The structural characteristics of photoaging in mice caused by the effects of ultraviolet A radiation

Sladjana Savic; Sonja Smiljic; Snezana Lestarevic; Aleksandra Ilic; Milica Mijovic; Predrag Mandic; Branislav Djerkovic

doi:10.5603/FM.a2019.0119

The structural characteristics of photoaging in mice caused by the effects of ultraviolet A radiation

Folia Morphol (Warsz). 2019 Nov 14. doi: 10.5603/FM.a2019.0119. Online ahead of print.

Authors

Sladjana Savic¹, Sonja Smiljic², Snezana Lestarevic³, Aleksandra Ilic⁴, Milica Mijovic⁵, Predrag Mandic⁶, Branislav Djerkovic⁵

Affiliations

¹ Department of Histology and Embryology, Medical Faculty Pristina, Kosovska Mitrovica, Serbia. sladjanasavic788@gmail.com.
² Department of Physiology, Medical Faculty Pristina, Kosovska Mitrovica,, Serbia.
³ Department of Histology and Embryology, Medical Faculty Pristina, Kosovska Mitrovica, Serbia.
⁴ Department of Medical Statistic and Informatics, Medical Faculty Pristina, Kosovska Mitrovica, Serbia.
⁵ Department of Pathology, Medical Faculty Pristina, Kosovska Mitrovica, Serbia.
⁶ Department of Anatomy, Medical Faculty Pristina, Kosovska Mitrovica, Serbia.

PMID: 31724149
DOI: 10.5603/FM.a2019.0119

Abstract

Background: Due to its deep penetration into the dermis, ultraviolet A (UVA) radiation is considered a primary factor in skin photoaging. The aim of this study is to use a qualitative and quantitative analysis to determine the structural parameters of skin photoaging in mice exposed to UVA radiation, with or without the application of a photoprotective cream.

Material 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 12500J/cm². A total of 78 animals were divided into 4 experimental and 2 control groups. All animals were shaved and the animals in 2 experimental groups were treated with a photoprotective cream half an hour before exposure. The samples of the treated skin were stained with Hematoxylin-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 photoaging were more evident in untreated groups of animals. Dysceratosis 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± 2.6μm and 12.7±2.3μm) 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±8.5μm) 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 (DEJ) was recorded in the group of treated, longer radiated animals (1467.6±94.6μm) (p=0.373). The lowest values of dermal thickness (115.9±10.5μm and 134.8±21.8μm) and volumetric density of the collagen fibers (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 photoaging was most pronounced in the groups of animals irradiated without the application of photoprotective cream.

Keywords: ImageJ; irradiation; mice; photoaging; photoprotection.