2415 Tenascin and wound healing in the human cornea

Purpose: Tenascin is an extracellular matrix glycoprotein which is expressed transiently in wound healing in human skin and animal corneas. In virro and ednbryological studies suggest that tenascin mediates cell adhesion/anti-adhesion, enhancunen~mlubltion of cell proliiation, and promotion of cell migration. At present there are no published data regarding human comeal wound healing, therefore we have examined tenascin expression in corneas of histopathology specimens obtained because of previous trauma. Method: 6um sections were cut from globes with perforating comeal injury (20). blunt corncal h-jury (5) and 5 penetrating keratoplasty specimens in which there had been previous surgery Cases were selected to encompass a range of time intervals between injury and removal (range <24 hours to 90 years). 10 globes enucleated for choroidal melanoma provided normal corneas. Tenascin was demonstrated with a monoclonal antibody specific for human tenascin @alto TN2). revealed by an avidin-biotin peroxidase complex (ABC) technique. Results: Strong TN2 immunopositivity was observed in regions of active inflammation, fibroblastic activity and vascularisation. Corneas from globes which had been mucleated within 7 days following injury were tenascin negative, while those which had mmained in situ for over 7 days were positive. However, no tenasin was detected in mature, avascular scar tissue, Normal corneas were tenascin negative. Condusien: These results indicate that there is a temporal sequence of tenascin expression in human comeal wound healing This, together with the expression oftenascin in areas of fibroblastic activity and vascularisation supports the view that tenascin is involved in human comeal wound healing processes.