A light and electron microscope study of aging parotid and submandibular salivary glands of Swiss-Webster mice.

Light and electron microscope comparisons were made of parotid and submandibular glands from male Swiss-Webster white mice 3, 13, and 18 months old. The glands from the 13- and 18-month-old mice were less organized and the parenchyma was not as dense. Fibrous connective tissue, intracellular lipofuscin granules, and residual body formation increased with age. In the cells of the parotid glands of 18-month-old mice, the nucleus-to-cytoplasm ratio was greater than in the specimens from the younger two ages. The granular convoluted tubules in submandibular glands of 18-month-old mice were the smallest of all age groups. The age changes appear comparable to those of rat and human salivary glands, yet this is an inexpensive animal model that achieves old age in less time than other animal models.