Abstract
Purpose: :
The aim of this study is to study the implication of Schwann cells in the corneal wound healing after refractive surgery.
Methods: :
Corneal Schwann cell cultures were obtained from PRK operated Lothmann Brown adult hens 7 days post surgery. Parallelly, an in vitro pre-degenerated hen corneal model was performed. Briefly, corneas were removed from 5 hens, splited in 2x2 mm pieces and explanted for 7 days in DMEM supplemented with fetal bovine serum (10%) and Neuregulin as specific Schwann cell growth factor.Schwann cell-like phenotype, in cultures, was determined by immunocytochemical techniques using antibodies against S100 calcium binding protein, Glial fibrillary acidic protein (GFAP) and p75 neurotrophin receptor.Corneal tissue samples of PRK treated hens, were processed for immunofluorescence using antibodies against α smooth muscle actin (αSMA) and TGFβ RII.Equivalent samples were collected, embedded in Araldite resin and processed for Transmission Electronic Microscopy (TEM).
Results: :
After PRK, peripheral nerve terminals became mutilated and early start to regenerate sprouting from terminal stumps. Schwann cell-like cells appear in great number associated to new axonal sprouts with reactivity against S100, GFAP and p75NTR but not to αSMA and TGFβ RII (fibroblast markers)Cultures from the same corneal tissue show an increase in number of Schwann cell-like population immunolabeled with S100, GFAP and p75NTR antibodies.Cultures from in vitro pre-degenerated corneal pieces show similar results.TEM demonstrate the intimate relationship between Schwann cell-like cells and newly formed axons during the regeneration of the epithelium.
Conclusions: :
Schwann cell-like cells proliferate largely after corneal injury or PRK procedures helping axonal regrowth and guiding nerve sprouts to recolonize the epithelium.
Keywords: glia • cornea: stroma and keratocytes • differentiation