Effect of 100% oxygen on E-selectin expression, recruitment of neutrophils and enterocyte apoptosis following intestinal ischemia-reperfusion in a rat

Abstract

Recent evidence suggests that neutrophil recruitment may initiate cell apoptosis in ischemic tissues. We have recently shown that enterocyte apoptosis is increased following intestinal ischemia-reperfusion (IR) injury. The purpose of the present study was to examine the effect of hyperoxia on E-selectin expression, neutrophil recruitment and enterocyte apoptosis following intestinal IR in a rat. Male Sprague-Dawley rats were divided into three experimental groups: (1) sham rats underwent laparotomy without vascular occlusion and were ventilated with air (Sham) (2) IR rats underwent occlusion of both the superior mesenteric artery and portal vein for 30 min and were ventilated with air (IR), and (3) IR-O2 rats underwent IR and were ventilated with 100% started 10 min before reperfusion and continued for 6 h (IR-O2). Intestinal structural changes were determined 24 h following IR. Immunohistochemistry for E-selectin (using E-selectin cleaved concentrated polyclonal antibody) was performed to identify E-selectin immunoreactivity localized to the endothelium of venules. The recruitment of neutrophils was calculated per 100 venules. Immunohistochemistry for Caspase-3 was performed for identification of apoptotic cells. Non-parametric one-way ANOVA test was used for statistical analysis with p less than 0.05 considered statistically significant. A significant increase in E-selectin expression in the jejunum (6.1 +/- 2.2 vs. 2.5 +/- 1.0 E-selectin positive vessels/100 vessels, p < 0.05) and ileum (12.1 +/- 2.7 vs. 3.3 +/- 1.2 E-selectin positive vessels/100 vessels, p < 0.05) and a concomitant increase in neutrophil recruitment in the ileum (5.5 +/- 1.6 vs. 1.3 +/- 0.6 adhered PMN's per 100 venules) were observed in IR rats compared to sham animals and were accompanied by increased cell apoptosis (p < 0.05). Treatment with 100% oxygen resulted in a significant attenuation in E-selectin expression in the ileum (2.7 +/- 1.1 vs. 12.1 +/- 2.7 E-selectin positive vessels/100 vessels, p < 0.05), and neutrophil recruitment in the jejunum (2.5 +/- 1.4 vs. 7.7 +/- 1.9 adhered PMN's per 100 venules, p < 0.05) and ileum (1.5 +/- 0.7 vs. 5.5 +/- 1.6 adhered PMN's per 100 venules, p < 0.05) compared to IR animals, and was accompanied by decreased cell apoptosis (p < 0.05). Hyperoxia inhibits enterocyte apoptosis following intestinal ischemia-reperfusion. Down-regulation of E-selectin expression with subsequent decrease in neutrophil recruitment may be responsible for this effect.

Ketamine reduces intestinal injury and inflammatory cell infiltration after ischemia/reperfusion in rats

“…36 The inhibition of neutrophil activation and infi ltration into the I/Rinjured intestine has been implicated in the protective mechanisms of various experimental therapeutic interventions. 37,38 The current study found that ketamine protection against intestinal I/R injury was related to a reduction of leukocytes, and particularly the infi ltration of neutrophils.…”

Ischemic preconditioning ameliorates intestinal injury induced by ischemia-reperfusion in rats

“…PMNs can aggregate together leading to a "no flow" phenomenon in ischemic tissue after reperfusion [10] . Moreover, PMNs could contribute to vasoconstriction and decreased blood flow via the release of potent cytotoxic cytokines [24] . In the present study, intestinal IR significantly induced infiltration of neutrophils or PMNs, as observed as and increased MPO level.…”

Antioxidantes enterais em lesões de isquemia e reperfusão em ratos

“…2011; 38(6): 422-428 beneficial effect on I/R injury in rat epigastric flaps, increasing significantly the viability of the flap 24 . The role of neutrophil infiltration was also demonstrated by the improvement in I/ R injury with ventilation with 100% oxygen 25 . In this study, groups E and C + E had higher villi height and less neutrophil infiltration, pointing thus to a correlation between mucosal damage and neutrophil infiltration.…”