[Mitochondrial DNA4568 deletions in guinea-pig associated with presbycusis].
OBJECTIVE
To determine weather or not the mtDNA(4568) deletions in guinea-pig contribute to the development of presbycusis.


METHODS
Forty-four guinea-pigs were divided into 2 groups: group A (young control group, normal hearing, 22 guineas) and group B (aged group). The group B was subdivided into group B(1) (old normal hearing, 6 guineas) and group B(2) (old hearing loss, 16 guineas). First the guineas were tested by auditory brainstem response (ABR), and then the Cortis's tissues, auditory nerve tissues, brain and blood were harvested and the total DNA was extracted. The mtDNA(4568) deletion was analyzed by PCR.


RESULTS
Hearing loss was occurred with age. The mtDNA(4568) deletion incidence of aged group in all tissues was significant higher than that of young control group (P< 0.05). The incidence of mtDNA deletion in Cortis's and auditory nerve with presbycusis (B(2) group) were significant higher than that of aged normal hearing group (B(1) group) (P< 0.05). The incidence of mtDNA deletion in brain and blood was not significantly different between presbycusis and aged normal hearing group (P> 0.05).


CONCLUSIONS
mtDNA(4568) deletion of guinea-pig possibly contributes to aging and mtDNA(4568) deletion in Cortis's and auditory nerve tissues of guinea-pig may be associated with presbycusis. There is no enough evidence to prove that the mtDNA(4568) deletions in brain and blood are related with presbycusis.
Wei
Xue-mei
XM
Department of Otorhinolaryngology, Chengdu 363rd Hospital, Chengdu, Sichuan, 610041, P. R. China. jennywxm@sohu.com
Yang
Yuan
Y
Liang
Chuang-yu
CY
Zheng
Zhong
Z
D000367:Age Factors; D000818:Animals; D001483:Base Sequence; D003056:Cochlear Nerve / Q000378:metabolism / Q000503:physiopathology; D004272:DNA, Mitochondrial / Q000235:genetics*; D016057:Evoked Potentials, Auditory, Brain Stem; D006168:Guinea Pigs; D009925:Organ of Corti / Q000378:metabolism / Q000503:physiopathology; D011304:Presbycusis / Q000235:genetics* / Q000503:physiopathology; D017384:Sequence Deletion
D004272:DNA, Mitochondrial