Immunofluorescent analysis of MMP-3 and MMP-10 protein localization in normal, diabetic, and keratoconus corneas. No specific staining is seen in normal and keratoconus (KC) corneas for both MMPs, as well as on sections of normal corneas incubated only with a secondary antibody (second AB, negative controls). Epithelial and keratocyte staining for MMP-10 (polyclonal antibody D248-6) is seen in non-DR diabetic corneas and it is significantly increased in DR corneas, especially in the epithelium. MMP-3 (monoclonal antibody 55-2A4) is only seen in stromal keratocytes in non-DR diabetic and especially, DR corneas. e, epithelium; s, stroma.