CELLULAR FIBRONECTIN AND TENASCIN IN EXPERIMENTAL PERFORATING SCLERALWOUNDS WITH INCARCERATION OF THE VITREOUS

Background: Posterior perforating eye injury carries a high risk of vi sual loss due to the formation of intravireal and epiretinal scar tiss ue. Intraocular scar formation in patients with retinal detachment has been shown to be associated with elevated intravitreal FN levels. The extracellular matrix glycoproteins fibronectin (FN) and tenascin (TN) have been located in epiretinal scar membranes. As both FN and TN are also involved in healing of cutaneous and corneal wounds, we undertoo k to study their expression in rabbit perforating scleral wounds with vitreous incarceration. Methods: A perforating scleral wound was produ ced and sutured without removal of vitreous from the wound in 18 pigme nted rabbits. The rabbits were killed at various times (1 h to 21 days ) after the operation, and the indirect immunohistochemical method was used for demonstration of FN and TN. Monoclonal mouse hybridoma antib odies 52 DH1 and 100 EB2, recognizing the cellular form of FN (cFN) an d TN, respectively, were used. Results: During the first pest-operativ e week immunoreaction for glycoproteins, both the locally produced cFN and TN, were observed at the scar tissue containing the prolabed vitr eous and the adjacent sclera. Subsequently, the reaction gradually shi fted to the vitreal side of the wound, and 3 weeks after the operation it was almost completely restricted to a separated mass of vitreous b eneath the scar. Conclusion: The expression of cFN and TN in the scler al scar and vitreous is indicative of their local synthesis. The shift of the expression of those proteins to the vitreal side of the wound with time suggests that the scarring process in the vitreous is delaye d compared to the sclera.