Purpose: To investigate the expression of the active form of gelatinases (gelatinase A: matrix metalloproteinase-2 [MMP-2] and gelatinase B: matrix metalloproteinase-9 [MMP-9]) in ocular surface disorders, we determined the presence of the active form of these gelatinases in the tear fluid of patients with corneal ulcer or ocular burn.
Methods: The subjects consisted of the ulcer group comprising 13 eyes, the burn group comprising 6 eyes, and the normal group comprising 10 eyes. Tear samples were taken by the method of the Schirmer test I. The tears were eluted using extraction buffer containing 0.01 M phosphate buffer solution (pH 7.2), 1% Tween 20 and 1 M NaCl, and analyzed by gelatin zymography.
Results: Only the proforms of MMP-2, and MMP-9 were detected in the normal group and in uncomplicated herpetic keratitis or herpetic keratitis cases complicated by mixed infection in the ulcer group. Active MMP-9 was detected in mild corneal ulcer cases and mild ocular burn cases. Both active MMP-2 and active MMP-9 were detected in endogenous corneal ulcer cases and severe burn cases, including perforation cases.
Conclusions: Both active gelatinases were detected in tears of severe corneal ulcer or severe ocular burn cases. The active form of gelatinase expression may be related to the severity of ulceration.