| Budget Amount *help |
¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 1996: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1995: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Research Abstract |
Purpose : Pseudomonal keratitis often results in severe corneal ulcer and perforation with poor visual prognosis. The corneal lesions could be attributable to proteolytic enzymes including MMP released in the corneas during the infection. However, little is known about the role and behavior of MMP in pseudomonal keratitis. Therefore, we investigated the effects of pseudomonal virulence factors on the cultured keratocyte with emphasis on MMP release. Methods : After rabbit keratocytes reached to confluent growth in PRMI-1640 containing 1o% FCS,the medium was changed to RPMI-1640 without FCS containing one of the following pseudomonal virulence factors : elastase (100,30,10,3 ng/ml), alkaline protease (100,30,10,3 ng/ml), exotoxin A (10,3,1,0.3 mg/ml) and LPS (30,10,3,1 mg/ml). At 48 hours, the culture media were harvested and processed for gelatin and casein zymography to analyze proteolytic enzymes (MMP). Morphologic changes of keratocytes under these conditions were also investigated. Results : Gelatinase A (MMP-2) was detected slightly in the control medium. Pseudomonal elastase enhanced remarkably the release of both MMP-2 and MMP-9 from the keratocytes. The activated forms of these MMPs were also observed. Alkaline protease showed a similar effect but did not activate any MMPs. Similar enhancements were observed also with LPS and to a lesser extent with exotoxin A.Conclusions : From the results that pseudomonal virulence factors enhanced the release of MMP from keratocytes, it is reasonable to conclude that corneal MMP might also contribute to ulceration in pseudomonal keratitis.
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