Comparison of the quantity of cochlear melanin in young and old C57BL/6 mice
Comparison of the quantity of cochlear melanin in young and old C57BL/6 mice
复制标题
DOI：
10.1001/archotol.133.2.151
复制
发表时间：
2007-02-01
影响因子：
--
通讯作者：
Nakashima, Tsutomu
中科院分区：
文献类型：
--
作者：
Hayashi, Hideo;Sone, Michihiko;Nakashima, Tsutomu
目的：阐明耳蜗黑色素与衰老之间的功能关系。设计：已在耳蜗迷路中描述了黑色素，并建议其保护耳蜗免受各种类型的创伤。研究表明，多个器官中黑色素的数量会随着年龄的增长而变化。然而，据我们所知，耳蜗的衰老变化尚未有记录。因此，我们对耳蜗真黑素和褐黑素含量进行化学定量，并使用高效液相色谱法对年轻和年老 C57BL/6 小鼠进行比较。由于耳蜗中的黑色素沉积物最广泛地存在于血管纹中，因此我们使用透射电子显微镜对纹状体进行了形态学检查。受试者：来自 C57BL/6 雄性和雌性小鼠近交系的耳蜗；研究了 6 只 10 周龄小鼠和 5 只 100 周龄小鼠。结果：幼龄小鼠耳蜗真黑素和褐黑素含量分别为 421 ng 和 480 ng，老年小鼠每个耳蜗 2060 ng 和 765 ng。在透射电子显微镜下，与年轻小鼠相比，老年小鼠的色素颗粒数量似乎更多，尤其是边缘细胞。结论：据我们所知，我们的研究结果是第一个定量证据，表明耳蜗黑色素与年龄相关的过度表达，以及真黑素和褐黑素的比例随着年龄的增长而变化，表明真黑素可能具有耳保护功能，防止与年龄相关的耳蜗退化。
Objective: To elucidate the functional relationship between cochlear melanin and aging.Design: Melanin has been described in the cochlear labyrinth and has been suggested to protect the cochlea from various types of trauma. The quantity of melanin has been shown to change with aging in several organs; however, to our knowledge, aging changes in the cochlea have not been documented. Therefore, we chemically quantified cochlear eumelanin and pheomelanin contents and compared these in young and old C57BL/6 mice using high-performance liquid chromatography. Because melanin deposits in the cochlea present most extensively in the stria vascularis, we morphologically examined the stria using transmission electron microscopy.Subjects: Cochleae from an inbred strain of C57BL/6 male and female mice; 6 at the age of 10 weeks and 5 at the age of 100 weeks were studied.Results: The quantities of cochlear eumelanin and pheomelanin were 421 and 480 ng per cochlea in young mice, and 2060 and 765 ng per cochlea in old mice, respectively. Under transmission electron microscopy, the number of pigmented granules seemed to be greater in older mice compared with younger mice, especially in marginal cells.Conclusion: To our knowledge, our findings are the first quantitative evidence to show an age-related overexpression of cochlear melanin and an alteration in the proportion of eumelanin and pheomelanin with aging, suggesting a possible otoprotective function of eumelanin against age-related cochlear deterioration.