The aim of this study was to evaluate the role of trans-resveratrol on Staphylococcus aureus-induced keratitis. Rabbit corneas (intact corneas, abraded corneas and abraded corneas exposed to inactivated S. aureus strains) were placed in an ex vivo culture model. The abraded corneas exposed to S. aureus were divided into two 1-h-treatment sub-groups: corneas treated with trans-resveratrol and corneas treated with vehicle. The tissues were examined by immunohistochemical analyses and quantitative real-time RT-PCR to determine whether resveratrol could reduce TLR2-mediated recognition of S. aureus on epithelial cells and, if so, whether this reduction repressed the expression of inflammatory cytokines. The results demonstrated that resveratrol treatment effectively downregulated cell surface TLR2 on cells stimulated by S. aureus and reduced the expression of interleukin-8 gene. In addition, the corneal culture model tested, which is simple and reproducible, could be an alternative to in vivo animal testing for the development of novel specific therapies.
Corneal inflammatory diseases are often associated to Staphylococcus aureus (limbitis, blepharo-conjunctivitis, superficial punctate keratopathy, staphylococcal marginal keratitis, and corneal abscesses). Except for corneal abscesses, S. aureus induced corneal inflammation seems to be related to host hypersensitivity rather than to a classical invasive infection. This new approach targeting the immune-modulation of the corneal epithelium seems to be an attractive alternative solution to conventional treatment consisting of corticosteroid drops.