Production of epidermal damage in mammalian skins by some simple aluminium compounds.

Abstract

The responses of mouse, rabbit and pig skin to topically applied solutions of six aluminium salts have been studied in relation to their pH and the deposition of aluminium in the stratum corneum. Epidermal changes consisting of hyperplasia, microabscess formation, dermal inflammatory cell infiltration and occasionally ulceration were evident in all three species treated with aluminium chloride (10%) and nitrate (10%), but not with aluminium sulphate (10%), hydroxide (10%), acetate (10%) or chlorhydrate (10 and 25%). In skins showing pathological changes, a high degree of aluminium deposition was present in the stratum corneum and the keratin was histochemically abnormal. It contained an unusually high concentration of protein-bound sulphydryl groups and phospholipid, and fluoresced differently to normal with the congo red technique. Although the irritant aluminium solutions were more acid than the non-irritant salts, pH was not considered to be responsible since solutions of hydrochloric acid or Universal buffer having an equivalent pH were of negligible effect. The results of this study indicate that as a result of an interaction of the aluminium cation with epidermal keratin, the latter becomes denatured and the stratum corneum is made more permeable. The manifestation of pathological changes is attributed to the penetration of the aluminium salts through the stratum corneum and their toxic effects on the cells of the epidermis.