Developmental Morphology of the Palatine Glands in Rats: An Electron Microscope Study

Abstract

Although minor salivary glands play a significant functional role in the oral cavity, their developmental morphology and cell differentiation has been scarcely studied. This study aimed to describe the development of rat palatine glands with regard to the ultrastructural morphology of the secretory cells and surrounding myoepithelial cells (MECs). Palatine glands from rats at embryonic ages (E) 18 and 20 days, and postnatal days (PN) 0, 3, 7, 10, 13, 21, 30, 42, and 60 were fixed and prepared for morphological analysis and immunocytochemical labeling of alpha‐smooth muscle actin (α‐SMA). At E18, epithelial cords were observed extending from the palatal epithelium and showed negative reactivity to α‐SMA. After luminization at E20, the cells of immature acini accumulated secretory granules of various densities: electron‐dense, electron‐lucent and some empty‐appearing granules. MECs were poorly differentiated at E20 and exhibited only slight α‐SMA expression. At birth, mucous and serous cells were typically located around a common lumen. Thereafter, serous cells began to move to the periphery to form demilunes by PN7. The mucous secretory granules of intermediate electron density became predominant around PN13. At PN21, these granules were dramatically reduced in number and most of the acini in adults contained acinar cells with numerous electron‐lucent granules, and a few serous demilune cells with electron‐dense granules. After birth, MECs progressively accumulated actin microfilaments until prominent α‐SMA expressing MECs invested the acini and the proximal part of the intercalated ducts in the adult. Anat Rec, 301:1820–1833, 2018. © 2018 Wiley Periodicals, Inc.

Developmental morphological analyses on the preglottal salivary gland in Japanese quails (Coturnix japonica)

“…All these stages occurred prehatching except the last one occurred post-hatching. Similar results were observed in human 33,34 , in pig 35 , in rat 36 in quail 37 and in duck 38 . The pattern of the development of the lingual gland in birds is like that described for mammals but the terminal buds are formed at the same time as the lumen of the glands 38 .…”

“…All these stages occurred prehatching except the last one occurred posthatching. Similar results were observed in human(de Mello Gomes, Nagai, Lourenço, & Coutinho-Camillo, 2019; Quir os-Terr on et al, 2019), in pig(Zhou et al, 2010), in rat(Hakami & Hand, 2018), in quail(Liman, Bayram, & Koçak, 2001), and in duck(Skieresz-Szewczyk, Cornillie, & Jackowiak, 2018). The pattern of the development of the lingual gland in birds is like that described for mammals but the terminal buds are formed at the same time as the lumen of the glands(Skieresz-Szewczyk et al, 2018).…”

The influence of Zingiber officinale Roscoe on the histological changes of soft palatal mucosa in streptozotocin-induced type 3 diabetes rat model

“…The histopathological findings of oral soft palatal mucosa in both control groups were concurrent with the results of Monroy et al [34] and Hakami and Arthur [35] studies. The soft palate oral epithelium appeared as thin less dense keratinized stratified squamous epithelium with large keratinocytes, bulky cytoplasm and often multiple nuclear lobes mostly in basal and spinous cell layers.…”

The Protective role of Nigella sativa versus Lepidium sativum on the submandibular salivary gland in hypercholesterolemic albino rat (Histological and Immunohistochemical study)

“…Alpha-smooth muscle actin (α-SMA) is actin isoform that expressed mainly around the vascular muscle cells, fibrogenesis and during detection of myoepithelial cells (MECs). There is strong correlation between alpha-SMA expression and myofibroblasts activation 16 ' 17 . In hyperlipidemic mice, there was significant increase in the expression levels of α-SMA 18 .…”