title: Involvement of TNF alpha, IL-1 beta and IL-1 receptor antagonist in LPS-induced rabbit uveitis.
abstract: The objective of the study was to investigate involvement of TNF alpha, IL-1 beta and IL-1 receptor antagonist (IL-1Ra) in lipopolysaccharide (LPS)-induced uveitis. Intravitreal injection of LPS (100 ng) to rabbits induced a massive leukocyte infiltration and protein leakage into the aqueous humor. Aqueous leukocyte counts and protein levels reached a peak 24 hr after this injection. The peak concentrations of aqueous TNF alpha (230 +/- 37 pg ml-1, at 9 hr) and IL-1 beta (185 +/- 80 pg ml-1, at 18 hr) preceded peak levels of aqueous leukocyte counts and protein levels. In contrast, the levels of aqueous IL-1Ra peaked at 48 hr (12,239 +/- 1964 pg ml-1) and a fairly high concentration of IL-1Ra remained when the inflammatory reactions subsided. Immunohistochemistry and leukocyte-depletion studies showed that infiltrating leukocytes were the major cellular sources of aqueous TNF alpha, IL-1 beta and IL-1Ra. Intravitreal injection of homologous TNF alpha (0.1-1.5 micrograms) or IL-1 beta (0.5-5 ng) reproduced a rapid leukocyte infiltration and protein leakage. Administration of anti-TNF alpha mAb (10 micrograms) suppressed the number of LPS-induced infiltrating neutrophils by 50%, mononuclear cells by 58%, and protein leakage by 42%. Administration of rabbit IL-1Ra (10 micrograms) also suppressed neutrophil influx by 78%, however, neither mononuclear cell influx nor protein leakage was inhibited by rabbit IL-1Ra. Co-administration of the two inhibitors enhanced inhibition of neutrophil infiltration to 88%, and protein leakage to 64%. We conclude that TNF alpha and IL-1 beta are the principal mediators of LPS-induced uveitis. Our observations also suggest that endogenous IL-1Ra may down-regulate inflammatory reactions.
authors.affiliation: Department of Pathology, Kumamoto University School of Medicine, Japan.
authors.forename: J S
authors.initials: JS
authors.lastname: Mo
authors.forename: A
authors.initials: A
authors.lastname: Matsukawa
authors.forename: S
authors.initials: S
authors.lastname: Ohkawara
authors.forename: M
authors.initials: M
authors.lastname: Yoshinaga
mesh_terms: D000818:Animals; D015536:Down-Regulation; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D007150:Immunohistochemistry; D007375:Interleukin-1 / Q000378:metabolism / Q000633:toxicity*; D007962:Leukocytes / Q000378:metabolism; D008070:Lipopolysaccharides / Q000633:toxicity*; D008212:Lymphocyte Depletion; D009000:Monocytes / Q000378:metabolism; D009504:Neutrophils / Q000378:metabolism; D011817:Rabbits; D017472:Receptors, Interleukin-1 / Q000037:antagonists & inhibitors*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism / Q000633:toxicity*; D014605:Uveitis / Q000139:chemically induced* / Q000378:metabolism
chemical_list: D007375:Interleukin-1; D008070:Lipopolysaccharides; D017472:Receptors, Interleukin-1; D014409:Tumor Necrosis Factor-alpha