title: Photo hen's egg test: a model for phototoxicity.
abstract: The aim of this investigation was to establish a new model for phototoxicity which is more advanced than the widely used cultures of yeasts, bacteria or cells of various origin, and at the same time to avoid animal testing. We studied the extraembryonal vasculature of the incubated hen's egg. This model was originally introduced by toxicologists as an alternative to the rabbit's eye irritation test (Draize test). In the photo hen's egg test, substances are applied to the embryo's yolk-sac blood vessel system at a non-toxic concentration and are irradiated with 5 J/cm2 ultraviolet A (UVA) (320-400 nm). Promethazine, haematoporphyrin, ciprofloxacin and 8-methoxypsoralen were tested in this system. Death of the embryo, membrane discoloration and haemorrhage are parameters for phototoxic damage, which were recorded during an observation period of 24 h. These well-known phototoxic substances induced pronounced damage of the yolk-sac membrane and blood vessels which was not found in the controls (test substance alone, UVA alone or untreated) using a 2 x 2 factorial test design. The photo hen's egg test serves as a valid screening model for substances supposed to be photosensitizers owing to a phototoxic mechanism.
authors.affiliation: Department of Dermatology, Heinrich-Heine-University Duesseldorf, Germany.
authors.forename: N J
authors.initials: NJ
authors.lastname: Neumann
authors.forename: E
authors.initials: E
authors.lastname: Hölzle
authors.forename: P
authors.initials: P
authors.lastname: Lehmann
authors.forename: M
authors.initials: M
authors.lastname: Rosenbruch
authors.forename: A
authors.initials: A
authors.lastname: Klaucic
authors.forename: G
authors.initials: G
authors.lastname: Plewig
mesh_terms: D000818:Animals; D000890:Anti-Infective Agents / Q000633:toxicity; D002642:Chick Embryo; D002939:Ciprofloxacin / Q000633:toxicity; D017324:Hematoporphyrin Derivative / Q000633:toxicity; D006634:Histamine H1 Antagonists / Q000633:toxicity; D008730:Methoxsalen / Q000633:toxicity; D010787:Photosensitivity Disorders / Q000517:prevention & control; D017319:Photosensitizing Agents / Q000633:toxicity; D011398:Promethazine / Q000633:toxicity; D018675:Toxicity Tests; D014466:Ultraviolet Rays / Q000009:adverse effects*; D015017:Yolk Sac / Q000098:blood supply / Q000187:drug effects / Q000528:radiation effects
chemical_list: D000890:Anti-Infective Agents; D006634:Histamine H1 Antagonists; D017319:Photosensitizing Agents; D002939:Ciprofloxacin; D017324:Hematoporphyrin Derivative; D011398:Promethazine; D008730:Methoxsalen