Effect of TIMP-1 and MMP in pterygium invasion

PURPOSE. The migration and invasion of tumor cells correlate with the interaction between MMP and TIMP. Therefore, the purpose of this study was to determine the role of MMP-9, MMP-10, and TIMPs in pterygium formation and progression. METHODS. MMP-9, MMP-10, and TIMP proteins were studied using immunohistochemistry on 82 pterygial specimens and 30 normal conjunctivas. Pterygium epithelial cells (PECs), cultured in a serum-free culture medium, and siRNA were used to knock down TIMP gene expression to understand the role of TIMP in pterygium invasion. RESULTS. Among the 82 pterygial samples, 29 specimens (35.4%) were positive for MMP-9 expression, 28 were positive for MMP-10 (34.1%), and 59 were positive for TIMP1 (72.0%). Staining for MMPs was limited to the cytoplasm of the epithelial layer. The TIMP staining was detected in the pterygium epithelium, fibroblasts and corneal epithelium. In the cell model, cell invasion and migration ability increased in TIMP knockdown PECs compared with the parental control. CONCLUSIONS. MMP-9 and MMP-10 may each play a role in pterygium formation, and TIMPs may contribute to pterygium invasion inhibition.