Effects of treatment with dithranol, etretinate and a combination of dithranol and etretinate on epidermal metabolism and histology. Mouse tail assay
Lubach, D.; Kietzmann, M.
Arzneimittel-Forschung 38(8): 1167-1170
1988
ISSN/ISBN: 0004-4172 PMID: 3196412 Document Number: 316866
The mouse tail assay is useful for studying dermatological therapeutics that influence epidermal differentiation. The effect of dithranol (0.1% w/v in acetone, topically; DI), etretinate (2 mg/kg body weight/d, orally; ET) and of the simultaneous administration of bothe preparations (DI/ET) on the epidermis of the mouse tail was examined. The thickness of the epidermis, the number of nuclei per defined epidermal section, and the development of a granular layer in the interfollicular areas were determined. The incorporation of 3H-thymidine-triphosphate onto the DNA and global protein synthesis were also determined in vitro. The incorporation rates of leucine and histidine into protein in vitro were measured separately. DI caused retention acanthosis and at the same time orthokeratotic differentiation of the interfollicular areas of the epidermis. Light microscopy of the tail epidermis after appplication of ET showed no significant changes. Administration of DI/ET yielded the same effects as treatment with DI alone. DI partially reduced the biochemical parameters. ET increases DNA-polymerase activity, global protein synthesis, and the incorporation rate of histidine. The biochemical results after treatment with DI/ET were very similar to those obtained after DI administration. From the histological and biochemical results it is is therefore concluded that the simultaneous administration of DI and ET produces the same effect as DI treatment alone.