Em. Raynor et al., AN ASSESSMENT OF COCHLEAR HAIR-CELL LOSS IN INSULIN-DEPENDENT DIABETES-MELLITUS DIABETIC AND NOISE-EXPOSED RATS, Archives of otolaryngology, head & neck surgery, 121(4), 1995, pp. 452-456
Objective: The purpose of this study was to investigate if insulin-dep
endent diabetes mellitus causes degenerative changes in the inner ear
and whether these changes are exacerbated by noise exposure. Methods:
Insulin-dependent diabetes mellitus was induced in male rats using str
eptozotocin (65 mg/kg of body weight, intravenously). Half the animals
were exposed to 95 dB of random noise for 12 hours per day over a per
iod of 6 months. The cochleae were removed, fixed, decalcified, dissec
ted, and the hair cells counted. Results: A significant loss of outer
hair cells was exhibited in both noise-exposed groups; however, althou
gh there was no significant difference between these two groups, the n
oise-exposed diabetic animals had significant loss in more turns than
did the noise-exposed control animals. The diabetic animals were not s
tatistically different from the control animals. Conclusion: These res
ults suggest that insulin-dependent diabetes mellitus may increase the
hair-cell loss caused by noise overstimulation.