Donois E, del Marmol V, Ghanem G, Surlève-Bazeille J E
Defense and Cell Regulation Factors, Animal Biology Institute, Talence, France.
J Invest Dermatol. 1998 Sep;111(3):422-8. doi: 10.1046/j.1523-1747.1998.00313.x.
The aim of the study was to compare two methods of quantitating eumelanins and pheomelanins, pigments synthesized by melanocytes. One is based on the high performance liquid chromatography quantitation of specific degradation products of each melanin type. The other requires image analysis, transmission electron microscopy, and stereology. In a previous study, we showed good correlations between both methods for total melanin but not for eumelanins or pheomelanins. We describe here the same comparison in more pigmented cells (nevus cells and stimulated HBL melanoma cells). Transmission electron microscopy micrographs were image analyzed to generate several primary parameters. Stereology was used for estimating melanosomal maturation, intracellular melanin content, and the number of melanized melanosomes per cell, for total melanin, eumelanins, or pheomelanins. Our results showed a good correlation between both methods for total melanin, eumelanins, and pheomelanins with an r equal to 0.99, 0.91, and 0.93, respectively, when all the points were used in the linear regression analyses. In the melanoma cell group (HBL cells cultured in media of different compositions), the chemical and morphometric estimations were not parallel in the case of eumelanins and pheomelanins. In addition, the stereologic and high performance liquid chromatography pheomelanins to eumelanins ratios were still not correlated. These results demonstrate the relevancy of the stereologic method, but the low level of melanization, the possible lack of specificity of melanogenesis in melanoma cells, and a problem of sensitivity of the stereologic method in this context seem to be obstacles in obtaining better results. The utilization of normal human melanocytes could give some answers to our hypotheses.
本研究的目的是比较两种定量测定真黑素和褐黑素的方法，这两种色素由黑素细胞合成。一种方法基于对每种黑素类型的特定降解产物进行高效液相色谱定量分析。另一种方法需要图像分析、透射电子显微镜和体视学。在之前的一项研究中，我们发现两种方法对总黑素的测定结果具有良好的相关性，但对真黑素或褐黑素的测定结果并非如此。我们在此描述了在色素沉着程度更高的细胞（痣细胞和经刺激的HBL黑色素瘤细胞）中进行的相同比较。对透射电子显微镜照片进行图像分析以生成几个主要参数。体视学用于估计黑素小体成熟度、细胞内黑素含量以及每个细胞中黑素化黑素小体的数量，用于总黑素、真黑素或褐黑素的测定。我们的结果表明，当在线性回归分析中使用所有数据点时，两种方法对总黑素、真黑素和褐黑素的测定结果具有良好的相关性，相关系数r分别为0.99、0.91和0.93。在黑色素瘤细胞组（在不同成分培养基中培养的HBL细胞）中，对于真黑素和褐黑素，化学测定和形态学测定结果并不平行。此外，体视学和高效液相色谱法测定的褐黑素与真黑素的比率仍然不相关。这些结果证明了体视学方法的相关性，但黑素化程度较低、黑色素瘤细胞中黑素生成可能缺乏特异性以及体视学方法在这种情况下的灵敏度问题似乎是获得更好结果的障碍。使用正常人黑素细胞可能会为我们提供一些假设的答案。
