Objective To improve the isolation and culture techniques of rat retinal pigment epithelial(RPE) cells and investigate the expression of matrix metalloproteinases(MMPs) in the cultured RPE cells.Methods The brown Norway(BN) rat RPE cells were isolated by a modified three-step enzyme digestion.The growth curves of the RPE cells of different passages were measured.The expression of marker protein CRALBP and cytokeratin,and MMPs in the RPE cells of different passages were observed by immunofluorescence microsc...