The Effect of A Polypeptide Factor Released by Polymorphonuclear Leukocytes (PMNs Factor)on Rabbit Corneal Epithelial Stem Cells

Choi, Si Hwan; Kim, Chang Sik

Abstract

In case of limbitis, cytokines secreted by PMNs might inhibit the function of corneal epithelial stem cells located at the limbal basal cell layer. The purpose of this study was to examine whether PMNs factor affected stem cells (SC). PMNs obtained from the peritoneal cavity of rabbits after 0.2% glycogen stimulation incubated in DMEM at 37 degrees C for 24 hours. PMNs factor was obtained from the medium using dialysis. The death or inhibition of growth of rabbit corneal epithelial cells (CE) by PMNs factor was studied in vitro. PMNs factor and PBS as a control were injected into the limbal region for clinical evaluation and histopathologic study. ID 50 of PMNs factor for cultured CE was equal to the amount of polypeptide produced by 1.29 x 0 (7) PMNs. Cultured rabbit CE shrank and began to die 24 hours after exposure to PMNs factor. Abnormal findings were observed 5 days and 8 months after injection of PMNs factor at the limbus by light and electron microscopy. Clouding, defect, and vascularization of CE were noted several months after injection of PMNs factor. PMNs in limbitis may damage corneal epithelial stem cells and cause epithelial instability of the cornea.