Intestinal and hemodynamic impairment following mesenteric ischemia/reperfusion

Area of Science:

• Gastroenterology
• Physiology
• Surgical Research

Background:

• Clinical intestinal ischemia/reperfusion (I/R) injury causes local and systemic dysfunction.
• A rat model of transient mesenteric occlusion is used to study I/R injury.
• Systematic analysis of intestinal permeability and hemodynamics in this rat model is lacking.

Purpose of the Study:

• To systematically analyze intestinal permeability and hemodynamic changes in a rat model of intestinal I/R injury.
• To evaluate the impact of I/R on the small bowel barrier function using various permeability markers.
• To assess the hemodynamic consequences of intestinal I/R in this animal model.

Main Methods:

• Rats underwent superior mesenteric artery occlusion for 60 minutes, followed by 4 hours of reperfusion.
• Intestinal permeability was assessed by measuring ex vivo apparent permeability coefficients (Papp) for mannitol, inulin, and dextran.
• Hemodynamic parameters, including mean arterial pressure (MAP) and heart rate (HR), were continuously monitored.

Main Results:

• Intestinal I/R increased ex vivo Papp for mannitol and inulin, but not dextran, indicating selective barrier dysfunction.
• Histological examination revealed significant disruption of the intestinal tissue.
• Reperfusion led to a sustained fall in MAP and initial decrease in HR, followed by an overshoot above baseline.

Conclusions:

• Intestinal I/R causes a selective loss of small bowel barrier function, primarily affecting low-molecular-weight compounds.
• The choice of permeability markers is critical for accurately evaluating intestinal damage.
• The observed hemodynamic instability underscores the need for therapeutic strategies to mitigate I/R-induced local and systemic effects.