Effect of Aging on the Structure and Sebum of Human Sebaceous Glands ; Morphological and Biochemical Study

为阐明人体皮脂腺功能随增龄的变化，对不同年龄段正常人额部皮脂腺进行了计算机体视学和电子显微镜检查，并对额部皮脂标本进行了生化分析。使用计算机图形分析系统(Cosmozone 2SA，尼康，东京)对皮脂腺进行三维分析。在女性中，皮脂腺的体积在10岁以下的受试者中较小，20多岁时最大，50岁后变小。在男性中，虽然体型在20多岁时也达到最大值，但在40多岁或50多岁时保持较大的体型，并在60岁时开始下降。皮脂腺平均体积越大，标准差值越大。巨大的皮脂腺立体显示气球样肿胀。皮脂腺体积的增加是由于皮脂细胞的数量和大小都增加了。在超微结构上，在…的大皮脂腺中青壮年较多，外周皮脂细胞呈长方体，成熟的皮脂细胞有大量大小相近的脂滴；少年儿童和老年人外周皮脂细胞扁平，成熟的皮脂细胞有大小不一的脂滴。这些形态和形态计量学数据表明，尽管中年个体的皮脂腺大小在性别之间存在差异，但两性皮脂腺存在明显的年龄相关结构变化。皮脂样品取自不同年龄段正常人额部皮肤。皮脂量在20多岁之前迅速增加，无论男女。女性在40岁以后逐渐下降，男性在40岁后维持在较高水平。用薄层层析法测定了皮脂样品中蜡酯/[胆固醇酯](WE/[C CE])的比值，该比值可能是反映皮脂腺活性的良好指标。这些比率随年龄的变化与女性皮脂量的变化相似，但在男性则不同。男性的比例在40岁以后下降，与女性相似，尽管男性的比例保持在比女性更高的水平。从皮脂样品中提取WE组分，采用熔融石英毛细管色谱柱进行脂肪酸甲酯的分析。我们的C_&lt；16：1&gt；的百分比也表现出与性别的WE/[C CE]比值相应的年龄相关性变化。从所有个体的24小时尿样中分离出尿雄激素，三甲基硅烷化，并提交气-液色谱分析。无论男女，睾丸酮的含量与皮脂中WE/[C CE]比值或C：1：1直链脂肪酸比例呈正相关。在女性中，17-酮类固醇的含量也与这些皮脂指数呈正相关，但在男性中，除婴儿期外，没有显示出这种相关性。男性皮脂腺的活动似乎主要受睾酮作为内在因素的控制，而女性皮脂腺似乎比男性皮脂腺对肾上腺雄激素更敏感。这些形态和生化的发现可能表明，人类皮脂腺的结构和功能在两性之间表现出明显的年龄相关性变化，但性别之间的变化模式存在一些差异，特别是在中年。较少

To elucidate the changes of human sebaceous gland function with aging, forehead sebaceous glands of normal individuals of various ages were examined by computer-stereography and electron microscopy, and their forehead sebum samples were biochemically analyzed. The three-dimensional analysis of sebaceous glands using a computer graphic analysis system (Cosmozone 2SA, Nikon, Tokyo) was performed. In females, the volumes of sebaceous glands were small in subjects of less than 10 years of age, the largest at 20s and became smaller after 50s. In males, although they also reached the maximum at 20s,they maintained the large sizes until 40s or 50s and began to decrease at 60s. The larger average volumes of sebaceous glands showed the larger standard deviation values. The large sebaceous glands stereographically revealed balloon-like swelling. The increase in volume of sebaceous gland was due to increases in both number and size of sebocytes. Ultrastructurally, in the large sebaceous glands of … More young adults the peripheral sebocytes were cuboid in shape and the mature sebocytes had a large number of lipid droplets of a similar size, whereas in the small ones of children and aged persons the peripheral sebocytes were flat in shape and the mature sebocytes had lipid droplets of various sizes. These morphological and morphometrical data suggest that there are distinct age-related structural changes of human sebaceous glands in both sexes, although there is a difference in their size between the sexes in middle-aged individuals. Sebum samples were obtained from the forehead skin of normal human individuals of various ages by an absorption method. The amount of sebum rapidly increased until 20s in both sexes. It gradually decreased after 40s in females, whereas it was maintained at a high level after 40s in males. Wax esters/[cholesterol + cholesterol esters] (WE/[C+CE]) rations, which may be a good index to express the sebaceous gland activities, in the sebum samples, were measured by thin-layer chromatography. The age-related change of the ratios was similar to that of sebum amounts in females, but it was not in males. The ratios in males decreased after 40s similarly to those in females, although they kept higher levels in males than females. The WE fractions were extracted from the sebum samples and their fatty acid methyl esters were analyzed by gas-liquid chromatography using fused-silica capillary column. The percentages of C_<16:1> in WE also showed age-related changes, corresponding to those of WE/[C+CE] ratios, in both sexes. Urinary androgens were separated from 24 hrs-urine samples of all the individuals, trimethylsilylated and submitted to analysis by gas-liquid chromatography. The amounts of testosterone showed age-related changes positively correlated with those of either WE/[C+CE] ratios or C_<16:1> straight chain fatty acid proportions in sebum in both sexes. The amount of 17-ketosteroid also revealed a positive correlation with these sebum indices in females, but in males it did not show such a correlation except for infancy period. The activity of male sebaceous glands seemed to be controlled principally by testosterone as an intrinsic factor, whereas the female sebaceous glands seemed to be more sensitive to adrenal androgens than male ones. These morphological and biochemical findings may indicate that human sebaceous glands show distinct age-related changes of structures and functions in both sexes, although there are some differences in the patterns of the changes between the sexes especially in middle ages. Less