The streaming submandibular gland

Abstract

Twenty female young adult rats were injected with tritiated thymidine (3HTdR). The animals were then killed in groups of five, at the following times: 1 hour, and 4, 16, and 23 days. Autoradiograms of sections through the submandibular gland were prepared, and the location of labelled cells in relationship to tubuli and acini was recorded. The different tubular and acinar cross sections could be distinguished by their cell number. Narrow tubuli had fewer nuclei than the wider ones. The nuclear number of a cross section was defined as its class and the location of a labelled epithelial cell was expressed in relationship to the class where it was found. The location of a labelled stromal cell was determined by the class of its neighboring tubular or acinar cross sections. The mean cell numbers of intercalated, granular, and striated duct cross sections were, respectively, 4.7, 10.5, and 10.2, while the average cell content of acini was 4.7 cells. One hour after labelling most labelled tubular epithelial and stromal cells were found in tubular cross sections (or low tubular classes), while in the acini, labelled epithelial and stromal cells were found mainly in wider cross sections (or higher acinar classes). Within the next 23 days labelled tubular cells and stroma proceeded into higher classes, while labelled acinar epithelium and stroma cells were displaced into narrower cross sections (or lower classes). The displaced tubular epithelium and stroma covered daily 0.26 classes. At this velocity the cell will reach the highest tubular class in 62 days and the estimated maximal tubular cell life span is 62 days.(ABSTRACT TRUNCATED AT 250 WORDS)

Reengineered salivary glands are stable endogenous bioreactors for systemic gene therapeutics

“…Interestingly, the life span of salivary epithelial cells in rodents has been estimated to be 125-200 days (33,34), but the ability of SGs cells to divide is a controversial issue (35,36). Our data suggest that either the transduced salivary ductal cells did not significantly divide during the 54-week period studied, in contrast to previous life-span estimates in rodents, or that if cell division occurred, transduced daughter cells remain functionally active within the SG tissue.…”

Label-retaining Cells in the Rat Submandibular Gland

“…The intercalated duct stem cells are localized to the proximal end, an ideal site to generate both duct and acinus. The intercalated duct has been suggested as a source of the acinus and the granular duct (Srinivasan and Chang 1975;Zajicek et al 1985;Moreira et al, 1990Moreira et al, ,1991Man et al 1995Man et al ,2001. At 3 days after unilateral gland extirpation, CldU-labeled nuclei appeared in all the parenchymal structures except for the granular duct.…”

Rat Salivary Gland Function after Fractionated Irradiation

“…The maximal life span for acinar cells is reported to be 60-120 days (37,38). Thus, the lower fraction of acinar cells could be explained by an impaired differentiation process.…”