Migration of Normal Corneal Epithelial Cells in Rats

Hann, Hoo Jae; Lee, Hee Lai

Abstract

In the stratified squamous epithelium, most of basal cells in the entire epithelium function as stem cells. But many researchers report that stem cells in the corneal epithelium are located exclusively in the limbus. We planned to investigate the morphological characteristics of migrating corneal epithelial cells by the electron microscopy. Sprague-Dawley rats at fullterm, postnatal day 5, 10, 15, and adult were used as experimental animals. The results are as follows. 1. Stratification of the corneal epithelium : The number of layers in the corneal epithelium was dramatically increased in the period between postnatal day 10 and 15. 2. Migration of the corneal epithelial cells : In the groups of postnatal day 10 and adult, wide intercellular spaces were noted. Especially in the adult, the limbal side of basal cells was being lifted from the Bowman's membrane and centripetal polarity of them are noted. According to the above results, the wide intercellular spaces at postnatal day 10 seems to be resulted from the migration of corneal epithelial cells for epithelial stratification. The centripetal polarity of limbal basal cells in adult rat suggests that only the limbal basal cells may function as stem cells in that period.