Changes of phagocytic capacity in basic fibroblast growth factor-transfected iris pigment epithelial cells in rats

Purpose. To evaluate differences of phagocytic capacities in rat retinal pigment epithelial (RPE) cells, iris pigment epithelial (IPE) cells, and basic fibroblast growth factor (bFGF) cDNA-transfected IPE (bFGF-IPE) cells in vitro. Methods. The RPE cells and IPE cells were isolated from adult Long Evans rats' eyes. The bFGF cDNA was transfected to the IPE using lipofection method. The bovine photoreceptor outer segments (POS) were isolated and labeled with Alexa 488 dye (fluorescent marker, EX: 494 nm, EM: 519 nm), and were applied to the cultured RPE, IPE, vector-IPE, and bFGF-IPE for 20 hours. The amount of phagocytosed POS in cells was photographed by fluorescence microscopy with fluorescein isothiocyanate (FITC) filter, and expressed as the ratio of the occupying area of fluorescence to the area of pigment epithelial cells in each observing field. Results. The phagocytic capacity of IPE and vector-IPE were about 70% of RPE, and that of bFGF-IPE increased to 150% of IPE. This increase was inhibited by pretreatment with anti-bFGF antibody to bFGF-IPE. Conclusions. IPE showed phagocytic capacity, but it reached only 70% of that in RPE. The stable expression of bFGF promoted its function.