Human epidermal thickness and skin aging

Abstract

Objective To clarify the association of age and sun exposure with human epidermal thickness, and to probe deeply into the changes of skin histology and epidermal thickness with skin aging.Methods Two hundreds and eleven full thickness skin samples were collected from 3 different age groups of healthy volunteers and then stained with haematoxylin and eosin to study the changes of epidermal thickness using image analysis software ( Image pro plus 6.0). The obtained values were analyzed with factorial design ANOVA and correlation analysis to detect any significant effects of age and sun exposure on epidermal thickness.Results With increasing age, the junction between epidermis and dermis became flattened, and stratum comeum got looser. There was a notable attrition of the epidermal thickness that could be correlated with age. The at-trition of epidermal thickness attributed to age did not vary between female and male volunteers. Epidermal cell layers thickness increased with cumulated sun exposure, but epidermal total thickness was not associated with sun exposure. There was no difference for epidermal thickness of different sun exposure between female and male volunteers. Conclusion During chronological aging, epidermal cells decrease in thickness with lowered metabolism. With cumulated sun exposure, epidermal cell layer thickness becomes thicker. There is no interaction between the effect of age and sun exposure and the epidermal thickness. Key words: Epidermal thickness; Age; Sun exposure; Skin aging