Thong H-Y, Jee S-H, Sun C-C, Boissy R E
Department of Dermatology, National Taiwan University Hospital, and College of Medicine, Taipei, Taiwan.
Br J Dermatol. 2003 Sep;149(3):498-505. doi: 10.1046/j.1365-2133.2003.05473.x.
One determining factor of skin colour is the distribution pattern of melanosomes within keratinocytes. Melanosomes in keratinocytes of light skin as in Caucasians are distributed as membrane-bound clusters, whereas the melanosomes in keratinocytes of dark skin as in African/American individuals tend to be larger and distributed individually. It has been shown that melanin content, melanin composition and the size of melanosomes in the human epidermis vary considerably with both ethnicity and chronic sun exposure.
To assess quantitatively the distribution pattern of melanosomes that have been transferred to keratinocytes in the photoprotected (volar forearm) skin from normal Asian individuals and to compare these data with those from light-skinned Caucasian and dark-skinned African/American individuals.
Electron microscopy was used.
We have demonstrated that melanosomes within keratinocytes of Asian skin are distributed as a combination of individual and clustered melanosomes with a proportion of 62.6% vs. 37.4%, respectively. This contrasts with dark and light skin keratinocytes where melanosomes are predominantly individual (88.9%) and clustered (84.5%), respectively. Analysis of mean +/- SD melanosome size also revealed a progressive variation in size with ethnicity, melanosomes in dark skin being the largest (1.44 +/- 0.67 microm(2) x 10-2) followed in turn by those in Asian skin (1.36 +/- 0.15 microm(2) x 10-2) and Caucasian skin (0.94 +/- 0.48 microm(2) x 10-2). In addition, it was shown that the melanosomes that are individually distributed tend to have a larger size than the clustered melanosomes.
The present data indicate that there may be a size gradient of melanosomes encompassing the global complexion coloration and that the melanosome distribution in keratinocytes of Asian skin is intermediate between that in light Caucasian and dark African/American skin.
肤色的一个决定因素是角质形成细胞内黑素小体的分布模式。白种人等浅色皮肤的角质形成细胞中的黑素小体以膜结合簇的形式分布，而非洲裔/美洲人等深色皮肤的角质形成细胞中的黑素小体往往更大且单独分布。研究表明，人类表皮中的黑色素含量、黑色素组成和黑素小体大小会因种族和长期阳光照射而有很大差异。
定量评估正常亚洲人光保护（掌侧前臂）皮肤中转移至角质形成细胞的黑素小体的分布模式，并将这些数据与浅色皮肤的白种人和深色皮肤的非洲裔/美洲人的数据进行比较。
采用电子显微镜检查。
我们已证明，亚洲皮肤角质形成细胞内的黑素小体以单个和聚集黑素小体的组合形式分布，比例分别为62.6%和37.4%。这与深色和浅色皮肤的角质形成细胞形成对比，深色皮肤角质形成细胞中的黑素小体主要为单个（88.9%），浅色皮肤角质形成细胞中的黑素小体主要为聚集（84.5%）。对平均±标准差黑素小体大小的分析还显示，黑素小体大小随种族逐渐变化，深色皮肤中的黑素小体最大（1.44±0.67μm²×10⁻²），其次是亚洲皮肤中的黑素小体（1.36±0.15μm²×10⁻²）和白种人皮肤中的黑素小体（0.94±0.48μm²×10⁻²）。此外，研究表明，单独分布的黑素小体往往比聚集的黑素小体更大。
目前的数据表明，黑素小体可能存在一个涵盖全球肤色的大小梯度，且亚洲皮肤角质形成细胞中的黑素小体分布介于浅色白种人和深色非洲裔/美洲人皮肤之间。
