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

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.