title: A quantitative method for measuring antipsoriatic activity of drugs by the mouse tail test.
abstract: Topical treatment of the mouse tail with antipsoriatic drugs enhances orthokeratotic cell differentiation in the epidermal scales. We developed a new evaluation system for this test which allows quantification of drug efficacy. Drugs were applied topically, once daily, 5 times a week, for 2 weeks. Two hours after the last treatment the animals were sacrificed, longitudinal sections of the tail skin were made and prepared for histological examination (hematoxylin-eosin staining). As indicator of orthokeratosis (OK), the length of the granular layer per scale was measured microscopically with a semiautomatic image evaluation unit and related to the total scale length (= % OK per scale). Drug activity was defined by the increase in the total length of orthokeratotic regions, 100% activity corresponds to a granular layer extending over the whole scale length. In this model dithranol and retinoic acid dose-dependently increased orthokeratosis up to 75 and 79%, respectively. Beech tar, in a concentration of 5% induced a 19% increase in orthokeratosis. Morphometric quantification by image analysis of the conversion of parakeratotic into orthokeratotic regions in mouse tail scales induced by topical drug treatment seems to be a suitable and reliable procedure to investigate new drugs from which antipsoriatic activity may be expected.
authors.affiliation: Grünenthal GmbH, Centre of Research, Aachen, FRG.
authors.forename: B
authors.initials: B
authors.lastname: Bosman
authors.forename: T
authors.initials: T
authors.lastname: Matthiesen
authors.forename: V
authors.initials: V
authors.lastname: Hess
authors.forename: E
authors.initials: E
authors.lastname: Friderichs
mesh_terms: D000818:Animals; D000875:Anthralin / Q000627:therapeutic use*; D004353:Drug Evaluation, Preclinical / Q000379:methods; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D011565:Psoriasis / Q000188:drug therapy*; D013623:Tail; D013638:Tars / Q000627:therapeutic use*; D014212:Tretinoin / Q000627:therapeutic use*
chemical_list: D013638:Tars; D014212:Tretinoin; D000875:Anthralin