Abstract
Purpose: :
To examine the status of phosphorylation of Smad2/3 in lens epithelial cells (LECs) in tissues of human post-operative capsular opacification (PCO). Smad2/3 can be phosphorylated in middle linker and C-terminal regions.
Methods: :
Seventeen specimens of PCO were examined with an informed consent from each patient. Four anterior capsules with lens epithelium that had been obtained during cataract surgery and one crystalline lens that had been extracted served as control. PCO samples were extracted from patients at day 6 to 10 years post-cataract/intraocular lens surgery. Paraffin sections of the specimens were immunostained for total Smad3, C-terminally phophorylated Smad2 (pSmad2C) and Smad2 with middle linker phosphorylation (pSmad2L). Peroxidase-conjugated antibody reaction and diaminobenzidine color reaction were performed.
Results: :
LECs in control specimens lacked nuclear staining of Smad. Smad2C was overall detected in cell nuclei of LECs in both Sommerrring’s ring of regenerated lenticular structure and in fibrous tissues of post-operative specimens. Smad2L was detected in elongated lens cells post-epithelial-mesenchymal transition (EMT), but not epithelial-shaped LECs adjacent to regenerated lens fibers.
Conclusions: :
Smad2/3 was phosphorylated in C-terminal or middle linker region in LECs post-cataract surgery. Phosphorylation in the C-terminal region might be related to regeneration of lenticular structure and that in the middle linker region to EMT.
Keywords: immunohistochemistry • signal transduction • EMT (epithelial mesenchymal transition)