Obstructive sialadenitis: a rat model.

Obstructive adenitis of major salivary glands is a common entity. Although the pathologic features are well recognized, the various cell types involved in the atrophy and subsequent regeneration of the obstructed salivary gland have been controversial. For this reason, an animal model of obstructive sialadenitis that induced atrophy in the rat parotid gland was developed. A clamp was devised that would occlude the main excretory duct of the gland inducing atrophy, but that, following removal, left the duct patent and allowed regeneration to occur. Both atrophy and regeneration were studied, and the results presented. The number and location of cycling acinar, intercalated, striated, and excretory duct cells were identified, using an antibody to proliferating cell nuclear antigen (PCNA). All cell types were induced to cycle during both the atrophy and regeneration phase, but the degree of cycling was more pronounced during regeneration. Three days after release of the duct obstruction, cycling acinar cells had increased 40-fold, while striated and intercalated ducts increased 6.5- and 5.0-fold, respectively. More importantly, peak cycling of acinar cells preceded, but paralleled, the increase in acinar cell composition of the gland. This model of obstructive sialadenitis indicates that all cell types are responsible for regeneration in the obstructed rat parotid gland.