Intraspecific Differences Regarding Granular Polymorphism in Granular Ducts’ Cells in Rats’ Mandibular Gland

Mandibular gland ducts’ system in rodents consist of intralobular ducts (intercalated, granular, striated) and interlobular one (main excretory duct). Granular ducts are located between intercalated and striated ducts, being present only in mandibular gland of the mouse, rat, hamster and gerbil. The biological material used for this study was represented by two strains from the same species, three Wistar rats and three Brown Norway rats. After the animals were euthanized, the mandibular glands were harvested and then processed for histological investigations. The tissue fragments were sectioned at 5μm thickness and then stained the sections using Tricrom-Goldners method. Our results emphasize that the granular ducts are well developed; regarding the shape, they are convoluted in both Wistar and Brown Norway rats, without any significant differences between the two strains. In Wistar rat, the granules in granular ducts cells are small to medium in size, with discrete polymorphism. In Brown Norway rat, the cytoplasm is loaded with granules as in Wistar rat, but these are several times larger and more polymorphic.