Non-insulin-dependent diabetic microangiopathy in the inner ear.
Hearing loss has long been associated with diabetes mellitus. Microangiopathy, associated with thickening of the basement membranes of small vessels, has been implicated as a major source of multiple system organ disease.


OBJECTIVE
This study was designed to evaluate changes in basement membrane thickness in the inner ear of laboratory animals suffering from non-insulin-dependent diabetes mellitus (NIDDM) with, and without, exposure to moderate intensity noise exposure in an attempt to extrapolate the same disease process in humans.


METHODS
Spontaneously hypertensive-corpulent non-insulin-dependent rats (SHR/N-cp) were selected as a genetic model for the above study. Both lean and obese rats were used in this study. A genetically similar control group of animals (LA/N-cp) were used as controls. These animals express both the lean and obese phenotypes, but they lack the NIDDM gene. Forty-eight animals in each group were sacrificed at the end of the study. The cochleas were dissected and fixed. The basement membrane of the stria vascularis was examined using transmission electron microscopy.


METHODS
This study was a laboratory-based, standard animal study.


RESULTS
This study was designed to show microangiography of the inner ear as related to NIDDM with, and without, obesity and noise exposure.


CONCLUSIONS
NIDDM alone does not cause statistically significant basement membrane thickening; however, NIDDM in combination with obesity and/or noise exposure did show significant thickening and the combination of all three showed the greatest thickening. NIDDM appeared to be the greatest contributing factor.
McQueen
C T
CT
Division of Otolaryngology/Head and Neck Surgery, University of North Carolina School of Medicine, Chapel Hill, USA.
Baxter
A
A
Smith
T L
TL
Raynor
E
E
Yoon
S M
SM
Prazma
J
J
Pillsbury
H C
HC
D000818:Animals; D001485:Basement Membrane / Q000648:ultrastructure; D003051:Cochlea / Q000648:ultrastructure*; D015834:Cochlear Diseases / Q000209:etiology* / Q000473:pathology; D003924:Diabetes Mellitus, Type 2 / Q000150:complications* / Q000473:pathology; D003925:Diabetic Angiopathies / Q000150:complications* / Q000473:pathology; D008833:Microcirculation; D008854:Microscopy, Electron; D009622:Noise / Q000009:adverse effects; D009765:Obesity / Q000150:complications / Q000473:pathology; D051381:Rats; D011918:Rats, Inbred SHR