Figure 4. uPA activities in the conditioned media of cultured normal conjunctival and pterygium fibroblasts of various stages measured by casein zymography. Fibroblast cell lines were isolated from pterygia specimens at various stages. Normal fibroblast cell lines were isolated from normal conjunctival specimens. Cells were cultured in serum-free culture medium for 48 h. The conditioned medium was collected, and the activity of uPA was measured by casein zymography. The u-PA standard from ELISA kits by American Diagnostica was used as the positive control (PC) and buffer was loaded alone as the negative control (NC). A: uPA activity of medium from normal and pterygium fibroblasts was analyzed by casein zymography. B: Comparison of levels of uPA activity in conditioned media from normal and pterygium fibroblasts. Data are given as mean±SD *Significant difference (p<0.05) between the normal and pterygium fibroblasts. C: Levels of uPA activity in conditioned media of fibroblasts from various stages of pterygium. Data are given as mean±SD *Significant difference (p<0.05) compared with stage I. #Significant difference (p<0.05) compared with stage II.