Three-dimensional aspects of the lingual papillae and their connective tissue cores in the tongue of rats: a scanning electron microscope study.

The aim of the present study was to describe the tridimensional morphological characteristics of the lingual papillae and their connective tissue cores (CTCs) in Sprague Dawley rats. Four types of papillae were reported on the dorsal surface. Filiform papillae were distributed on the tongue surface and after epithelial maceration a conic and multifilamentary shape of the CTCs was revealed. Fungiform papillae were reported on the rostral and middle regions covered by a squamous epithelium. After the removal of the epithelium, the shape of a volcano with the taste orifice at its top was noted. Foliate papillae were composed of five pairs of epithelial folds situated on the lateral-caudal margin of the tongue. After the removal of the epithelium, they were shown to be limited by thin laminar projections. The vallate papilla with an oval shape was present in the caudal region and delimited by an incomplete groove. The morphological characteristics of the lingual papillae of Sprague Dowley rats, three-dimensional SEM images, and the types of papillae on the dorsal surface were similar to those reported previously in other rodent mammals. The maceration technique revealed the details of extracellular matrix with varied shapes form of connective tissue cores.

Three-dimensional aspects of the structural characteristics and kidney angioarchitecture of adult and aged Wistar rats: a scanning electron microscopy study.

The aim of this study was to describe the structural morphological characteristics and organization of the kidney angioarchitecture in adult and aged Wistar rats using different scanning electron microscopy (SEM) methods. Twenty male Wistar rats (Rattus norvegicus) were divided into two groups: the Adult Group (n = 10), which included animals at 3 months of age, and the Aged Group (n = 10), which included animals at 24 months of age. Kidney samples from both groups were analyzed using three distinct SEM methods: coronal sections, cryofracturing and vascular corrosion casts/angioarchitecture. This study demonstrates the specificity of each technique for three-dimensional morphological analyses of the kidney using SEM. In the coronal sections, it was possible to view the structures on a given plane; the stratigraphy was best observed in the cryofracture method, and the vascular corrosion casts showed the organization and arrangement of the angioarchitecture. Thus, we concluded that the SEM methods together provide the best description of the morphological characteristics of normal and pathological kidneys of adult and aged Wistar rats.

Fine structure of myotendinous junction between the anterior belly of the digastric muscle and intermediate tendon in adults rats.

This study analyzed the ultrastructural characteristics of the myotendinous junction (MTJ) between anterior belly of digastrics muscle and the intermediate tendon in adult rats. Six male Wistar rats were used and were anesthetized with an overdose of urethane and sacrificed by intracardiac perfusion with modified Karnovsky solution, postfixed in 1% osmium tetroxide, dehydrated in increasing series of alcohols and embedded in Spurr resin for transmission electron microscopic analysis. Ultrastructural analysis showed conical shape of the fiber extremity in MTJ region, highlighting the presence of numerous mitochondria arranged in groups in the subsarcolemmal and intermyofibrillary regions. Atypical MTJ characteristics were seen interspersed with bundles of collagen fibers. Classic characteristics such as finger-like processes by means of sarcoplasmic projections were observed among interdigitations. Terminals and periphericals bundles of myofibrils showed close relationship with the adjacent muscle fiber's endomysium through lateral junctions. In the distal portion, it was observed that the communication region of microtendons forming the intermediate tendon of digastric muscle, and it can highlight the columns disposition of tenocytes. In conclusion, the MTJ ultrastructure between the anterior belly of digastric muscle and intermediate tendon of adult rats showed classical morphologic descriptions and presented an atypical region revealed by the subspecialization between the myofibrils bundles and collagen fibers in the MTJ region.