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目的探讨豚鼠听觉器官中线粒体DNA(mitochondrialDNA,mtDNA)4568缺失与老年性聋的关系。方法将44只豚鼠分为两组A组青年豚鼠22只;B组老年豚鼠22只。再将B组分为B1组(老年听力正常组6只)和B2组(老年聋组16只)。应用听觉脑干反应(auditorybrainstemresponse,ABR)测试豚鼠听力阈值,以左耳听阈为评判标准,并提取耳蜗螺旋器、听神经、大脑颞叶组织和外周血中的DNA,采用PCR技术检测mtDNA4568大片段缺失的情况,并与耳聋程度作比较。结果老年聋组(B2)豚鼠的ABR平均听阈值为(57.33±4.65)dBSPL,明显高于老年听力正常组B1[(23.00±1.43)dBSPL]和青年组[A组(15.90±1.05)dBSPL];老年组不同器官组织中mtDNA4568缺失率均明显高于青年组;老年聋组耳蜗螺旋器组织和听神经组织中mtDNA4568缺失率明显高于老年听力正常组;而大脑颞叶组织mtDNA4568缺失率在两组间差异无统计学意义;血液中仅极少数存在mtDNA缺失,未纳入统计分析。结论豚鼠mtDNA4568缺失的发生与老龄有关;与听觉有关的耳蜗螺旋器组织和听神经组织中mtDNA4568缺失与老年性聋有关;大脑颞叶组织和外周血中mtDNA4568缺失与老年性聋的关系尚待进一步研究。
Objective To investigate the relationship between mitochondrial DNA (mtDNA) 4568 deletion and senile deafness in guinea pig auditory organs. Methods Forty-four guinea pigs were divided into two groups, 22 young guinea pigs in group A and 22 old guinea pigs in group B. Group B was divided into B1 group (6 elderly normal hearing group) and B2 group (16 elderly deaf group). The auditory brainstem response (ABR) was used to test the hearing threshold of guinea pigs. Left ear auditory threshold was taken as the criterion and the DNA of cochlear spiral, auditory nerve, temporal lobe of brain and peripheral blood was extracted. PCR was used to detect the deletion of mtDNA4568 large fragment Of the situation, and compared with the degree of deafness. Results The mean hearing threshold of ABR was (57.33 ± 4.65) dBSPL in senile deaf group (B2), which was significantly higher than that in the elderly normal hearing group B1 [(23.00 ± 1.43) dBSPL] and in the youth group [15.90 ± 1.05 dBSPL] ; The deletion rate of mtDNA4568 in different organs of the aged group was significantly higher than that of the young group; the deletion rate of mtDNA4568 in the cochlear spiral organ and auditory nerve tissue of the senile deaf group was significantly higher than that of the elderly normal hearing group; while the loss rate of mtDNA4568 in the temporal lobe tissue was lower in the two groups There was no significant difference between the two groups; there were only a few mtDNA deletions in the blood, which were not included in the statistical analysis. Conclusions The deletion of mtDNA4568 in guinea pigs is related to aging. The loss of mtDNA4568 in the cochlear spiral organs and auditory nerve tissues associated with hearing is related to senile deafness. The relationship between mtDNA4568 deletion in the temporal lobe tissue and peripheral blood and senile deafness remains to be further studied .