Increased proliferation of the epithelium of the proximal alimentary tract of EFA-deficient rats: A light and electron microscopy study

Abstract

Rats of a Wistar strain fed a lipid-poor diet which is deficient in essential fatty acids (EFA) developed hyperkeratosis and increased cell proliferation of the stratified squamous epithelium of the upper alimentary tract. The frequency and severity of hyperkeratosis was significantly increased in the forestomach in both male and female EFA-deficient rats but, in the esophagus, only in the male, whereas hyperkeratosis was not seen in mouth epithelium. In EFA-deficient rats, the mitotic index was increased in the epithelium of palate and tongue ( P < 0.001), as well as in esophagus ( P < 0.025) and forestomach ( P < 0.005). Sex-linked differences in the mitotic index were noted, being higher in female than in male rats, in both control and experimental animals. Electron microscopy showed that in the epithelium of the forestomach of the EFA-deficient rat the squamous cells presented decreased number of desmosomes, widening of the intercellular spaces, diminution of surface folds, and increased binding of ruthenium red. This suggested that the surface of these cells was altered in the EFA-deficient condition. Present observations indicated that cell proliferation and differentiation of the stratified squamous epithelium of the upper alimentary tract are upset in various degrees in EFA-deficient rats.