Microvascular and epithelial permeability measurements in laboratory animals

Disruption of the mucosal permeability barrier is an acute life-threatening consequence of intestinal transplantation. The major aim of organ preservation techniques is to maintain the mucosal barrier and its function. Thus, assessment of microvascular and epithelial permeability is an important tool to determine the efficacy of therapeutic interventions. The use of murine models is particularly advantageous, as numerous immunological approaches (e.g., monoclonal antibodies) and genetically modified animal strains have been developed. Large animal models are also useful because they allow online detection of mucosal permeability changes. In this review, we summarize the available methodologies for measuring microvascular and epithelial permeability in the intestines of laboratory animals. We describe the advantages of various photometric and intravital microscopic methods for the assessment of microvascular permeability. Techniques that determine the inward and outward direction of mucosal permeability changes (including radioenzymatic, fluorimetric, and intravital microscopy methods) are also discussed.