Ultrastructure of submandibular salivary glands of mouse: TEM and HRSEM observations

KEY WORDS submandibular salivary gland; Golgi apparatus; mitochondria; TEM; HRSEMABSTRACT The fine structure of submandibular glands of mouse were analyzed using light mi-croscopy (LM), high resolution scanning electron microscopy (HRSEM), and transmission electron mi-croscopy (TEM) methods. For LM, the specimens were embedded in Spurr resin, stained by toluidinblue solutions. For TEM, the tissues of submandibular salivary glands were fixed with modified Kar-novsky solution and postfixed with osmium tetroxide. For HRSEM, the tissues were fixed with 2% os-mium tetroxide solution in 1/15M sodium phosphate buffer (pH 7.4). The samples were immersed suc-cessively in dymethylsulphoxide and freeze cracked. The maceration was made in diluted osmium te-troxide for 24–48 h. The samples were examined by high resolution scanning electron microscopy. Theintracellular components of acinar and ductal cells revealed clearly the Golgi apparatus, rough endo-plasmic reticulum, secretory granules, and mitochondria. The end bulbs of Golgi lamellae and flat-tened cisterns of rough endoplasmic reticulum showed the luminal surface. A few mitochondria wereidentified intermingling between the rough endoplasmic reticulum and the mitochondriales cristae inthree-dimensional HRSEM images. Secretory granules were numerous and presented different sizes.Small granules of ribosomes were attached on cistern surface, measuring 20–25 nm in diameter.Numerous arranged microvilli were found on the luminal surface of secretory canaliculus. The contactsurfaces of acinar cells revealed complicated interdigitations by cytoplasmic processes. The mitochon-dria of duct cells were disposed vertically and surrounded by basal infoldings of plasma membranes.Basementmembraneshoweda spongy-likestructurehavinganirregularsurfacewithvariousstrandsand meshesof finecollagenfibrils. Microsc. Res. Tech. 74:1154–1160, 2011.