Effects of ligation and irradiation on the submaxillary glands in rats

Rat submaxillary glands were exposed to excretory duct ligation, high-energy electron irradiation, or a combination of both. Ligation was done on the left excretory ducts, while 24 Gy irradiation was given within 8 days in three divided doses of 8 Gy. In the combined insults, the excretory ducts (one duct per rat) were first ligated, followed by 24 Gy irradiation. The effects were analysed by morphological methods. Ligation of excretory ducts caused morphological disorganization of the gland parenchyma, with resultant disappearance of secretory granules of serous cells, shrinkage of mucous cells, dilation of ducts, pronounced fibrosis and infiltration of inflammatory cells. When irradiated, some serous cells disappeared, leaving empty fibrosed spaces, while mucous cells showed no consequential radio-damage. The combined treatment of ligation of excretory ducts and irradiation caused extensive morphologic evidence of irreversible damage, i.e. no serous cells remained, disfigured and very shrunk mucous cells extremely dilated ducts, infiltration of leukocytes and fibrotic changes of the glands.