THERAPEUTIC INTERVENTION WITH CHICKEN EGG-WHITE OVOMACROGLOBULIN AND A NEW QUINOLONE ON EXPERIMENTAL PSEUDOMONAS KERATITIS

Background: Chicken egg white ovomacroglobulin (ovoM) is a potent protease inhibitor with broad-spectrum activity against various proteases. The combined effects of ovoM and the new quinolone, ofloxacin (OFLX) on experimental Pseudomonas aeruginosa keratitis were investigated. Methods: The in vitro inhibitory effects of ovoM on protease activity in culture fluid of clinically isolated P. aeruginosa and on activity of human neutrophil elastase and cathepsin G were assayed using azo-casein as substrate. Albino rabbits received intrastromal injection of the isolated Pseudomonas strain (1 x 10(5) colony-forming units). At 16 h after inoculation, three treatment groups - 0.1% ovoM alone, 0.3% OFLX alone, and a combination of both -and a non-treatment control group were tested. Results: Protease activity in the culture solution and human neutrophil elastase was inhibited by ovoM, whereas cathepsin G was not inhibited effectively. In vivo additive therapeutic effects of ovoM and OFLX were observed at 96 h (P < 0.05 compared with OFLX alone). Conclusion: The results indicate that inhibition of proteolytic activity with ovoM is useful in preventing stromal degradation in P. aeruginosa keratitis.