Cochlear lateral wall changes secondary to hypercholesterolemia and noise exposure in the chinchilla model

Abstract

Objective: To investigate the effects of hypercholesterolemia on the cochlear lateral wall structures in chinchillas and its impact on the susceptibility of the inner ear structures to noise exposure. Materials and Methods: Fifteen chinchilla temporal bones were selected from the Animal Temporal Bone Collection of the Paparella Otopathology and Pathogenesis Laboratory at the University of Minnesota. The experimental group was subjected to 3-month 1% cholesterol diet, while the control group maintained a standard diet. After 3 months, the experimental group's left ears exposed to noise trauma for 10 minutes while right ears did not. One month later the animals were euthanized, and the temporal bones harvested from the animals underwent histopathological examination with morphometric assessments of stria vascularis (SV) and spiral ligament (SL). Results: Histopathological analysis revealed no significant differences (p > 0.05) in total SL area across cochlear turns between the experimental and control groups. However, distinct variations were observed in SV area within the lower basal (p<0.01) and upper basal (p = 0.01) turns of the hypercholesterolemia and noise-exposed group compared to the control group. Conclusion: Hypercholesterolemia is one of the conditions that may contribute to sensorineural hearing loss. This study highlights its importance in auditory health by revealing the relationship between hypercholesterolemia and cochlear lateral wall structures, and increased susceptibility to noise-induced damage.

Keywords

• hypercholesterolemia
• noise exposure
• cochlear lateral wall
• chinchilla

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