Cheng-Che E Lan1, Yu-Ting Hung2, Ai-Hui Fang3, Wu Ching-Shuang4. 1. Department of Dermatology, Kaohsiung Medical University Hospital, and College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan. 2. Department of Medical Laboratory Science and Biotechnology, College of Health Science, Kaohsiung Medical University, Kaohsiung, Taiwan. 3. Department of Microbiology, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan. 4. Department of Medical Laboratory Science and Biotechnology, College of Health Science, Kaohsiung Medical University, Kaohsiung, Taiwan; Institute of Biomedical Sciences, National Sun Yat-Sen University, Kaohsiung, Taiwan. Electronic address: m785034@kmu.edu.tw.
Abstract
BACKGROUND: Ultraviolet A (UVA) radiation is the most relevant component of solar radiation-induced skin aging. Sunscreens were used to minimize the harmful effects of UV radiation on our skin by reducing UV irradiance. We previously found that at equivalent fluence, UVB radiation at low irradiance (LI) has higher photocarcinogenic potential as compared to its high irradiance (HI) counterpart. OBJECTIVES: To examine the effects of equivalent fluence of UVA radiation administered at different irradiance on photoaging. METHODS: Both the hairless mice (SKH-1) and human dermal fibroblasts were irradiated with high irradiance UVA (HIUVA) or low irradiance UVA (LIUVA; 50% irradiance of HIUVA) at equivalent fluence. Parameters related to skin photoaging were evaluated. RESULTS: For hairless mice receiving equivalent fluence of UVA radiation, LIUVA treated mice showed prominent skin aging as compared to its HIUVA treated counterpart. In addition, LIUVA radiation induced higher reactive oxygen species (ROS) production and c-Jun N-terminal kinases (JNK) phosphorylation as compared to their HIUVA treated counterparts. Pretreatment with N-acetylcysteine (NAC) abrogate the difference between HI and LIUVA radiation on fibroblasts in terms of intracellular ROS, JNK phosphorylation, MMP-1 expression and type I collagen expression. CONCLUSION: UVA radiation administered at LI (a scenario similar to sunscreen use) led to more severe aging process as compared to its HI counterpart. Unexpected negative effect may be imposed on the skin if sunscreen use is accompanied by longer duration spent under the sun.
BACKGROUND: Ultraviolet A (UVA) radiation is the most relevant component of solar radiation-induced skin aging. Sunscreens were used to minimize the harmful effects of UV radiation on our skin by reducing UV irradiance. We previously found that at equivalent fluence, UVB radiation at low irradiance (LI) has higher photocarcinogenic potential as compared to its high irradiance (HI) counterpart. OBJECTIVES: To examine the effects of equivalent fluence of UVA radiation administered at different irradiance on photoaging. METHODS: Both the hairless mice (SKH-1) and human dermal fibroblasts were irradiated with high irradiance UVA (HIUVA) or low irradiance UVA (LIUVA; 50% irradiance of HIUVA) at equivalent fluence. Parameters related to skin photoaging were evaluated. RESULTS: For hairless mice receiving equivalent fluence of UVA radiation, LIUVA treated mice showed prominent skin aging as compared to its HIUVA treated counterpart. In addition, LIUVA radiation induced higher reactive oxygen species (ROS) production and c-Jun N-terminal kinases (JNK) phosphorylation as compared to their HIUVA treated counterparts. Pretreatment with N-acetylcysteine (NAC) abrogate the difference between HI and LIUVA radiation on fibroblasts in terms of intracellular ROS, JNK phosphorylation, MMP-1 expression and type I collagen expression. CONCLUSION: UVA radiation administered at LI (a scenario similar to sunscreen use) led to more severe aging process as compared to its HI counterpart. Unexpected negative effect may be imposed on the skin if sunscreen use is accompanied by longer duration spent under the sun.
Authors: Vega Widya Karisma; Wei Wu; Mingxing Lei; Huawen Liu; Muhammad Farrukh Nisar; Matthew D Lloyd; Charareh Pourzand; Julia Li Zhong Journal: Front Cell Dev Biol Date: 2021-02-11