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Phototoxicity of narrowband ultraviolet ( UV ) B (311 nm) compared with broadband UVB in the photo hen's egg test
Author(s) -
Bafteh P.R.,
Siegesmund M.,
Kuerten V.,
Neumann N.J.
Publication year - 2015
Publication title -
british journal of dermatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.304
H-Index - 179
eISSN - 1365-2133
pISSN - 0007-0963
DOI - 10.1111/bjd.13221
Subject(s) - porphyria , medicine , phototoxicity , dermatology , chemistry , biochemistry , in vitro
Summary Background Broadband ultraviolet B (BB‐UVB) is a well‐established treatment option in dermatology. However, during the last decade BB‐UVB has increasingly been replaced by narrowband UVB 311 nm (NB‐UVB), especially in the therapy of psoriasis, atopic eczema and vitiligo. Several studies have indicated a better therapeutic response for almost all indications compared with BB‐UVB. Objectives The aim of our study was to investigate the phototoxic effects of NB‐UVB in comparison with BB‐UVB in vivo . Methods Therefore, we employed the photo hen's egg test (PHET), an established phototoxic model, based on the yolk sac blood vessel system of incubated hen's eggs. NB‐UVB and BB‐UVB dosages increasing from 30 up to 1200 mJ cm −2 were applied on 17 test groups (each n = 12 eggs) and two unirradiated test groups served as controls. Twenty‐four hours after irradiation we observed the following test parameters: lethality, membrane discoloration and haemorrhages. Results Following our results, the lethal half dose (LD50) was 60 and 720 mJ cm −2 for BB‐UVB and NB‐UVB, respectively. These LD50 dosages provoked severe membrane discoloration and haemorrhaging. Summarizing our results, the LD50 of NB‐UVB was 12‐fold higher than BB‐UVB. Conclusions Interestingly, these findings are in good accordance with the literature, where the minimal erythema dose (MED) of NB‐UVB in human skin is up to 14 times higher than the MED of BB‐UVB. These results show that the PHET is a valid test model to evaluate the phototoxic effects of various UVB wavelengths. Moreover, our results indicate that regarding the investigation of phototoxic effects the PHET might serve as a model representative for human skin, which might reduce the extent of photoprovocation in humans in the future.