The role of ischemic preconditioning in the expression of apoptosis-related genes in a rat model of intestinal ischemia-reperfusion injury

Abstract Purpose: To analyze the effects of ischemic preconditioning (IPC) in the expression of apoptosis-related genes in rat small intestine subjected to ischemia and reperfusion. Methods: Thirty anesthetized rats underwent laparotomy and were drive into five groups: control (CG); ischemia (IG); ischemia and reperfusion (IRG); IPC and ischemia (IG+IPC); IPC and ischemia and reperfusion (I/RG+IPC). Intestinal ischemia was performed by clamping the superior mesenteric artery for 60 minutes, whereas reperfusion lasted for 120 minutes. IPC was carried out by one cycle of 5 minutes of ischemia followed by 10 minutes of reperfusion prior to the prolonged 60-minutes-ischemia and 120-minutes-reperfusion. Thereafter, the rats were euthanized and samples of small intestine were processed for histology and gene expression. Results: Histology of myenteric plexus showed a higher presence of neurons presenting pyknotic nuclei and condensed chromatin in the IG and IRG. IG+IPC and I/RG+IPC groups exhibited neurons with preserved volume and nuclei, along with significant up-regulation of the anti-apoptotic protein Bcl2l1 and down-regulation of pro-apoptotic genes. Moreover, Bax/Bcl2 ratio was lower in the groups subjected to IPC, indicating a protective effect of IPC against apoptosis. Conclusion: Ischemic preconditioning protect rat small intestine against ischemia/reperfusion injury, reducing morphologic lesions and apoptosis.

Celio-mesenteric trunk associated with giant omphalocele: surgical consequences / Tronco celíaco-mesentérico asociado con onfalocele gigante: consecuencias quirúrgicas

We report the first case of a newborn presenting with a celio-mesenteric trunk variation associated with a giant omphalocele. The celio-mesenteric trunk was unexpected and unseen during the staged surgical closure. After partial reintegration of the liver, the newborn presented refractory hypovolemia with anuria, leading to redo surgery. This procedure revealed ischemia of the liver and necrosis of the entire gastrointestinal tract except the colon. Despite treatment, including liver externalization, the infant did not survive. The autopsy revealed a celio-mesenteric trunk, a rare anomaly characterized by a common origin of the celiac axis and the superior mesenteric artery from the aorta. This association may explain the dramatic consequences of the staged closure procedure. Awareness of the association of celio-mesenteric trunk and omphalocele would allow the surgeon to take extra care during this delicate surgery.

Presentamos el primer caso de un recién nacido que presenta una variación del tronco celíaco-mesentérico asociada con un onfalocele gigante. El tronco celíaco-mesentérico fue inesperado y no se vio durante las etapas del cierre quirúrgico. Después de la reintegración parcial del hígado, el recién nacido presentó hipovolemia refractaria con anuria, lo que condujo a la repetición de la cirugía. Este procedimiento reveló isquemia del hígado y necrosis de todo el tracto gastrointestinal excepto el colon. A pesar del tratamiento, incluyendo la externalización hepática, el bebé no sobrevivió. La autopsia reveló un tronco celíaco-mesentérico, una rara anomalía caracterizada por un origen común del tronco celíaco y la arteria mesentérica superior, a partir de la aorta. Esta asociación puede explicar las dramáticas consecuencias del procedimiento durante las etapas del cierre. El conocimiento de la asociación de tronco celíaco-mesentérico y onfalocele permitiría al cirujano tomar especial cuidado durante esta delicada cirugía.

Ischemic postconditioning assessment in the liver of rats undergoing mesenteric ischemia and reperfusion

Abstract Introduction: Ischemic postconditioning is a method that shows evidence of efficacy in minimizing reperfusion injury; however, its effectiveness in preventing injuries in distant organs is still unknown, especially in those who have undergone mesenteric ischemia and reperfusion. Objective: To evaluate the effect of ischemic postconditioning in preventing reperfusion injury in the liver of rats submitted to mesenteric ischemia and reperfusion, comparing two different methods of ischemic postconditioning. Methods: 30 Wistar male rats were used, distributed into three groups: Group A: Ten rats submitted to intestinal ischemia for 30 minutes followed by reperfusion for 60 minutes; Group B: Ten rats subjected to ischemia and reperfusion; after ischemia, two cycles of reperfusion (two minutes each) interleaved with two cycles of ischemia (two minutes each); and Group C: Ten rats subjected to ischemia and reperfusion; after ischemia, four cycles of reperfusion (30 seconds each) interspersed with four cycles of ischemia (30 seconds each). After the experiment, the left lobe of the liver was resected for subsequent histological analysis, using the following classification: grade 1 - centrilobular congestion; grade 2 - centrilobular congestion with some degeneration of hepatocytes in one or two central veins; and grade 3 - multifocal centrilobular congestion and degeneration of portal hepatocytes. Results: The mean degree of liver damage found was 1.8 in group A, 1.7 in group B and 1.3 in group C. There was no statistically significant difference between the groups. Conclusion: Ischemic postconditioning was unable to minimize reperfusion injury in rats undergoing mesenteric ischemia and reperfusion.

Importance of duration and number of ischemic postconditioning cycles in preventing reperfusion mesenteric injuries. Experimental study in rats

PURPOSE:To evaluate the effect of ischemic postconditioning(IPC) on intestinal mucosa of rats subjected to ischemia and reperfusion process comparing two cycles of reperfusion and ischemia lasting two minutes each and four cycles of reperfusion and ischemia lasting 30 seconds eachMETHODS: Thirty Wistar rats were distributed into three groups: group A (10 rats), ischemia (30 minutes) and reperfusion (60 minutes); group B (10 rats), ischemia and reperfusion plus IPC by two lasting two minutes each; and Group C (10 rats), ischemia and reperfusion plus IPC by four cycles lasting 30 seconds each. Finally, a segment of small intestine was resected for histological analysis. We analysed the results according to Chiu et al. classification and proceeded to the statistical treatment by Kruskal-Wallis test (p<0.05).RESULTS: The mean degree of tissue injury according to Chiu et al. classification were: Group A, 2.77; in group B, 1.4; and group C, 1.4. B X C (p<0.05).CONCLUSIONS: Ischemic postconditioning was able to minimize reperfusion injury of rats undergone mesenteric ischemia and reperfusion process. There was no difference in the effectiveness of the method comparing two cycles of two minutes with four cycles of 30 seconds by H&E histological evaluation of the ileum after 60-minute reperfusion.