CHARACTERIZATION OF ARACHIDONIC-ACID METABOLISM AND THE POLYMORPHONUCLEAR LEUKOCYTE RESPONSE IN MICE INFECTED INTRACORNEALLY WITH PSEUDOMONAS-AERUGINOSA

Purpose. To examine the activity of myeloperoxidase (MPO) and the conc entrations of the proinflammatory metabolites of arachidonic acid (AA) in ocular tissue of mice that are either capable or incapable of rest oring corneal clarity during an intraocular Pseudomonas aeruginosa inf ection. Methods. For a period of 11 days after infection, whole eyes w ere enucleated and homogenized in buffer from mice given only an initi al infection as well as from mice given a subsequent infection in the previously uninfected eye either 4 or 8 weeks after the initial infect ion. Tissue-free supernatants from the ocular homogenates were used fo r the determination of MPO activity by quantitating the conversion of specific substrate by spectrophotometric methods and for the quantitat ion of AA metabolites by ELISA. Results. Overall, animals reinfected a t 4 and 8 weeks had a lower inflammatory response when compared to the mice given only the initial infection. The lowest levels of LTB(4) an d MPO activity, indicators of PMN involvement, were observed in the th e 8-week reinfected mice, which restored corneal clarity in an enhance d manner. Conclusions. These results suggest that induced ocular PMN r esponses may play a role, in part, in the inflammatory response leadin g to the tissue destruction observed during ocular P. aeruginosa infec tion.