Changes of cytochemical markers in the conjunctival and corneal epitheliumafter corneal debridement

1. The aim of this study was to determine the epithelial changes of the con junctiva and cornea up to 7 days after corneal debridement and the changes highlighted included (1) proliferation, (2) production of growth factor, (3 ) changes in calcium binding protein marker, (4) production of cytokine, an d (5) maturity of the regeneration corneal epithelium. 2. The cytochemical changes of the corneal and conjunctival epithelia of ra bbit were analyzed up to 7 days after debridement. 3. An increase in proliferating cell, nuclear antigen (PCNA) was observed i n the limbal epithelia 12 hr after lesion and reached a peak by 48 hr. 4. Some proliferating limbal cells also contained epidermal growth factor ( EGF) beginning 24 hr after injury. The early limbal cell proliferation and the EGF production and their persistence until 7 days after lesion were lik ely involved with the process of regeneration, 5. Other positive markers appeared after lesion included tumor necrosis fac tor (TNF alpha) and calcium binding proteins S100A and S100B, which appeare d mainly within the first 48 hr after lesion and then started to decline. T he short appearance and the relatively small quantity of TNF alpha indicate d that this cytokine was probably not very important in the repair process and its appearance might be related to the injury induced. The presence of S100A and S100B could be associated with both cell death after injury and t he proliferation of new epithelium. 6. The cornea epithelium was still immature 7 days after lesion in that it still contained cytokeratin. 7. In conclusion, the critical hours of peak c onjunctival and corneal changes after corneal debridement were in the first 2 days.