PDGF-BB Induces Proliferation, Migration and Fibrinolytic Activity of Cultured Bovine Hyalocytes

Abstract

Abstract: : Purpose: To investigate the effect of PDGF-BB on the proliferation, migration and fibrinolytic activity of cultured bovine hyalocytes. Methods: The expression of PDGF receptor α/ß and its phosphorylation in response to PDGF-BB was analyzed by western blotting. PDGF-BB-induced proliferation and migration were evaluated by thymidine uptake and Boyden’s chemotaxis assay, respectively. The fibrinolytic activity of the hyalocytes was assessed by zymography using total cell lysates. To clarify the intracellular signaling, the hyalocytes were preincubated with PD98059 (a MAPK kinase inhibitor) or wortmannin (a PI3-kinase inhibitor) before stimulation. Results: The hyalocytes expressed PDGF receptor α and ß, both of which were immediately phosphorylated in response to PDGF-BB. PDGF-BB induced thymidine uptake and migration of the hyalocytes in a concentration (0-10 ng/ml)-dependent manner. Although the thymidine uptake was almost completely inhibited by PD98059, the migration was not affected by PD98059. Conversely, wortmannin showed no apparent effect on the thymidine uptake, but significantly inhibited PDGF-BB-induced hyalocytes’ migration (70.0%, p<0.01). Total cell lysate of hyalocytes lysed fibrin plate, and the fibrinolytic activity was intensified by PDGF-BB. This intensification was blocked by PD98059 treatment in part. Conclusions: PDGF-BB induces proliferation and migration of the hyalocytes through the different intracellular signaling pathway. The hyalocytes seem to participate in the fibrinolysis in the PDGF-rich condition such as vitreous hemorrhage.

Keywords: vitreous • proliferation