Effect of temporary hypoxia on the permeability of the rat aorta.

Hypoxia was produced experimentally in the infrarenal portion of rat abdominal aorta by ligating it at both ends for one hour. Permeability changes of the injured segment were followed up by means of a colloidal iron tracer after different periods of recirculation. The tracer could be demonstrated in intercellular junctions and subendothelial space already after one hour of recirculation. The permeability disorder was at its peak two days after the injury and it ceased by the tenth day. Insudation of the media by plasma increased proportionally with the endothelial permeability change and it was accompanied by marked ultrastructural alterations.