Differential protein synthesis in steroid-treated ocular surface epithelium

Topical prednisolone and cortexolone, a known glucocorticoid receptor antagonist, differentially affected the synthesis of proteins in normal corneal epithelium and migrating conjunctival epithelium after complete corneal deepithelialization, as measured by 35S-methionine incorporation and SDS-PAGE (sodium dodecyl sulfate-polyacrylamide gel) electrophoresis. Application of either prednisolone or cortexolone to corneal epithelium resulted in similar protein synthesis patterns, each showing two new protein bands of about 15K and 32K. Cortexolone, but not prednisolone, initiated the appearance of several protein bands of different molecular weights in the migrating conjunctival epithelium, while treatment with prednisolone plus cortexolone resulted in a pattern of protein bands which resembled the saline-treated control. Crude extracts of prednisolone-treated migrating epithelium also enhanced the inhibition of phospholipase A2 activity, and this prednisolone-induced inhibition was reversed by cortexolone.