A Novel Model of Bacterially-Induced Acute Anterior Uveitis in Rats and the Lack of Effect from HLA-B27 Expression

Background: Humans with the major histocompatibility antigen B27 (HLA-B27) are especially at risk for developing rheumatic disorders such as ankylosing spondylitis and Reiter's syndrome. Acute anterior uveitis (AAU) often occurs in association with these diseases or in HLA B27 positive individuals without joint disease. Methods: We induced acute anterior uveitis in Lewis rats by a standard model, the intraperitoneal injection of 200 μg of Escherichia coli endotoxin. We also developed a novel model of uveitis secondary to gram-negative infection. Results: Transgenic rats that expressed a low copy number of the B27 gene did not differ statistically from litter mate controls in the intensity of anterior uveitis as judged by histology, enumeration of cells in aqueous humor, protein in aqueous humor, or slit lamp examination. The majority of rats exposed to live Salmonella enteritidis or Yersinia enterocolitica 0:3 using either an oral or intravenous route of infection developed anterior uveitis. In contrast to the disease induced by endotoxin that is most intense 24 hours after the endotoxin challenge, uveitis induced by live bacteria usually began 7 to 9 days after exposure to bacterial products, was more often unilateral, persisted for as long as 3 weeks, and was sometimes recurrent. The expression of HLA-B27 did not appear to influence the incidence or severity of uveitis in B27+ low copy heterozygous animals. Conclusion: This rat model of AAU should facilitate evaluation of bacterial antigenic component(s) involved in the pathogenesis of live gram-negative bacteria induced AAU.