Anthralin and tar with UVB increase epidermal cell proliferation in asebia mice.

Abstract

The asebia mouse has chronic epidermal cell hyperproliferation. The epidermal labelling index (LI) for asebia was more than double that for BALB/cJ mice (7.3%vs. 2.7%). Using the asebia model of chronic epidermal hyperproliferation we examined the changes in epidermal LI and epidermal thickness after 3 weeks of treatment with certain treatments used for psoriasis. Changes in LI were generally paralleled by changes in thickness. UVB alone did not significantly increase the LI. UVB plus 0.1% anthralin in propylene glycol (PG) significantly increased the LI to 13.7% but this increase was largely due to the UVB plus PG. Crude coal tar (1%) increased the LI to 15.2%. The combination of UVB and 1% crude coal tar increased the LI even further to 26.2%. The LI did not show an additional increase when the concentration of crude coal tar was increased to 2% or 4%, These findings of increased epidermal cell proliferation in a model of chronic epidermal hyperproliferation are similar to published findings of increased epidermal cell proliferation in the normal skin of humans and hairless mice after multiple applications of these treatments whereas psoriatic lesions respond to these treatments with a reduction in epidermal cell proliferation.