TNF-alpha production in the cornea in response to Pseudomonas aeruginosa challenge

Pseudomonas aeruginosa can cause ulcerative bacterial keratitis or contact lens-induced acute red eye (CLARE) in humans. The present study used a mous e model of ocular infection and inflammation to examine the relationship be tween TNF-alpha and inflammation in the cornea in response to challenge wit h either a strain of P. aeruginosa causing keratitis or a GLARE strain. Con stitutive TNF-alpha mRNA was detected in the epithelium. mainly towards the periphery. After infection with the keratitis-inducing strain (6294), TNF- alpha expression was elevated four-fold by 24 h post-challenge. No detectab le induction of TNF-alpha mRNA was seen with GLARE strain (Paer1) challenge at any lime point. The TNF-alpha protein production detected by ELISA show ed a corresponding pattern to the mRNA expression, which also correlated wi th pathological changes. These results suggest that invasive strains of P. aeruginosa create greater pathological changes as a result of elevated TNF- alpha production, which contributes to inflammation during keratitis in viv o.