AIM: To detect and compare the levels of matrix metalloproteinases (MMPs) secreted by primary and recurrent human pterygium fibroblasts (HPFs). METHODS: Primary and recurrent HPFs as well as human conjunctival fibroblasts (HCF) were cultured in RPMI 1640 medium at the same conditions. The protein levels of MMP-1, MMP-3 and MMP-9 were determined by enzyme-linked immune sorbent assay (ELISA), respectively. RESULTS: 1) The protein level of MMP-1 in serum-free supernatant from cultured primary and recurrent HPFs was higher than that in normal HCFs (P <0.05); similarly, the protein level of MMP-1 in serum-free supernatant from cultured primary HPFs was higher than that in recurrent HCFs (P <0.05). 2) The protein level of MMP-3 in serum-free supernatant from cultured primary HPFs was higher than that in normal HCFs (P <0.05); meanwhile, the protein level of MMP-3 in serum-free supernatant from cultured recurrent HPFs was lower when compared with that in primary HPFs and normal HCFs (P <0.05). 3) MMP-9 was not detected in primary and recurrent HPFs in the conditioned medium. CONCLUSION: The protein levels of MMP-1 and MMP-3 in supernatant secreted by primary HPFs are different from recurrent HPFs. Different pathological mechanisms may exist between primary and recurrent pterygia.
