Growth factors in cultured pterygium fibroblasts: Immunohistochemical and ELISA analysis

Background: In order to study growth factors in the pathogenesis and recurrence of pterygium, we grew pterygium tissues in culture and compared fibroblasts from primary and from recurrent pterygia with reference to the fibroangiogenic growth factors basic fibroblast growth factor (b-FGF), platelet-derived growth factor (PDGF), transforming growth factor beta (TGF-beta) and tumor necrosis factor alpha (TNF-alpha). Methods: We used indirect immunohistochemical procedures against human b-FGF, PDGF, TGF-beta and TNF-alpha. As controls, we used cultured normal human conjunctival fibroblasts. A serum-free conditioned medium (CM) from confluent fibroblasts derived from primary and recurrent explants was assessed by enzyme-linlied immunosorbent assay to determine the level of the above-mentioned growth factors. Results: Immunoreactivity of b-FGF was stronger in recurrent than in primary pterygium fibroblasts. PDGF immunolabeling was stronger in primary than in recurrent pterygium fibroblasts. TGF-beta and TNF-alpha immunolabeling was weak in both pterygia. All these growth factors were very sparse in normal conjunctival fibroblasts. Basic-FGF and TGF-beta(1) were found in the CM from both primary and recurrent pterygium, while PDGF and TNF-alpha were not detectable. Conclusion: The strong immunoreactivity and the release of b-FGF in cultured fibroblasts of recurrent pterygia suggest that fibroblasts may play an important role in the recurrence of pterygium.