Comparative morphological analysis of minor salivary glands in porcine species using histological and histochemical evaluation

The present work was undertaken to explore the anatomical distribution, histology, and histochemistry of minor salivary glands of pigs during their postnatal life. The heads of ten healthy adult pigs were procured from a local slaughter house immediately after decapitation. The fresh tissues were collected from minor salivary glands. Histologically, these glands were found in the propria-submucosa layer of the mucous membrane of the oral cavity. Depending on their location, the secretory acinar units were either mucous, serous, or mixed in nature. Serous demilunes were also observed at the periphery of the mucous secretory units. In addition to the plasma cells, myoepithelial cells were also found between the base of the secretory cells and the surrounding basal lamina. The duct system consists of intralobular and interlobular ducts. The intercalated ducts were characterized by the presence of small-sized lumens and lined with simple cuboidal epithelium. Striated ducts were lined with simple to stratified columnar epithelium having one to two cell layer thickness with characteristic longitudinal striations in the basal third. Large interlobular ducts were localized at the level of interlobular septae and were lined with stratified columnar epithelium and also showed the presence of goblet cells. Histochemical studies revealed the presence of weakly acidic sulfated mucosubstances, sialomucins, glycogen, mucopolysaccharides, mucin, and protein in the mucous secretory units. However, the serous acini and ducts showed a negative reaction to all these histochemical moieties. Micrometrical studies revealed that the acinar and luminal diameters of the mucous acini were larger than that of serous units. However, the diameter of the interlobular ducts was larger than that of the intercalated and striated ducts, which indicates that there was a significant difference both at the 1% and at the 5% levels. This study provided detailed insights into the anatomical and histological characteristics of minor salivary glands of pigs. Thus, understanding the anatomy, morphometry, and histology of the minor salivary glands is essential for a correct decision concerning medical and/or surgical intervention of such affections. This study will be helpful in the field of surgery and also aid in the diagnosis of pathological conditions of these glands, and therefore this study establishes a basis for future research on this model.