[Rat hearing loss and hearing organs mitochondrial DNA4834 deletions associated with hypercholesteremia].
OBJECTIVE
To determine whether or not the rat hypercholesteremia contributes to hearing organs mtDNA4834 deletion and involves in the development of hearing loss.


METHODS
The rat hypercholesteremia model (n = 38) was established by feeding with high cholesterol diet and the control group (n = 22) with common diet for 6 months. The rats were tested for auditory sensitivity using auditory brainstem response (ABR). Twenty-one left cochleae and 27 left cochlear nuclei from experimental group and 10 left cochleae and 13 left cochlear nuclei from control group were harvested. The total DNA of them was extracted. mtDNA was amplified by nest PCR to examine the presence of mtDNA4834 deletion.


RESULTS
Our result showed: (1) There is a significant increase in serum cholesterol level and ABR threshold in the experimental group. (2) The mitochondrially-encoded tRNA and ND1 segments were amplified from all samples, as well as mtDNA4834 deletions. (3) The incidence of mtDNA4834 deletions in hearing organs of hypercholesteremia rats was significantly higher than that of the control group (P < 0.05).


CONCLUSIONS
Extended hypercholesteremia can induce hearing loss, and mtDNA4834 deletion in hearing organs may be one of the pathogenic mechanisms.
Zhao
H
H
Department of Otorhinolaryngology Head and Neck Surgery, General Hospital of PLA, Beijing 100853, China.
Huang
D
D
Han
D
D
Han
W
W
Dai
P
P
D000818:Animals; D004272:DNA, Mitochondrial / Q000235:genetics*; D016057:Evoked Potentials, Auditory, Brain Stem; D006312:Hearing Loss, Bilateral / Q000209:etiology / Q000235:genetics*; D006937:Hypercholesterolemia / Q000235:genetics*; D066298:In Vitro Techniques; D051381:Rats; D017208:Rats, Wistar; D017384:Sequence Deletion
D004272:DNA, Mitochondrial