Growth of cell populations of the intralobular duct in the submandibular gland of the mouse during postnatal development

Abstract

The growth of cell populations of intercalated ducts (ID), striated ducts (SD) and convoluted granular tubules (CGT) of the submandibular gland of the mouse was analyzed, during the period of 14 to 84 days of postnatal life, by means of morphometric methods. The absolute number of cells in each type of duct was submitted to curve fitting by means of linear regression analysis, and the obtained equations were: y = 13.22 + 0.87x for ID cells in the growth period of 14 to 84 days; y = -18.82 + 3.69x and y = 176.03 - 1.93x for SD cells in the periods of growth and decay of cells, from 14 to 35 and 35 to 84 days, respectively; and y = 90.59 + 4.60x for CGT cells in the growth period of 28 to 84 days. Based on these equations, the daily accumulation (growth rate) or loss (decaying rate) of cells in the period covered by each equation was calculated. Thus, the rate of growth of ID cells was 0.87 x 10(5) cells/day; the growth and decline rates of SD cells were 3.69 x 10(5) cells/day and -1.93 x 10(5) cells/day, respectively; and the growth rate of CGT cells was 4.60 x 10(5) cells/day. The analysis of the accumulation or loss of cells and the balance of cell populations in the various types of ducts revealed that SD cells were transformed into CGT cells and that the growth of these cells population also depends on the formation of new cells through proliferative activity, probably in the intercalated ducts.

Effects of glucocorticoid on postnatal development of rat sublingual glands

“…Nuclei of proliferating cells in the late G1 phase to the S phase, G2 phase, and M phase of the cell cycle therefore stain positive to anti-PCNA immunohistochemical staining, which is thus capable of detecting cellular proliferative potential. The proliferative activity of cells that compose the salivary glands reportedly changes with gland development (Chang and Barka, 1974, Redman, 1995, Taga and Sesso, 1998, Taga and Sesso, 2001, Taga and Pardini, 2002. Taga et al (1998) found that with respect to the cellular proliferative potential of rat sublingual glands, proliferation of serous and mucous acinar cells peaked on day 5 after birth and gradually declined thereafter, with a slight increase in proliferation on day 20 followed by another decline.…”