Background: Due to its deep penetration into the dermis, ultraviolet A (UVA) radiation is considered a primary factor in skin photoageing. The aim of this study is to use a qualitative and quantitative analysis to determine the structural parameters of skin photoageing in mice exposed to UVA radiation, with or without the application of a photoprotective cream. Materials and methods: The experiment consisted of the radiation of female BALBc mice in a solarium by UVA rays, up to total dosages of 7800 J/cm2 and 12500 J/cm2. A total of 78 animals were divided into four experimental and two control groups. All animals were shaved and the animals in two experimental groups were treated with a photoprotective cream half an hour before exposure. The samples of the treated skin were stained with haematoxylin eosin and Van-Gieson staining methods. All measurements, except for the presence of dyskeratosis, were taken using ImageJ 150i software. Results: In the study, the signs of skin photoageing were more evident in untreated groups of animals. Dyskeratosis was more frequent in both of the untreated groups of animals (p= 0.004 and p= 0.003). The lowest values of epidermal thickness (13.8±2.6 μm and 12.7±2.3 μm) were present in both of the untreated groups of animals (p< 0.001 and p< 0.001). The highest values of stratum corneum thickness (34.3±8.5 μm) were observed in the untreated, shorter radiated group of animals (p< 0.001) which was irradiated for the shortest period of time. Beside the control groups, the highest length of dermo-epidermal junction was recorded in the group of treated, longer radiated animals (1467.6±94.6 μm; p= 0.373). The lowest values of dermal thickness (115.9±10.5 μm and 134.8±21.8 μm) and volumetric density of the collagen fibres (31.92±3.19% and 29.40±4.54%) were present in both untreated groups of animals (p< 0.001, p< 0.001, p= 0.035). Conclusions: Skin photoageing was most pronounced in the groups of animals irradiated without the application of photoprotective cream.

Abstract

Background: Due to its deep penetration into the dermis, ultraviolet A (UVA) radiation is considered a primary factor in skin photoageing. The aim of this study is to use a qualitative and quantitative analysis to determine the structural parameters of skin photoageing in mice exposed to UVA radiation, with or without the application of a photoprotective cream. Materials and methods: The experiment consisted of the radiation of female BALBc mice in a solarium by UVA rays, up to total dosages of 7800 J/cm2 and 12500 J/cm2. A total of 78 animals were divided into four experimental and two control groups. All animals were shaved and the animals in two experimental groups were treated with a photoprotective cream half an hour before exposure. The samples of the treated skin were stained with haematoxylin eosin and Van-Gieson staining methods. All measurements, except for the presence of dyskeratosis, were taken using ImageJ 150i software. Results: In the study, the signs of skin photoageing were more evident in untreated groups of animals. Dyskeratosis was more frequent in both of the untreated groups of animals (p= 0.004 and p= 0.003). The lowest values of epidermal thickness (13.8±2.6 μm and 12.7±2.3 μm) were present in both of the untreated groups of animals (p< 0.001 and p< 0.001). The highest values of stratum corneum thickness (34.3±8.5 μm) were observed in the untreated, shorter radiated group of animals (p< 0.001) which was irradiated for the shortest period of time. Beside the control groups, the highest length of dermo-epidermal junction was recorded in the group of treated, longer radiated animals (1467 …