Abstract
Abstract: :
Purpose: SDF–1 is a chemotactic and angiogenic factor that has been proved to play a role in the recruitment of endothelial progenitor cells (EPCs) into ischemic tissues. We tested the hypothesis that SDF–1 induces pterygial vasculogenesis by acting as regulator of EPCs. Methods: To elucidate the angiogenic factors in the pterygial derived fibroblast and pterygial tissue, the mRNA expression of HIF, SDF, VEGF, VEGFR–1 and VEGFR–2 was examined by RT–PCR. Expressions of SDF–1 and VEGF were evaluated in normal conjunctival and pterygial fibroblast by immunocytochemistry and Western blotting. To investigate the effect of SDF–1 on EPCs migration activity, a migration assay was performed using a 24–well microchemotaxis chamber. EPCs apoptosis, induced by serum starvation, was also quantified to determine whether SDF–1 exerts a survival effect on EPCs by TUNEL staining. Results: Among the hypoxia related factors, the mRNA of SDF–1 and VEGF were expressed in pterygial cells and tissue. The higher protein expressions of SDF–1 and VEGF were detected in the pterygial fibroblast than the normal conjunctival fibroblast by immunohistochemistry and Western blotting. When the effect of SDF–1 on EPCs’ migration was examined, double chamber assay showed a dose–dependent EPCs migration at 10 and 100 ng/ml of SDF–1 (p<0.05). As a result of TUNEL staining, the number of apoptotic EPCs was significantly decreased by SDF–1 treatment. Conclusions: These findings indicate that SDF–1 possibly augments pterygial fibrovasculogenesis by acting as chemotactic factor in recruitment of EPCs