IMMUNOLOCALIZATION OF PROTOONCOGENE PRODUCTS IN KERATOCYTES AFTER EPITHELIAL ABLATION, ALKALI BURN AND PENETRATING INJURY OF THE CORNEA IN RATS

Background: We examined the immunolocalization of proto-oncogene produ cts, including c-Fos and c-Jun, in the rat cornea during epithelial an d stromal wound healing after simple epithelial ablation, penetrating injury or alkali burn. Methods: Eighty-four male Wistar rats were divi ded into three groups and subjected to treatments as follows: (a) abla tion of central corneal epithelium leaving basement membrane intact, ( b) alkali burn in the central cornea with 1 N NaOH and (c) penetrating injury at the central cornea. The affected eyes were then enucleated after various intervals of healing. The frozen sections were immunohis tochemically stained with the antibodies against proto-oncogene produc ts. Results: c-Fos- and c-Jun-immunoreactive cells were detected in th e epithelium around the epithelial defect from 60 to 120 min after the se treatments. The distribution of these cells were varied in these th ree types of injury. The immunoreactivities for these proteins were al so detected in keratocytes after epithelial ablation. In the corneas w ith alkali burn, the immunoreactivities were detected in the keratocyt es in the whole corneal stroma, and these immunoreactions were stronge r than those observed in simple epithelial ablation. In the corneas wi th penetrating injury, such immunoreaction was seen only in keratocyte s around the wound. Conclusion: These findings indicate that activator protein 1-mediated transcriptional activation for epithelial migratio n is initiated in the early phase after each injury, and that stromal keratocytes are also transcriptionally activated not only by alkali bu rn or penetrating injury but also by simple epithelial ablation in whi ch basement membrane was not affected.