title: Photosensitivity of murine skin greatly depends on the genetic background: clinically relevant dose as a new measure to replace minimal erythema dose in mouse studies.
abstract: Artificial UV irradiation of murine skin is a frequently used method for testing photosensitivity, study carcinogenesis and photoprotective effects of different compounds. However, doses of UV radiation and mouse strains used in experiments vary greatly. The genetic background of mice may influence the photosensitivity as melanin content, pigmentation and hair cycle parameters are dissimilar. Doses of UV are often expressed in relation to the minimal erythema dose (MED) that was not necessarily determined for the given strain. We set out to standardize the method of measuring photosensitivity in three commonly used mouse strains, C57BL/6N, Balb/c and SKH-1. We found that MED may not be determined for some strains as erythema development in mice with diverse genotypes differs greatly. We measured the oedema response in vivo and ex vivo by using OCT. Given the strain-specific variability of erythema, we introduced Clinically Relevant Dose (CRD) as a new term to replace MED in experiments, to describe the lowest dose that triggers a perceptible skin reaction in mice. Not only the CRD but the proportion of erythema and oedema were different in strains examined. C57BL/6N mice display skin reactions at the lowest UVB dose, while SKH-1 hairless mice show changes, mostly oedema, after higher doses of UVB. The cellular composition and skin thickness were examined by histopathology. IL-1beta and IL-6 levels in skin correlated with the increasing doses of UVB. Despite the variations in the degree of erythema and oedema, no major differences in cytokine expressions were seen among various strains of mice.
authors.affiliation: Department of Dermatology, Dermatooncology and Venerology, Semmelweis University School of Medicine, Budapest, Hungary.
authors.forename: Nóra
authors.initials: N
authors.lastname: Gyöngyösi
authors.affiliation: Department of Dermatology, Dermatooncology and Venerology, Semmelweis University School of Medicine, Budapest, Hungary.
authors.forename: Kende
authors.initials: K
authors.lastname: Lőrincz
authors.affiliation: Department of Dermatology, Dermatooncology and Venerology, Semmelweis University School of Medicine, Budapest, Hungary.
authors.forename: András
authors.initials: A
authors.lastname: Keszeg
authors.affiliation: Department of Dermatology, Dermatooncology and Venerology, Semmelweis University School of Medicine, Budapest, Hungary.
authors.forename: Dóra
authors.initials: D
authors.lastname: Haluszka
authors.affiliation: Department of Dermatology, Dermatooncology and Venerology, Semmelweis University School of Medicine, Budapest, Hungary.
authors.forename: András
authors.initials: A
authors.lastname: Bánvölgyi
authors.affiliation: Department of Ophthalmology, Semmelweis University School of Medicine, Budapest, Hungary.
authors.forename: Erika
authors.initials: E
authors.lastname: Tátrai
authors.affiliation: Department of Dermatology, Dermatooncology and Venerology, Semmelweis University School of Medicine, Budapest, Hungary.
authors.forename: Sarolta
authors.initials: S
authors.lastname: Kárpáti
authors.affiliation: Department of Dermatology, Dermatooncology and Venerology, Semmelweis University School of Medicine, Budapest, Hungary.
authors.forename: Norbert M
authors.initials: NM
authors.lastname: Wikonkál
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D004487:Edema / Q000209:etiology; D004890:Erythema / Q000209:etiology; D005260:Female; D053583:Interleukin-1beta / Q000378:metabolism; D015850:Interleukin-6 / Q000378:metabolism; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D010787:Photosensitivity Disorders / Q000235:genetics*; D012867:Skin / Q000378:metabolism / Q000473:pathology / Q000528:radiation effects*; D014466:Ultraviolet Rays / Q000009:adverse effects*
chemical_list: C587672:IL1B protein, mouse; D053583:Interleukin-1beta; D015850:Interleukin-6; C577686:interleukin-6, mouse
keywords: UV irradiation; clinically relevant dose; minimal erythema dose; mouse skin; optical coherence tomography