Résumé
PURPOSE: Heat shock proteins (Hsps) are expressed by various types of stress, and known to play an important role in protecting cellular homeostasis. We hypothesized that Hsps may protect tissue damage and cataract formation in endotoxin-induced uveitis. METHODS: Lewis rats were exposed to 43degreesC balanced salt solution or arsenite for inducing Hsps, then received LPS injection 6 hours later. We evaluated the inflammatory grade and cataractous lens change. Histological examination, measurement of nitric oxide concentration in anterior chamber and SDS-PAGE analysis of lens protein change were also performed. RESULTS: Western blotting of rat lens revealed that Hsps progressively increased by 6 hour after heating and peaked at 12 hours. The inflammatory grade and cataractous lens change were less in Hsps expressed. Nitric oxide concentration were also lowered in Hsps expressed groups. Analysis of lens protein revealed that normally expressed 66.2 KDa protein disappeared in all groups after LPS injection but recovered in Hsps expressed groups with time. CONCLUSIONS: This result suggests that Hsps may protect tissue damage and cataract formation in endotoxin-induced uveitis. This effect may be associated with decreased nitric oxide. The study demonstrates that preconditioning to induce larger amount of Hsps by heat shock or drug may decrease inflammation and cataractogenesis induced by uveitis and surgery. We conclude that induction of Hsps may be useful as a new therapeutic modality against uveitis-induced cataract.