Lipopolysaccharide tolerance inhibits eye inflammation. II. Preliminary studies on the mechanism

E. L. Howes Jr and J. T. Rosenbaum

The effect of endotoxin tolerance on ocular inflammation was studied in rabbits. Compared with a control group, a passive Arthus reaction in tolerant rabbits was characterized by a sharp decline in the expected increase in vascular permeability and slightly reduced leukocyte extravasation. Aqueous humor withdrawal (paracentesis) and intravitreal injection of prostaglandin E2 were also examined in lipopolysaccharide (LPS)-tolerant rabbits; in both circumstances, ocular protein exudation was decreased. These studies suggest that the prostaglandin system is particularly affected in the ocular responses of LPS-tolerant rabbits, and raise the possibility that other phenomena described in LPS tolerance may have a similar basis.