PURPOSE. To characterize phenotypic differences between anterior and posterior corneal keratocytes after stimulation with the profibrotic agent transforming growth factor-beta1 (TGF-1) in vitro. METHODS. Sixteen corneas from healthy felines were obtained immediately after death. Lamellar dissection was performed to separate the anterior and posterior stroma at approximately 50% depth either manually (n ϭ 2) or with a Moria microkeratome (300-m head; n ϭ 14). Cells from the anterior and posterior stroma were cultured separately but under identical conditions. Using immunohistochemistry and Western blot techniques, Ki-67 staining and relative expression of Thy-1, alpha smooth muscle actin (␣-SMA), and fibronectin were assessed after stimulation with different TGF-1 concentrations. In addition, anterior and posterior cells cultured in different concentrations of TGF-1 were wounded with a razor blade, and the wound area and time to closure were determined. RESULTS. Stimulation by all concentrations of TGF-1 increased the proportion of Ki-67-positive cells in anterior and posterior cell cultures, but this increase was noted earlier in posterior cells than in anterior cells. Increasing TGF-1 concentration also increased the relative expression of Thy-1, ␣-SMA, and fibronectin in anterior and posterior fibroblasts. However, anterior cells expressed these fibrotic markers at lower TGF-1 concentrations than did posterior keratocytes. After mechanical wounding, posterior cells closed the wound area faster than did anterior cells at all concentrations of TGF-1. CONCLUSIONS. The present experiments show that anterior and posterior corneal keratocytes exhibit different sensitivities to the profibrotic growth factor TGF-1. This heterogeneity of keratocyte response may impact wound closure after mechanical wounding. (Invest Ophthalmol Vis Sci
