Abstract
Purpose: :
To mimic, in vitro, the different stages and events that take place during corneal stromal wound repair. Studying how each growth factor acts independently.
Methods: :
The effect of TGF-β, FGF-b and PDGF-BB on proliferation, migration, and differentiation was evaluated in human corneal keratocyte cultures. First, we tested different concentrations of each factor to obtain the optimal concentrations in the proliferation process. These tests were performed in cultures before and after making the wounds. Then, keratocytes were cultured in different media: Dulbecco's modified Eagle's medium (DMEM/F12) or DMEM/F12 supplemented with TGF-β, FGF-b, PDGF-BB (at the optimal concentrations previously obtained) or fetal bovine serum (FBS). Cultures were fixed after different time points and then we studied wound closure time, proliferation, migration and differentiation.
Results: :
The growth factors studied activated the keratocytes to proliferate, differentiate into myofibroblast or fibroblast, and migrate, similar to the in vivo keratocytes response to injury.At the beginning of the process, proliferation is led by FGF-b and PDGF-BB, and after several days, factors synthesized and released by the same cells (serum-free) induced this proliferation.Migration needs the action of several factors at the same time (FBS), although an important role is played by the PDGF-BB.The most important role in differentiation to the myofibroblast phenotype was due to TGF-β with expression of α-SMA. Addition of FGF-b or PDGF-BB induced differentiation to the fibroblast phenotype; however, the cells with PDGF-BB showed more spindle shaped morphology those treated with FGF-b.
Conclusions: :
The signaling factors chosen were involved in different events of wound repair; however, each factor has a dominant function.
Keywords: cornea: stroma and keratocytes • growth factors/growth factor receptors • wound healing