Gerbilline cholesteatoma development Part III. Increased proliferation index of basal keratinocytes of the tympanic membrane and external ear canal.
OBJECTIVE
To quantify the rate of basal cell division for keratinizing epithelium (KE) of the tympanic membrane (TM) and external ear canal (EAC) in spontaneous and induced gerbilline cholesteatomas.


METHODS
Cholesteatomas (3 spontaneous and 5 by induction) were labeled with tritiated thymidine for autoradiography and a KE proliferation index (PI) was determined. The PI was defined as the average number of labeled cells/mm overall and per anatomic region.


RESULTS
For all regions combined, the PI was 27.3 in ears with cholesteatoma and 4.1 in normal ears (P < 0.0001). Additionally, there were significant regional differences in the PI in both normal ears and ears with cholesteatoma.


CONCLUSIONS
The KE of cholesteatomas in gerbils proliferates at approximately 7 times the rate measured in control ears.


CONCLUSIONS
Hyperproliferation of keratinocytes is a causative factor in the development and progression of spontaneous and experimental cholesteatomas in gerbils.
Tinling
Steven P
SP
Department of Otolaryngology-Head and Neck Surgery, School of Medicine, University of California-Davis, Otolaryngology Research Laboratory, 1515 Newton Court, Davis, CA 95616, USA. sptinling@ucdavis.edu
Chole
Richard A
RA
D000818:Animals; D001345:Autoradiography; D049109:Cell Proliferation; D002781:Cholesteatoma / Q000473:pathology* / Q000662:veterinary; D004195:Disease Models, Animal; D018450:Disease Progression; D004424:Ear Canal / Q000473:pathology*; D004427:Ear Diseases / Q000473:pathology* / Q000662:veterinary; D005500:Follow-Up Studies; D005849:Gerbillinae; D015603:Keratinocytes / Q000473:pathology*; D008297:Male; D051381:Rats; D014432:Tympanic Membrane / Q000473:pathology*