Gelatinase expression in ocular surface disorders.

PURPOSE

To determine the expression of gelatinase A [matrix metalloproteinase (MMP)-2] and gelatinase B (MMP-9) in ocular surface disorders, we carried out examinations of the eyes of patients with such disorders.

METHODS

The cases consisted of a normal group comprising three eyes as the control and a patient group comprising six eyes of patients with ocular surface disorders. These groups underwent the following examinations. (1) Gelatin zymography: Tear samples taken by using the Schirmer I test were eluted and analyzed by gelatin zymography. (2) Immunohistochemical study: By using the alkaline phosphate-anti-alkaline phosphatase or avidin-biotin complex method, corneal or conjunctival tissue was examined for the presence of MMP-2, MMP-9, and membrane type 1 (MT1)-MMP, which activates MMP-2. (3) Reverse transcription-polymerase chain reaction (RT-PCR): Total RNA was eluted from the specimens, and the expression patterns of MMP-2, MMP-9, and MT1-MMP mRNA were analyzed.

RESULTS

(1) Gelatin zymography: Only the proforms of MMP-2 and MMP-9 were detected in the normal group. Both active MMP-2 and active MMP-9 were detected in all studied cases in the patient group. (2) Immunohistochemical study: In the normal group, only MMP-2-positive cells were present in conjunctival epithelium. In the patient group, cells positive for MMP-2, MMP-9 and MT1-MMP were present in the epithelium of the conjunctiva or cornea except in one thermal burn case. (3) RT-PCR: In the normal group, only MMP-2 expression was observed. MMP-2, MMP-9, and MT1-MMP mRNA expression was observed in three cases in the patient group.

CONCLUSIONS

MMP-2, MMP-9, and MT1-MMP, which activates MMP-2, were expressed in the patients with various ocular surface disorders. In ocular surface disorders, therefore, the expression of gelatinases is upgraded.