Intra-epithelial lipids in the dorsoposterior area of the tongue in new-born rats

The mucosa covering the posterior surface of the tongue in new-born rats wa s studied by scanning and transmission electron microscopy. The results dem onstrated that in the first days of extra-uterine life in the epithelium of this mucosa there is an accumulation of lipidic material, which appeared a s round or oval droplets with a mean diameter of about 0.8-1.0 mu m. Their density was homogeneously low and they did not contain fibrillar or granula r material. In the first day of extra-uterine life, the droplets were scarc e and mainly localized ill the dorsal surface of the vallate papilla. In th e following days, the lipid deposit was present in large areas of the poste rior surface of the tongue. At the end of the first week of extra-uterine l ife, as well as in adult animals, the lipids were rather scarce. A multiloc ular lipid deposit was also visible in superficial cells detaching from the mucosa. With magnetic resonance spectroscopy, lipids extracted from the po sterior mucosa of the tongue appealed mainly saturated. Small amounts of un saturated and polyunsaturated, lipid were also detectable. These findings s uggest that in the first week of extra-uterine life, specialized areas of t he oral epithelium store lipid. (C) 1999 Elsevier Science Ltd. All rights r eserved.