Essential fatty acid deficient hairless mouse: a model of chronic epidermal hyperproliferation

Abstract

Epidermal DNA synthesis increased approximately 3-fold in hairless mice that were fed a diet deficient in essential fatty acids (EFA deficient) for 65 days, compared with animals fed a standard diet. Autoradiographic labeling indices showed a 330% increase in the EFA deficient mice over controls. The animals developed evidence of a diffuse thickening, scaling and loss of elasticity of the skin after 40 days on the EFA deficient diet. Histologically, the epidermis of the EFA deficient animals showed acanthosis, hypergranulosis, hyperkeratosis and increased intracellular epidermal spaces. Increased mitotic indices were found with Feulgen staining. This is further evidence that deficiencies of essential fatty acids are associated with disturbance of normal epidermal cell proliferation and control of keratinization. A single application of topical 0.1% betamethasone valerate to EFA deficient mice reduced the epidermal DNA synthesis to that of normal diet mice. Linoleic acid (10%) topically over 2 wk also returned epidermal DNA synthesis to normal levels.