Three-dimensional structure of the lingual papillae of healthy rats and rats with experimental diabetes mellitus (in the context of mechanism of development of diabetic glossitis)

We studied the three-dimensional structure and patterns of distribution of the lingual papillae of healthy rats (the norm) and their changes in the process of development of diabetes mellitus І type. The research was conducted on 65 laboratory rats of the Weestar line. The research investigated the mucus shell and the microcirculatory network of the tongue. The distribution and three-dimensional structure of the papillae of the tongue were studied using a scanning electron microscope. It was found that there are 5 morphological subspecies of filiform papillae on the dorsal surface of body of the tongue: true filifom, flattened, thin and giant conical and brush-like. Isolated fungiform papillaе are unevenly distributed between filiform papillaе. The dorso-lateral edge of the dorsal lingual surface is covered by foliate papillae. The unique oval papilla vallate is located in the back-end of the middle line of the root of the tongue. The far back of the root of the tongue lacks papillae, is flattened and covered by squamous formations. The distribution and types of lingual papillae is similar in rats to other rodents. In the process of development of diabetic glossitis a reduction in the height of different types of papillae of the tongue was observed, and an increase in the amount of keratinized mass, which plays a role in the fixation of microflora on the surface of the mucus shell, which as a result may lead to development of inflammatory process in the tongues of rats with experimental diabetes mellitus. The stages of morphological and morphometric changes in the mucus shell and microcirculatory network of the tongues of rats with diabetes mellitus were investigated, the characteristic signs of these changes were marked. On the basis of morpho-functional changes of the tongues of rats with experimental streptozotocin induced diabetes mellitus, two stages of development of pathomorphological changes were distinguished: 1) reactive changes (2–4th week) and 2) destructive processes (6–8th week). At the end of the first stage there was a reduction in height of the filiform papillae and width of mushroom-like papillae in the mucus shell of the tongue, an increase in its keratinization, a considerable reduction in the number of cells in the deeper layers of the epithelium of the tongue and the adsorption capacity of superficial epіtheliocites diminished, a significant reduction in the diameter of path clearance of all departments of the microcirculatory network is traced here. At the end of the secondary stage, there was a reduction in the sizes of all papillae of the back of the tongue, in all links of the microcirculatory network there was a development of diabetic microangiopathy which is characterized: by narrowing of the arterial and exchange links on a background expansion of capacity link. The question of influencing the pathological process in the vessels of the microcirculatory network on the state of the mucus shell of the tongue in animals with experimental streptozotocin induced diabetes mellitus is discussed