Abstract

In an attempt to elucidate the morphologic changes of normal aging skin, the present study was undertaken in human facial and chest well skin of individuals aged from 4 months to 76 years old. Biopsied skin was studied with light microscope, scanning electron microscope, and transmission electron microscope, using both conventional and tannic acid staining. The morphologic changes in the skin were noted as follow: 1. Structurally, the aged epidermis gradually became somewhat thinner, with flattening of the dermoepidermal interface. The number of melanocytes also decreased. 2. Abnormalities of elastic fibers such as loss of oxytalan fibers were observed from age 30. It was the initial sign of the aging process of elastic fibers, followed by abnormal changes in elaunin and mature elastic fibers. The degree of facial skin abnormality was rather more severe than that of the chest wall skin. 3. In individuals more than 50 years old, the age related changes in mature elastic fibers were more severe. Transmission electron microscopically, the electron density in elastin was irregular. The elastic fibers also showed pores and irregular splitting with fragmentation. Fine granular materials were scattered near the elastin. 4. Scanning electron microscopically, the elastic fibers in young adult skin showd ribbon-like fibers aligned in the same direction. They were either cylindrical or elliptical, having smooth surface. In old skin, the elastic fibers ran in various directions, forming complicated networks. These were larger, more elliptical and more branched than those in young adult skin. In summary, histologic changes of aging are much more prominent in sun-exposed skin(facial skin) than in sun protected skin(chest wall skin). A completely different spectrum of elastic fiber abnormalities was found in individuals more than 30 years old. The result indicates that elastic fiber abnormalities are related to aging skin.

• Keywords: Skin;Age-related change;