Abstract
Objectives The present study aimed to give a glimpse of the normal distribution of intermediate
filaments within the parotid gland parenchyma of mongrel dogs and to reveal the pathological
changes that may occur as a result of the effects of diabetes mellitus or atrophy
of the gland caused by the ligation of the excretory duct to discover whether there
is a similarity in these pathological behaviors.
Materials and Methods Twelve healthy mongrel dogs were used in the experiment and were divided into three
groups: group I (the control group), group II (dogs with alloxan-induced diabetes),
and group III (dogs with the right-side duct-ligated parotid gland). The dogs were
sacrificed 45 days after the parotid excretory duct were tied. The right parotid gland
of all groups was dissected and prepared for histological and immunohistochemical
expression of cytokeratin 17 assay.
Results Histological findings confirmed that the parotid gland parenchyma of the diabetic
group had glandular atrophy characterized by the loss of gland structure, degenerated
acini, and dilatation of the duct system. Moreover, there is a predominance of the
fibrous component with the presence of fat cells within the gland compartments. On
the contrary, the excretory duct-ligated group undergoes severe glandular atrophy
of the previous character with the presence of duct-like structure as well as extravasation
and vasodilatation. Immunohistochemical expression of cytokeratin 17 in control parotid
using an immunoperoxidase technique showed that cytokeratin expression varies from
negative to mild in all ducts and some serous acinar cells. The gland parenchyma of
the diabetic group showed mild to strong cytokeratin expression of duct cells more
concentrated in the apical part with moderate to strong expression of diffuse type
in some serous acini. The intensity of cytokeratin 17 in gland compartments of the
excretory duct-ligated group revealed a variation in expression that ranged from negative
to strong diffuse staining throughout the gland.
Conclusion The severity and prevalence of cytokeratin 17 in our results are predictive of the
pathological influence of both diabetes mellitus and duct ligation on the cytokeratin
intracellular filaments of the salivary gland parenchyma in a different way that interferes
with saliva production and/or secretion leading to xerostomia.
Keywords parotid gland - duct ligation - diabetes - cytokeratin 17
