Differences in Corneal Cytokine Levels with Surfactant-Induced Ocular Irritation in Rats

Abstract

Previously, we have characterized pathological differences in corneal injury caused by surfactants known to have differing irritation potentials. The purposes of this study were to determine if differences in corneal cytokine levels occur following surfactant-induced corneal injury, and if these differences might relate to extent of corneal injury. Ten μ1 of a slightly, moderately, or severely irritating surfactant was placed directly on the corneas of rats. After 15 min, the rats were sacrificed and the corneas were removed. Corneas were cultured for 1, 3, 5, or 24 h. Supernatants and corneal lysates were collected at these time points and levels of interleukin (IL)-1α, IL-1β IL-6, and tumor necrosis factor (TNF)α were determined using enzyme-linked immunoassays. For these time points but for separate sets of corneas, light microscopic examinations were performed. On microscopic examination, the slight irritant damaged the superficial epithelium, the moderate irritant principally damaged the epithelium and stroma, and the severe irritant damaged the epithelium, stroma, and endothelium. Differences in the levels of lysate and supernatant IL-loc and supernatant IL-1β and IL-6 were observed, but differences in the levels of TNFα were not detected. The