UV-A Radiation Impairs Sebaceous-Gland-Related Skin Barrier Function by Inducing Inflammation and Altering...

Sebaceous glands (SGs) secrete sebum to form a protective barrier that maintains skin health. However, exposure to ultraviolet A (UV-A) radiation damages the skin barrier, leading to dryness and inflammation.

In this study, we investigated how UV-A radiation alters SG function, focusing on inflammation and changes in the composition of intracellular sebum-like lipids. We also explored the role of SG-related mechanisms in UVA-radiation-induced skin barrier damage.

Human primary sebocytes were cultured from SGs isolated from human skin samples and exposed to different doses of UV-A radiation. Inflammatory cytokines released into the culture medium were measured, followed by gene expression analysis using mRNA extracted from cells to examine specific target genes. Intracellular sebum-like lipid composition was analyzed using liquid chromatography-tandem mass spectrometry, and skin barrier function was evaluated using a three-dimensional reconstructed human epidermis (3D skin) model.

UV-A irradiation increased inflammatory cytokine levels in the culture medium and altered the expression levels of several genes. Intracellular sebum-like lipid composition was also modified following UV-A irradiation, with notable sex differences. Furthermore, the skin barrier function was impaired in 3D skin models cultured with the supernatant from UV-A-irradiated sebocyte cultures.

This study demonstrated that UV-A radiation stimulated sebocytes to release inflammatory cytokines and altered gene expression. Additionally, UV-A irradiation modified the intracellular sebum-like lipid composition in a sex-dependent manner, contributing to skin barrier damage.