TGF-BETA-2 INCREASES ALPHA-SMOOTH MUSCLE ACTIN EXPRESSION IN BOVINE RETINAL-PIGMENT EPITHELIAL-CELLS

Purpose. To examine whether transforming growth factor-beta 2 (TGF-bet a 2) induces the expression of alpha-smooth muscle actin (SMA), a bioc hemical marker of myofibroblasts, in cultured bovine retinal pigment e pithelial (RPE) cells. Methods. Bovine RPE cells were cultured in F-12 nutrient mixture supplemented with 5% fetal bovine serum (FBS), with or without TGF-beta 2 (0.01-10 ng/ml) for 6 days. During this culture period, cells did not reach a confluence. Alpha-SMA was detected immun ocytochemically with a mouse monoclonal antibody, and the ratio of the number of alpha-SMA positive cells to the total number of cells was c alculated. Results. About 10% of the cells in control cultures with on ly FBS were positive for alpha-SMA. TGF-beta 2 increased the ratio of positive cells dose-dependently (p < 0.0001), while a neutralizing ant ibody against TGF-beta 2 blocked this effect. Conclusions. TGF-beta 2 induced expression of alpha-SMA in bovine RPE cells.