Study of warm ischemia followed by reperfusion on a lower limb model in rats: effect of allopurinol and streptokinase

The influence of allopurinol and post-conditioning on lung injuries induced by lower-limb ischemia and reperfusion in Wistar rats

PURPOSE

To analyze the effects of allopurinol and of post-conditioning on lung injuries induced by lower-limb ischemia and reperfusion.

METHODS

Thirty rats were used. They were divided in 5 groups: (1) group A: abdominal aortic dissection only, (2) group B: ischemia and reperfusion, (3) group C: administered allopurinol (100mg/Kg) a few hours before procedure, (4) group D: post-conditioned and (5) group E: administered allopurinol and post-conditioned. With the exception of group A, all groups were submitted to infrarenal aortic ischemia for 2 hours, and reperfusion for 72 hours. After euthanasia, lungs were removed for histological analysis. They were graded under two scores: pulmonary injury (neutrophil infiltration, interstitial edema, vascular congestion, and destruction of lung architecture) and lymphocytic score (neutrophil infiltration, lymphoid aggregate and secondary follicle).

RESULTS

On the pulmonary injury score, the degree of injury was smaller than in groups D and E, when compared to group B, p<0.05. Group C did not obtain the same result (p>0,05). On the lymphocytic score, there was no statistic difference among groups, p>0.05.

CONCLUSION

Both post-conditioning and the combination of allopurinol and post-conditioning were effective in remote lung protection induced by lower-limbs I/R. When used in isolation, allopurinol showed no protective effect.

A Study on the Effects of the Use of Propofol in Experimental Model Inferior Epigastric Island Flap on Ischemia-Reperfusion Injury

Problems concerning vascular blood flow are the most frequently encountered ones after flap applications. The flap tissue starts to develop ischemia in patients with a vascular blood flow insufficiency. And reperfusion starts in those patients in whom the ischemia is temporary, triggering an ischemia-reperfusion injury depending on the duration of the ischemia. The aim of this study was to evaluate the effect of propofol, which is an anesthetic agent known to have an antioxidant effect and a free radical scavenging feature on the ischemia-reperfusion injury created on an experimental epigastric island flap.Thirty Sprague-Dawley rats were used in the study. The rats were divided into 3 groups of 10 rats each. Inferior epigastric artery-based abdominal flaps were prepared in all the groups. In group 1 (sham), the flap was elevated but no ischemia was applied. In groups 2 (control) and 3 (propofol), the flap was exposed to ischemia for 2 hours after it was elevated. All the rats were sacrificed and biochemical and histopathological assessments were made on the tissue samples taken on the 14th day. As a result of a comparison between the groups, the flap viability rates and the superoxide dismutase, total antioxidant capacity, and catalase values were found to be significantly higher (P < 0.001) in the propofol group while the malondialdehyde and total oxidative stress values were lower (P < 0.001). Based on the data obtained from the present study, the use of propofol was observed to have a protective effect against ischemia-reperfusion injuries in flap surgeries.

Challenges in replantation of complex amputations

Surgical ingenuity has resulted in continuing microsurgical innovation in replantation. In this article, the authors define complex amputations as those that stretch the boundaries or fall outside traditionally defined indications for replantation. They discuss management of difficult situations involving multiple digit amputations, multiple-level amputations, prolonged ischemia, and multiple trauma. The role of transpositional and ectopic replantation, as well as the requirement for secondary procedures in replantation is also discussed. Although technically challenging, microsurgical management of complex amputations ultimately results in far superior outcomes.

Ischemic preconditioning attenuates remote pulmonary inflammatory infiltration of diabetic rats with an intestinal and hepatic ischemia-reperfusion injury

PURPOSE

To assess ischemic preconditioning (IPC) effects in pulmonary lesion in intestinal and hepatic ischemia-reperfusion (IR) injury models using diabetic rats.

METHODS

Diabetes (DM) was induced in 28 male Wistar rats by alloxan (42 mg/kg, IV). After 28 days, severe DM rats were submitted to intestinal or hepatic IR injury with or without IPC. Intestinal IR (30 min of mesenteric artery occlusion and 30 min of reperfusion; n=6) and IPC groups (10 min ischemia, 10 min reperfusion, followed by intestinal IR; n=6), and Hepatic IR (30 min of hepatic pedicle occlusion and 30 min of reperfusion; n=5) and IPC groups (10 min ischemia, 10 min reperfusion, followed by hepatic IR; n=5), were compared to DM rats group (n=6). Plasmatic lactate, glycemia were measured before and after IR injury. Histomorphology of lung was performed counting inflammatory cells. Data was expressed in mean± SE. P<0.05.

RESULTS

Glycemia and lactate were similar among groups. IPC did not interfere in these parameters. On histological evaluation, IR increased inflammatory cells infiltration in pulmonary parenchyma compared to control in both IR injury models. IPC attenuated inflammatory infiltration in lungs.

CONCLUSION

Ischemic preconditioning protects against remote ischemia-reperfusion injury in lung on intestinal or hepatic ischemia-reperfusion model with acute diabetes.

Postischemic poly (ADP-ribose) polymerase (PARP) inhibition reduces ischemia reperfusion injury in a hind-limb ischemia model

BACKGROUND

Several experiments were designed to determine whether the systemic, postischemic administration of PJ34,which is a poly-adenosine diphosphate (ADP)-ribose polymerase inhibitor, decreased tissue injury and inflammation after hind-limb ischemia reperfusion (I/R).

METHODS

C57BL6 mouse limbs were subjected to 1.5 h ischemia followed by 24-h reperfusion. The treatment group (PJ) received intraperitoneal PJ34 (30 mg/kg) immediately before reperfusion, as well as 15 min and 2 h into reperfusion. The control group (CG) received lactated Ringer's alone at the same time intervals as PJ34 administration. The skeletal muscle levels of adenosine triphosphate (ATP), macrophage inflammatory protein-2 (MIP-2), keratinocyte derived chemokine (KC), and myeloperoxidase (MPO) were measured. Quantitative measurement of skeletal muscle tissue injury was assessed by microscopic analysis of fiber injury.

RESULTS

ATP levels were higher in limbs of PJ versus CG mice (absolute ATP: 4.7 +/- 0.35 vs 2.3 +/- 0.15-ng/mg tissue, P = .002). The levels of MIP-2, KC, and MPO were lower in PJ versus CG mice (MIP-2: 1.4 +/- 0.34 vs 3.67 +/- 0.67-pg/mg protein, P = .014; KC: 4.97 +/- 0.97 vs 12.65 +/- 3.05-pg/mg protein, P = .037; MPO: 46.27 +/- 10.53 vs 107.34 +/- 13.58-ng/mg protein, P = .008). Muscle fiber injury was markedly reduced in PJ versus CG mice (4.25 +/- 1.9% vs 22.68 +/- 3.0% total fibers, P = .0004).

CONCLUSION

Systemic postischemic administration of PJ34 preserved skeletal muscle energy levels, decreased inflammatory markers, and preserved tissue viability post-I/R. These results support PARP inhibition as a viable treatment for skeletal muscle I/R in a clinically relevant post hoc scenario.

Intestinal ischemia/reperfusion induces bronchial hyperreactivity and increases serum TNF-alpha in rats

INTRODUCTION

Intestinal or hepatic ischemia/reperfusion induces acute lung injury in animal models of multiple organ failure. Tumor necrosis factor (TNF)- alpha is involved in the underlying inflammatory mechanism of acute respiratory distress syndrome. Although the inflammatory cascade leading to acute respiratory distress syndrome has been extensively investigated, the mechanical components of acute respiratory distress syndrome are not fully understood. Our hypothesis is that splanchnic ischemia/reperfusion increases airway reactivity and serum TNF-alpha levels.

OBJECTIVE

To assess bronchial smooth muscle reactivity under methacholine stimulation, and to measure serum TNF-alpha levels following intestinal and/or hepatic ischemia/reperfusion in rats.

METHOD

Rats were subjected to 45 minutes of intestinal ischemia, or 20 minutes of hepatic ischemia, or to both (double ischemia), or sham procedures (control), followed by 120 minutes of reperfusion. The animals were then sacrificed, and the bronchial response to increasing methacholine molar concentrations (10(-7) to 3 x 10(-4)) was evaluated in an ex-vivo bronchial muscle preparation. Serum TNF-alpha was determined by the L929-cell bioassay.

RESULTS

Bronchial response (g/100 mg tissue) showed increased reactivity to increasing methacholine concentrations in the intestinal ischemia and double ischemia groups, but not in the hepatic ischemia group. Similarly, serum TNF-alpha (pg/mL) concentration was increased in the intestinal ischemia and double ischemia groups, but not in the hepatic ischemia group.

CONCLUSION

Intestinal ischemia, either isolated or associated with hepatic ischemia, increased bronchial smooth muscle reactivity, suggesting a possible role for bronchial constriction in respiratory dysfunction following splanchnic ischemia/reperfusion. This increase occurred in concomitance with serum TNF-alpha increase, but whether the increase in TNF-alpha caused this bronchial contractility remains to be determined.