The Effects of All-trans-retinoic Acid on the Proliferation of Cultured Keratinocytes from External Ear and Cholesteatoma

Bang, Jin Hyun; Yoon, Tae Hyun

Abstract

BACKGROUND AND OBJECTIVES: Cholesteatoma is a disease of the temporal bone, affecting the squamous epithelium and invading into the middle ear cavity. Retinoic acid (RA) is known to inhibit or accelerate the proliferation of normal keratinocytes depending on its concentration. This study was aimed at investigating the effects of different concentrations of RA on the proliferation of cultured keratinocytes from the external ear and cholesteatoma and whether the effect is different according to the origin of tissue.
MATERIALS AND METHODS
Patients undergoing tympanomastoid surgery for cholesteatoma were selected, and cholesteatoma matrix and skin were obtained from their middle ears and external ears, respectively. After culturing keratinocytes from the external ear and cholesteatoma, cells were cultured for 7 days in the medium 154 (Cascade, USA), and 10(-6)M RA or 10(-7)M RA was added twice every three days. The control group was cultured without the addition of RA. The absorbance was estimated at 490 using CellTiter 96(TM)AQ(ueous) Non-Radioactive Cell Proliferation Assay, nm and the survival fraction was calculated and compared with the control group.
RESULTS
Proliferation of keratinocytes from the external ear and cholesteatoma was inhibited when the concentration of RA was 10-6 M and accelerated when the concentration of RA was 10(-7)M. The accelerated effect of retinoic acid on the proliferation of keratinocyte seems to be less prominent in the cholesteatoma tissue than in the skin of normal ear canal.
CONCLUSION
Retinoic acid can inhibit or accelerate the proliferation of cholesteatoma keratinocytes dependining on its concentration.