Cholesterol-ester of epithelial cell lines derived from the epithelium of tympanic membrane and external auditory canal

Abstract

We established epithelial cell lines derived from epithelium of Pars flaccida, Pars tensa, and external auditory canal of rabbits of 2 months. The cell lines have following characters; 1. They are grown in growth medium. 2. If they are inhibited of proliferation by contact inhibition, a number of fatty droplets, appear in the cytoplasm. 3. Those fatty droplets disappear when inoculated, while they are enhanced by an addition of insulin (10u/ml) into the growth medium.
We elucidated the types of lipid droplets by using Iatroscan TH-10. And concerning the mechanism of production of lipid droplets, we collected the low density lipoprotein (LDL) from the plasma of rabbits and cultured these cells in the medium containing LDL.
Results; 1. The lipid droplet in the cell was cholesterol-ester. 2. The lipid droplet of cytoplasm disappeared when the cells were cultured in the medium containing LDL. We considered that the epithelial cell lines established continues to have the system synthesizing cholesterol.