Purchase this article with an account.
J.–C. Jung, M.–I. Huh, K.–C. Kim, E.–J. Lee, S.–S. Kang; Concert Function of Transforming Growth Factor–Betas as Well as Spatial Activation of Smad2 and p38MAPK Involving in Corneal Fibrosis . Invest. Ophthalmol. Vis. Sci. 2006;47(13):5037.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Chick cornea has a very similar structure and composition to that of human cornea. The goal of this study was to analyze the presence and distribution of three TGF–ß isoforms, and to investigate TGF–ß–mediated signaling pathways controlling fibrotic wound repair in chick model system.
A 1–mm full–thickness button of central corneas was ablated, and corneal wounds were allowed to heal for 2 weeks. Indirect immunohistochemistry for TGF–ß1, –2, and –3, pSmad2, p38MAPK, and α–smooth muscle actin (α–SMA) was performed on paraffin–embedded healing corneas at various times after penetrating wound.
In normal corneas, all TGF–ßs, and pSmad2 and p38MAPK were weakly detected in the Bowman’s membrane or occasional basal epithelial cells. In healing corneas after penetrating wound, TGF–ß1 was mainly deposited in the fibrin clot, but was not detected in the stromal cells. Interestingly, strong TGF–ß2 signal was detected in the healing epithelial and endothelial cells, and also numerous active fibroblasts/myofibroblasts. On the other hand, strong TGF–ß3 signal was detected temporally and spatially in the basal epithelial cells, but not detected at all in the stromal and endothelial cells. Myofibroblasts were first appeared in the wound edge just underneath of repairing epithelium and posterior region of wound stroma at day 3, and numerous myofibroblasts populated in the entire repairing stroma by day 7. However, myofibroblasts was populated in the anterior and posterior repairing stroma by day 14. In extensively fibrotic healing stroma, both p38MAPK and α–SMA staining was similarly detected in the numerous stromal cells. Although strong pSmad2 staining was detected in the active fibroblasts at wound region, its staining pattern was not closely related with α–SMA staining. However, we found that α–SMA staining pattern was very similar to that of TGF–ß2 and p38MAPK.
All TGF–ßs have a distinct and specific distribution in the chick corneas during fibrotic wound healing. The present study suggests that initially deposited TGF–ß1 in the fibrin clot is an important factor for an initial cell migration, and subsequent fibrotic response regulated by TGF–ß2 is mediated by concerted action of pSmad2 and p38MAPK.
This PDF is available to Subscribers Only