Tissue analysis of Brazilian gracile opossum digestory tube (Gracilinanus microtarsus Wagner, 1842) (Marsupialia: Didelphidae)

Abstract

The alimentary habit reflects in the morphology of digestive organs. In this sense, microscopic studies are useful to analyze the tissue composition of each organ and allow greater comparisons with other marsupials described in the literature. For this reason, the aim of this study was realize a microscopic description of the digestive tube in Gracilinanus microtarsus Wagner, 1842 (Marsupialia: Didelphidae). Six adults specimens were used (3 males and 3 females). Samples from organs of digestive tube were fixed in 10% folmaldehyde solution. The samples were dehydrated in increasing concentrations of ethanol (70%-100%), diaphanized in xylol, paraffin-embedded, cut into a microtome and stained by H. E., Picrossirius, Schiff periodic acid, Toluidine Blue and Masson’s Trichrome. The material was analyzed and photographed through a Nikon Eclipse E-400 Photomicroscope. This study demonstrated, for the first time, the histological constitution of the digestive tube of G. microtarsus. It has been demonstrated that the digestive tube is formed by the esophagus, stomach, small intestine (duodenum, jejunum and ileum) and large intestine (cecum, colon and rectum). These organs were constituted by five distinct layers, a serosa coating externally the organ, a muscular, a submucosa, a muscular of the mucosa, and a mucosa with epithelium that varied between squamous keratinized in the esophagus to prismatic-type in the other organs. This study demonstrated that the digestive tube of animals studied is similar to that described in other marsupials Didelphidae described in the literature with the same food habit. Future immunohistochemical studies may demonstrate the enzymatic complex involved in digestion and the cellular and molecular mechanisms involved in the uptake of nutrients by the digestive tube in this species.