The hamster cheek pouch--an experimental model to study postischemic macromolecular permeability.

In order to study permeability changes after local ischemia the cheek pouch of the hamster was everted for intravital microscopy. Macromolecular permeability was quantified as leakage of fluoroscein labelled dextran (Mw 70,000). Temporary ischemia with total circulatory arrest of the whole cheek pouch was obtained by a cuff mounted around the everted cheek pouch where it leaves the mouth of the hamster. At reperfusion after repeated ischemic periods of 5 min no leaks were seen. A prolongation of the ischemic period to 30 min resulted in a temporary increase in the number of postcapillary venular leaks. When the occlusion was repeated the response was significantly smaller. An occlusion period of 60 min gave no further increase in macromolecular permeability. Locally applied histamine was used to test the reactivity of the cheek pouch. It was concluded that the model is suited for studies of permeability increase after local ischemia.