Changing myoepithelial cell distribution during regeneration of rat parotid glands.

Abstract

The distribution of the myoepithelial cells during regeneration of the rat parotid gland after atrophy induced by one week of parotid duct ligation was investigated by immunohistochemistry for actin and transmission electron microscopy (TEM). Immunohistochemically, residual ducts were surrounded by actin-positive cells when clips were removed from the duct. Three days later, most of the newly formed acini originating from the residual ducts were also embraced by actin-positive cells. After 10 days, actin-positivity tended to be seen as dots around acini that decreased in number day by day. On day 21 actin-positive cells mainly surrounded intercalated ducts with only a few positive reactions identified at the acinar periphery. Electron microscopically, residual ducts and newly formed acini were peripherally embraced by myoepithelial cells before day 5. After day 7, shift of myoepithelial cells from the periphery of acini to the duct-acinar junctional region was identified. Then few myoepithelial cells were identified at the periphery of acini. These observations indicate that myoepithelial cells migrate from the acinar periphery to the duct-acinar junctional region during rat parotid regeneration, and that such behaviour is closely related to that seen during rat parotid development.

Morphological Changes of Myoepithelial Cells in the Rat Submandibular Gland Following the Application of Surgical Stimuli

“…Previous studies have shown that surgical treatments induce cell proliferation in the salivary gland [15, 40, 41]. The present results, therefore, suggest that surgical resection and incision of the unilateral submandibular gland induce proliferation of MECs in residual and NC glandular tissues.…”

“…Compensatory hypertrophy has been reported in the liver following partial resection, and in the lung after unilateral excision [48]. The quantitative compensation of secretory function by proliferation of acinar cells and MECs during regeneration has also been reported [15, 40, 41]. Our recent study showed that salivary gland resection induced acinar cell differentiation from the intercalated duct in the residual tissue of the operated side, as well as the NC side in adult rats [25].…”

Proliferation and distribution of myoepithelial cells during atrophy of the rat sublingual gland

“…The second hypothesis involves migration of myoepithelial cells. It has been suggested that myoepithelial cells migrate from acini to intercalated ducts during regeneration of rat parotid glands (16). In atrophic sublingual glands, myoepithelial cells may shift from small to large ducts.…”

“…Myoepithelial cells are generally located around acini and intercalated ducts in salivary glands (6, 13, 14); however, it has been reported that there are myoepithelial cells at the periphery of striated and interlobular excretory ducts in human salivary glands (15) and that the myoepithelial cell distribution changes during development (6, 9) and regeneration (16) of rat parotid glands.…”

Grundlagen der In-vivo-Regeneration im Kopf-Hals-Bereich

“…Die Ursprungszellen für die Regeneration von Azinuszellen nach deren vollständiger Ablation sind Zellen der Gangepithelien [142]. Während dieser Regeneration nehmen myoepitheliale Zellen Kontakt zu den sich neu bildenden Azini auf [141]. Über die molekularen Signale, die sich zwischen diesen Zellen während der Regeneration abspielen, ist derzeit nichts bekannt.…”