Abstract
Abstract: :
Purpose: Retransplantation of in vivo grown corneal epithelium after amniotic membrane (AM) transplantation with limbal autograft is a new modality with good results in treating severe corneal burn injuries to avoid late complications such as persistent epithelial defect, pseudopterygium, and corneal opacification. The aim of this study was to characterize and compare the ultrastructural changes occurring in in vivo cultivation of corneal epithelium on amniotic membrane at several different time points using electron microscope and immunohistochemical stain and to determine of optimal time for its retransplantation Methods: Corneal burn patients (n = 7) with corneal epithelial defect and severe limbal damage were selected. Initially, AM transplantation with limbal autograft was performed at the acute stage of corneal burn injury to reconstruct the damaged ocular surface. One to ten (mean interval; 4.43±2.88) months later, the central part of AM containing an in vivo grown corneal epithelium with keratocytes was excised and retransplanted at adjacent lesions such as persistent epithelial defect, pseudopterygium and corneal opacification. The excised corneal epithelium with AM were examined by light microscope and transmission electron microscope. Immunohistochemical staining of cytokeratin K3/K12 and collagen IV were used for differentiated corneal epithelium and basement membrane, respectively. Results: In electron microscopy, at 1st and 2nd month after in vivo expansion, the cultivated epithelium on AM showed an undifferentiated epithelium and an incomplete basement membrane. But, after 3rd month, the cultivated epithelium began to be differentiated multilayered epithelium with well developed hemidesmosome and basement membrane. These findings were further confirmed by immunohistochemical study, the cultivated corneal epithelium and newly formed basement membrane were stained with cytokeratin K3 and collagen IV respectively at 3rd month. Conclusions: At least 3 months is needed for normal proliferation and differentiation of in vivo cultivated corneal epithelium on AM. Therefore, the retransplantation of in vivo cultivated corneal epithelium must be considered in a useful way.
Keywords: cornea: epithelium • immunohistochemistry • microscopy: electron microscopy