Abstract
Purpose:
The aim of this study was to demonstrate if the platelet derived growth factor-BB (PDGF-BB) treatment can accelerate the stromal wound repair without fibrosis development. Understanding the role played by the PDGF-BB in the corneal wound healing, will lead to improve the knowledge into tissue maintenance and the wound healing modulation. This will allow us to direct the cellular behavior and ultimately, make more effective treatments avoiding fibrosis development. This study shows the role of PDGF-BB in the stromal wound repair contrasting it with the transforming growth factor β1 (TGFβ1) treatment, as a well-known inductor of fibrosis.
Methods:
Human corneal fibroblasts (HCFs) were cultured in serum-free media alone (SFM) or with PDGF-BB or TGFβ1. After making a linear wound, closure time, proliferation, migration, differentiation and extracellular matrix (ECM) synthesis were analyzed from day 1 to 15 by immunocytochemistry, quantitative real-time polymerase chain reaction (RT-PCR) and Western blot.
Results:
In PDGF-BB-treated wounds the closure was significantly faster than in the other two groups (p<0.05). An early peak in proliferation was observed in this group. Differentiation to myofibroblasts was slow and gradual over the time. On the contrary, in TGFβ1-treated cells the differentiation was obvious from early times to the end of the study and the wound closure did not occur. HCFs treated with PDGF-BB appear like typical fibroblasts but showed more spindle shaped morphology than that observed in SFM treated cells.<br /> The mRNA expression of perlecan, syndecan-4 (SDC4), focal adhesion kinase (FAK), and α5β1 integrin (all of them present during the normal stromal wound healing in vivo) was significantly up-regulated in PDGF-BB (p<0.01). On the other hand, the mRNA expression of collagen type III (a scarring and fibrosis marker) was undetected. The levels of these proteins showed similar results.<br /> The localization of FAK, α5β1 and SDC4 in focal adhesions (FA) showed a totally different pattern among the groups demonstrating their importance in the migration process.
Conclusions:
The PDGF-BB treatment can accelerate the wound healing process by an increase in cell proliferation and migration, avoiding the excessive myofibroblast differentiation and synthesizing a repair ECM without fibrosis.