A human skin model to evaluate the protective effect of compounds against UVA damage

Abstract

OBJECTIVE: The main function of skin is to protect the body from external aggressions. Over time, normal skin ageing is accelerated by external stresses such as smoking, pollution, chemical products and radiation. UV light, in particular UVA, causes DNA damage, apoptosis and morphological modifications, which are responsible for both premature ageing and cancer. The aim of this study was to establish a discriminatory and sufficiently reproducible cutaneous model for evaluating UVA damage, to enable testing for effectiveness of potentially protective compounds. METHODS: The cutaneous model is based on Human skin explants irradiated with UVA. Deleterious effects on epidermis were observed and quantified by haematoxylin-eosin staining and by immunofluorescence of ɣ-H2Ax, cytokeratin 5, involucrin and loricrin protein. Dermis deterioration was evaluated by transmission electronic microscopy and zymography in situ. RESULTS:We were able to observe and quantify deleterious effects associated with UVA irradiation: epidermal and dermal disruption, appearance of Sunburn cells, increased DNA damage and induced apoptosis. The use of this model in the evaluation of protective compounds was first confirmed using sunscreens, then further validated with a panel of active ingredients which showed beneficial effects on epidermis morphology and DNA integrity after UVA exposure. CONCLUSION: We have developed a model and a standardized protocol, based on the use of human skin explants,

Preservation of epidermal melanocyte integrity in an ex vivo co‐culture skin model with sebocytes

“…Similar skin explants models were utilized in assessment of melanocytes disorders and the different factors that affect them. [36][37][38][39][40] Comparative studies between these models are required. Oil red staining is an established method for demonstrating lipids in lipogenic cells, such as sebocytes.…”

Prevalent skin and dermatoses care in older adults treated at a private clinic and its relationship with comorbidities

“…The fact that 26.25% of the older adults did not know what skin cancer is can justify the lack of care in relation to protection from the sun, because, in general, people are more engaged in preventive attitudes if they know about the damage and/or risks 18 . Sun exposure also causes other changes such as, for example, solar elastosis 3 which translates into increased fragmentation and porosity of the elastic fibers in the dermis 19,20 .…”

Role of miRNAs in melanin metabolism: Implications in melanin‐related diseases

“…UV is a common carcinogen in the environment, which can be divided into UVC (200-280 nm), UVB (280-320 nm), and UVA (320-400 nm). [89][90][91] UV is mostly absorbed by the epidermis, especially as α-melanin (MSH) and UV radiation. 92,93 After Melan-a cells are irradiated with a small dose of UV (60 mJ/cm 2 ), the expression of miRNA changes, which will produce a large amount of melanin, and can promote the transfer and transport of melanosomes.…”

“…UV is a common carcinogen in the environment, which can be divided into UVC (200–280 nm), UVB (280–320 nm), and UVA (320–400 nm) 89‐91 . UV is mostly absorbed by the epidermis, especially UVA and UVB, and only long‐wave UVC can be transmitted to the dermis.…”