Role of p38 Map Kinase Cascade in Conjunctival Wound Healing In Vitro

Abstract

Abstract: : Purpose:To examine the role of cell signaling by p38 mitogen-activated kinase (MAPK), one of the TGF ß-stimulated signals, in cell migration, proliferation and type I collagen production in cultured human subconjunctival fibroblasts. Methods: Subconjunctival fibroblasts were obtained by outgrowth of subconjunctival tissues excised during strabismus surgery with the informed consent from each patient. Effects of a p38MAPK inihibitor (SB202190) on type I collagen production and wound closure in monolayer cell sheet were examined in confluent cultures in the presence or absence of TGFß1 at 10 ng/ml. Concentrations of collagen type I peptide in both culture medium and cell lysate in conditions above mentioned were determined using enzyme immunoassay kits. Cell proiliferation was assayed by BrdU incorporation.Results: The p38 inhibitor reduced the production of type I collagen by the fibroblasts treated by exogenous TGFß1, but had no effect on that in untreated fibroblasts. Adding the p38 inhibitor reduced the ratio of in vitro wound closure, but did not affect with the cell proliferation.Conclusions: Signaling cascade through p38MAPK has an important role in up-regulation of type I collagen accelerated by exogenous TGFß1, but has a minimal effect on basal level collagen expression. P38MAPK has also an important role in migration of cultured subconjunctival fibroblasts. These data suggest an anti-fibrotic effect of a p38MAPK inhibitor in a specialized injured site with a minimal effect on uninjured ocular surface.

Keywords: wound healing • signal transduction • conjunctiva