Development of the rat sublingual gland: A light and electron microscopic immunocytochemical study

Abstract

Cell differentiation in the rat sublingual gland occurs rapidly and is largely complete by birth. To study differentiation of the serous and mucous cells of the sublingual gland, we used antibodies to the secretory proteins CSP-1, SMGB, PSP, and SMGD, and sublingual mucin as specific cell markers. Glands from rats at ages 18, 19, and 20 days in utero, and postnatal days 0, 1, 5, 9, 14, 18, 25, 40, and 60 were fixed and prepared for morphological analysis and immunocytochemical labeling. At age 18 days in utero, a few cells in the developing terminal bulbs contained mucous-like apical granules that labeled with anti-mucin. Other cells had mixed granules with a peripheral lucent region and a dense core of variable size that occasionally labeled with anti-SMGD. Additionally, presumptive serous cells with small dense granules that contained CSP-1 and SMGB were present. At age 19 days in utero, the dense granules of these cells also labeled with anti-SMGD. By age 20 days in utero, mucous cells were filled with large, pale granules that labeled with anti-mucin, and serous cells had numerous dense granules containing CSP-1, SMGB, PSP, and SMGD. Fewer cells with mixed granules were seen, but dense regions present in some mucous granules (MGs) labeled with anti-SMGD. After birth, fewer MGs had dense regions, and serous cells were organized into well-formed demilunes. Except for PSP, which was undetectable after the fifth postnatal day, the pattern of immunoreactivity observed in glands of neonatal and adult animals was similar to that seen by age 20 days in utero. These results suggest that mucous and serous cells have separate developmental origins, mucous cells differentiate earlier than serous cells, and cells with mixed granules may become mucous cells. Anat Rec 266: 30 -42, 2002.

Granule types and their morphological changes in terminal cluster and acinar cells in the late pre‐ and early postnatal rat sublingual gland

“…Therefore, cell death appeared to be a rare event. Wolff et al (2002) also suggested that mucous and serous cells of the rat sublingual grand differentiate from separate lineages. Although we found no evidence to support their hypothesis, we clarified the granule types and their morphological changes in terminal-cluster and acinar cells in the late pre-and early postnatal rat sublingual gland.…”

“…Ball et al (1993) and Mirels et al (1998) also demonstrated that highly electron-dense granules in secretory cells from the early postnatal mouse parotid gland, and in cells from the serous demilune of the mature rat sublingual gland contain protein B1. Furthermore, Wolff et al (2002) showed that by age 20 days in utero, mucous cells in the rat sublingual gland have granules labeled with antimucin, and serous cells have numerous granules containing CSP-1, SMGB, PSP, and SMGD. These results suggest that some proteins are present throughout Type I and II granules and in the electron-dense portion of Type III granules.…”

Three dimensional image analysis of minor salivary glands in 180-day rats born with macrosomia

“…The formation and acinar differentiation of the mixed secretion salivary glands occur mainly prenatally [25,26], and the intra-uterine forming epigenetic changes in metabolism and the morphofunctional state of the glands can persist for life and affect the cariogenic situation in oral cavity.…”

Comparative Study of the Proliferative Activity of Serous- and Mucous-type Acinar Cells in Developing Mongolian Gerbil Mixed Salivary Glands.

“…Studies of developmental changes in the ultrastructure and peroxidase activity in rat sublingual and submandibular gland acinar cells also suggest that the serous cells differentiate into seromucous or mucous cells during histogenesis of the endpieces [6,7]. In a different interpretation of an immunocytochemical study of the expression pattern of several secretory proteins in developing rat sublingual glands, Wolff et al [9] suggested that the serous and mucous cells differentiate via separate cell lineages. It is necessary to examine the relationship between their expression pattern and proliferative activity of the secretory cells.…”