Abstract
Purpose: :
To investigate the roles of endogenous TGF beta-signaling in the migration of rabbit corneal endothelium. Effects of exogenous TGF beta and EGF on it were also studied.
Methods: :
An excised rabbit cornea with a scraping partial defect of the endothelial layer was placed in organ-culture. Effects of exogenous EGF or TGF beta1/2 or both on endothelial migration toward the defect was examined. Roles of endogenous TGF beta on endothelial migration were evaluated by using an ALK 5 inhibitor (SB431542). Effects of a JNK inhibitor, a p38MAP kinase inhibitor (SB203580) or a MAP kinase inhibitor (U0126) on such cell migration were also assayed.
Results: :
EGF group promoted corneal endothelium spreading compared with control group (p<0.05). Exogenous TGF beta1 and TGF beta2 did not have significant difference compared with control group. TGFbeta1 and TGF beta2 group reversed promotion of corneal endothelium spreading by exogenous EGF (p<0.05). U0126, SB203580 and SB431542 group inhibited corneal endothelium spreading compared with control group (p<0.05). SB203580 group inhibited corneal endothelium spreading more markedly as compared with U0126 group (p<0.05). JNK inhibitor group did not have significant effect on endothelium migration.
Conclusions: :
Exogenous TGF beta1/2 counteracts EGF-promotion of migration of corneal endothelial cells, but an endogenous TGF beta signal is essential to endothelium migration. p38 and MAP kinase are both involved in its migration.
Keywords: cornea: endothelium • wound healing • signal transduction