摘要
目的 探讨内耳缺血及mtDNA 4977缺失与老年性聋的关系 ,确定老年性耳聋颞骨中mtDNA缺失的病理基础。方法 对 41例不同分组的 6 7侧颞骨应用巢式PCR和三重巢式PCR检测mtDNA 4977缺失 ,应用图像分析技术测量血管管腔与血管的截面积比值。结果 在老年性聋组检出mtDNA 4977缺失的总发生率为 5 0 .0 % (17/34,缺失阳性耳数 /总耳数 )。在老年对照组检出mtDNA4977缺失总发生率为 2 1.1% (4 /19) ,与病变组比较差异无显著意义 (P <0 .0 5 )。非老年对照组 10例14耳均未检出mtDNA 4977缺失 ,缺失率为 0。mtDNA 4977缺失阳性的老年性耳聋颞骨的神经滋养血管管壁增厚 ,管腔狭窄程度较缺失阴性组严重 ,并且mtDNA 4977缺失与内耳血管管腔狭窄程度的关系较mtDNA 4977缺失与年龄的关系更为密切。结论 mtDNA 4977缺失与内耳的供血血管状况关系密切 ,内耳供血血管狭窄、内耳缺血可能是造成颞骨mtDNA 4977缺失的主要原因之一 ,并在老年性聋发病过程中起一定的促进作用。
Objective To find the relationship among the most common mitochondrial DNA (mtDNA) 4 977 bp deletion, aging and deterioration of acoustic organ and determine the pathologic factors causing mtDNA 4 977 bp deletion. Methods Sixty-seven temporal bones from a presbycusis group, an age-matched control group and a young control group were evaluated. The nested PCR and tri-nested PCR techniques were used to test the presence of mtDNA 4 977 deletion. Computer imaging processing was used to measure the parameters of blood vessels in the internal acoustic meatus. Results Temporal bones from patients aged 50 years or over frequently showed mtDNA 4 977 deletions. In presbycusis patients, 17 of 34 ears showed mtDNA 4 977 deletion, whereas only 4 of 19 ears from the age-matched control group showed mtDNA 4 977 deletions. mtDNA 4 977 deletions were often seen in the spiral ganglion and vestibular ganglion neurons. In the presbycusis group, the lumen of the vasa nervosum of the internal auditory meatus showed a more severe reduction in patients with mtDNA 4 977 deletion than in those without deletion. Conclusion There is a strong correlation between presbycusis and mtDNA 4 977 deletion. We hypothesize that cochlear hypoxia may cause mtDNA 4 977 deletions and other mtDNA mutants which in turn may cause a reduction of mitochondrial oxidative phosphorylation and decreased auditory nerve function. The symptoms of neural presbycusis, however, may appear only after mtDNA metabolism decreases below a specific threshold.
出处
《中华医学杂志》
CAS
CSCD
北大核心
2000年第12期897-900,共4页
National Medical Journal of China
