Location of corneal epithelial stem cells under in vivo and in vitro conditions / 中国组织工程研究

ABSTRACT

BACKGROUND:There are two types of epithelial stem cells in the ocular surface tissuecorneal epithelial stem cells and conjunctival epithelial stem cells. The corneal epithelial stem cells play an important role in renewal of corneal epithelial cells and maintenance of corneal transparency. OBJECTIVE:To study the location of corneal epithelial stem cells using laser in vivo confocal microscopy and immunofluorescent staining. METHODS:Patients with unilateral limbal stem celldeficiency who went to Henan Eye Institute from September 2009 to September 2012 were enrol ed in this study. Bilateral eyes were scanned by laser in vivo confocal microscopy, and the healthy eye was imaged as a control. The central cornea and limbus were scanned and images were recorded for statistical analysis. The eye bal s were obtained from Henan Eye Bank, China. Central cornea and limbus were dissected and embedded in the OCT compound for frozen section and the proper thickness of the section was 5-7μm. Immunofluorescent staining was used to detect the expression of p63, ABCG2, K3 and Connexin 43 in the epithelial layers of central cornea and limbus. RESULTS AND CONCLUSION:Twenty-four patients diagnosed with unilateral limbal stem celldeficiency were recruited. Under confocal microscopy, in the affected eyes, the typical morphology of conjunctival epithelial cells and goblet cells was detected instead of corneal epithelial cells;in the limbus, a great amount of fiber scarring tissue was detected instead of Vogt palisade, rete pegs and pigment cells. Immunofluorescent staining showed the expression of p63, ABCG2 was mainly in the basal layer of limbal epithelium, especial y in the outer and middle parts, but the expression of p63 and ABCG2 was not detected in the epithelial celllayers of central cornea. K3 and Connexin43 were not expressed in suprabasal layers of limbal epithelium, but in central cornea, they were expressed highly in the whole epithelial celllayers. Laser in vivo confocal microscopy and immunofluorescent staining showed the corneal epithelial stem cells were located in the basal layer of outer and middle limbal epithelium, mainly in Vogt palisade and rete pegs.