Pain assessment in animal models is challenging, as behavioral tests often lack sensitivity. Particularly under analgesia, it is unclear whether pain occurs without medication. Imaging of pain-associated pathways, such as σ1 receptor (σ1R) expression, offers a promising approach to better understand underlying mechanisms. Therefore, this study evaluated [¹⁸F]fluspidine positron emission tomography/computed tomography (PET/CT) imaging for detecting σ1R-mediated pain after partial liver resection in rats. Postoperative pain was assessed in eighteen female Wistar rats undergoing skin incision or partial liver resection. Nine untreated rats served as controls. Carprofen was administered for three consecutive days after surgery. PET/CT imaging was performed on postoperative days 1, 4, and 7. At each time point, organs and incision sites of three animals were harvested for histological analysis. Postoperative pain and welfare were monitored by observational score sheets, the Open Field test, Rat Grimace Scale, Von Frey test, fecal corticosterone metabolites, and hemograms. Despite analgesic treatment, PET/CT and immunohistochemistry revealed elevated σ1R expression at the abdominal incision site on day 1 after partial liver resection in comparison to the other groups, likely due to the additional peritoneal opening. σ1R expression normalized by day 4. No behavioral indicators of pain or distress were observed, though mechanical hypersensitivity was detected on day 4 in all groups, likely due to carprofen side effects. [18F]Fluspidine PET/CT imaging sensitively detected postoperative pain-associated σ1R expression independent of analgesia. This imaging modality could remarkably refine pain monitoring, opening to further studies using different pain and analgesia models. [¹⁸F]Fluspidine PET/CT imaging demonstrates high sensitivity in detecting pain-associated σ1R upregulation despite non-steroidal anti-inflammatory drug administration. This approach offers valuable insights for refining pain assessment, improving severity grading, and enhancing the reliability and translational value of preclinical pain models.

Organ shortage has led to the increasing utilization of livers retrieved from donors after circulatory death (DCD). These pre-damaged organs are susceptible to further warm ischemia and exhibit minimal tolerance for cold storage. The aim was thus to examine the effects of fibrinolysis combined with Venous Systemic Oxygen Persufflation (VSOP) on the preservation of DCD livers in vivo. Livers of male Lewis rats were explanted after 45 min of warm ischemia, cold-stored for 18 h, and transplanted into a recipient animal. Livers were left untreated or underwent either VSOP or fibrinolysis via Streptokinase (SK) or received combined SK and VSOP. Combined treatment exhibited improved microvascular flow at 168 h (p = 0.0009) and elevated microperfusion velocity at 24 h post-transplantation (p = 0.0007). Combination treatment demonstrated increased portal venous flow (PVF) at 3 and 24 h post-transplantation (p = 0.0004, p < 0.0001), although SK and VSOP analogously achieved increases at 24 h (p = 0.0036, p = 0.0051). Enzyme release was decreased for combination treatment (p = 0.0002, p = 0.0223) and lactate dehydrogenase (LDH) measurements were lower at 24 h post-transplantation (p = 0.0287). Further supporting findings have been obtained in terms of serum cytokine levels and in the alterations of endothelial injury markers. The combination treatment of SK + VSOP might provide improved organ integrity and viability and may therefore warrant further investigation as a potential therapeutic approach in the clinical setting of DCD.

Ischemia-reperfusion injury remains a fundamental problem during organ transplantation logistics. One key technical factor is the rapid allograft rewarming during the time of vascular reconstruction in the recipient. In this pilot study, a new thermal insulation bag (TIB) for organ transplantation was used. Insulation capacity, tissue compatibility, and usability were tested initially ex vivo on porcine kidneys (n = 24) followed by the first in vivo usage. Fourteen female German landrace pigs underwent kidney auto-transplantation after 24 h cold storage (4 °C). During the implantation process the kidney was either insulated with the new TIB, or it was not thermo-protected at all, which represents the clinical standard. In this proof-of-concept study, the usability (knife-to-skin-time) and the general thermal capacity (30 min warm storage at 38 °C ex vivo p < 0.001) was shown. The clinical outcome showed significant differences in the determination of CRP and pi-GST levels. Syndecan-1 Antibody staining showed clear significant higher counts in the control group (p < 0.01) indicating epithelial damage. However, the effect on renal outcomes in not severely pre-damaged kidneys does not appear to be conclusively significant. A close follow-up study is warranted, especially in the context of marginal organs or in cases where anastomosis-times are prolonged due to surgical complexity (e.g., multiple vessels and complex reconstructions).

Plasma coagulation as a form of electrocautery is used in liver surgery for decades to seal the large liver cut surface after major hepatectomy to prevent hemorrhages at a later stage. The exact effects of plasma coagulation on liver tissue are only poorly examined. In our porcine model, the coagulation effects can be examined close to the clinical application. A combined laser Doppler flowmeter and spectrophotometer documents microcirculation changes during coagulation at 8 mm tissue depth noninvasively, providing quantifiable information about hemostasis beyond the subjective clinical impression. The temperature at coagulation site is assessed with an infrared thermometer prior and post coagulation and with a thermographic camera during coagulation, a measurement of the gas beam temperature is not possible due to the upper threshold of the devices. The depth of coagulation is measured microscopically on hematoxylin/eosin stained sections after calibration with an object micrometer and gives an exact information about the power setting-coagulation depth-relation. The sealing effect is examined on the bile ducts as it is not possible for a plasma coagulator to seal larger blood vessels. Burst pressure experiments are carried out on explanted organs to rule out blood pressure related effects.

Objective Argon plasma coagulation (APC) and helium plasma coagulation (HPC) are electrosurgical techniques that provide noncontact monopolar electrothermal haemostasis. Although these techniques have been widely used clinically during the last three decades, their in vivo effects on liver tissue remain unclear. Methods We investigated the effects of different power levels (10–100 W) of APC and HPC on liver coagulation in 11 Landrace pigs. Capillary blood flow and capillary blood flow velocity were recorded with a combined laser Doppler flowmeter and spectrophotometer. The temperature, clinical biochemical parameters, blood gas parameters, bile duct-sealing effect, and coagulation depth were measured. Results APC and HPC significantly reduced the capillary blood flow and capillary blood flow velocity compared with baseline flow. No significant temperature change was measured on the liver surface immediately after coagulation. The clinical biochemical and blood gas parameters were not different before and after coagulation. The coagulation depth was positively correlated with the device power setting. Conclusions These results prove that APC and HPC provide sufficient superficial haemostasis. No significant systemic effects occurred following coagulation. The depth of the coagulation effect can be controlled through selection of the output power level.

Guest Editor Gabriele Schackert, Dresden The abstracts are available online, free of charge, under http://www.karger.com/Article/FullText/445224 Published online: April 20, 2016 www.karger.com/esr DOI: 10.1159/000445224 Basel • Freiburg • Paris • London • New York • Chennai • New Delhi • Bangkok • Beijing • Shanghai • Tokyo • Kuala Lumpur • Singapore • Sydney 35 Eur Surg Res 2016;57:34–80 DOI: 10.1159/000445224 Abstracts: 133rd Congress of the German Society of Surgery (DGCH) www.karger.com/esr © 2016 S. Karger AG, Basels: 133rd Congress of the German Society of Surgery (DGCH) www.karger.com/esr © 2016 S. Karger AG, Basel 1 Role of ENTPD2 in Liver Regeneration and Liver Fibrosis L. Feldbruegge1, S. Mitsuhashi1, E. Csizmadia1, M. Schmelzle2, S. Robson1 1Beth Israel Deaconess Medical Center, Boston, USA 2Charité, Berlin, Germany Background: Ecto-nucleoside triphosphate diphosphohydrolases (ENTPD) comprise a family of cell surface located transmembrane proteins that regulate purinergic signaling by catalyzing extracellular nucleotides, such as ATP and ADP. The prototype ENTPD1/CD39 is expressed on endothelium and sinusoidal immune cells, and is a regulator of liver regeneration. The closely related enzyme ENTPD2 is expressed on portal fibroblasts and perivascular cells. In vitro co-incubation studies show that this enzyme on fibroblasts regulates proliferation of cholangiocytes. Its role in liver function in vivo however, has not yet been determined. Herein, we examine pathophysiological functions of ENTPD2 in liver regeneration and liver fibrosis using a newly generated ENTPD2 deficient mouse line. Materials and Methods: Global ENTPD2 knockout mice and matched wild type mice were subjected to 2/3 hepatectomy as a model for liver regeneration, and to 6 weeks of carbon tetrachloride (CCl4) treatment to induce liver fibrosis. Outcomes were compared by studying serum liver function tests, liver histology and immunohistochemistry. Collagen content of liver tissue was determined biochemically by measuring relative hydroxyproline content. Results: ENTPD2 null mice develop normally on the C57BL6 background and do not show abnormalities in liver morphology at baseline. After partial hepatectomy, hepatic ENTPD2 mRNA expression in wild type mice decreased in the first 24 hours and then significantly increased to 3 times basal level at day 5. Serum ALT and other parameters of liver injury as well as the rate of hepatocellular proliferation were comparable in both groups, and there was no relevant difference in liver mass regeneration. However, when fibrosis was induced by CCl4 treatment, mice deficient for ENTPD2 showed significantly more collagen deposition as measured by hydroxyproline content. Histological analysis confirmed more severe fibrosis in the knockout mice while there was no significant difference in liver function tests. Conclusion: ENTPD2 null mice show no major hepatic developmental abnormalities and appear to maintain normal liver regeneration responses when subjected to the acute injury of partial hepatectomy in otherwise healthy livers. In the setting of chronic hepatocellular injury by CCl4 ingestion however, ENTPD2 deficient mice show significantly more fibrosis. As this ecto-enzyme is expressed by myofibroblastic cells surrounding bile ductules within portal triads, and deletion promotes fibrogenesis, we propose that ATP scavenging by ENTPD2 might represent a novel therapeutic target in fibrotic liver disease. 2 Platelets Promote CD133+BMSC Adhesion to Murine Micro and Hepatic Sinusoidal Endothelium Independent of ADP Stimulation Under Flow Condition J. Kirchner1, C. Duhme1, N. Lehwald1, K. Wieferich1, M. Schmelzle2, N.H. Stoecklein1, A. Krieg1, W.T. Knoefel1, J. Schulte am Esch1 1Universitätsklinikum der Heinrich Heine Universität Düsseldorf, Düsseldorf, 2Chirurgische Kliniken der Charité am Campus Virchow-Klinikum, Berlin, Germany Background: We previously demonstrated the therapeutic potential of hematopoetic CD133+ bone marrow stem cells (CD133+BMSC) to promote clinical liver regeneration and the potential of platelets for CD133+BMSC homing along human micro endothelium under shear stress. In this study, we have established a murine model to gain the option of investigation of null and overexpressing cells for homing relevant factors. Furthermore, we evaluated a putative adhesion promoting effect of platelets for CD133+BMSC-homing along hepatic sinusoidal vasculature. Materials and Methods: Commercially available mouse primary dermal micro vasculature endothelial cells (dMECC57BL/6) and mouse hepatic sinusoidal endothelial cells (mSEC) were cultured in capillaries in a live cell imaging system (Bioflux). Primary CD133+BMSC were purified from bone marrow flushed from murine tibiae and femori utilizing FACsorting. dMEC or mSEC were co-cultured under shear stress with CD133+BMSC and platelet rich plasma (PRP) or platelet poor plasma (PPP) as control prepared from murine BMSC donors. To test the effect of pre-stimulation of platelets for adhesion of CD133+BMSC, murine PRP was pre-stimulated with ADP monitored by aggregometry utilizing the Bohrlight-transmission method. Latter prevented over-stimulation with clot-formation. Results: Murine CD133+BMSC co-infused with PRP demonstrated mean adhesion rates of 144% (±17% StdDev; Abstracts 36 Eur Surg Res 2016;57:34–80 DOI: 10.1159/000445224 Abstracts: 133rd Congress of the German Society of Surgery (DGCH) www.karger.com/esr © 2016 S. Karger AG, Basels: 133rd Congress of the German Society of Surgery (DGCH) www.karger.com/esr © 2016 S. Karger AG, Basel p < 0.005) along dMEC under flow if contrasted to PPP co-incubation. Pre-stimulation of platelets with ADP demonstrated a further increase leading to improved adhesion of CD133+BMSC compared to unstimulated conditions. Analogue to micro endothelium a boost of mean adhesion rates of CD133+BMSC to 131% (±9% StdDev; p < 0.05) was observed subsequent to unstimulated PRP co-infusion along mSEC. Conclusion: Our data indicate platelets to trigger adhesion of CD133+BMSC to murine micro vasculature analogue to men in a stimulation independent manner. Further we demonstrate here for the first time that thrombocytes bear the capacity to promote BMSC-adhesion to hepatic vasculature. These data may add to the understanding of mechanisms by which platelets support hepatic generation and offer novel strategies to increase the efficacy of therapeutic BMSC-application in clinical liver disease. 3 Peptide XIB13 Reduces Capillary Leak in a Rodent Burn Model L. Von der Lohe1, K. Zhuravleva2, H. Lauer2, M. Lehnhardt2, J. Kolbenschlag1, K. Schossleitner3, P. Petzelbauer3, O. Goertz1 1Martin-Luther Krankenhaus, Berlin, 2Bergmannsheil Bochum, Bochum, Germany; 3Medical University Vienna, Wien, Austria Background: Edema due to capillary leak is a generalized and life threatening event in sepsis and major burns for which there is no causal treatment. Local burn wounds are an ideal model to investigate the impact of a new therapeutic agent on edema formation. We aimed to identify peptide sequences of cingulin that can attenuate stress-induced endothelial cytoskeleton disarrangement in vitro and which reduce burninduced edema in vivo. Materials and Methods: Cingulin-derived peptides were screened in high content cell culture assays monitoring actin displacement and endothelial cell/cell contacts. The ears of male hairless mice were inflicted with full thickness burns using a hot air jet. Mice with and without burn injuries were treated with Xib13 or solvent by continuous intraperitoneal application for 3 days. Edema, microcirculation, leukocyteendothelial interactions and angiogenesis – measured as nonperfused area – were investigated over a 12-day period using intravital fluorescence microscopy. Results: Xib13 reduced endothelial stress formation and stabilized endothelial tight junctions in cell-cultures. In the burn model, Xib13 improved angiogenesis compared to controls (non-perfused area on day 12: 5.7 ± 1.5% vs. 12.0 ± 2.1%; p b 0.05). Edema was significantly reduced at all observation points in Xib13-treated animals as compared to controls (day 12: 67.6 ± 2.6% vs. 83.2 ± 6.4%). Furthermore a dose dependent effect could be observed. Conclusion: Xib13 improved angiogenesis, reduced edema formation. Since edema formation is a serious parameter for burn conversion and is associated with survival it could provide a new treatment option for patients with burn injuries. 4 Horizontal Transfer of microRNA by Bone Marrow Derived Microparticles Modulates Inflammation after Experimental Liver Resection M. Schmelzle1, K. Splith2, I. Kämmerer2, C. Hegewald2, L. Feldbrügge3, J. Schulte am Esch4, J. Pratschke1, S. Robson3, S. Kuhn2 1Charité – Universitätsmedizin Berlin, Campus VirchowKlinikum, Berlin, 2Universität Leipzig, Leipzig, Germany; 3Beth Israel Deaconess Medical Center, Harvard University, Boston, USA; 4Universitätsklinikum Düsseldorf, Düsseldorf, Germany Background: Mechanisms involved in the communication between bone marrow stem cells and resident cells in the regenerating liver remain uncertain. We aimed to study implications of horizontal miRNA transfer by bone marrow (BM) derived plasma microparticles (MP) with regard to modulations of vascular inflammation and apoptosis of primary liver cells after partial hepatectomy. Materials and Methods: Partial hepatectomy was performed in C57Bl/6 wild type and Cd39 null mice, with latter being unable to phosphohydrolyze pro-inflammatory extracellular adenosine triphosphate (ATP) to adenosine. MP were isolated from the plasma and cell culture supernatant via two-step ultracentrifugation. Gene and miRNA expression was analyzed using qPCR. For fusion studies, MP were labeled with Cy3-labeled RNA oligonucleotides and stained with the PKH67. Fusion was imaged by FACS and confocal microscopy. Cell viability and apoptosis rate was measured using a commercial apoptosis assay. Results: After partial h

Background The long-term outcome of intestinal transplantations is still not favorable, which is partly due to the intestinal susceptibility to ischemia. There are several indications that the inflammatory response to ischemia-reperfusion injury is mediated by cyclooxygenases and that their inhibition may be associated with improved organ function. The aim of this study was to analyze if cyclooxygenase (COX) inhibitors could improve the early posttransplant outcome after orthotopic small bowel transplantation. Methods Small bowel transplantation was performed between rats to test the impact of nonselective (Piroxicam), preferential (Meloxicam), and selective COX-2 inhibitors (Parecoxib). The donor intestines were either perfused and stored with inhibitor or had inhibitor administered intravenously after transplantation. Results Using COX inhibitors, a sequential increase of posttransplantation intestinal integrity could be shown, with Parecoxib the least effective and Meloxicam the most effective treatment. These differences were in line with the downregulation of COX-2 activity by the inhibitors. Functionally, the same tendency could be seen in diminished expression of proinflammatory molecules, decreased leucocyte inflammation, and significantly improved graft microcirculation. In most cases, the intravenous administration was more effective. However, the COX inhibitors used were shown to cause relevant hepatotoxicity under nearly all conditions, but particularly under intravenous administration. Only Meloxicam in histidine-tryptophan-ketoglutarate was demonstrated to be a safe drug without hepatotoxic side effects. Conclusions The activity of COX contributes to ischemia-reperfusion injury after intestinal transplantation. In this comparative study, the administration of the preferential COX-2 inhibitor Meloxicam via histidine-tryptophan-ketoglutarate showed the best graft-protective attributes and the lowest hepatotoxic side effects.

Background/Aim: The global shortage of donor organs for transplantation has necessitated the expansion of the organ pool through increased use of organs from less ideal donors. Venous systemic oxygen persufflation (VSOP) and oxygenated machine perfusion (OMP) have previously demonstrated beneficial results compared to cold storage (CS) in the preservation of warm-ischemia-damaged kidney grafts. The aim of this study was to compare the efficacy of VSOP and OMP for the preservation of warm-ischemia-damaged porcine kidneys using the recently introduced Ecosol preservation solution compared to CS using Ecosol or histidine-tryptophan-ketoglutarate solution (HTK). Materials and Methods: Kidneys from German Landrace pigs (n = 5/group) were retrieved and washed out with either Ecosol or HTK after 45 min of clamping of the renal pedicle. As controls, kidneys without warm ischemia, cold stored for 24 h in HTK, were employed. Following 24 h of preservation by VSOP, OMP, CS-Ecosol, or CS-HTK, renal function and damage were assessed during 1 h using the isolated perfused porcine kidney model. Results: During reperfusion, urine production was significantly higher in the VSOP and OMP groups than in the CS-HTK group; however, only VSOP could demonstrate lower urine protein concentrations and fractional excretion of sodium, which did not differ from the non-warm-ischemia-damaged control group. VSOP, CS-Ecosol, and controls showed better maintenance of the acid-base balance than CS-HTK. Reduced lipid peroxidation, as reflected in postreperfusion tissue thiobarbituric acid-reactive substance levels, was observed in the VSOP group compared to the OMP group, and the VSOP and CS-Ecosol groups had concentrations similar to the controls. The ratio of reduced to oxidized glutathione was higher in the VSOP, OMP, and CS-Ecosol groups than in the CS-HTK group and controls, with a higher ratio in the VSOP than in the OMP group. Conclusion: VSOP was associated with mitigation of oxidative stress in comparison to OMP and CS. Preservation of warm-ischemia-damaged porcine kidneys by VSOP was improved compared to OMP and CS, and was comparable to preservation of non-warm-ischemia-damaged cold-stored kidneys.

BACKGROUNDEcosol, an extracellular-type, colloid-based preservation solution, has recently been introduced for washout, cold storage, and machine perfusion preservation of kidney grafts. Here, we assessed the efficacy of Ecosol compared to the widely used Histidine-Tryptophan-Ketoglutarate solution (HTK) for 24-h cold storage preservation of warm ischemia-damaged kidney grafts.MATERIAL AND METHODSBefore recovery, warm ischemia was induced by clamping the renal pedicle for 45-min. Thereafter, kidneys were washed-out and cold-stored for 24-h in Ecosol or HTK solution. Kidneys recovered without warm ischemia and cold-stored for 24-h in HTK served as controls (n=5). Renal function and damage parameters were assessed during 1-h normothermic reperfusion using the isolated perfused porcine kidney model.RESULTSRenal function did not differ between Ecosol and controls and was significantly reduced in HTK compared to controls. Total output of urine was higher in Ecosol compared to HTK. Intrarenal resistance and urine protein concentrations in Ecosol were lower compared to HTK and equal to controls. In the Ecosol group, oxygen consumption during reperfusion was higher and reduced tissue lipid peroxidation products were detected compared to HTK.CONCLUSIONSThe preservation quality of warm ischemia-damaged, cold-stored porcine kidneys was improved using the recently developed Ecosol preservation solution compared to HTK.

Background: The isolated perfused porcine kidney (IPPK) model has been the method of choice for the early preclinical evaluation of kidney graft preservation techniques. The preferred reperfusion conditions have not yet been determined. Here, we examined the effects of pressure- or flow-controlled perfusion and oxygenation by pure oxygen or carbogen (95% O2/5% CO2) on normothermic reperfusion in the IPPK model. Methods: Porcine kidneys were cold-stored for 24 h in histidine-tryptophan-ketoglutarate solution and reperfused for 1 h with normothermic whole blood/Krebs-Henseleit buffer medium (20/80%). Kidneys (n = 5/group) were flow-controlled reperfused with pure oxygen (1 ml/min/g; Flow-O2) or pressure-controlled reperfused (85 mm Hg mean arterial pressure) and oxygenated with either pure oxygen (Pressure-O2) or carbogen (Pressure-O2/CO2). Renal function and damage were assessed during reperfusion and NGAL and HIF-1α levels were analyzed using an ELISA. Results: Pressure-O2 and Pressure-O2/CO2 were associated with significantly better renal hemodynamics and acid-base homeostasis compared to Flow-O2. Urine protein concentrations and the fractional excretion of sodium were lower with both Pressure-O2 and Pressure-O2/CO2 than with Flow-O2. NGAL and HIF-1α levels were also lower with Pressure-O2 and Pressure-O2/CO2 than with Flow-O2. Only Pressure-O2/CO2 could demonstrate a significantly increased urine production compared to Flow-O2. The structural integrity was well preserved in the Pressure-O2 and Pressure-O2/CO2 groups, whereas diffuse and global glomerular destruction was observed in the Flow-O2 group. Conclusion: In the IPPK model, the application of pressure-controlled reperfusion with carbogen oxygenation, and to a lesser extent with pure oxygen, maintained physiological renal function for 1 h, thus providing a reliable and reproducible ex vivo evaluation of kidney preservation quality.

Background: Energy-based technologies for tissue sealing and cutting are increasingly supplementing current standards used for haemostasis and dissection during laparoscopic surgery. For their safe and efficacious use in clinical practice, these instruments have to guarantee sufficient burst resistance and low thermal damage to adjacent tissue in combination with good cutting characteristics. Material and methods: The novel laparoscopic, bipolar electrosurgical sealing and cutting instrument BiCision (R) was compared to a commercially available laparoscopic device (EnSeal (TM)) on visceral and peripheral arteries and veins in an animal model. Results: For all parameters investigated (burst pressure, cut quality, tissue adhering to the instrument, time needed to seal and cut the vessel and thermal damage), BiCision (R) was at least as good as EnSeal (TM). Regarding the burst pressure, BiCision (R) was superior over EnSeal (TM) in arteries: 600 mmHg (+/- 478) versus 241 (+/- 269) mmHg, respectively (p < 0.0001*). In veins, almost equivalent burst pressures of 155 +/- 134 mmHg (BiCision (R)) and 173 +/- 139 mmHg (EnSeal (TM)) were obtained. Conclusion: BiCision (R) appeared to be as good as or even superior to EnSeal (TM). Since EnSeal (TM) has already been shown to be safe and has been successfully used in clinical practice, BiCision (R) is assumed to be as efficient and reliable as EnSeal (TM) under pre-clinical conditions.

In order to reduce the number of animal experiments, the use of non-heart-beating donors (NHBDs) from a commercial abattoir has been proposed. Since the use of slaughterhouse organs is legally not defined as animal experiment, this would fulfil international standards as an alternative to animal experiments. The development of intravascular thrombosis after cardiac arrest negatively impacts organ preservation and thus viability during ischaemic storage and reperfusion. A fibrinolytic preflush with streptokinase might overcome these limitations. Therefore, the functional and histomorphological integrity of kidneys preserved immediately with intact circulation (control group A) and kidneys preserved after cardiac arrest with a 30 min period of warm ischaemia (WI) (group B) was compared with kidneys preflushed with 12.5 kU/L (group C) or 50 kU/L streptokinase (group D) after 30 min WI prior to preservation. We could demonstrate that kidneys preflushed with 12.5 kU/L streptokinase (group C) performed better than those without streptokinase pretreatment after WI (group B). Parameters like oxygen consumption, perfusion pressure, laboratory values, lactate dehydrogenase level and lipidperoxidation were closer to that of the control (group A) than in groups B and D. The higher streptokinase concentration of 50 kU/L (group D) resulted histologically in a more pronounced tissue damage and an attenuated renal function, indicating toxic effects. On the basis of our results we believe streptokinase preflushed slaughterhouse kidneys to be an adequate alternative to organs from laboratory animals with the potential to further reduce the number of animal experiments.