LIPOPOLYSACCHARIDE-INDUCED ACUTE RED EYE AND CORNEAL ULCERS

Using a new animal model, the aims of this study were to assess the ro le played by purified lipopolysaccharide (LPS) and neutrophils in the pathogenesis of acute red-eye reactions (ARE) and corneal ulcers. In a ddition, IL-1 alpha was assessed for its implications in the formation of corneal ulcers. Following corneal abrasion, eyes of rabbits underw ent single or double exposures to various doses of LPS from Pseudomona s aeruginosa or Serratia marcescens. This protocol induced ARE symptom s, and their severity depended on the dosage, number of LPS exposures, and type of LPS used (LPS from S. marcescens showing highest virulenc e). Corneal ulcers were induced by delivering a high dose of Serratia LPS (100 9 mu g) followed by a low dose (10 mu g). Histopathological e xamination revealed that both ARE and corneal ulceration were associat ed with prominent neutrophil infiltration. In addition, many lymphocyt es and other monocytic cells infiltrated ulcerated ocular tissue. Tear fluids obtained from ulcerated eyes contained high concentrations of a protein recognized by anti-rabbit IL-1 alpha antibodies as demonstra ted by immunoblotting studies. The results indicate that LPS can induc e ARE and corneal ulceration in the absence of any live bacteria. More over, the findings implicate the accumulation of neutrophils and IL-1 alpha-related proteins In the pathogenesis of ARE and corneal ulcers. (C) 1997 Academic Press Limited