Characterization of melanin in human iridal and choroidal melanocytes from eyes with various colored irides
Characterization of melanin in human iridal and choroidal melanocytes from eyes with various colored irides
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DOI：
10.1111/j.1755-148x.2007.00415.x
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发表时间：
2008-02-01
影响因子：
4.3
通讯作者：
Ito, Shosuke
中科院分区：
文献类型：
--
作者：
Wakamatsu, Kazumasa;Hu, Dan-Ning;Ito, Shosuke
虹膜颜色的变异与几种重要眼部疾病的发病率有关，包括葡萄膜黑色素瘤和年龄相关性黄斑变性。本研究的目的是确定培养的人虹膜黑色素细胞中黑色素的数量和类型与虹膜颜色的关系。从不同虹膜颜色的供体眼中分离出61个纯葡萄膜黑色素细胞培养物。采用化学降解法和高效液相色谱法测定细胞中真黑素（EM）和褐黑素（PM）的含量。用微量分析法和分光光度法测定黑色素总量。用高效液相色谱法和分光光度法测定总黑色素含量，r = 0.872 （P < 0.0001）。虹膜黑色素细胞和脉络膜黑色素细胞中黑色素的数量和类型差异无统计学意义（P < 0.05）。细胞衰老后，EM、PM和总黑色素水平显著升高。在生长和衰老的黑色素细胞中，黑色素的数量和类型与虹膜颜色密切相关。深色虹膜（深褐色和褐色）眼细胞的EM含量、EM/PM比值和总黑色素均显著高于浅色虹膜（淡褐色、绿色、黄褐色和蓝色）眼细胞（P < 0.0001）。浅色虹膜组的葡萄膜黑色素细胞中PM含量略高于深色虹膜组，但差异无统计学意义（P < 0.05）。目前的研究表明，虹膜颜色是由葡萄膜黑色素细胞中黑色素的数量和类型决定的。这些结果表明，具有深色虹膜的眼睛的葡萄膜黑色素可能在表面具有黑色素并起抗氧化剂的作用，而具有浅色虹膜的眼睛的葡萄膜黑色素则暴露出黑色素核心并起促氧化剂的作用。
Variance in iris color is related to the incidence of several important ocular diseases, including uveal melanoma and age-related macular degeneration. The purposes of this study were to determine the quantity and the types of melanin in cultured human uveal melanocytes in relation to the iris color. Sixty-one cell cultures of pure uveal melanocytes were isolated from donor eyes with various iris colors. The amount of eumelanin (EM) and pheomelanin (PM) of these cells was measured by chemical degradation and microanalytical high-performance liquid chromatography (HPLC) methods. The total amount of melanin was measured by both microanalytical methods and spectrophotometry. Total melanin content, measured by HPLC and spectrophotometry, correlated well with r = 0.872 (P < 0.0001). The quantity and type of melanin in iridal and choroidal melanocytes showed no significant difference (P > 0.05). When cells became senescent, the levels of EM, PM and total melanin were significantly increased. In both growing and senescent melanocytes, the quantity and type of melanin were closely correlated to the iris color. In cells from eyes with dark-colored irides (dark brown and brown), the amount of EM, the ratio of EM/PM and total melanin were significantly greater than that from eyes with light-colored irides (hazel, green, yellow-brown and blue) (P < 0.0001). The quantity of PM in uveal melanocytes from eyes with light-colored irides was slightly greater than that from dark-colored irides, although not statistically significant (P > 0.05). The present study shows that iris color is determined by both the quantity and the type of melanin in uveal melanocytes. These results suggest a possibility that uveal melanin in eyes with dark-colored irides is eumelanic at the surface and acts as an antioxidant while that in eyes with light-colored irides exposes pheomelanic core and behaves as a pro-oxidant.