Influence of endotoxin-induced keratitis on the reducing potential of glutathione in the cornea of animals with experimental syndrome of the dry eye

Introduction. Modern methods of treatment of keratitis are not always effective. Particular difficulties arise when treating keratitis in patients with symptoms of the dry eye. Objective: To determine the degree of disturbances in the thiol system in the tissues of the anterior eye in the development of keratitis in animal models of dry eye syndrome. Material and methods. In the experiment 36 Chinchilla rabbits weighing 2.2?2.9 kg were divided into 4groups: Group 1 ? control (7rabbits), group 2 ? under the experiment (6 rabbits), animals with the dry eye syndrome, Group 3 ? experimental (12 rabbits), animals with keratitis, Group 4 ? experimental (11 rabbits), animals with keratitis and dry eye syndrome. Experimental keratitis was caused by intrastromal injection of 50 mcl of a 0.2 % solution of endotoxin ? lipopolysaccharide phosphate buffer. For the development of the dry eye syndrome, there was used 0.1 % BAC solution prepared on the isotonic phosphate buffer (pH 7.3?7.4). Instillation was made daily (twice a day) for two weeks. The concentration of reduced and oxidized glutathione in the cornea and lacrimal fluid was determinedspectrophotometrically by the methods of enzymatic analysis. The data obtained were subjected to statistical analysis using the package SPSS 11.0. Results. The development of keratitis in animals with the dry eye syndrome is accompanied by a sharp reliable drop in reduced glutathione compared with keratitis without dry eye syndrome. Thus, on the 7th and 14th day of the observation the concentration of reduced glutathione in the cornea was reduced by 23.8 % and 21.8 % respectively. The presence of the dry eye syndrome in the development of inflammation in the cornea causes a high degree of oxidative stress in it, as evidenced by the significant increase of the oxidized form of glutathione both in the cornea (21.8 %) ? 7 days, 19.8 % ? 14 hours), and tear (7 day ? 26.3 % on day 14?46.0 %). Conclusion. Summarizing the data obtained in the study of the thiol status of the cornea in the development of inflammation in it in the conditions of the dry eye syndrome, it can be concluded that the sharp decline in the detoxification and reduction potential of the reduced/oxidized glutathione must be considered when determining the orientation of pathogenetic therapy of the pathological condition of the body.