EFFECTS OF BASIC FGF AND TGF(BETA-1) ON F-ACTIN AND ZO-1 ORGANIZATIONDURING CAT ENDOTHELIAL WOUND-HEALING

Previous studies suggest the existence of two separate and distinct me chanisms of endothelial wound healing (i.e., cell migration and cell s preading), which may be controlled by unique, injury-dependent, wound- related factors. The purpose of our study was to evaluate potential bi ologic mediators regulating healing of the growth arrested cat endothe lium by using an ex vivo, organ culture model. Three buttons were punc hed from each cornea of 11 cats with a 6-mm trephine. A 1- to 2-mm dia meter endothelial scrape injury (SI) was made, and buttons were cultur ed in (a) serum-free media (SFM), (b) serum plus media (20% fetal calf serum), (c) SFM plus basic fibroblast growth factor (bFGF), (d) SFM p lus bFGF and heparin, (e) SFM plus transforming growth factor-beta 1 ( TGF(beta 1)), or (f) SFM plus TGF(beta 1) and anti-TGF(beta 1). At var ious times from 8-48 h after injury, buttons were stained with phalloi din and anti-ZO-1, and imaged by using laser scanning confocal microsc opy. Evaluation of SI in cat corneal buttons under serum-free conditio ns showed maintenance of normal endothelial differentiation, indicatin g that the organ-culture SI model mimics in vivo SI. Addition of TGF(b eta 1) produced a dramatic reorganization of apical F-actin and develo pment of stress fibers, as well as the loss of normal cell border-asso ciated ZO-1 distribution. The effects of TGF(beta 1) were blocked by t he neutralizing antibodies to TGF(beta 1). Addition of serum or bFGF p roduced much less pronounced changes in F-actin and ZO-1 distribution. These results suggest that TGF(beta 1) may play a critical role in mo dulating the wound-healing response of the corneal endothelium.