Characterization of a chronic UV-induced photoaging mouse model: insights into skin barrier dysfunction, extracellular matrix remodeling, and altered adipogenesis

Chronic exposure to ultraviolet (UV) radiation, known as photoaging, accelerates skin aging by inducing molecular, histological, and functional changes. This study established a mouse model using SKH-1 hairless mice to investigate chronic UV-induced photoaging over eight weeks. SKH-1 hairless mice were exposed to a combination of UVA and UVB, and the progression of skin damage was monitored through physical, histological, and molecular parameters, with a focus on erythema, transepidermal water loss, and collagen and hyaluronan (HA) metabolism. Significant reductions in HA content and alterations in DNA repair markers, such as γH2AX, were observed, highlighting the impact of chronic UV exposure on skin structure and function. Reactive adipogenesis and increased epidermal thickness were noted, reflecting adaptive responses to UV-induced damage. By investigating these parameters over the evaluation period, we provide a comprehensive time-course analysis of the progressive impact of UV-induced photoaging, offering insights into the underlying mechanisms and potential therapeutic targets to prevent or delay photoaging.