Danshen protects liver grafts from ischemia/reperfusion injury in experimental liver transplantation in rats.

Reperfusion injury remains one of the major problems in transplantation. Free radicals and disturbance of microcirculation are the supposed main contributors. Recent evidence shows that Danshen, a traditional Chinese drug used in vascular diseases, can scavenge radicals and improve microcirculation. This study investigates its effect on liver transplantation (LTx). Before organ recovery, female Sprague-Dawley rats (210-240 g) received intravenous Danshen or the same volume of Ringer solution as control. LTx was performed after 1 h of cold storage. Microperfusion, leukocyte-endothelium interaction and latex-bead phagocytosis were evaluated with in vivo microscopy. Survival, transaminases and histology were assessed. Immunohistology was used for TNF-alpha levels. anova and Fisher's exact test were employed for statistical analyses as appropriate. Survival increased from 60% in controls to 100% (P < 0.05). AST and LDH decreased from 3969 +/- 1255 U/l and 15444 +/- 5148 U/l in controls to 1236 +/- 410 U/l and 5039 +/- 1594 U/l, respectively (P < 0.05). In vivo microscopy revealed decreased leukocyte-adherence and increased blood flow velocity in sinusoidal zones after administration of Danshen (P < 0.05), while latex-bead phagocytosis was found in 60% of controls (P < 0.05). The TNF-alpha index decreased from 2.08 +/- 0.09 in controls to 1.09 +/- 0.09 (P < 0.05). This study clearly demonstrates hepatoprotective effects after experimental LTx, which can be explained via anti-oxidative effects, improved microcirculation and decreased Kupffer cell activation.

Capsaicin reduces tissue damage in experimental acute pancreatitis.

OBJECTIVES: Calcitonin gene-related peptide (CGRP) is released from perivascular pancreatic nerves. It effects vasomotion and cytokine liberation in inflammatory processes, including acute pancreatitis (AP). Calcitonin gene-related peptide liberation is stimulated by capsaicin, a substance of red hot chili peppers. Aim of the study was to investigate the influence of exogenous capsaicin on experimental AP. METHODS: Acute pancreatitis was induced in rats by glycodeoxycholic acid and cerulein. Animals were divided into 4 groups: (1) severe AP, (2) severe AP+capsaicin, (3) control without AP, and (4) control+capsaicin. After 24 hours, survival, histology, and CGRP were evaluated (n=6/group). In additional animals, erythrocyte flow and leukocyte activation were evaluated by intravital microscopy 6 hours after AP induction (n=6/group). RESULTS: In the control groups, all animals survived without histological alterations. Mortality in severe AP was 67%. Capsaicin reduced mortality to 16% (P<0.05). Acute pancreatitis animals developed pancreatic inflammation and necrosis, which was significantly less after capsaicin application. Intravital microscopy in severe AP showed reduced erythrocyte velocity and increased leukocyte adhesion, which was nearly normalized by capsaicin (P<0.01). Calcitonin gene-related peptide increased in both capsaicin groups, indicating endogenous CGRP liberation (P<0.01). CONCLUSION: Capsaicin releases endogenous CGRP with improved pancreatic microcirculation and reduced inflammation in experimental AP. This underlines neuropeptide activity in the pathogenesis of AP.

The influence of selenium substitution on microcirculation and glutathione metabolism after warm liver ischemia/reperfusion in a rat model.

Ischemia/reperfusion (I/R) injury is a variable yet unavoidable complication in liver surgery and transplantation. Selenium-dependent glutathione-peroxidases (GPx) and selenoproteins function as antioxidant defense systems. One target in preventing I/R injury is enhancing the capacity of endogenous redox defense. It was the aim of this study to analyze the effects of selenium substitution on liver microcirculation, hepatocellular injury and glutathione status in a model of partial warm liver ischemia in the rat. Sodium selenite was administered in three different dosages i.v.: 0.125 microg/g, 0.25 microg/g and 0.375 microg/g body weight and compared to an untreated control group (each n=10). Intravital microscopy was performed after 70 min of partial warm liver ischemia and 90 min of reperfusion. Liver tissue and plasma samples were taken at the end of the experiment for laboratory analysis. Microcirculation improved significantly in all therapy groups in contrast to control animals. ALT levels decreased significantly whereas malondialdehyde levels remained unchanged. In liver tissue, selenium supplementation caused an increase in the amount of total and reduced glutathione without changes in oxidized glutathione. This effect is likely mediated by selenite itself and selenoprotein P rather than by modulating GPx activity. We were able to show that selenite substitution has an immediate protective effect on I/R injury after warm hepatic ischemia by acting as a radical scavenger and preserving the antioxidative capacity of the liver.

Reduction of skeletal muscle injury in composite tissue allotransplantation by heat stress preconditioning.

Ischemia-reperfusion injury is a dominant factor limiting tissue survival in any microsurgical tissue transplantation, a fact that also applies to allogeneic hand transplantation. The clinical experience of the 12 human hand transplantations indicates that shorter ischemia times result in reduced tissue damage and, ultimately, in better hand function. Heat stress preconditioning and the accompanying up-regulation of the heat shock protein 72 have been shown to reduce the ischemia-reperfusion injury following ischemia of various organs, including organ transplantation. The aim of this study was to reduce the ischemia-reperfusion injury in a model of composite tissue allotransplantation. Allogeneic hind limb transplantations were performed from Lewis (donor) to Brown-Norway rats. Donor rats in group A (n = 10) received a prior heat shock whereas rats in group B (n = 10) did not receive any prior heat shock. Group C served as a control group without transplantation. The transplantations were performed 24 hours after the heat shock, at which time the heat shock protein 72 was shown to be up-regulated. The outcome was evaluated 24 hours after transplantation by nitroblue tetrazolium staining and wet-to-dry weight ratio of muscle slices (anterior tibial muscle). The nitroblue tetrazolium staining showed a significant reduction of necrotic muscle in group A (prior heat shock) (p = 0.005). The wet-to-dry ratio was significantly reduced in group A (prior heat shock), indicating less muscle edema and less tissue damage (p = 0.05). Heat shock preconditioning 24 hours before an ischemic event leads to an up-regulation of heat shock protein 72 in muscle and to a tissue protection reducing ischemia-reperfusion injury in composite tissue transplantation.