Abstract
Purpose :
Sunlight wavelengths of different energy are key environmental factors in the development of skin photo-damage, photoaging, and carcinogenesis. High-energy wavelengths of ultraviolet radiation zone (UVR) are known etiologic agents in the pathogenesis of basal cell carcinoma (BCC) and contributes to photodamage in dermal layers of the skin. Clinical data from our laboratory shows that lower eyelid BCC tends to develop under moderate-to-severe elastosis. In this study, we evaluated the acute effect of different artificial sunlight exposures in keratinocytes and fibroblasts, and assessed the consequences of partial-to-full UVR blockage.
Methods :
Four human cell types were used: two normal primary epidermal keratinocytes, and two normal fibroblasts. Cells were exposed to one sun by a Tri-Sol solar simulator (300-1800 nm). Exposure conditions included full sun (FS), exposure to long path filters that partially or completely blocked UVR, and a non-sun light exposure block (B). Following solar stimulation, we evaluated the cells’ metabolic capacity and total reactive oxygen species (ROS) production in the presence or absence of antioxidant N-acetyl Cysteine (NAC).
Results :
The primary keratinocytes’ metabolic capacity was unaffected when exposed to FS, similarly as B. The FS significantly decreased the metabolic capacity of the fibroblasts. When wavelengths below 360 nm were blocked, both cell types experienced a significant decrease in their metabolic capacity. Co-incubation with NAC during exposure prevented a decrease in metabolic capacity of both keratinocytes and fibroblasts, particularly with filtered UVR. In both cells, FS exposure induced a significant increase in total ROS when compared to B exposure. In fibroblasts, unlike keratinocytes, blockage of UVR resulted in higher levels of ROS when compared to FS exposure.
Conclusions :
Exposure to FS induces different acute effects in keratinocytes and fibroblasts. Filtered UVR causes a significant decrease in the metabolic capacity in both cell types, which is prevented by NAC. ROS levels increase when cells are exposed to FS; fibroblasts, contrary to keratinocytes, show higher ROS levels when UVR is blocked. Our data suggest that the decrease in cellular metabolic activity caused by complete UVR blockage could be due to increased ROS levels as it was rescued by NAC.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.