Morphological and functional changes in the tight junctions of the bile canaliculi induced by bile duct ligation.

Thin sections after bile duct ligation showed that the depth of tight junctions appeared to increase and that the distance between individual punctate contacts appeared to become irregular and wider than in controls. The freeze fracture replicas clearly demonstrated these changes in the tight junction morphology. Changes were noted most conspicuously in the tight junction three weeks after ligation. Measurements of the junctional morphology in control and ligated specimens showed that the junctional depth had increased two fold in the latter, whereas the number of strands had scarcely changed. Lanthanum tracer experiments showed that the tight junctions did not permit the passage of the tracer in normal nor ligated rats. It was concluded that the mechanism of obstructive jaundice could not be related to changes in junctional morphology causing increased junctional permeability.