Purpose: To determine whether the cornea contains and expresses, at the gene level, the major plasmin inhibitor alpha2-antiplasmin.
Methods: Corneal sections were immunostained for alpha2-antiplasmin. Extracts of human corneal stroma, epithelium, and endothelium were subjected to immunodot blot and Western blot analysis. Total RNA and alpha2-antiplasmin specific primers were used for RT-PCR. The cDNA was sequenced.
Results: Alpha2-antiplasmin was observed in all three corneal layers by immunolocalization and Western blots. The major alpha2-antiplasmin form observed in most extracts was the 70-kDa form. Total alpha2-antiplasmin was present at 0.119 +/- 0.014 microg/epithelium (n = 10) and 1.45 +/- 0.47 microg/stroma (n = 10). Alpha2-antiplasmin mRNA was detected in epithelial and stromal extracts and cultured human corneal stromal cells. The sequences of the PCR products were identical to that for human alpha2-antiplasmin.
Conclusions: Alpha2-antiplasmin and its mRNA are present in the cornea and may serve to regulate corneal plasmin activity.