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Natural products are favored in the study of skin photodamage protection recently. Isoquercetin, namely 3-O-glucoside of quercetin, can be isolated from various plant species. In present research, the protective effect of isoquercitrin on UVB-induced injury in cells and mice skin were investigated. Our study reveals that 400 μM of isoquercitrin exhibits the best viability on UVB-irradiated HaCaT cells, and beneficial effects against oxidative stress UVB-induced in skin tissue by decreasing the levels of reactive oxygen species (ROS) and malondialdehyde (MDA), and simultaneously enhancing the activity of superoxide dismutase (SOD). Additionally, isoquercitrin was identified as an anti-inflammatory agent by reducing the level of COX-2 by Western blot analysis, and inflammatory cytokines such as IL-6, IL-1β, and TNF-α by ELISA, and UVB-induced epidermal thickening evidenced by H&E staining. It also effectively prevented UVB-induced collagen fibers from degradation identified by Masson staining. Isoquercitrin significantly inhibited MAPK pathway by downregulating the levels of AP-1, MMP-1, MMP-3, phospho-p38, phospho-JNK, phospho-ERK, cleaved caspase-9, cleaved caspase-3, and JAK2-STAT3 pathway by western blot analysis. In conclusion, isoquercitrin pretreatment protected mice skin from UVB irradiation-induced injury effectively, and the underlying mechanism may involve MAPK and JAK2-STAT3 signaling pathways., (© 2024 American Society for Photobiology.)

The field of sun protection is quickly changing and the research article by Douki et al., published in the current issue of Photochemistry and Photobiology, reported key experimental data that will certainly help the development of better sun care products. Mutagenic photoproducts (CPDs, cyclobutane pyrimidine dimers and 6-4PPs, pyrimidine-6-4-pyrimidone photoproducts) were formed in the reconstructed human epidermis (RHE) by UVB (312 nm) irradiation, and their concentrations were detected by HPLC-MS/MS as a function of time after the UVB treatment. RHE had been previously exposed or not (control) to blue light (427 nm). Both CPDs and 6-4PPs were shown to last longer in blue-light irradiated RHE, proving the inhibition of the DNA repair by blue light exposure. This is a highly relevant information because sunscreens allow people to enjoy longer periods under the sun and consequently, to endure very high doses of blue light. The work also reported results obtained with RHEs previously treated with a sunscreen formulation containing a broadband filter that offers blue-light protection. Interestingly, authors observed that the DNA repair was not significantly inhibited in RHE previously treated with the sunscreen offering broadband protection. Readers will find a scientifically sound proof of the importance of blue-light protection in sun care products., (© 2024 American Society for Photobiology.)

Exposure to ultraviolet radiation (UV-R), from both natural and artificial tanning, heightens the risk of skin cancer by inducing molecular changes in cells and tissues. Despite established transcriptional alterations at a molecular level due to UV-R exposure, uncertainties persist regarding UV radiation characterization and subsequent genomic changes. Our study aimed to mechanistically explore dose- and time-dependent gene expression changes, that may drive short-term (e.g., sunburn) and long-term actinic (e.g., skin cancer) consequences. Using C57BL/6N mouse skin, we analyzed transcriptomic expression following exposure to five erythemally weighted UV-R doses (0, 5, 10, 20, and 40 mJ/cm 2 ) emitted by a UV-R tanning device. At 96 h post-exposure, 5 mJ/cm 2 induced 116 statistically significant differentially expressed genes (DEGs) associated with structural changes from UV-R damage. The highest number of significant gene expression changes occurred at 6 and 48 h post-exposure in the 20 and 40 mJ/cm 2 dose groups. Notably, at 40 mJ/cm 2 , 13 DEGs related to skin barrier homeostasis were consistently perturbed across all timepoints. UV-R exposure activated pathways involving oxidative stress, P53 signaling, inflammation, biotransformation, skin barrier maintenance, and innate immunity. This in vivo study's transcriptional data offers mechanistic insights into both short-term and potential non-threshold-dependent long-term health effects of UV-R tanning., (© 2024 His Majesty the King in Right of Canada. Photochemistry and Photobiology published by Wiley Periodicals LLC on behalf of American Society for Photobiology. Reproduced with the permission of the Minister of Health Canada.)

In recent years, interest is growing in the biological cutaneous effects of high-energy visible light (400-450 nm). In the present study, we explored the impact of blue light (BL) on the repair of pyrimidine dimers, the major class of premutagenic DNA damage induced by exposure to sunlight. We unambiguously demonstrate that the exposure of in vitro reconstructed human epidermis to environmentally relevant doses of BL strongly decreases the rate of repair of cyclobutane pyrimidine dimers and pyrimidine (6-4) pyrimidone photoproducts induced by a subsequent UVB irradiation. Using the highly sensitive and specific liquid chromatography-tandem mass spectrometry assay, we did not observe induction of pyrimidine dimers by BL alone. Finally, we showed that application, during the BL exposure step, of a formula containing a new filter, named TriAsorB and affording BL photoprotection, prevented the decrease in DNA repair efficiency. These results emphasize the potential deleterious effects of BL on DNA repair and the interest in providing adequate skin protection against this wavelength range of sunlight., (© 2024 The Author(s). Photochemistry and Photobiology published by Wiley Periodicals LLC on behalf of American Society for Photobiology.)

Helianthus annuus seed byproduct is a residual product obtained after seed oil extraction. The present study investigated the preventive and repair effects of the H. annuus seed byproduct ethanol extract (HSE) on ultraviolet radiation (UVR)-induced injury in human immortalized keratinocytes (HaCaTs) and human skin fibroblasts (HSFs). Results revealed that the total phenolic acid and oligosaccharide content in HSE was >50%. HSE had a stronger preventive effect on UVR-induced injury than the repair effect. Moreover, phenolic acids were the main active component of HSE mediating the preventative effect. In HaCaTs and HSFs, HSE prevented UVR-induced injury by inhibiting excessive ROS production. It reduced the secretion of tumor necrosis TNF-α, IL-1α, IL-1β, IL-6, and IL-8 by inhibiting the level of ROS, thus reducing inflammation-mediated injury to skin cells. In addition, HSE inhibited the expression of various mRNA kinases in the MAPK-ERK/p38/JNK pathway. This downregulated the expression of activator protein-1 (AP-1) mRNA and further reduced the secretion of matrix metalloproteinase (MMP)-1, MMP-3, and MMP-9 as well as reduced UVR-induced injury to the cells. In conclusion, HSE is a broad-spectrum, natural UV filter with high efficiency and low toxicity that has the potential to be used in sunscreen products., (© 2023 American Society for Photobiology.)

Sunlight, and more specifically the UV component, induces several skin damages, including sunburns, erythema and photoaging. The purpose of this work is to set up an ex vivo human skin model to assess the capacity of active principles in protecting skin from the deleterious effects of solar radiation. Ex vivo human skin biopsies were cultured in an air-liquid interface and exposed to solar-simulated radiation (SSR, 300-750 nm). L-Carnosine (0.2% and 2%) was applied topically to be tested as photoprotective compound. The effect on oxidative stress induction, photoaging and skin transcriptional profile was assessed by evaluating reactive oxygen species, advanced glycosylation end products formation and gene expression changes. In our model, SSR increases ROS production and AGE accumulation and affects the expression of genes related to oxidative stress, pigmentation, immunity, inflammation and photoaging. Among these pathways, 11 genes were selected as biomarkers to evaluate the skin solar radiation response. Results showed that L-Carnosine provides effective prevention against solar radiation damages reducing ROS, AGEs and mitigating the modulation of the selected biomarker genes. In conclusion, we report that our ex vivo skin model is a valuable system to assess the consequences of solar light exposure and the capacity of topically applied L-Carnosine to counteract them., (© 2023 Symrise Sri and The Authors. Photochemistry and Photobiology published by Wiley Periodicals LLC on behalf of American Society for Photobiology.)

Saussurea medusa polysaccharide, the polysaccharide extract of Saussurea medusa Maxim, a traditional Chinese herbal medicine, is used to combat intense ultraviolet radiation, cold, and hypoxia in patients, as well as during drought. This polysaccharide has rich medicinal and ecological values. We aimed to determine whether saussurea medusa polysaccharides can reduce ultraviolet B (UVB)-induced skin photoaging. Seventy-five male Kunming mice were divided into five groups: control, UVB-only, UVB plus vitamin E (VE group), UVB plus saussurea medusa (2 g/kg), and UVB plus saussurea medusa (6 g/kg). The control group was irradiated with normal light, while the other four groups were subcutaneously administered 10 mL/kg/day D-galactose and irradiated with narrow-spectrum UVB for 40 min daily. From day 11, the VE group was administered 0.25 g/kg/day vitamin E, while the saussurea medusa intervention groups were administered 2 and 6 g/kg/day saussurea medusa polysaccharide. After 30 days of continuous administration, treatment with saussurea medusa polysaccharides was found to reduce UVB-induced skin photoaging in mice by elevating the levels of superoxide dismutase, glutathione peroxidase, and hydroxyproline (HYP), while reducing the level of MDA, and inhibiting the EGFR/MEK/ERK/c-Fos pathway. Overall, our findings suggest that treatment with saussurea medusa polysaccharides positively influences skin photoaging., (© 2023 American Society for Photobiology.)

Ultraviolet radiation (UVR) is the major exogenous agent that disturbs tissue homeostasis and hastens the onset of age-related phenotypes (photoaging). Exposure to UV-B radiation promotes apoptosis in human skin cells via induction of Reactive Oxygen Species (ROS)-mediated Endoplasmic Reticulum (ER) stress by activating the PERK-eIF2α-CHOP pathway, which plays a major role in exacerbating skin photoaging. Alleviating the production of ROS and boosting the antioxidant capacity of cells is the foremost therapeutic strategy to avert the repercussions of ultraviolet radiation exposure. In this study, we investigated the role of 3-(1'-methyltetrahydropyridinyl)-2,4-6-trihydroxy acetophenone (IIIM-8) in thwarting the UV-B-induced photoaging. We observed that IIIM-8 ameliorates UV-B-induced oxidative stress, ER stress, Loss of Mitochondrial membrane potential, MAPK activation and Inflammation in irradiated skin cells. Ultraviolet radiation-related damage to fibroblasts within the dermis leads to collagen degradation-the hallmark of photoaging. IIIM-8 substantially restored the synthesis of collagen and prevented its degradation via the downregulation of matrix metalloproteinases. Topical application of IIIM-8 prevented BALB/c mice skin from UV-B-induced leukocyte infiltration, epidermal thickening and disruption of Extracellular matrix components. Implying that IIIM-8 has a strong photoprotective property and has potential to be developed as a topical therapeutic/cosmeceutical agent against UV-B-induced photoaging., (© 2023 American Society for Photobiology.)

Acute ultraviolet B (UVB) irradiation predominantly leads to various skin disorders caused by photodamage. The major causes of UVB-induced photodamage include oxidative stress, inflammatory infiltration and collagen degradation. The aim of the study was to elucidate whether DNP had protective effect on the skin of KM mice when exposed to UVB irradiation. The DNP protective properties to skin appearance and histopathological alterations in KM mice were evaluated by hematoxylin-eosin staining, toluidine blue staining, Gomori staining and Masson's trichrome staining and mast cell staining. In this study, DNP pretreatment promoted the activities of antioxidant enzymes, including superoxide dismutase, catalase and glutathione peroxidase, while decreased malondialdehyde level in UVB-irradiated skin, along with downregulation of proteins expression of matrix metalloproteinases and reduction in the level of the proinflammatory cytokines. Based on these findings, we demonstrated that DNP displayed strong ameliorative effects on UVB-induced acute photodamage for the first time, indicating that it would be a promoting ingredient candidate that could be used in antiphotodamage., (© 2023 American Society for Photobiology.)

The Antarctic region is a place of increasing interest. A growing number of personnel are working outdoors in extreme environmental conditions. They receive significant exposure to solar ultraviolet radiation (UVR) and are thereby at increased risk of adverse consequences. The aim of this study was to evaluate the UVR dose received by the outdoor workers at the Bulgarian Antarctic Base. Ten Caucasian healthy subjects, 8 males and 2 females with a mean age of 38 years (29-51) were enrolled. Of them, 5 were scientists and 5 were logistic workers. We measured the accumulated daily dose of UVR assessed by standard erythemal dose (SED) in the two groups. All subjects wore personal dosimeters located near the face-he only noncovered skin area. The dosimeters were factory calibrated for use in the Antarctic region. No statistical difference (P = 0.441) could be revealed between the SEDs in the two groups. The maximum UVR dose detected in a single day was 67.9 SEDs, and the highest cumulative dose was 548.03 SEDs. Study results are showing extreme measurements of UVR received by the members of the expeditions. We suggest meticulous UV protection for outdoor workers., (© 2022 American Society for Photobiology.)

Melanoma incidence is increasing, with poor prognosis cases growing faster in California Hispanics than in non-Hispanic whites. Ultraviolet Radiation (UVR) exposure as a child has been found to disproportionately increase the risk of melanoma. To determine correlates of UVR exposure in this high-risk population, we conducted a study in predominately Hispanic 4th and 5th grade classrooms in Los Angeles County, a high UVR environment, during the spring. To address potential reporting bias, electronic UV dosimeters were utilized to objectively measure the association between UVR exposure and constructs (acculturation, sun protective behavior and knowledge, family interventions) obtained on baseline questionnaires (n = 125). Tanning attitude (wanting to get a tan) was associated with lower median time spent outside (1.73 min versus 22.17, AUC 82.08, Sensitivity 0.78, Specificity 0.73) and standard erythemal dose (SED) on weekends, but positively associated with sun protective knowledge. Sun protective knowledge and family discussion of sunscreen were also inversely associated with objectively measured time outside. Students spent a median 30.61 (IQR 19.88) minutes outside per day (SED 0.30, IQR 0.20), with only 35.70% of it occurring in nonschool hours. We determined the majority of UVR exposure in this population occurs at school, providing valuable guidance for future interventions., (© 2022 The Authors. Photochemistry and Photobiology published by Wiley Periodicals LLC on behalf of American Society for Photobiology.)

Two krypton-chloride germicidal excimer lamp units (Care222 TRT-104C11-UI-U3, USHIO Inc.) were installed in the examination room of an ophthalmology department. The irradiation dose was set not to exceed the former (i.e., before 2022) threshold limit value (TLV) (22 mJ cm -2 /8 h) recommended by the ACGIH. Section 1: The eyes and lids of the six ophthalmologists (5 wore glasses for myopic correction) who worked in the room for a mean stay of 6.7 h week -1 were prospectively observed for 12 months. Slitlamp examinations revealed neither acute adverse events such as corneal erosion, conjunctival hyperemia, and lid skin erythema nor chronic adverse events such as pterygium, cataract, or lid tumor. The visual acuity, refractive error, and corneal endothelial cell density remained unchanged during the study. Section 2: The irradiation of samples placed on the table or floor using the same fixtures in the room (5-7.5 mJ cm -2 ) was associated with >99% inhibition of φX174 phage and >90% inhibition of Staphylococcus aureus. In conclusion, no acute or chronic health effects in human participants was observed in a clinical setting of full-room ultraviolet germicidal irradiation by 222-nm lamp units, and high efficacy in deactivation of microorganisms was determined in the same setting., (© 2022 The Authors. Photochemistry and Photobiology published by Wiley Periodicals LLC on behalf of American Society for Photobiology.)

The most recent data relating to the incidence of, and mortality from, the three commonest forms of skin cancer, namely basal cell carcinoma (BCC), squamous cell carcinoma (SCC) and cutaneous melanoma (CM), in the Black African, Colored, Asian/Indian and White population groups in South Africa are reviewed. While exposure to solar ultraviolet radiation is the major environmental risk factor for BCC in all four groups, for SSC in the White and Asian/Indian groups and for CM in the White group, this is unlikely to be the case for most SCCs in the Black African group and for most CMs in the Black African and Asian/Indian groups. Strategies for practical personal photoprotection in South Africa are discussed with particular emphasis on people at heightened risk of skin cancer including the White population group, those with HIV or oculocutaneous albinism and outdoor workers., (© 2022 American Society for Photobiology.)

This article is a highlight of the paper by Snell et al. in the current issue of Photochemistry and Photobiology (Snell et al. Photochem. Photobiol. 2022). The authors utilized an organotypic human skin model and transgenic SKH-1 mice to determine the oxidative stress response induced by topical treatment of trichloroisocyanuric acid (TCIC), a common disinfectant used in swimming pool. Additionally, they determined molecular mechanisms associated with topical TCIC pretreatment followed by ultraviolet (UV) radiation exposure. This work provides the first example that cutaneous delivery of TCIC significantly increases UV-induced skin inflammation, suggesting a previously unidentified potential of TCIC. If translatable to human skin, these findings could be important for human skin health implications., (© 2022 The Authors. Photochemistry and Photobiology published by Wiley Periodicals LLC on behalf of American Society for Photobiology.)

This study aims to evaluate the influences of ultraviolet radiation A and B (UVA + B) exposure on the liver and heart organs of albino rats. Female Wistar Albino rats, whose hair of the dorsal skin was shaved, were exposed to a combined UVA + B radiation for 2 h/day, for 4 weeks in order to be compared with the control group. Histopathological findings in vital organs (liver and heart) were evaluated. Tissues were fixed in 10% buffered formalin (pH = 7.2) and embedded in paraffin. The histopathological findings were examined on the H&E stained sections with light microscopy. The results show that the liver and the heart were injured in the UVA + B group. Liver tissue in the UVA + B group showed minimal vacuolation, enlargement of hepatocytes and bile duct proliferation, and the heart tissue showed hibernomas; uniform large cells resembling brown fat with coarsely granular to multivacuolated cytoplasm that is eosinophilic or pale with a small central nucleus. The number of hibernoma cases was significantly higher in the UVA + B group compared with the control group (P = 0.021). The control group showed normal liver and heart histology with normal adipose tissue in the pericardium. As a result, UVA + B exposure has toxic effects, especially on the liver and the heart of Wistar albino rats. UV radiation may cause such adverse effects in humans. Therefore, protection against the harmful effects of UV radiation is of significant importance for skin and organs., (© 2022 American Society for Photobiology.)

Far-UVC radiation, typically defined as 200-235 nm, has similar or greater anti-microbial efficacy compared with conventional 254-nm germicidal radiation. In addition, biophysical considerations of the interaction of far-UVC with tissue, as well as multiple short-term safety studies in animal models and humans, suggest that far-UVC exposure may be safe for skin and eye tissue. Nevertheless, the potential for skin cancer after chronic long-term exposure to far-UVC has not been studied. Here, we assessed far-UVC induced carcinogenic skin changes and other pathological dermal abnormalities in 96 SKH-1 hairless mice of both sexes that were exposed to average daily dorsal skin doses of 400, 130 or 55 mJ cm -2 of 222 nm far-UVC radiation for 66 weeks, 5 days per week, 8 h per day, as well as similarly-treated unexposed controls. No evidence for increased skin cancer, abnormal skin growths or incidental skin pathology findings was observed in the far-UVC-exposed mice. In addition, there were no significant changes in morbidity or mortality. The findings from this study support the long-term safety of long-term chronic exposure to far-UVC radiation, and therefore its potential suitability as a practical anti-microbial approach to reduce airborne viral and bacterial loads in occupied indoor settings., (© 2022 The Authors. Photochemistry and Photobiology published by Wiley Periodicals LLC on behalf of American Society for Photobiology. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.)

The aim of this research was to determine the effects of adding red seaweed meal rich in ultraviolet radiation absorbing compounds (UACs) to the diet of juvenile prawn Artemesia longinaris and its possible protective effects under stress by ultraviolet radiation (UVR). Three experimental diets were prepared: control diet (D) and two diets supplemented with red seaweed Grateloupia cf. turuturu meal at two inclusion levels (D1: 1 g/100 g; D2: 2 g/100 g). Three experiments were carried out: a) 45-day feeding, b) digestibility, and c) radiation exposure experiment. After the 45-day feeding experiment, no significant differences were found in growth and survival. Accumulation of UACs was detected only in animals fed D1 and D2, and concentration was significantly higher in animals fed D2, with concentrations (12.58 ± 3.50 OD g -1 ) and (3.17 ± 0.4 OD g -1 ) after 45-day feeding and after 7-day UVR exposure, respectively. After 7 days of exposure to different light treatments, significant differences were recorded inradical scavenging activities. In all UVR treatments, rapid signal decay was recorded in the first 5 min of reaction. The red seaweed Grateloupia cf. turuturumeal constitutes an interesting source of photoprotective compounds as an additive in the diet of A. longinaris., (© 2022 The American Society for Photobiology.)

We investigated whether topical brimonidine delayed or enhanced the development of squamous cell carcinoma (SCC) when ultraviolet radiation (UVR) was applied to a well-established murine model. Hairless female mice (n = 125) were randomized into five groups and treated as follows: 1% brimonidine cream before UVR (Group 1), 0.33% brimonidine gel before UVR (Group 2), 1% brimonidine cream after UVR (Group 3), UVR only (control; Group 4) and 1% brimonidine cream only (control; Group 5). For each animal, the first four tumors were recorded and followed until three tumors reached 4 mm or one tumor reached 12 mm in diameter. All animal experiments continued for up to 365 days or until death. Application of 1% brimonidine cream before UVR delayed tumor development relative to control mice treated with UVR alone (P = 0.000006). However, when 0.33% brimonidine gel was applied before UVR (P = 0.313) or 1% brimonidine cream was applied after UVR (P = 0.252), there was no significant delay in tumor development relative to control mice treated with UVR alone. The development of the second and third tumors followed a similar pattern. Topical 1% brimonidine cream applied before UVR exposure delayed SCC development in hairless mice. In contrast, when brimonidine was applied after UVR there was no significant delay in tumor development. These results suggest that the 1% brimonidine cream probably absorbed the UVR, and therefore, a delay in tumor formation was only seen when brimonidine was applied before irradiation. However, there can be multiple reasons for this delay in photocarcinogenesis., (© 2022 The Authors. Photochemistry and Photobiology published by Wiley Periodicals LLC on behalf of American Society for Photobiology.)

Collagen-tripeptide (CTP) and galacto-oligosaccharide (GOS), which improve collagen homeostasis and barrier function in the skin, are widely used in the food industry to improve wrinkle-related parameters and skin health. In this study, the photoprotective effect of CTP/GOS mixtures (3:1, 1:1, and 1:3) in ultraviolet (UV) B-irradiated hairless mice was examined. Skin parameter analysis, histological approaches, molecular biology techniques and HPLC analysis were applied to investigate the photoaging protective effect, signaling pathways and changes in the microbiota. Oral administration of CTP/GOS mixtures ameliorated photoaged physical parameters and serum levels of pro-inflammatory cytokines compared to UV-irradiated control group. Administration of the 1:3 mixture showed significant changes in the extracellular matrix-related gene expression compared to other mixture groups. The cecal short-chain fatty acid (SCFA) content showed a significant increase in the CTP/GOS mixed group with a higher GOS content than the control group. In the 16S rRNA-based analysis of cecal microbiota, the relative abundance ratio of the Akkermansia genus belonging to the Verrucomicrobia phylum was higher in CTP and GOS mixture-administered groups than in the UV-irradiated control group. Taken together, CTP/GOS mixtures showed a synergistic effect on photoprotective activity through changes in the gene expression, cytokine levels and intestinal microbiota composition., (© 2022 American Society for Photobiology.)

The epidermis maintains a cellular calcium gradient that supports keratinocyte differentiation from its basal layers (low) to outer layers (high) leading to the development of the stratum corneum, which resists penetration of UV radiation. The calcium-sensing receptor (CaSR) expressed in keratinocytes responds to the calcium gradient with signals that promote differentiation. In this study, we investigated whether the CaSR is involved more directly in protection from UV damage in studies of human keratinocytes in primary culture and in mouse skin studied in vivo. siRNA-directed reductions in CaSR protein levels in human keratinocytes significantly reduced UV-induced direct cyclobutane pyrimidine dimers (CPD) by ~80% and oxidative DNA damage (8-OHdG) by ~65% compared with control transfected cells. Similarly, in untransfected cells, the CaSR negative modulator, NPS-2143 (500 nm), reduced UV-induced CPD and 8-OHdG by ~70%. NPS-2143 also enhanced DNA repair and reduced reactive oxygen species (ROS) by ~35% in UV-exposed keratinocytes, consistent with reduced DNA damage after UV exposure. Topical application of NPS-2143 also protected hairless Skh:hr1 mice from UV-induced CPD, oxidative DNA damage and inflammation, similar to the reductions observed in response to the well-known photoprotection agent 1,25(OH) 2 D 3 (calcitriol). Thus, negative modulators of the CaSR offer a new approach to reducing UV-induced skin damage., (© 2022 The Authors. Photochemistry and Photobiology published by Wiley Periodicals LLC on behalf of American Society for Photobiology.)

Photoaging refers to the extrinsic aging resulting from ultraviolet (UV) irradiation, which impacts skin appearance and is accompanied by the risk of skin carcinoma. Developing natural products as photoprotective agents is of great interest in cosmetic industry nowadays. The present study aimed at investigating the possible use of Artemisia sieversiana Ehrhart essential oil (AEO) for the prevention of photoaging induced by UVB. AEO was characterized by chamazulene, which accounted for 38.92% among total 51 identified compounds. In in vitro assays, AEO was found to be a moderate antioxidant and good UVB filter with photostability. A UVB-induced photoaging mice model was established with three AEO formulations (0.1%, 0.5% and 1.5%, w/w) topically applied prior to UVB irradiation. The activities of catalase, particularly superoxide dismutase of skin increased, while malondialdehyde content decreased in AEO groups as compared with model controls. The production of matrix metalloproteinases (MMP-1 and MMP-3) and depletion of hydroxyproline in skin were inhibited by AEO in a dose-dependent manner. Histological evaluation indicated that AEO decreased epidermal thickness, inflammatory cell infiltration, collagen degradation and elastin aberrance. These findings indicated that AEO could be a promising sunscreen agent in protecting the skin against photoaging., (© 2021 American Society for Photobiology.)

Nucleotide excision repair (NER) is one of the main pathways for genome protection against structural DNA damage caused by sunlight, which in turn is extensively related to skin cancer development. The mutation spectra induced by UVB were investigated by whole-exome sequencing of randomly selected clones of NER-proficient and XP-C-deficient human skin fibroblasts. As a model, a cell line unable to recognize and remove lesions (XP-C) was used and compared to the complemented isogenic control (COMP). As expected, a significant increase of mutagenesis was observed in irradiated XP-C cells, mainly C>T transitions, but also CC>TT and C>A base substitutions. Remarkably, the C>T mutations occur mainly at the second base of dipyrimidine sites in pyrimidine-rich sequence contexts, with 5'TC sequence the most mutated. Although T>N mutations were also significantly increased, they were not directly related to pyrimidine dimers. Moreover, the large-scale study of a single UVB irradiation on XP-C cells allowed recovering the typical mutation spectrum found in human skin cancer tumors. Eventually, the data may be used for comparison with the mutational profiles of skin tumors obtained from XP-C patients and may help to understand the mutational process in nonaffected individuals., (© 2021 American Society for Photobiology.)

Intense and constant exposure to UVB radiation can lead to inflammation and oxidative stress, which are associated with many cutaneous disorders, including photoaging and skin cancer. Antioxidant plant materials that are rich in polyphenols, such as the ethyl acetate fraction (EAF) from Eugenia hiemalis leaves, and phenolic compounds represent a promising approach to protect the skin against UVB-induced damage. The present study evaluated the photochemoprotective potential of the EAF and its 2,6-di-O-galloylarbutin (1) isolate. The EAF and the phenolic antioxidant (1) reduced UVB-induced L929 fibroblast death. The EAF prevented UVB-induced damage in fibroblasts by inhibiting the intracellular production of reactive oxygen species and lipid peroxidation, especially in pretreated cells. Topical treatment with an emulsion with 1% EAF prevented/attenuated UVB-induced inflammation and oxidative stress in the skin in hairless mice by controlling the increase in myeloperoxidase activity, reducing superoxide anion production, maintaining radical-scavenging ability and ferric reducing power, and controlling the depletion of reduced glutathione and catalase levels. The EAF also inhibited the increase in epidermal thickness, mast cell infiltration, the number of sunburn cells and collagen fiber destruction that were triggered by UVB. The in vitro and in vivo results indicated that the EAF is a bioactive agent that is able to protect the skin against the harmful effects of UVB., (© 2021 American Society for Photobiology.)

In the last few years, the focus of phototherapy has shifted toward the visible (400-700 nm) part of the electromagnetic spectrum of light. Lately, it has been demonstrated that visible light (VL) can have both beneficial and detrimental effects, especially on the skin. Previously and until now, the most harmful effects on the skin are associated with ultraviolet radiation (UVR). After exposure to natural light, the most evident and immediate change is observed on skin pigmentation. Various wavelengths within the visible spectrum have been reported to alter skin pigmentation. However, the underlying mechanisms are incompletely understood so far. The article aims to shed light on the progress made in the photobiology field (photobiomodulation, PBM) to study the role of visible light on skin melanocytes., (© 2021 The Authors. Photochemistry and Photobiology published by Wiley Periodicals LLC on behalf of American Society for Photobiology.)

Overexpression of PD-L1 (CD274) on tumor cells may represent a hallmark of immune evasion, and overexpression has been documented in several tumors including cutaneous squamous cell carcinoma (cSCC). While PD-L1/PD-1 activity in the skin has been primarily described in inflammatory models, our goal was to examine PD-L1 expression in human keratinocytes exposed to UV irradiation. We assessed PD-L1 expression in human sun-protected (SP) and sun-damaged (SD) skin, actinic keratosis (AK), and cSCC using IHC and protein microarray. Both methods found low baseline levels of PD-L1 in SP and SD skin and significantly increased expression in cSCC. Next, we examined PD-L1 expression in acute models of UV exposure. In human SP skin exposed to 2-3 MED of UV (n = 20), epidermal PD-L1 was induced in 70% of subjects after 24 h (P = 0.0001). SKH-1 mice exposed to acute UV also showed significant epidermal PD-L1 induction at 16, 24 and 48 h. A time- and dose-dependent induction of PD-L1 was confirmed in cultured human keratinocytes after UV, which was markedly reduced in the presence of MEK/ERK, JNK or STAT3 inhibitors. These findings suggest that UV induces upregulation of PD-L1 through established, pharmacologically targetable stress-signaling pathways in keratinocytes., (© 2021 American Society for Photobiology.)

The COVID-19 pandemic has generated a great deal of interest in ultraviolet germicidal irradiation (UVGI) as an important means to disinfect air and surfaces. The traditional lamp employed for UVGI has been the low-pressure mercury-discharge lamp that emits primarily at 254 nm in the ultraviolet photobiological band UV-C (100-280 nm). The recent development of even shorter-wavelength UV-C lamps, such as the Krypton-Chloride, 222-nm lamp, has led to greater concerns about the UV-C generation of ozone. It is well known that wavelengths below 240 nm more readily generate ozone. However, there is a great misunderstanding with regard to the actual generation and dissipation of ozone molecules by UV-C lamps. A review of this subject is much warranted. An overview of the ozone generation of various UV-C light sources is presented to give users a better understanding of risk and how to assure control of ozone when employing UV-C lamps., (© 2021 American Society for Photobiology.)

The COVID-19 pandemic has greatly heightened interest in ultraviolet germicidal irradiation (UVGI) as an important intervention strategy to disinfect air in medical treatment facilities and public indoor spaces. However, a major drawback of UVGI is the challenge posed by assuring safe installation of potentially hazardous short-wavelength (UV-C) ultraviolet lamps. Questions have arisen regarding what appear to be unusually conservative exposure limit values in the UV-C spectral band between 180 and 280 nm. We review the bases for the current limits and proposes some adjustments that would provide separate limits for the eye and the skin at wavelengths less than 300 nm and to increase both skin and eye limits in the UV-C below 250 nm., (© 2021 The Authors. Photochemistry and Photobiology published by Wiley Periodicals LLC on behalf of American Society for Photobiology.)

Far-UVC devices are being commercially sold as "safe for humans" for the inactivation of SARS-CoV-2, without supporting human safety data. We felt there was a need for rapid proof-of-concept human self-exposure, to inform future controlled research and promote informed discussion. A Fitzpatrick Skin Type II individual exposed their inner forearms to large radiant exposures from a filtered Krypton-Chloride (KrCl) far-UVC system (SafeZoneUVC, Ushio Inc., Tokyo, Japan) with peak emission at 222 nm. No visible skin changes were observed at 1500 mJ cm -2 ; whereas, skin yellowing that appeared immediately and resolved within 24 h occurred with a 6000 mJ cm -2 exposure. No erythema was observed at any time point with exposures up to 18 000 mJ cm -2 . These results combined with Monte Carlo Radiative Transfer computer modeling suggest that filtering longer ultraviolet wavelengths is critical for the human skin safety of far-UVC devices. This work also contributes to growing arguments for the exploration of exposure limit expansion, which would subsequently enable faster inactivation of viruses., (© 2021 The Authors. Photochemistry and Photobiology published by Wiley Periodicals LLC on behalf of American Society for Photobiology.)

Germicidal ultraviolet radiation (GUV) provides a means of dramatically reducing airborne spread of microorganisms in residential and workspace environments. Regarding design and use of GUV, both efficacy and safety data have accumulated over several decades, with a substantial increase of attention during the current COVID-19 pandemic. Considerations for skin and eye safety previously resulted in guidance on exposures in institutional and workplace settings. This report details the evolution of limits for skin exposures, with particular attention to the risk of skin neoplasia., (© 2020 American Society for Photobiology.)

In this study, ocular biologically effective exposure to solar ultraviolet radiation (UVBE) is investigated with six kinds of sun protective measures (spectacle lenses, sunglasses, cap, bonnet, straw hat and under parasol). Ocular UV exposure measurements were performed on manikins during the summer period in Shenyang city (41.64° N, 123.50° E, 66 m a.s.l.), China. The measurements include the ocular UV exposure of an unprotected eye and the ambient UV as a control concurrently. Based on the relative spectral weighting factors of the International Commission on Non-Ionizing Radiation Protection (ICNIRP), the ocular biologically effective UV is calculated and compared with the 8-h exposure limits of ICNIRP (30 J m -2 ). The UV index (UVI) of the measurement days is 0-8, and the 8-h (8:00-16:00 China Standard Time, CST) cumulated UVBE of the unprotected eye is 452.0 J m -2 . The 8-h cumulated UVBE of the eye with spectacle lenses, sunglasses, cap, bonnet, straw hat and under parasol are 364.2, 69.1, 51.4, 49.0, 56.8 and 110.2 J m -2 , respectively. Importantly, it should be noted that the eye could be exposed to risk despite protective measures. The 8-h cumulated UVBE of the eye with protection is ca 1.6-15.1 times the exposure limit, respectively. As indicated in the present study, during summer months, high exposure to the sun for more than 30 min without eye protection and more than 1 h with eye protection is not advisable. The protection measures could effectively reduce the UVBE reaching the eye, yet there is still a high degree of risk when compared with the ICNIRP 8-h exposure limits., (© 2020 American Society for Photobiology.)

Aging, a universal and unique process, occurs both intrinsically (chronological) and extrinsically (photoaging). Ultraviolet-A (UV-A)-mediated stress is a growing health hazard to mankind as it is the major cause of photoaging, which could lead to much damage of skin cells and tissues ranging from tan, burn, or even cancer. The present study focuses on the role of antioxidants and other natural compounds which have been widely used in oral/topical applications to combat and delay the effects of photoaging using model nematode Caenorhabditis elegans. Compounds like green tea extract, naringenin, and naringin, which are known for their antioxidant properties, were able to extend life span and healthspan of the nematode in normal as well as under UV-A-mediated stress conditions. Regulation of both the stress-responsive genes (skn-1 and sir-2.1) and the aging-regulating genes (daf-2 and age-1) was attributable for these conditions. Interestingly, it was observed that these compounds when combined in equal ratios by weight worked synergistically to combat the aging process. Pronounced synergistic effects were observed during UV-A-mediated stress conditions, suggesting that these could be used as potential antiphotoaging compounds which will be of greater significance for health-based research., (© 2019 American Society for Photobiology.)

Ginsenosides are compounds responsible for the primary pharmacological effects of American ginseng. Compound-Y (C-Y) is a minor ginsenoside and a metabolite of Panax ginseng. In this study, we investigated the protective effect of ginsenoside UVB-irradiated NHDFs and its potential for use as an antihyperpigmentation agent through ginsenoside C-Y as a functional food and cosmetic ingredient. Ginsenoside C-Y is a natural antioxidant isolated from the American ginseng PDD-ginsenoside. Our data showed that ginsenoside C-Y block UVB-exposed ROS, restrict MMP-1 production and promote procollagen type I synthesis. Interestingly, ginsenoside C-Y suppresses UVB-exposed VEGF, and TNF-α secretion, could be related with NFAT signal path. Ginsenoside C-Y has exhibited photoaging effects by increasing TGF-β1 level, fortifying Nrf2 nuclear translocation and restricting AP-1 and MAPK phosphorylation. Assessment of the melanogenic response indicated that ginsenoside C-Y inhibited melanin secretion and tyrosinase activity and decreased melanin content in Melan-a and zebrafish embryos. These results suggest that ginsenoside C-Y can be used as a potential botanical agent to protect premature skin from UVB-induced photodamage and prevent skin hyperpigmentation., (© 2019 American Society for Photobiology.)

According to the World Health Organization and partner organizations, no protection against ultraviolet (UV) radiation is required on days with "low" values (i.e., values <3) of the Global Solar Ultraviolet Index (UVI). Erythemal irradiance (E er ) data of such days were analyzed to evaluate this claim. Measurements from 9 stations of the German solar UV monitoring network from 2007 to 2016 yielded 14,431 daily E er time series of low UVI days. Erythemal doses for certain fixed time intervals-acquired from measurements on horizontal planes-were compared with the average minimal erythemal dose (MED) of skin phototype II. Doses from days with rounded UVI values of 0 were insufficient to induce erythema and even on days with rounded UVI values of 1 doses exceeding 1 MED of skin type II could only be acquired under very specific circumstances of prolonged exposure. Conversely, sun exposure on days with rounded UVI values of 2 can indeed provide doses sufficient to induce erythema in skin type II after two hours around noon. In conclusion, our analyses do not support the claim of harmlessness currently associated with the entire low UVI exposure category in public guidance on interpretation of the UVI., (© 2019 American Society for Photobiology.)

In vivo and in vitro studies have shown that prolonged oral administration of flavanol-rich cocoas extracts have photoprotective effects. The aim of the present study was to assess the photoprotective activity of short-time administration of a new variety of naturally selected cocoa extract rich in bioactive compounds. We selected a cocoa powder particularly rich in polyphenols, flavanols, caffeine, theobromine and theophylline. We then investigated, in 10 healthy subjects, the photoprotective effects of one week of daily oral administration of two doses of such powder. Phototesting with solar simulated radiation was performed at baseline and after cocoa supplementation. Visual assessment of the minimal erythema dose and spectrophotometric measurement of the "a" parameter were done after 24 h from the irradiation. Oral daily supplementation of 1 g of high-flavanol cocoa was not effective but a one-week administration of 4-6 g of cocoa induced a statistically significant increase in the visual erythema threshold and a significant reduction in the "a" parameter. We demonstrated that a new variety of naturally selected cocoa extract, even when administered for a short time, retains a dose-dependent photoprotective effect. These results are also indicative of the fact that topical sunscreens could be supplemented by a specific diet., (© 2019 American Society for Photobiology.)

The potential role of infrared radiation in photodermatoses has received very little attention, even though the main sources of radiation used for photobiological studies (UVA, UVB and visible light) include infrared radiation. The objective of the work was to assess whether infrared radiation is involved in the development of skin lesions in patients with different types of photodermatoses. Twenty patients with different photodermatoses were exposed to UVA, UVB and visible radiation using a high-pressure mercury UVA lamp, a fluorescent broadband UVB lamp, a tungsten bulb and a slide projector for visible radiation. Part of the radiation emitted by these lamps was water-filtered to block infrared radiation above 1300 nm. All 20 patients developed lesions when exposed to different light sources used for phototest. When exposed to same sources without infrared radiation, 17 patients (85%) did not develop any lesions and the other three (15%) developed less severe lesions than in the area exposed to unfiltered light. Our results show that infrared radiation was necessary for the development of skin lesions in 85% of the patients with photodermatoses in our study. We believe that infrared radiation studies should be included in standard photobiology protocols., (© 2018 The American Society of Photobiology.)

Shade is an important means of protection against harmful effects of sun ultraviolet (UV) exposure, but not all shades are identically protective. UV rays scattered by the atmosphere and surroundings can reach the skin indirectly. To evaluate the relative contribution of the direct, diffuse, and reflected radiation in UV protection provided by different sizes of shade structure, we used SimUVEx v2, a numeric tool based on 3D graphic techniques and ambient ground UV irradiance. The relative UV exposure reduction was expressed by the predictive protection factor (PPF). Shade structures were found to predominantly reduce exposure from direct radiation (from 97.1% to 99.9% for the upper body areas such as the head and the neck), with greater protection from larger shade structures and structures closer above the subject. Legs were the least protected anatomical zone from any shade structure above the subject with PPF ranging from 18.5% to 68.1%. Throughout the day, except for lower solar zenith angles (SZA), small and high shade structures provide the lowest protection (between 20% and 50%), while small and low shade structure show PPF between 35% and 65% and large and high shade structures reach PPF higher than 60%., (© 2018 The American Society of Photobiology.)

Solar ultraviolet radiation is the primary risk factor for skin cancers and sun-related eye disorders. Estimates of individual ambient ultraviolet irradiance derived from ground-based solar measurements and from satellite measurements have rarely been compared. Using self-reported residential history from 67 189 persons in a nationwide occupational US radiologic technologists' cohort, we estimated ambient solar irradiance using data from ground-based meters and noontime satellite measurements. The mean distance moved from city of longest residence in childhood increased from 137.6 km at ages 13-19 to 870.3 km at ages ≥65, with corresponding increases in absolute latitude difference moved. At ages 20/40/60/80, the Pearson/Spearman correlation coefficients of ground-based and satellite-derived potential solar ultraviolet exposure, using irradiance and cumulative radiant exposure metrics, were high (=0.87-0.92). There was also moderate correlation (Pearson/Spearman correlation coefficients = 0.51-0.60) between irradiance at birth and at last-known address, for ground-based and satellite data. Satellite-based lifetime estimates of ultraviolet radiation were generally 14-15% lower than ground-based estimates, albeit with substantial uncertainties, possibly because ground-based estimates incorporate fluctuations in cloud and ozone, which are incompletely incorporated in the single noontime satellite-overpass ultraviolet value. If confirmed elsewhere, the findings suggest that ground-based estimates may improve exposure assessment accuracy and potentially provide new insights into ultraviolet radiation-disease relationships in epidemiologic studies., (© 2018 The American Society of Photobiology.)

Nonmelanoma and melanoma skin cancers are attributable to DNA damage caused by ultraviolet (UV) radiation exposure. One DNA photoproduct, the cyclobutane pyrimidine dimer (CPD), is believed to lead to DNA mutations caused by UV radiation. Using radiative transfer simulations, we compare the number of CPDs directly induced by UV irradiation from artificial and natural UV sources (a standard sunbed and the midday summer Mediterranean sun) for skin types I and II on the Fitzpatrick scale. We use Monte Carlo radiative transfer (MCRT) modeling to track the progression of UV photons through a multilayered three dimensional (3D) grid that simulates the upper layers of the skin. By recording the energy deposited in the DNA-containing cells of the basal layer, the number of CPDs formed can be quantified. The aim of this work was to compare the number of CPDs formed in the basal layer of the skin and by implication the risk of developing cancer, as a consequence of irradiation by artificial and natural sources. Our simulations show that the number of CPDs formed per second during sunbed irradiation is almost three times that formed during solar irradiation., (© 2018 The American Society of Photobiology.)

Erythema is widely considered an indicator of skin cancer susceptibility, but assessments are challenging in black skin because melanin can mask erythema under traditional visual and advanced objective Commission Internationale de l'Eclairage (CIE) L*a*b* assessments. Using spectral measurements (400-700 nm) from a spectrophotometer, an algorithm was developed to measure erythema in white Caucasians (n = 9) and black West Africans (n = 11) 19-24 h postsolar simulated radiation (SSR) exposures to the volar forearm. The derived spectrum achieved showed a strong maximum peak for hemoglobin at 580 nm and a linear slope between 650 and 700 nm for melanin absorption, as reported by other authors. Absorption by hemoglobin at 580 nm was used as a proxy for erythema, and melanin was quantified between 650 and 700 nm. Our algorithm corrected the erythema measurements for stray specular (mirror-like) reflection and the melanin-masking effect. A linear relationship between SSR exposure and erythema was evident (p < 0.0001 for white and black skin), and white skin is 8.4 times more responsive to SSR compared to black skin. The prediction of ultraviolet radiation sensitivity is vital in both clinical and investigative dermatology especially in the determination of starting phototherapy doses. Our methodology allows for the accurate assessment of erythema independent of constitutive pigmentation., (© 2018 The American Society of Photobiology.)

Black currants (Ribes nigrum L, RN) are known as a "super fruit" to possess for their many potential health benefits such as the alleviation of oxidative stress-related disorders. However, little skin photoaging-related research has been done on the use of this agent. In the present study, we investigated the protective effects of RN in UVB-irradiated human dermal fibroblasts (NHDFs). RN treatment in UVB-irradiated skin models alleviated UVB-mediated photoaging through several mechanisms: Treatment with RN downregulated MAPK-related signaling models, such as those of activation protein 1 (AP-1) and nuclear factor kappa B (NF-κB). In addition, phase II gene heme oxygenase-1 (HO-1) was modulated by the increase in nuclear factor erythroid 2-related factor 2 (Nrf2) in the nuclear, and finally, transforming growth factor TGF-β was upregulated in vitro. Further study indicated that UVB-induced production of MMP-1 and IL-6 could be inhibited by PD 98059 (an inhibitor of ERK) and SP600125 (an inhibitor of JNK). Thus, RN improved the expression of type I procollagen and inhibited UVB-induced MMP-1 and IL-6 secretion through inactivating MAPK cascades. Therefore, RN is a suitable target for further investigation as an antiphotoaging agent and may have applications in the skincare industry., (© 2018 The American Society of Photobiology.)

One approach to protect the human skin against harmful effects of solar ultraviolet (UV) radiation was to use natural products as photoprotectors. In this work, the extract from specie Phyllanthus orbicularis K was evaluated as a protective agent against the photodamage by UVB, UVA artificial lamps, and environmental sunlight exposure. The plasmid DNA solutions were exposed to radiations using the DNA dosimeter system in the presence of plant extract. The DNA repair enzymes, Escherichia coli Formamidopyrimidine-DNA glycosylase (Fpg) and T4 bacteriophage endonuclease V (T4-endo V), were employed to discriminate oxidized DNA damage and cyclobutane pyrimidine dimers (CPD), respectively. The supercoiled and relaxed forms of DNA were separated through electrophoretic migration in agarose gels. These DNA forms were quantified to determine strand break, representing the types of lesion levels. The results showed that, in the presence of P. orbicularis extract, the CPD and oxidative damage were reduced in irradiated DNA samples. The photoprotective effect of extract was more evident for UVB and sunlight radiation than for UVA. This work documented the UV absorbing properties of P. orbicularis aqueous extract and opened up new vistas in its characterization as protective agent against DNA damage induced by environmental sunlight radiation., (© 2018 The American Society of Photobiology.)

Notoginseng is a traditional herbal medicine widely used for medicinal therapy in Asia, as it contains numerous ginsenosides with pharmacological effects. In this study, we submitted Notoginseng stem-leaf (NGL) ginsenosides to an enzyme to create a reaction with the monomer products of ginsenoside C-Mx and then investigated the ability of ginsenoside C-Mx to protect the skin against ultraviolet B-induced injury in normal human dermal fibroblasts (NHDFs). Ginsenoside C-Mx alleviated UVB-induced intracellular reactive oxygen species (ROS), MMP-1 and IL-6 expression while accelerating TGF-β and procollagen type I secretion. In addition, ginsenoside C-Mx reversed UVB-induced procollagen type I reduction by regulating the TGF-β/Smad signaling pathway. Moreover, ginsenoside C-Mx inhibited activation of AP-1 transcription factor, an inducer of MMPs. Ginsenoside C-Mx displayed an outstanding antioxidant capacity, increasing expression of cytoprotective antioxidants such as HO-1 and NQO-1 expression by enhancing the nuclear accumulation of Nrf2. Interestingly, application of ginsenoside C-Mx treatment (1, 10, 20 μm) significantly diminished UVB-induced suppressed NF-κB expression, decreasing the over-released inflammatory cytokines. Taken together, our findings indicated that ginsenoside C-Mx may act as a promising natural cosmetic ingredient for prevention and treatment of UVB-induced skin damage., (© 2018 The American Society of Photobiology.)

The maintenance of ground-based instruments to measure the incidence of ultraviolet radiation (UVR) from the Sun demands strict and well-developed procedures. A piece of equipment can be out of service for a couple of weeks or months for calibration, repair or even the improvement of the facilities where it has been set up. However, the replacement of an instrument in such circumstances can be logistically and financially prohibitive. On the other hand, the lack of data can jeopardize a long-term experiment. In this study, we introduce a semiempirical approach to the determination of the theoretical daily erythemal dose (DED t ) for periods of instrumental absence in a tropical site. The approach is based on 5 years of ground-based measurements of daily erythemal dose (DED) linearly correlated with parameters of total ozone column (TOC) and reflectivity (R PC ) from the Ozone Monitoring Instrument (OMI) and the cosine of solar zenith angle at noon (SZA n ). Seventeen months of missing ground-based data were replaced with DED t , leading to a complete 5-year series of data. The lowest and the highest values of typical DED were 2411 ± 322 J m -2 (1σ) (winter) and 5263 ± 997 J m -2 (summer). The monthly integrated erythemal dose (mED) varied from 59 kJ m -2 (winter) to 162 kJ m -2 (summer). Both of them depended mainly on cos(SZA n ) and R PC . The 12-month integrated erythemal dose (12-ED) ranged from 1350 kJ m -2 to 1546 kJ m -2 , but it can depend significantly on other atmospheric parameter (maybe aerosols) not explicitly considered here., (© 2018 The American Society of Photobiology.)

Photoprotection is essential to prevent the long-term deleterious effects of ultraviolet (UV), including skin cancer and photoaging. So far, there has been an increase in the use of natural bioactive phytochemicals for the development of more effective skin photoprotective agents. However, the molecular mechanisms underlying the photochemoprotection activity of such compounds remain largely unknown. The objective of this study was to investigate the effects of a Sechium edule fruit extract (SEE) in terms of photoprotection against UVA in primary human keratinocytes. We found that SEE protected keratinocytes against UVA-induced cytotoxicity, decreased the intracellular amounts of reactive oxygen species, and reduced oxidatively induced DNA lesions after UVA exposure. Furthermore, SEE decreased the induction of CPD lesions in UVA-irradiated keratinocytes and exhibited increased DNA repair of such photoproducts at 24 h postexposure. Finally, using DNA repair biochips, we demonstrated that SEE-treated keratinocytes had DNA enzymatic repair activities more efficient for abasic sites, CPD and thymine glycols. Therefore, the benefits of SEE against UVA could be explained by a combination of antioxidant activity, the reduction in DNA damage, and the enhancement of DNA repair capacities., (© 2017 The American Society of Photobiology.)

Continuous exposures to ultraviolet radiation can lead to harmful effects on human skin. Professional drivers may spend more than 8 h per day inside a vehicle. This study describes an analysis of the UVER (erythemal ultraviolet radiation) received by a driver and passenger inside a vehicle. A three-door Peugeot 206 was used for the study. VioSpor Blue Line dosimeters (with a response profile close to that of human skin) were used to measure the erythematic dose of UV radiation (able to produce erythema on human skin). Four dosimeters were placed in the driver's position and another four in the passenger's position. Daily irradiance was analyzed for a day in April using PMA radiometers. The measurements were obtained on relatively clear days from February to December 2009 between 9:30 A.M. and 3 P.M. Additionally, a prediction was made of the time required to produce an erythema on the driver's skin. UVER exposure, in some of the driver's positions, exceeds the Exposure Limits given by the International Commission on Non-Ionizing Radiation Protection (ICNIRP). Skin protection measures should be taken into account by professional drivers to prevent the harmful effects of UVER radiation., (© 2017 The American Society of Photobiology.)

Sorbus commixta is a traditional oriental medicinal plant that grows in East Asian countries such as Korea, Japan and China. The twig of S. commixta has been considered valuable for centuries to treat diseases including asthma, cough and other bronchial disorders. However, the effect of S. commixta twig extract on human skin has not been investigated well. The present study aimed at assessing the antiphotoaging effect of S. commixta twig ethanol extract (STE) on ultraviolet B (UVB)-induced matrix metalloproteinase (MMP) levels and its underlying mechanism in human dermal fibroblasts. In this study, we found that STE (12.5-50 μg mL -1 ) treatment significantly inhibited UVB-induced MMP-1, MMP-2 and MMP-3 expression, concomitant with a downregulation of intracellular ROS generation. These effects might be associated with a STE-induced inhibition of the mitogen-activated protein kinase (MAPK) pathway. Furthermore, STE also downregulated UVB-induced c-Fos expression in a concentration-dependent manner, but had no inhibitory effect on c-Jun phosphorylation. Taken together, these results indicate that STE may be an antiphotoaging agent and that its effect may occur via its inhibition of MMPs expression and MAPK pathway activation., (© 2017 The American Society of Photobiology.)

The sun protection factor (SPF) is the most important quantity to characterize the performance of sunscreens. As the standard method for its determination is based on clinical trials involving irradiation of human volunteers, calculations of sunscreen performance have become quite popular to reduce the number of in vivo studies. Such simulations imply the calculation of UV transmittance of the sunscreen film using the amounts and spectroscopic properties of the UV absorbers employed, and presuppose the validity of the Beer-Lambert law. As sunscreen films on human skin can contain considerable concentrations of UV absorbers, it is questioned whether the Beer-Lambert law is still valid for these systems. The results of this work show that the validity of the Beer-Lambert law is still given at the high concentrations at which UV absorbers occur in sunscreen films on human skin., (© 2017 The American Society of Photobiology.)

Ultraviolet radiation (UVR) is one of the most important environmental factors involved in photoaging. Exposure to UVR leads to dysregulation of expression of cell cycle-related proteins which play key role in skin photodegradation that pretends to develop carcinogenesis. This study examines the role of various UVB doses on the expression of transforming growth factor beta (TGF-β), Smad2, cathepsin K, progerin and matrix metalloproteinases (MMPs)-1,-3,-8,-9. A group consisting of 63 healthy individuals underwent one of the following treatments: (1) whole body exposed to UVB irradiation on each of 10 consecutive days with 0.7 MED, or (2) whole-body irradiation as described followed by a single erythemal UVB dose on a small body area, or (3) irradiated only with a single erythemal UVB dose on small body area, or (4) were not irradiated at all (control group). When we compared all irradiated groups to the control group, there was significantly higher expression of TGF-β, MMP-1,-3,-9 and cathepsin K proteins evaluated by Western blot method. The results suggest the role of UVB in impairment of proteins expression that is involved in cell cycle's regulation. Changes in the protein expression involved by acute and chronic UVR confirm its essential role in skin photodestruction. Moreover, obtained result indicates the tendency to occurrence of photoadaptation phenomenon., (© 2017 The American Society of Photobiology.)

Ultraviolet-A light (UVA)-induced DNA damage and repair in red blood cells to investigate the sensitivity of African catfish to UVA exposure is reported. Fishes were irradiated with various doses of UVA light (15, 30, and 60 min day -1 for 3 days). Morphological and nuclear abnormalities in red blood cells were observed in the fish exposed to UVA compared with controls. Morphological alterations such as acanthocytes, crenated cells, swollen cells, teardrop-like cells, hemolyzed cells, and sickle cells were observed. Those alterations were increased after 24 h exposure to UVA light and decreased at 14 days after exposure. The percentage of apoptosis was higher in red blood cells exposed to higher doses of UVA light. No micronuclei were detected, but small nuclear abnormalities such as deformed and eccentric nuclei were observed in some groups. We concluded that exposure to UVA light induced DNA damage, apoptosis, and morphological alterations in red blood cells in catfish; however, catfish were found to be less sensitive to UVA light than wild-type medaka., (© 2017 The American Society of Photobiology.)

This study investigated poly(ADP-ribose) polymerase-1 (PARP-1) activation in cultured human lens epithelial cells exposed to two levels of UVB light (312 nm peak wavelength), 0.014 and 0.14 J cm -2 ("low" and "high" dose, respectively). At the low dose, PARP-1 and poly(ADP-ribose) (PAR) polymers acted to repair DNA strand breaks rapidly with no subsequent major effects on either cell morphology or viability. However, following the high UVB dose, there was a dramatic second phase of PARP-1 activation, 90 min later, which included a sudden reappearance of DNA strand breaks, bursts of reactive oxygen species (ROS) formation within both the mitochondria and nucleus, a translocation of PAR from the nucleus to the mitochondria and an ultimate 70% loss of cell viability occurring after 24 h. The results provide evidence for an important role for PARP-1 in protecting the human lens epithelium against low levels of UVB light, and possibly participating in the triggering of cell death following exposure to toxic levels of radiation., (© 2017 The American Society of Photobiology.)