大鼠肝缺血及再灌注所致小肠过氧化损伤及丹参的保护作用

目的 观察大鼠肝缺血再灌注小肠过氧化损伤及丹参预处理的保护作用.方法 首先将SD大鼠随机分为正常对照组(CO组)、假手术组(SO组)、缺血再灌注组(IR组)、丹参预处理组(SM组),分别在肝缺血30、45、60 min时取上段空肠进行大体病理学检测;然后在肝缺血45 min条件下,动物亦随机分为4组(CO组、SO组、IR组、SM组),按再灌注后不同时间(0、3、12、24、72 h)分为5个亚组,每组5只.SM组在阻断第一肝门30 min前经尾静脉推注丹参注射液6 g/kg加生理盐水40 ml/kg,其余各组按40 ml/kg给予生理盐水尾静脉注入,SO组开腹后仅解剖肝门,不钳夹肝蒂.分别在再灌注0、3、12、24、72 h取上段空肠行病理学检查、丙二醛(MDA)含量测定、髓过氧化物酶(MPO)活性测定.结果 空肠黏膜损伤评分随肝缺血时限延长而加重;在肝缺血45 min再灌注不同时限点SM组空肠黏膜损伤较IR组明显减轻,且肠组织MDA含量、MPO活性均低于IR组(P<0.05).结论 肝缺血再灌注所致小肠明显淤血性损伤,MDA含量、MPO活性升高,丹参预处理对肝缺血再灌注所致小肠损伤具有保护作用.     

Mesna ameliorates intestinal mucosa damage after ifosfamide administration in the rabbit at a dose-related manner

BACKGROUND: Cancer chemotherapy may lead to mucositis, a serious dose-limiting side effect. The alkylating agent ifosfamide is used in the treatment of various forms of cancer in combination with the uroprotective thiol mesna (2-mercaptoethane-sulfonate). The aims of this study were to assess the dose response intestinal mucosa damage of ifosfamide and to investigate the potential protective effect of mesna on rabbit intestinal epithelium. MATERIALS AND METHODS: Fifty New Zealand White rabbits were randomly assigned to 10 groups of five animals each and received intravenously every week for 10 weeks either normal saline, ifosfamide, mesna, or ifosfamide plus mesna at three escalating dose levels (ifosfamide: 30, 45, or 60 mg/kg; mesna: 12, 18, or 24 mg/kg divided into two equal doses administered 4 h apart). Intestinal mucosa damage was assessed on the basis of crypt cell apoptosis and proliferation as well as intestinal morphometry. Apoptosis was detected by agarose gel electrophoresis and quantified by the DNA fragmentation assay and a standard terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick-end labeling (TUNEL) method by which the percentage of fragmented DNA and the apoptotic index were determined, respectively. The mitotic index and the crypt-villus (c/v) unit height were also measured in histological sections. RESULTS: Ifosfamide caused a dose-related increase of crypt cell apoptosis and shortening of c/v unit, while it had a steady antimitotic effect. Mesna as a sole agent had no apoptotic or trophic effect on intestinal mucosa and hence no effect on intestinal morphometry. However, mesna, when administered concurrently with ifosfamide, ameliorated apoptosis, hypoproliferation, and mucosal atrophy at a dose-related manner. CONCLUSIONS: Ifosfamide causes intestinal mucosa damage, which may be ameliorated in a dose-related manner by coadministration of mesna.     

丙泊酚与肝脏缺血/再灌注损伤

缺血/再灌注对肝脏造成损伤.众多资料显示丙泊酚对肝脏缺血/再灌注损伤有保护作用,这一保护作用与其抗氧化,阻断钙超载,减轻炎性细胞导致的损伤有关.肝脏缺血/再灌注也影响了丙泊酚的代谢.     

Biliverdin protects rat livers from ischemia/reperfusion injury

OBJECTIVE: To explore putative cytoprotective functions of biliverdin during hepatic ischemia/reperfusion (I/R) injury in rat models. MATERIAL AND METHODS: Male Sprague Dawley (SD) rat livers were harvested and stored for 24 hours at 4 degrees C in University of Wisconsin (UW) solution (n=18), and then perfused with blood for 2 hours on an isolated rat liver perfusion apparatus equipped for temperature (37 degrees C), pressure (13 cm H2O), and pH (7.3) maintenance. Biliverdin was added to the blood at concentrations of 10 and 50 micromol in two groups of six animals. Portal vein blood flow, bile production, and GOT/GPT levels were assessed serially. At the conclusion of the experiment, liver samples were collected for histologic evaluation using Suzuki criteria. RESULTS: BV exerted protective effects against liver I/R injury. Adjunctive biliverdin improved portal venous blood flow (mL/min/g) from the beginning of reperfusion (1.33+/-0.17 versus 0.98+/-0.15; P<.001) and increased bile production (mL/g) as compared with the control group (3.40 versus 1.88; P<.003). I/R-induced hepatocellular damage as measured by GOT/GPT release (IU/L) was diminished in the biliverdin group (91 versus 171 and 46 versus 144, respectively; P<.0001). Improved liver function by biliverdin was accompanied by preservation of the histologic structure as assessed by Suzuki criteria (3.7+/-1.4 versus 6.8+/-0.8 in untreated controls; P<.005). CONCLUSIONS: Biliverdin attenuates the ischemia/early reperfusion injury of rat liver grafts as assessed by hemodynamics, function, enzyme analysis, and histology. This study provides the rationale for novel therapeutic approaches using biliverdin to maximize the organ donor pool through the safer use of liver transplants despite prolonged periods of cold ischemia.     

Akt activation protects rat liver from ischemia/reperfusion injury

BACKGROUND: Apoptosis as well as necrosis may play an important role in hepatic ischemia/reperfusion (I/R) injury. Akt, a serine-threonine protein kinase, is known to promote cell survival. We investigated whether gene transfer of constitutively active or dominant negative Akt could affect hepatic I/R injury. MATERIALS AND METHODS: Hepatic I/R injury was induced in rats by Pringle's maneuver for 20 min followed by reperfusion. Adenoviruses encoding a constitutively active form of Akt (myrAkt), a dominant negative form of Akt (dnAkt), or beta-galactosidase (LacZ) were injected through the tail vein 72 h before hepatic I/R. RESULTS: Terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling (TUNEL) staining demonstrated a significant increase in the positive cells 240 min after reperfusion. Immunoblotting with phospho-Akt antibody showed phosphorylation of Akt from 90 to 180 min after reperfusion. The expression of myrAkt reduced the number of TUNEL-positive cells and hepatic necrosis around the central veins in the liver after reperfusion. This expression also significantly inhibited the increase in serum alanine aminotransferase (297 +/- 131 IU/L, P < 0.05) 120 min after I/R, compared with increases in uninfected (1761 +/- 671 IU/L), LacZ adenovirus (1528 +/- 671 IU/L)-, and dnAkt adenovirus (1342 +/- 485 IU/L)-infected rats. MyrAkt expression phosphorylated Bad and inhibited the release of cytochrome-c after reperfusion. No difference in nuclear translocation of nuclear factor (NF)-kappaB, p65 was seen among the three groups of rats, however. CONCLUSION: Adenoviral gene transfer of myrAkt could inhibit apoptotic cell death and subsequent hepatic I/R injury in the rat, through Bad, not NF-kappaB.     

上调intermedin表达对大鼠肾脏缺血再灌注的保护作用

目的 观察上调肾脏intermedin( IMD)表达对大鼠肾脏缺血再灌注(I/R)的影响.方法 24只健康雄性Wistar大鼠随机分为假手术组、肾脏I/R组、IMD+I/R组、空质粒+I/R组,每组6只.所有动物于I/R术24h后杀检,取肾组织进行光镜检查,留取血清测定尿素氮(BUN)和血清肌酐(Scr)的浓度.免疫组织化学方法、半定量RT-PCR、Western印迹检测肾组织IMD表达及部位.Western印迹测定内皮素1(ET-1)、肿瘤坏死因子α(TNF-α)蛋白的表达.结果 HE、PAS染色结果显示,I/R组肾小管及间质病理损伤显著重于假手术组,IMD+I/R组小管间质损伤程度较肾脏I/R模型组及空质粒+I/R模型组明显减轻(1.5±0.8比7.6±2.3和7.0±1.8,均P＜0.05].与假手术组[(BUN 3.85±0.21 mmol/L,Scr(48.67±3.61) μmol/L相比,I/R组、IMD+I/R组以及空质粒+I/R组BUN(10.13±2.14) mmol/L,( 7.73±1.03) mmol/L,( 9.77±1.92) mmol/L和Scr(80.33±7.15) μmol/L,(58.50±:3.27)μmol/L,(75.67±7.58) μmol/L均明显升高(均P＜ 0.05),其中IMD+I/R组较I/R组以及空质粒+I/R组BUN和Scr水平显著降低(均P＜ 0.05).免疫组化结果显示,假手术组IMD呈弱阳性表达,主要位于肾小管间质细胞胞质内,I/R组肾组织IMD在肾小管上皮细胞和间质表达较假手术组上调;IMD+I/R组肾组织中IMD表达较I/R组明显上调(P＜0.01).与I/R组及空质粒+I/R组相比IMD+I/R组肾组织IMD mRNA,相对含量分别增加了60.7％、66.1％,蛋白相对含量分别增加了51.4％、55.9％.此外,与I/R组相比,IMD+I/R组肾组织ET-1、TNF-α蛋白表达显著降低(ET-1:0.17±0.02比0.08±0.02;TNF-α:0.35±0.02比0.21±0.04,均P＜0.05).结论 在大鼠肾脏I/R前上调IMD表达可能通过抑制ET-1、TNF-α表达保护肾脏结构及功能.     

Intravascular heparin protects muscle flaps from ischemia/reperfusion injury

Heparin has been found to decrease ischemia/reperfusion injury in skeletal muscle and other tissue/organ systems. The timing of heparin administration to the muscle vasculature has not been explored. We investigated the use of heparinized blood as a washout solution during ischemia to reduce ischemia/reperfusion injury. A rat cutaneous maximus muscle free flap was subjected to a 10-hr period of room temperature ischemia, then was heterotopically transplanted to the groin via microsurgical revascularization to the femoral vessels. In three experimental groups, flaps were subjected to brief ex vivo perfusion with autologous heparinized blood, at 2, 5, or 8 hr into the 10-hr ischemic interval. In the two other groups, the flaps were not perfused, and the animals were systemically heparinized either before ischemia or before transplantation, respectively. A control group underwent no flap perfusion or systemic heparinization. After transplantation, flaps were given a 48-hr period of in vivo reperfusion, then were harvested for evaluation. Flaps undergoing ex vivo perfusion or preischemic heparinization had no significant differences in weight gain (edema) compared with flaps receiving posttransplant heparinization or no heparinization (controls). The dehydrogenase staining of muscle biopsies was significantly faster (indicative of viable tissue) for perfused flaps and the flaps for which the animals received preischemic heparinization, when compared with flaps for which the animals received posttransplant heparinization or no heparinization. From these results, we conclude that heparin offers protection from ischemia/reperfusion injury when it can be introduced into the vascular network either prior to or during the ischemia period. These findings suggest the possibility of using heparinized washout solutions to enhance survival in amputated extremities. © 1995 Wiley-Liss, Inc.     

Thymoglobulin induction protects liver allografts from ischemia/reperfusion injury

BACKGROUND: Interventions that minimize hepatic ischemia/reperfusion injury (IRI) can expand the donor organ pool. Thymoglobulin (TG) induction therapy has been shown to ameliorate delayed graft function and possibly decrease IRI in cadaver renal transplants recipients. This controlled randomized trial was designated to assess the ability of TG to protect against IRI in liver transplant recipients. PATIENTS AND METHODS: Twenty-two cadaveric liver transplant recipients were randomized to receive either TG (1.5 mg/kg/dose) during the anhepatic period and QOD x2 doses or no TG. No differences in recipients' demographics were present and donor characteristics were similar in terms of age, cause of death, and cold ischemia time. Maintenance immunosupression consisted of Tacrolimus (or Cyclosporine) and steroids for both groups. Donor biopsies were obtained during organ procurement, cold storage and 1 h after re-vascularization. Post-operative liver function tests were monitored. Early graft function, length of stay, patient and graft survival rates, incidence of primary non-function and rate of rejection were assessed. RESULTS: Patient and graft survival at 3 months was 100%. There was no incidence of primary graft non-function and no need for re-transplantation. The incidence of acute rejection was similar between the two groups. Patients in the TG group had significant decreases in alanine aminotransferase test at day 1 compared to the control group (p = 0.02). There were also near significant decreases of total bilirubin at day 5 and shorter length of hospitalization. Liver biopsy (at procurement, when cold, and post-reperfusion) of TG group demonstrated a trend for increased central ballooning. CONCLUSION: The TG allowed for more compromised liver grafts to be transplanted with less clinical evidence of IRI and improved function. Further studies on the degree of apoptosis in the liver biopsy post-reperfusion are underway.     

A novel CCR5/CXCR3 antagonist protects intestinal ischemia/reperfusion injury

Chemokines and chemokine receptors have been demonstrated to be critical regulators in a variety of physiologic and pathologic immune responses. In particular, CCR5 and CXCR3 have been reported to play important roles in the alloimmune response. In this study, we investigated the therapeutic efficacy of a novel small-molecule compound, TAK779, an antagonist targeting both CCR5 and CXCR3 in intestinal ischemia/reperfusion (I/R) injury. We utilized an established murine intestinal I/R injury model. TAK779 treatment significantly improved mouse survival after 60 minutes of intestinal ischemia. We then examined the local intestinal expression of several cytokines and chemokines at 2 hours after reperfusion using real-time PCR. TAK779 treatment downregulated the expression of several cytokines, including TNF-alpha, IFN-gamma, and IL-4, suggesting that the beneficial effect of TAK779 was associated with inhibition of local immune activation. We further examined the systemic response after TAK779 treatment. Lung tissue damage was significantly prevented by the treatment, as determined by lung wet-to-dry weight ratios at 4 hours after intestinal I/R injury. In addition, we observed that CCR5 expression in the lung was significantly downregulated by the treatment, suggesting that TAK779 inhibited the infiltration of CCR5-positive cells into the remote organ. Our data suggest the critical role of CCR5 and CXCR3 in intestinal I/R injury and therapeutic efficacy of a novel small compound, TAK779, for protection against the intestinal I/R injury.     

依达拉奉对大鼠小肠缺血-再灌注所致肺损伤的保护作用

目的探讨依达拉奉对大鼠小肠缺血-再灌注所致肺损伤的保护作用。方法雄性SD大鼠18只,随机均分为假手术组(Sham组),缺血-再灌注组(IR组)和依达拉奉组(E组)。Sham组只分离肠系膜上动脉,不做其他处理;IR组分离肠系膜上动脉,从大鼠尾静脉注射与E组等量的生理盐水后,用无创动脉夹夹闭120min后移去动脉夹,再灌注120min;E组在缺血-再灌注前静脉注射依达拉奉6mg/kg。再灌注120min后采集标本。肺组织HE染色后病理学检测,采集腹主动脉血液检测大鼠血清中TNF-α和IL-6浓度,取肺组织检测髓过氧化物酶(MPO)活性和丙二醛(MDA)浓度。结果与Sham组比较,IR组肺泡上皮细胞广泛水肿、炎性细胞浸润、肺泡肺萎陷、肺毛细血管扩张出血;E组肺组织病理改变较IR组明显改善,肺泡炎性渗出减少;E组病理评分为(2.1±0.7)分,明显低于IR组的(5.7±1.1)分,IR组病理评分明显高于Sham组的(1.5±0.2)分(P0.01);血清中TNF-α和IL-6的浓度明显少于IR组,肺组织中MPO活性和MDA浓度明显低于IR组(P0.01)。结论依达拉奉能够明显改善小肠缺血-再灌注性肺损伤。     

肠缺血/再灌注对肝脏自由基的影响及亚甲蓝的抗损伤作用

目的 研究肠缺血/再灌注(I/R)后氧自由基(ROS)对远隔器官肝脏的损伤作用,探讨亚甲蓝(MB)抗肝脏损伤的作用机制。方法 新西兰白兔32只,体重2.3～2.9 kg,随机分为4组,(1)正常组:本组仅做假手术处理。(2)I/R组:本组通过夹闭兔肠系膜前动脉1h复制肠I/R模型。(3)治疗A组:本组于松夹后静脉内给予MB 3 mg·kg-1。(4)治疗B组:本组于松夹后静脉内给予MB 15 mg·kg-1。颈总动脉置管,连续监测血压。于夹闭前、松夹即刻、松夹后30 min、1h和2h取血测定血中MDA浓度。实验结束后取一小块肝组织用于测定超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、黄嘌呤氧化酶(XO)及MDA。结果与I/R前基础值比较,I/R组血中MDA水平I/R后显著增加,同时血压显著下降;而治疗A组及B组血中MDA水平于I/R后均未显著增加。与正常组比较,I/R组肝组织MDA水平显著增高,而正常组与两个治疗组间肝组织中MDA无显著差异。结论 MB能减少肠I/R后ROS的生成并能对抗ROS对肝脏的损伤作用。     

培高利特对前脑缺血/再灌注损伤的影响

海马CA1区对脑缺血最为敏感,即使短暂的脑缺血也可造成锥体细胞凋亡。我们的前期研究发现,多巴胺D：受体激动剂培高利特（pergolide）可显著减轻沙土鼠脑缺血／再灌注损伤后行为学异常,减少海马CA1区锥体细胞凋亡,其脑保护作用与诱导bcl-2并抑制bax基因的表达有关。既往研究表明,脑缺血后c-jun表达的增高与细胞凋亡密切相关。本实验应用HE染色法、DNA原位末端标记（TUNEL）法及免疫组织化学染色方法,观察对沙土鼠前脑缺血再灌注后海马CA1区神经元凋亡和c-jun表达的影响,探讨培高利特发挥脑保护作用的基因调控机制。     

Danshen protects kidney grafts from ischemia/reperfusion injury after experimental transplantation

Danshen (DS) is used for treatment of various ischemic events in the traditional Chinese medicine. Hence, this study was designed to investigate its effect on ischemia/reperfusion injury (IRI) after experimental kidney transplantation (eKTx). Nephrectomized Sprague–Dawley rats underwent eKTx. Some animals were infused with 1.5 ml DS 10 min before surgery. Kidney grafts were transplanted after cold storage for 20 h in Histidine–Tryptophane–Ketoglutarate solution. After reperfusion blood samples were collected for blood urinary nitrogen (BUN), creatinine, lactate dehydrogenase (LDH), and alanine transaminase. Further, tissue was assessed for morphologic and pathophysiologic changes. Donor preconditioning with DS (DS-d) significantly decreased BUN, creatinine, LDH, and aspartate aminotransferase to 65–97% of controls while preconditioning of the recipient (DS-r) decreased values to 58–82% ( P  < 0.05). Tubular damage and caspase-3 decreased significantly in both DS-d and DS-r (DS-d: 96% and 67%, DS-r: 83% and 75% of controls) while heat shock protein 72 and superoxide dismutase increased significantly (DS-d: 143% and 173%, DS-r: 166% and 194% of controls). Further, inducible nitric oxide synthase and tumor necrosis factor-α decreased (DS-d: 84% and 61%, DS-r: 79% and 67% of controls) after DS. Preconditioning of both donors and recipients with DS significantly reduces IRI and thus improves graft function after eKTx.     

IL-10 is not protective in intestinal ischemia reperfusion injury

BACKGROUND: Ischemia/reperfusion of the small intestine disrupts gut barrier function, increases bacterial translocation, and activates systemic pro-inflammatory responses. Pharmacological treatment with the anti-inflammatory cytokine interleukin-10 (IL-10) following ischemia to muscle reduces the severity of local and systemic inflammation. While endogenous IL-10 is protective in murine models of acute endotoxemia, its physiological role during direct gut injury is unknown. PATIENTS AND MATERIALS: Mice genetically deficient in IL-10 (IL-10(-/-)) and their normal littermates (IL-10(+/+)) underwent 20 to 50 min of gut ischemia by occlusion of the superior mesenteric artery. RESULTS: Both short- and long-term (>16 h) survival after reperfusion of IL-10(-/-) mice was identical to that of the wild-type littermates, with 50% mortality observed at 35 min of occlusion. The small bowel demonstrated discrete gross areas of hemorrhage and ischemia localized to the jejunum. No significant difference in the extent or time for occurrence of macroscopic or microscopic intestinal damage to the small bowel was observed in IL-10(-/-) or IL-10(+/+) mice, despite the marked elevation in serum IL-6. CONCLUSIONS: The absolute serum concentration of IL-6 in the presence or the absence of IL-10 does not affect local or systemic response to ischemic intestinal injury. These results also demonstrate that the anti-inflammatory cytokine IL-10 does not play a significant local or systemic protective role in this model of ischemia/reperfusion.     

Montelukast protects against testes ischemia/reperfusion injury in rats

Introduction:

In this study, we investigate the effect of montelukast on histologic damage induced by testicular torsion-detorsion in rats.

Methods:

Twenty-one male Sprague-Dawley rats were separated into 3 groups, each containing 7 rats. A sham operation was performed in group 1 (control). In group 2 (ischemia-reperfusion [IR]/untreated), 1-hour detorsion of the testis was performed after 6 hours of unilateral testicular torsion. In group 3 (I-R/dextroamphetamine), after performing the same surgical procedures as in group 2, montelukast was given intraperitoneally. In all experimental rats, ipsilateral orchiectomies were performed for histological examination and tissue malondialdehyde (MDA), glutathione and myeloperoxidase assays.

Results:

Montelukast treatment significantly decreased the I-R-induced elevation in testes tissue MDA and glutathione levels were found to be preserved. The level of myeloperoxidase (MPO) activity was significantly increased in the testes tissue of the IR/untreated group. However, in I-R/montelukast treatment group significantly decreased testes tissue MPO level. Histopathologically, the in the group 2 rats, edema, congestion, hemorrhage between seminiferous tubules and necrosis of the germinal cells were predominant features in sections. However, most of the specimens in the montelukast treated group 3 showed grades-I and II injury. Additionally, the testicular injury score was lower in group 3 rats compared with group 2.

Conclusion:

The current findings demonstrate that the montelukast decreased the severity of testicular injury by reversing the oxidative effects of testes I-R.     

Curcumin protects against ischemia/reperfusion injury in rat kidneys

OBJECTIVES: Renal ischemia followed by reperfusion leads to acute renal failure in both native kidneys and renal allograft. We investigated the effect of curcumin on ischemia-reperfusion (I/R) injury and the antioxidant effects of curcumin in rats. METHODS: Thirty rats were randomly divided into five experimental groups (control, sham, curcumin, I/R and I/R+curcumin, n=6 each). Curcumin was administered (200 mg kg(-1)) orally to curcumin and I/R+curcumin groups for 7 days. Then, the rats were subjected to bilateral renal ischemia for 45 min and followed by reperfusion for 24 h. All rats were killed and kidney function tests, serum and tissue nitric oxide (NO), protein carbonyl (PC), malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) levels were determined. Histopathological examinations were also performed. RESULTS: Curcumin significantly improved the urea and cystatin C levels in I/R+curcumin group compared to I/R group (p<0.05). Reduction of serum GSH-Px was significantly improved by curcumin (p<0.001), but SOD enzyme activity did not alter (p>0.05). Treatment with curcumin also resulted in significant reduction in serum and tissue MDA, NO and PC and for tissue that were increased by renal I/R injury (p<0.001 for serum and p<0.05 for tissue, respectively). In histological examination, the rats treated with curcumin had nearly normal morphology of the kidney. CONCLUSIONS: Based on our results, it can be concluded that curcumin protects the kidneys against I/R injury via its antioxidant effects.     

Preconditioning protects against ischemia/reperfusion injury of the liver

Ischemic preconditioning (IPC) of an organ may induce protection against the injury caused by longer duration of ischemia and subsequent reperfusion. In a standardized model of such injury in the rat liver, we used the following protocol to investigate whether adenosine played a role in IPC by preventing its enzymatic degradation by dipyridamole pretreatment according to the following protocol: group 1, non-ischemic control rats; group 2, ischemic control rats subjected to 60 minutes of ischemia by clamping of the common hepatic artery followed by 60 minutes of reperfusion; group 3, IPC with 10 minutes of ischemia followed by 15 minutes of reperfusion, prior to the ischemia/reperfusion period as in group 2; group 4, pharmacologic preconditioning with administration of dipyridamole prior to the ischemia/reperfusion period as in group 2. Peripheral liver blood flow was significantly reduced during clamping (groups 2 to 4). After unclamping, blood flow was still reduced in the ischemic rats (group 2) but had returned to preclamp values in the animals that had been subjected to ischemic (group 3) or pharmacologic (group 4) preconditioning. Liver cell injury was significantly increased in the ischemia group (group 2) only. In our experimental model of ischemia/reperfusion injury in the rat liver, we found an equally beneficial effect with ischemic and pharmacologic preconditioning. Adenosine appears to be a crucial factor in IPC.