in the presence of a proteasome inhibitor, which maintains the total p53 levels, whereas it does not affect the dephosphorylation of pp53. These results suggest the possibility that kinases that phosphorylate p53 might be affected by CHX administration. In summary, CHX protects HepG2 cells from serum withdrawal-induced apoptosis through inhibiting the synthesis of p53 and the phosphorylation of p53.     

Inhibition of lipid peroxidation by superoxide dismutase following regional intestinal ischemia and reperfusion

In a feline model of regional intestinal ischemia, reoxygenation resulted in a rise in the concentration of oxidized glutathione, from 2.3 +/- 0.7 to 4.1 +/- 0.5% of the total glutathione. Also conjugated diene as an indirect measurement for lipid peroxidation increased after reperfusion from 2.5 +/- 0.5 mumol/g to 5.5 +/- 1.2 micrograms mol/g tissue. These results are in line with the hypothesis that ischemia results in an accumulation of hypoxanthine and a conversion of xanthine dehydrogenase into its O2-dependent form. Upon reoxygenation, hypoxanthine can be oxidized giving yield to a burst of O2-. and its interconversion products. These may initiate peroxidative tissue damage. Pretreatment of the cats with superoxide dismutase inhibited the biochemical alterations and protected the tissue from peroxidation damage.     

野生型p16和p53抑癌基因共转染对 K562细胞增殖的抑制作用

抑癌基因p16和p53在抑制肿瘤的发生中起重要作用，在髓细胞白血病细胞系K562中检测出这两种基因有纯合缺失。为探讨野生型p16和p53基因的转染与表达对K562细胞的生长影响，采用了脂质体介导外源野生型p16和p53共转染K562细胞，用免疫细胞化学染色检测p16和P53基因的表达，检测细胞生长曲线，采用流式细胞术进行细胞周期分析。结果显示，共转染后p53和p16在K562细胞中表达阳性率分别为23％和28％；细胞生长受到一定程度的抑制，G1期细胞的比例增加，S期细胞减少，与单独转染p53或p16基因的抑制作用有明显差别(P＜0.05)。结论：外源野生型p16和p53基因的共转染比转染单基因对K562细胞生长有更明显的抑制作用，有可能成为白血病基因治疗的一种方法。     

Mechanical conversion of post-ischaemic ventricular fibrillation: effects on function and myocyte injury in isolated rat hearts

Ventricular fibrillation (VF) and ventricular tachycardia (VT) are common phenomena during reperfusion. In experimental research many hearts have to be excluded from haemodynamic evaluation because of severe arrhythmias. Theoretically, electroconversion or mechanical conversion (MC) might be used to convert VF or VT. MC induces a physical shock analogous to a chest thump. The aim of this study was to investigate the efficacy of MC in isolated, perfused rat hearts, and to see whether MC itself induced myocardial cell injury and functional impairment. Langendorff-perfused rat hearts (n = 89) from several experimental series subjected to 30 min of global ischaemia and 60 min of reperfusion were retrospectively analysed. Left ventricular systolic (LVSP), end-diastolic (LVEDP), and developed (LVDP) pressures, coronary flow (CF), and heart rate (HR) were measured. If VF or VT continued for 1 min during reperfusion, MC was attempted by a flick of the forefinger to the right ventricle. If VF or VT still occurred, MC was repeated. Hearts that did not have regular beating after 20 min of reperfusion were excluded. Release of cardiac troponin T (cTnT) was measured before ischaemia and after 20 min of reperfusion. Forty-four out of 89 hearts had VF or VT during reperfusion. Thirty-five hearts were converted, 18 of which were converted by one or two MCs only. The higher the total number of MCs employed, the more cTnT was released. After 20 min of reperfusion, LVEDP, LVDP and CF were better in hearts with a higher number of MCs and with increased release of cTnT. After 60 min of reperfusion, LVEDP was still improved in hearts with more cTnT release, whereas LVSP was lower, and LVDP and CF were independent of the number of MCs. There was no consistent correlation between release of cTnT and heart dysfunction. In conclusion, MC effectively converted VF or VT. MCs increased post-ischaemic myocardial cell damage, as judged from increased cTnT release. Post-ischaemic dysfunction was partly attenuated in hearts with multiple MCs, and did not correlate with release of cTnT. We feel that MCs should not be used in isolated, perfused hearts.     

Recombinant, refolded tetrameric p53 and gonadotropin-releasing hormone-p53 slow proliferation and induce apoptosis in p53-deficient cancer cells

The p53 tumor suppressor is mutated in over 50% of human cancers. Mutations resulting in amino acid changes within p53 result in a loss of activity and consequent changes in expression of genes that regulate DNA repair and cell cycle progression. Replacement of p53 using protein therapy would restore p53 function in p53-deficient tumor cells, with a consequence of tumor cell death and tumor regression. p53 functions in a tetrameric form in vivo. Here, we refolded a wild-type, full-length p53 from inclusion bodies expressed in Escherichia coli as a stable tetramer. The tetrameric p53 binds to p53-specific DNA and, when transformed into a p53-deficient cancer cell line, induced apoptosis of the transformed cells. Next, using the same expression and refolding technology, we produced a stable tetramer of recombinant gonadotropin-releasing hormone-p53 fusion protein (GnRH-p53), which traverses the plasma membrane, slows proliferation, and induces apoptosis in p53-deficient, GnRH-receptor-expressing cancer cell lines. In addition, we showed a time-dependent binding and internalization of GnRH-p53 to a receptor-expressing cell line. We conclude that the GnRH-p53 fusion strategy may provide a basis for constructing an effective cancer therapeutic for patients with tumors in GnRH-receptor-positive tissue types.     

Induction of caspase-dependent, p53-mediated apoptosis by apigenin in human neuroblastoma

Neuroblastoma is a pediatric tumor accounting for 15% of childhood cancer deaths and has a poor prognosis in children >1 year of age. We investigated the ability of apigenin, a nonmutagenic dietary flavonoid that has been shown to have antitumor effects in various tumor cell lines, to inhibit growth and induce apoptosis of the human neuroblastoma cell lines NUB-7, LAN-5, and SK-N-BE(2). Apigenin inhibited colony-forming ability and survival, and induced apoptosis of NUB-7 and LAN-5 cells. The presence of the C2-C3 double bond and the 4'-OH group on the flavonoid structure correlated with the growth-inhibitory potential of apigenin. Furthermore, apigenin inhibited NUB-7 xenograft tumor growth in anonobese diabetic/severe combined immunodeficiency mouse model, likely by inducing apoptosis. Apigenin did not inhibit survival of primary sympathetic neurons, suggesting that it is not toxic to nontransformed cells. The mechanism of action of apigenin seems to involve p53, as it increased the levels of p53 and the p53-induced gene products p21WAF1/CIP1 and Bax. Furthermore, apigenin (15-60 micromol/L) induced cell death and apoptosis of neuroblastoma cells expressing wild-type but not mutant p53. Apigenin increased caspase-3 activity and PARP cleavage, and Z-VAD-FMK, a broad-spectrum caspase-3 inhibitor, rescued NUB-7 cells from apigenin-mediated apoptosis indicating that apigenin induced apoptosis in acaspase-dependent manner. Overexpression of Bcl-X(L) rescued NUB-7 from apigenin-induced cell death, suggesting that Bax activity is important for the action of apigenin. Apigenin is thus a candidate therapeutic for neuroblastoma that likely acts by regulating a p53-Bax-caspase-3 apoptotic pathway.     

高氧液对家兔心肌缺血/再灌注细胞凋亡的影响

目的观察高氧液对心肌缺血/再灌注心肌梗死面积、心肌结构和细胞凋亡参数的影响,探讨高氧液抗心肌缺血/再灌注损伤的保护作用机制。方法家兔心脏左冠状动脉前降支缺血/再灌注动物模型,缺血30min,再灌注2h。60只家兔随机数字表法分成3组:对照组(I组,n=20)只暴露左冠状动脉前降支,不结扎;缺血/再灌注组(Ⅱ组,I/R组,n=20),在缺血再灌注前10min静脉注射生理盐水(20ml/kg);高氧液治疗组(Ⅲ组,n=20),在缺血前10min静脉注射高氧液(20ml/kg)。分别按TCC法染色,用图像分析系统计算梗死面积;原位末端TUNEL法检测细胞凋亡指数;免疫组化ABC法检测Fas、Bcl-2的含量,同时电镜观察心肌细胞的超微结构。结果III组心肌梗死细胞面积为(2.29±0.02)cm,与II组的(3.38±0.07)cm比较,梗死面积明显缩小。II组的AI(20.8±0.36),明显高于I组(4.1±0.25),P<0.01,t=170.4,III组的AI(13.3±0.35)显著低于II组,P<0.01,t=66.8,但仍高于I组,P<0.01,t=92.8。I组Fas的OD值为2.80±0.07,II组3.70±0.05,III组3.10±0.04。I组Bcl-2的OD值为2.7±0.02,II组0.60±0.03,III组2.90±0.02。结论高氧液具有抗心肌缺血/再灌注损伤的作用,其作用机制可能是通过调节Fas和Bcl-2介导的心肌缺血/再灌注细胞凋亡而实现。     

Inhibition of coagulation and inflammation by activated protein C or antithrombin reduces intestinal ischemia/reperfusion injury in rats

OBJECTIVE: To examine whether administration of activated protein C or antithrombin reduces local splanchnic derangement of coagulation and inflammation and attenuates intestinal dysfunction and injury following intestinal ischemia/reperfusion. DESIGN: Randomized prospective animal study. SETTING: University research institute. SUBJECTS: Adult male Wistar rats, weighing 300-325 g (n = 72). INTERVENTIONS: Rats were subjected to superior mesenteric artery occlusion consisting of 20 or 40 mins of ischemia and 3 hrs of reperfusion. A randomized intravenous administration of vehicle (0.9% NaCl), heparin, antithrombin, or activated protein C was performed during ischemia, 15 mins before reperfusion. Coagulation and fibrinolysis variables obtained from portal blood were correlated with mucosal fibrin deposition (determined by anti-rat fibrin antibody staining), intestinal function (glucose/water clearance), and intestinal injury (histologic evaluation by Park/Chiu score). MEASUREMENTS AND MAIN RESULTS: Activated protein C- or antithrombin-treated animals demonstrated less ischemia/reperfusion-induced intestinal dysfunction and histologic changes compared with control animals, whereas intravenous administration of heparin only showed less histologic derangement. Activated protein C- or antithrombin-treated animals showed less thrombin generation, fibrin degradation products, and fibrin deposition compared with control animals, as confirmed by histologic examination, whereas heparin administration showed only a limited reduction of portal fibrin degradation product concentrations. Furthermore, activated protein C or antithrombin administration markedly inhibited the inflammatory response, as reflected by reduced interleukin-6 plasma concentrations to baseline values, whereas heparin had no effect. CONCLUSIONS: Administration of activated protein C or antithrombin inhibited local and systemic derangement of coagulation and inflammation following intestinal ischemia/reperfusion, diminished mucosal fibrin deposition, and attenuated ischemia/reperfusion-induced intestinal injury. These observations suggest that activated protein C or antithrombin reduces ischemia/reperfusion-induced intestinal injury, both through their anticoagulant and anti-inflammatory effects.